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PASS
Spirent Journal of
LTE EPC PASS Test
Methodologies February 2011 Edition
Spirent Journal of LTE EPC PASS Test Methodologies | © Spirent Communications 2011
1
Introduction
Today’s Devices Under Test (DUT) represent complex, multi-protocol network elements with an emphasis
on Quality of Service (QoS) and Quality of Experience (QoE) that scale to terabits of bandwidth across the
switch fabric. The Spirent Catalogue of Test Methodologies represents an element of the Spirent test
ecosystem that helps answer the most critical Performance, Availability, Security and Scale Tests (PASS)
test cases. The Spirent Test ecosystem and Spirent Catalogue of Test Methodologies are intended to help
development engineers and product verification engineers to rapidly develop and test complex test
scenarios.
How to use this Journal
This provides test engineers with a battery of test cases for the Spirent Test Ecosystem. The journal is
divided into sections by technology. Each test case has a unique Test Case ID (Ex. TC_MBH_001) that is
universally unique across the ecosystem.
Tester Requirements
To determine the true capabilities and limitations of a DUT, the tests in this journal require a test tool that
can measure router performance under realistic Internet conditions. It must be able to simultaneously
generate wire-speed traffic, emulate the requisite protocols, and make real-time comparative
performance measurements. High port density for cost-effective performance and stress testing is
important to fully load switching fabrics and determine device and network scalability limits.
In addition to these features, some tests require more advanced capabilities, such as
Integrated traffic, routing, and MPLS protocols (e.g., BGP, OSPF, IS-IS, RSVP-TE, LDP/CR-LDP) to
advertise route topologies for large simulated networks with LSP tunnels while simultaneously
sending traffic over those tunnels. Further, the tester should emulate the interrelationships
between protocol s through a topology.
Emulation of service protocols (e.g., IGMPv3, PIM-SM, MP-iBGP) with diminution.
Correct single-pass testing with measurement of 41+ metrics per pass of a packet.
Tunneling protocol emulation (L2TP) and protocol stacking.
True stateful layer 2-7 traffic.
Ability to over-subscribe traffic dynamically and observe the effects.
Finally, the tester should provide conformance test suites for ensuring protocol conformance and
interoperability, and automated applications for rapidly executing the test cases in this journal.
Further Resources
Additional resources are available on our website at http://www.spirent.com
Spirent Journal of LTE EPC PASS Test Methodologies | © Spirent Communications 2011
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Table of Contents
Testing the Long Term Evolution (LTE) Evolved Packet Core (EPC) ............................................3
4G-EPC_001 3GPP non-roaming CS fallback scenario test for Short Message Service (SMS) .. 4
4G-EPC_002 MME 4G to 3G inter-RAT mobility performance test ........................................ 10
4G-EPC_003 MME 3G to 4G inter-RAT mobility performance test ........................................ 15
4G-EPC_004 Validation of a SGW’s dual GTP and PMIP support ........................................... 20
4G-EPC_005 PGW capacity and session loading with incremental dedicated bearer allocation
27
4G-EPC_006 GGSN/PGW converged multi-RAT session loading test ..................................... 35
4G-EPC_007 SGSN/MME converged multi-RAT session loading test ..................................... 40
4G-EPC_008 Policy and Charging Rules Function (PCRF) 3GPP session loading test ............. 46
4G-EPC_009 Policy and Charging Rules Function (PCRF) 3GPP2 session loading test ........... 51
4G-EPC_010 SGW/PGW converged gateway capacity test .................................................... 56
4G-EPC_011 GGSN/PGW converged gateway multi-RAT capacity test ................................. 60
4G-EPC_012 SGSN/MME converged node multi-RAT capacity test ....................................... 66
4G-EPC_013 SGW/PGW converged gateway session performance test ................................ 71
Appendix A – Telecommunications Definitions ..................................................................... 76
Appendix B – MPEG 2/4 Video QoE ...................................................................................... 83
Spirent Journal of LTE EPC PASS Test Methodologies | © Spirent Communications 2011
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Testing the Long Term Evolution (LTE)
Evolved Packet Core (EPC)
Long Term Evolution (LTE), technology, aka 4G, supports the next generation of mobile services. Moving
far beyond basic voice and texting, this new technology offers the promise of the first truly global wireless
standard, increasing speed and capacity for networks with download speeds in excess of 300 Mbps and
uplinks of greater than 100 Mbps.
At the core of this revolution is the Evolved Packet Core (EPC). The EPC is a new, high-performance, high-
capacity all-IP core network that addresses LTE requirements to provide advanced real-time and media-
rich services with enhanced Quality of Experience (QoE). Composed of four new elements - the Mobility
Management Entity, the Serving Gateway, the Packet Data Network Gateway and the Policy and Charging
Rules Function - the main purpose of the EPC is to guarantee increased data rates, subscriber numbers,
seamless mobility and end-to-end QoS and QoE.
There are several key aspects of the EPC that must be validated before any LTE deployment. The Evolved
Packet Core must be tested in terms of extreme capacity and performance. In the past, mobile network
evaluation, due to lower rates in data traffic, was used mainly to verify the path from UE to core network.
With the changes introduced in LTE, testing requires simulation from hundreds of Gbps to Tbps of data
generated by millions of subscribers.
Such subscribers may be moving across the LTE network or roaming from and to legacy networks. LTE
promises seamless mobility for any type of mobile terminal and requires planning and care on the part of
operators and device manufacturers alike. Mobility testing is necessary to prevent service interruption in
both the physical and service layers.
The new horizon offered by LTE in terms of high data performance has opened a window for service
providers to satisfy the ever increasing demand for time-sensitive applications such as video streaming,
real-time gaming or voice. Testing the EPC with real-world end-to-end traffic simulations is the key to
building a robust EPC solution that allows carriers to optimize deployment while guaranteeing QoE and
QoS.
SGi
S12
S3
S1-MME
PCRF
Gx
S6a
HSS
Operator's IP Services
(e.g. IMS, PSS etc.)
Rx
S10
UE
SGSN
LTE-Uu
E-UTRAN
MME
S11
S5 Serving Gateway
PDN Gateway
S1-U
S4
UTRAN
GERAN
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4G-EPC_001 3GPP non-roaming CS fallback scenario test for Short
Message Service (SMS)
Abstract
This test case determines whether a 4G MME (DUT) correctly handles Short Message Service
(SMS) CS Fallback scenarios as defined in TS 23.272. This is achieved by generating combined UE
Attaches to the 4G Network (LTE), launching Mobile Originated SMS transfers, and generating
paging messages from a 3G-UMTS MSC for Mobile Terminated SMS. Without this validation, the
user will not know if the DUT is capable of controlling both 3G-MSC and 4G UE-eNodeB to
support SMS.
Description
Defined as an all flat-IP based architecture, 4G doesn’t have basic voice and SMS support. Circuit
Switch (CS) domain services are to be supported, in principle, by VoIP and IMS, for example.
However, at the beginning of 4G deployment, it may take some time before IMS and VoIP
services can be provided due to the size of the target coverage area, the time required for
planning, and other factors.
To solve this problem, the CS Fallback scenario has been defined as a function for combining 4G
and CS, allowing 4G terminals to switch back to 3G radio access to use CS services. This function
consists of three elemental capabilities: notifying a mobile terminal in a 4G cell that a call request
is being made from a 3G-CS system, enabling the mobile terminal receiving the request to switch
radio access systems, and a 4G/3G combined mobility management.
The steps necessary to support the SMS CS Fallback call scenario (from the MME point of view)
are given in more detail below.
UE registration
When a UE attaches to the 4G radio access network, it performs a combined attach. A new IE,
mobile class mark, will be sent in an Attach Request asking the MME to perform a combined
attach. Once the Attach Request is received, the MME sends a Location Update Request
informing the MSC of the UE’s location. The UE is now known to 4G and the CS network.
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Mobile Originated SMS
When a 4G UE wants to send an SMS to a 3G based terminal, it issues a Service Request to the
MME. The MME generates a Forward Short Message to the MSC and waits for delivery
confirmation. Upon reception from the MSC of the delivery receipt, the MME notifies the 4G UE.
Mobile Terminated SMS
The MSC sends a Paging message to the MME indicating the intention of delivering an SMS and
the MME pages the 4G UE. The paged UE sends a Service Request message to the MME, which in
1. Attach Request
3. Derive VLR number
4. Location Update Request
5. Create SGs association
7. Location Update Accept
UE MME HSS MSC/VLR
2. Step 3 to step 16 of the Attach procedure specified in TS 23.401
6. Location update in CS domain
8. Step 17 to step 26 of the Attach procedure specified in TS 23.401
MS/UE MME MSC/VLR HLR/HSS SMS-
IWMSC SC
1. EPS/IMSI attach procedure
3. Uplink NAS Transport
4. Uplink Unitdata
5. Forward Short Message
6. Message transfer
7. Delivery report 8. Delivery report
9. Downlink Unitdata
10. Downlink NAS Transport
2. UE triggered Service Request
4a. Downlink Unitdata
4a. Downlink NAS Transport
11. Uplink NAS Transport
12. Uplink Unitdata
13. Release Request
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turn, sends it to the MSC. The MSC builds the SMS message to be sent and forwards it to the
MME. The MME encapsulates the SMS message in a NAS message and sends the message to the
UE. Upon reception, the UE acknowledges receipt of the SMS message to the MSC via the MME.
Target Users
MME feature developers and testers wanting to validate the behavior of the MME.
Service providers wanting the test 4G and 3G inter-working features for CS domain services.
Target Device Under Test (DUT)
4G Mobile Management Entity (MME) node
Reference
3GPP TS. 23.272 and 23.401
Relevance
MME CS Fallback capable nodes are key components for early provision of CS terminals having
4G capabilities.
Version
1.0
Test Category
4G EPC Testing
PASS
[ ] Performance [X] Availability [ ] Security [ ] Scale
SMS -
2. Message transfer
3. Send Routeing Info For Short Message
4. Forward Short Message 5. Paging
6. Paging 7. Paging
9b. Downlink NAS Transport
9c. Uplink NAS Transport
13. Delivery report 12. Delivery report
8. Service Request
MS/UE eNodeB MSC/VLR HLR/HSS SMS -
MME SMS-
GMSC SC
1. EPS/IMSI attach procedure
8a. Service Request
9d. Uplink Unitdata
10. Uplink NAS Transport 11. Uplink Unitdata
14. Downlink Unitdata 16. Release Request
15. Downlink NAS Transport
9a. Downlink Unitdata
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Required Tester Capabilities
Support of 4G S11, S1-C and SGs interfaces in the same session
Complete UE, eNodeB simulation with session loading capabilities
SGW emulation to complete LTE Attach procedure
MSC emulation to terminate the SGs interface. This emulator not only has to keep track of UE
location areas during registration, but it also has to be capable of generating Paging Requests
and SMS transfer for the mobile terminated scenarios
Topology Diagram
Test Procedure
1. Set-up the 4G UEs:
a. Configure Attaches and Mobile Originated SMSs. Set up at least one S1-C interface
endpoint and assign it to Tester Port A. This endpoint provides the necessary elements
to simulate UEs and eNodeBs connected to the DUT via the S1 interface during the
Attach and Short Message Service transfer procedures.
i. Set up 10 subscribers.
ii. Configure the S1-NAS layer so UEs perform combined EPS/IMSI Attaches and
Detaches.
iii. Configure the SMS service for Mobile Originated SMS:
1. Activate the SMS service.
2. Define the SMS rate toward a non 3G UE in terms of short message
services per second.
b. When configuring the UE, eNodeB and MME, include Tracking and Location Update
Information.
eNodeB
MSC
SGW
MME(DUT)
Test Port A (S1-C)
Test Port B (SGs)
Test Port C (S11)
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2. Set up the S11 interface endpoint and assign it to Tester Port C. This endpoint simulates the
SGW during the Attach process.
3. Set up an MSC-Node Emulator and assign it to Tester Port B.
i. Configure the MSC-Node for Session Loading of Mobile Terminated SMS. Such node
will trigger SMS messaging toward the mobile in the form of Paging messages.
Verify that the MSISDN numbers match the numbers defined in (1), for the 4G (UEs
Originator and Destination Service Addresses).
ii. Configure Paging loading parameters for Mobile Terminating SMS:
1. Message Interval: time between two consecutive SMSs.
2. Message Cycle: Continuous generation or fixed number.
3. Paging Interval at the SGs interface.
4. To execute:
a. Run all the UE attaches.
b. Activate Session Loading in the eNodeB, for Mobile Originated SMS.
c. Activate Session Loading in the MSC Emulator, for Mobile Terminated SMS.
Control Variables & Relevance
UE/eNodeB
Variable Relevance Default Value
Subscribers Total number of 4G subscribers to register and originate SMS. 1
Activation Rate Number of subscribers performing registering and sending an SMS per second.
1.0
Message Cycle Continuous generation or fixed number of SMS. Continuous
MSC Emulator
Variable Relevance Default Value
Subscribers Total number of 4G subscribers to register and originate SMS. 1
Message Interval Time between two consecutive SMSs. 1000 ms
Message Cycle Continuous generation or fixed number of SMS. Continuous
Paging Interval Time between consecutive Paging messages. 30 seconds
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Key Measured Metrics
Metric Relevance
MSC Location Update Received Number of 4G UEs recognized by the DUT as performing a combined attach.
eNodeB Attaches Attempted Attaches attempted.
MSC Paging Sent Paging Messages sent by the MSC for the Mobile Terminated Scenario.
eNodeB Paging Received Paging Messages processed by the DUT and sent to the eNodeB.
eNodeB NAS Sent SMS forwarded from the UE to the DUT MSC for the Mobile Originated Scenario.
MSC NAS SMS Received SMS processed by the DUT and sent to the MSC for the Mobile Originated Scenario.
MSC NAS SMS Sent SMS forwarded from the MSC to the DUT for the Mobile Terminated Scenario.
eNodeB NAS SMS received SMS processed by the DUT and sent to the UE for the Mobile Terminated Scenario.
Desired Result
The DUT should:
1. Register each UE to the MSC that performs a combined attach.
2. Send Paging to the UE when the MSC indicates the reception of a SMS message destined to
one of the 4G UEs, and complete SMS delivery (Mobile Terminating) to the UE.
3. Notify the MSC of the arrival of an SMS message generated by a 4G UE and complete the
SMS delivery to the MSC.
Analysis
Using Wireshark on Tester Ports A and B:
1. Verify that for each UE Attach requested, there is a Location Update Request sent to the
MSC. This indicates the MME understands the combined registration procedure.
2. Mobile Originated: Locate each UE Service Request procedure and verify that for each, the
MME receives the SMS from the UE and forwards it to the MSC in an Uplink Unitdata
message and then waits for the delivery report and passes it to the UE.
3. Mobile Terminated: Locate each Paging message and verify that the MME transmits such a
message to the eNodeB. Use the trace to identify the Service Request message from MME to
MSC and verify the reception of the SMS from the MSC.
Using the Test Results:
1. The number of eNodeB Attach Attempts should match the MSC Location Update received.
2. Mobile Originated: The number of UE/eNodeB NAS SMS Sent should match MSC NAS SMS
received.
3. Mobile Terminated: The number of UE/eNodeB NAS SMS Sent should match MSC NAS SMS
received and it should be equal to the number of eNodeB Paging Received.
Spirent Journal of LTE EPC PASS Test Methodologies | © Spirent Communications 2011
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4G-EPC_002 MME 4G to 3G inter-RAT mobility performance test
Abstract
This test case determine whether a 4G MME (DUT) correctly hands over 4G UEs to a 3G-based
network when indicated by the 4G eNodeB. This is achieved by generating Handover Requests
from one or multiple eNodeBs toward the DUT over the S1-C interface. Without this validation,
the user will not know if the DUT is capable of inter-working with 3G networks and also meeting
performance requirements.
Description
When a 3G/4G UE capable device that it is currently active in a 4G network moves into a 3G
network that provides better service, the network triggers the procedures for handing over to
the UMTS network. In other words, the 4G-to-3G Inter RAT handover is network controlled
through the 4G access system.
In this context, the MME is responsible for giving guidance for the UE and the target network
about how to transfer to the new radio access system. This information is given during the
handover preparation and should be transported completely transparently through the 4G
system to the UE.
The 4G to 3G handover process is described in TS 23.401. To seamlessly complete the migration
from one network to the other, the procedure follows the steps below, as seen from the MME
point of view.
1. The eNodeB notifies the DUT (MME), of the intention to relocate the UE to the new network
via a Handover Required message.
2. The MME notifies the target SGSN of the imminent appearance of the UE in the 3G network
by sending a Forward Relocation Request. The request contains the necessary 3G and 4G
signaling information to help set up the proper channels in the target network (IMSI, Tunnel
Endpoint Identifier Signaling, MM Context, PDP Context, Target Identification, RAN
Transparent Container, RANAP Cause).
3. When resources for the transmission of user data within the 3G network have been
allocated, the Forward Relocation Response message is sent from the SGSN to MME. This
message indicates that the UMTS network is ready to receive user plane information from
the source network. If Indirect Forwarding applies, the MME sends a Create Indirect Data
Forwarding Tunnel Request message to the Serving GW.
4. The source MME completes the preparation phase toward source eNodeB by sending the
message Handover Command. The Handover Command message contains a list of addresses
and TEID to use when sending user data traffic. The list may come from the 3G network, in
the case of direct forwarding, or received from the Serving GW, in the case of indirect
forwarding.
5. When the UE completes the radio access handover and notifies the SGSN, the SGSN informs
the source MME by sending the Forward Relocation Complete Notification.
6. At this point, the MME acknowledges the relocation message above and proceeds to release
the resources in the 4G network allocated to the UE.
7. The release process is accomplished with a Delete Session Request message to the SGW.
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8. The MME notifies the eNodeB of the relocation in order to release the resources.
Target Users
NEM feature validation and load/performance testers.
Service provider load/performance and integration testers.
Target Device Under Test (DUT)
4G Mobility Management Entity (MME)
Reference
3GPP TS. 23.401
Relevance
LTE will not be fully functional from day one. There is a need for legacy systems to support a
majority of customers. Although LTE development groups insist on recommending an upgrade of
the existing SGSNs and GGSNs, no service provider wants to manipulate a deployed and
functioning network infrastructure. For some point of time both legacy and LTE systems must
work together.
Version
1.0
Test Category
4G-EPC
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PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
S1-C, S11 and S3 full interface simulation
SGW and PGW combined emulation
eNodeB emulation
Session Loading from the eNodeB emulation
Low level Security
Decoupled control and user plane, for control plane testing only
Session measurements (counters and delays)
Message measurement (counters and delays)
Topology Diagram
Test Procedure
1. Set up the source network (4G), as follows:
a. Set up at least one simulated S1-C interface endpoint and assign it to Tester Port A. This
endpoint simulates the eNodeB and loads the DUT with Handover Required messages.
i. Set up a range of UEs, up to 150,000 for example. These UEs attach to the LTE
network and perform the handover as soon as the session has been established.
ii. To simplify, select one default bearer only (no dedicated bearers) .
iii. Define the inter-technology session loading parameters. In particular:
1. Mobility Rate in Handoffs per second.
eNodeB
SGW
SGSN
MME(DUT)
Test Port A (S1-C)
Test Port C (S11)
Test Port C (S3)
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2. To simplify, select a Single Handoff per UE.
b. Set-up an S11 interface endpoint and assign it to Tester Port B. This endpoint simulates
the SGW and acts upon the commands received by the DUT. Verify that identifiers and
other key parameters match the configuration of Tester Port A (IMSI, APN).
2. Setup the target network (3G), as follows:
a. Set up at least one simulated S3 interface endpoint and assign it to Tester Port C. This
endpoint simulates the target SGSN and acts upon the commands received by the DUT.
It also indicates to the MME when the UE arrives on the 3G network by issuing Forward
Relocation Complete notifications.
b. Define the characteristics of the target Iu-PS interface that will be configured via the
Forward Relocation Request command from the DUT.
c. Ensure that identifiers on the target network match the identifiers of the source
network.
Control Variables & Relevance
Variable Relevance Default Value
Subscribers Total number of 4G subscribers that are going to handoff to the 3G Network
1
Mobility Rate Number of subscribers performing a Handover per second
1.0
Mobility Rate Interval Distribution
Stochastic distribution of the Handover Attempts (fixed, Poisson)
Fixed
Key Measured Metrics
Metric Relevance Metric Unit
Actual Handoff Rate Final performance of the DUT in terms of handoffs per second
Handoff/second
Handoffs Attempts Total number of Handoffs attempted Handoffs
Handoff Failures Total number of Handoffs failed Handoffs
Average Handoff Delay
Indicates how long it takes the DUT to complete the Handoff
Seconds
Desired Result
If the DUT behaves correctly, it should:
1. Perform the handover procedure as described in TS 23.401.
2. Maintain, for any mobility rate below nominal:
a. Handover delay < 500 ms.
b. Success rate > 95%.
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Analysis
Using Wireshark:
1. Verify that as soon as the SGSN issues a Forward Relocation Request the MME begins
exchanging messages with the emulated SGW and eNodeB.
2. The message exchange should follow TS 23.401.
Using the Test Results:
1. Verify that the actual mobility rate (handoffs/second) on the DUT is met and continuous.
2. Verify that handoff failures divided by handoff attempts is below 0.95.
3. Verify that the average handoff delay remains below 500 ms.
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4G-EPC_003 MME 3G to 4G inter-RAT mobility performance test
Abstract
This test case determines whether a 4G MME (DUT) will correctly accept and handle services
from incoming 3G Mobile Terminals (UE) that are moving from a 3G network to a 4G one. This is
achieved by generating Forward Relocation Requests from one or multiple SGSNs toward the
DUT over the S3 interface. Without this validation, the user will not know if the DUT is capable of
inter-working with 3G networks and also, meet performance requirements.
Description
When an 3G/4G UE capable device that it is currently receiving service from the UMTS network
roams into a 4G network that provides better service, the network triggers the procedures for
handing over to the LTE network.
The 3G-to-4G handover process is described in TS 23.401. The UTRAN to E-UTRAN inter-RAT
handover procedure takes place when the network decides to perform a handover. The decision
to perform a PS handover from UTRAN to E-UTRAN is taken by the network (RNC), based on
radio condition measurements reported by the UE.
To seamlessly complete the migration from one network to the other, the procedure follows the
steps below, as seen from the MME point of view.
1. The SGSN notifies the DUT (MME) of the intention to relocate the Mobile Terminal to the
new network.
2. The MME creates the necessary sessions in the SGW.
3. The MME notifies the eNodeB of the handover occurrence and the need to set up the EPS
bearers.
4. The target eNodeB allocates the requested resources and returns the applicable parameters
to the target MME in the message Handover Request Acknowledge.
5. The MME notifies the SGSN that the selected E-UTRAN section of the network is prepared to
acquire the 3G-to-4G roaming UE.
6. When the eNodeB detects the UE, the eNodeB sends an HO Notify to the MME.
7. The MME notifies the SGSN of the completion of the handover request and the SGW that
the target MME is now responsible for all the bearers the UE established.
8. After acknowledgement from the SGW, the user traffic can flow through the 4G bearers.
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The DUT should be able to seamlessly carry over this handover procedure, which in practical terms
translates to:
Handover Delays < 500 ms
Success Rate > 95%
Target Users
NEM feature validation and load/performance testers.
Service provider load/performance and integration testers.
Target Device Under Test (DUT)
4G Mobility Management Entity (MME)
Reference
3GPP TS. 23.401
Relevance
LTE will not be fully functional from day one. There is a need for legacy systems to support a
majority of customers. Although LTE development groups insist on recommending an upgrade of
the existing SGSNs and GGSNs, no service provider wants to manipulate a deployed and
functioning network infrastructure. For some point of time both legacy and LTE systems must
work together.
Version
1.0
UEs
eNodeB
RNC
SGSN
MME SGW
PGW
NodeB( 1 )
( 2 )
( 3 )
( 5 )
( 4 )
( 6 )
( 7 )
( 8)
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Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
S1-C, S11 and Gn full interface simulation
SGW and PGW combined emulation
eNodeB emulation
Session loading from the SGSN emulation
Low level security
Decoupled control and user plane, for control plane testing only
Session measurements (counters and delays)
Message measurement (counters and delays)
Topology Diagram
Test Procedure
1. Set up the source network (3G), as follows:
a. Set up at least one simulated S3 interface endpoint and assign it to Tester Port C. This
endpoint simulates the SGSN and loads the DUT with Forward Relocation Requests:
i. Set up a range of UEs, up to 150,000 for example.
ii. Define the inter-technology session loading parameters. In particular:
1. Mobility Rate in Handoffs per second.
2. To simplify, select a Single Handoff per UE.
2. Set up the target network (4G), as follows:
eNodeB
SGW
SGSN
MME(DUT)
Test Port A (S1-C)
Test Port C (S11)
Test Port C (S3)
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a. Set up at least one simulated S1-C interface endpoint and assign it to Tester Port A. This
endpoint simulates the destination eNodeB and acts upon the commands received by
the DUT. It also indicates to the MME when the UE arrives on the 4G network by issuing
Handover Notify commands.
b. Set up an S11 interface endpoint and assign it to Tester Port B. This endpoint simulates
the SGW and acts upon the commands received by the DUT.
c. Ensure that identifiers on the target network match the identifiers of the source
network.
Control Variables & Relevance
Variable Relevance Default Value
Subscribers Total number of 3G subscribers to handoff to the 4G network.
1
Mobility Rate Number of subscribers performing a handover per second.
1.0
Mobility Rate Interval Distribution
Stochastic distribution of the Handover Attempts (fixed, Poisson).
Fixed
Key Measured Metrics
Metric Relevance Metric Unit
Actual Handoff Rate Final performance of the DUT in terms of handoffs per second.
Handoff/second
Handoffs Attempts Total number of handoffs attempted. Handoffs
Handoff Failures Total number of handoffs failed. Handoffs
Average Handoff Delay
Indicates how long it takes the DUT to complete the handoff.
Seconds
Desired Result
If the DUT behaves correctly, it should:
1. Perform the handover procedure as described in TS 23.401.
2. Maintain, for any mobility rate below nominal:
a. Handover delay < 500 ms.
b. Success rate > 95%.
Analysis
Using Wireshark:
1. Verify that as soon as the SGSN issues a Forward Relocation Request, the MME begins
exchanging messages with the emulated SGW and eNodeB.
2. The message exchange should follow TS 23.401.
Using the Test Results:
1. Verify the actual mobility rate (handoffs/second) on the DUT is met and continuous.
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2. Verify that handoff failures divided by handoff attempts is below 0.95.
3. Verify that the average handoff delay remains below 500 ms.
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4G-EPC_004 Validation of a SGW’s dual GTP and PMIP support
Abstract
This test case determines whether a 4G Serving GW (DUT) is capable of simultaneously handling
GTP- and PMIP-based traffic due to the presence of a visiting Mobile Terminal (UE) roaming from
an all-PMIP-based network to a GTP based one, or vice versa (e.g, CDMA or WiMax terminals).
This is achieved by generating sessions from one or multiple MMEs with different types of
protocol indicators for the DUT. Without this validation, the user will not know if the DUT could
be used to support roaming scenarios that include local breakout.
Description
A basic functionality of the LTE Serving Gateway (SGW) is to be the mobility anchor for the 4G
Network, not only for LTE devices moving across a home network, but also for roaming devices
belonging to any type of mobile network (e.g., inter-3GPP-access and non-3GPP access).
One classic example is when subscribers of a GTP-only network roam into a PMIP network while
the PDN GW for home routed traffic uses GTP. This means the Serving GW selected for the
subscribers may need to support both GTP and PMIP so that it is possible to set up both local
breakout and home-routed sessions for these subscribers.
The support for both GTP and PMIP protocols on the same visited network is called Direct
Peering.
The direct peering scenario consists of one of the two roaming partners providing support for
both variants of roaming (e.g. a PMIP operator would support a GTP-based roaming interface
toward a GTP-only roaming partner, or vice versa) to make roaming possible.
S6a
HSS
S8
S3
S1 - MME
S10
UTRAN
GERAN
SGSN
MME
S11
Serving
Gateway UE
“ LTE
- Uu ”
E - UTRAN
S12
HPLMN
VPLMN
PCRF
Gx Rx
SGi Operator’s IP
Services
(e.g. IMS, PSS etc.)
PDN
Gateway
S 1 - U
S4
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Case A: Visiting GTP-based UE in a PMIP-based network
When roamers whose subscription is owned by the GTP-based operator attach to the EPS
network of the PMIP-based operator, they are assigned a GTP-capable GW acting in the role of
Serving GW (which means that GTPv2 is used on the S8 interface to connect the visited Serving
GW with the local PDN GW). The SGW selection is carried out by MME or SGSN based on the
subscriber's HPLMN and in the case of the Serving GW supporting both GTP and PMIP, the
MME/SGSN should indicate the Serving GW which protocol should be used over S5/S8 interface.
Case B: Visiting PMIP-based UE in a GTP-Based network
When roamers whose subscription is owned by the PMIP-based operator attach to the EPS
network of the GTP-based operator, they are assigned a PMIP-capable GW acting in the role of
Serving GW (which means that PMIPv6 is used on the S8 interface to connect the visited Serving
GW with the local PDN GW). The SGW selection is carried out by MME or SGSN based on the
subscriber's HPLMN and in the case of the Serving GW supporting both GTP and PMIP, the
MME/SGSN should indicate the Serving GW which protocol should be used over S5/S8 interface.
Serving GW
(PMIP)
vPCRF
Gxc
GTP – HPLMN PMIP – VPLMN
PMIP GTP
S9
Serving GW
(GTP)
Towards other PMIP
operators
PDN GW (GTP)
PCRF
Gx
GTP
Towards other PMIP
operators
GTP – VPLMN
Serving GW
(GTP)
a) PMIP VPLMN – GTP HPLMN
b) GTP VPLMN – PMIP HPLMN
PDN GW (PMIP)
hPCRF
Gx
PMIP – HPLMN
PMIP
S9
PDN GW (GTP)
Gx
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Target Users
NEM feature validation and load/performance testers.
Service provider load/performance and integration testers.
Target Device Under Test (DUT)
4G Serving Gateway (SGW) with dual GTP and PMIP Support.
Reference
3GPP 23.401 and 23.402
Relevance
This test case validates that a same Serving GW can be selected and configured for a specific type
of network (GTP or PMIP), while assuring support for roamers from other types of networks.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting
At least two simulated MMEs and two simulated/emulated PGWs
GTP and PMIP (IPv4 or IPv6) protocols simultaneously
Low level security
Combined UE traffic generation using GTP and/or PMIP
Decoupled control and user plane, for control plane testing only
IPv4 and IPv6 UEs and Nodes and IPv4 or IPv6 transport
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Topology Diagram
Test Procedure Case B: Home-PMIP and Visited-GTP
1. Set up the Visited network as follows:
a. Set up at least one simulated MME S11 endpoint and assign it to Tester Port A. This
endpoint simulates the MME and loads the SGW with Session Requests for a GTP S5
interface:
i. Set up a range of UEs, up to 10,000 for example (IMSI, ULI,).
ii. The UEs perform session loading testing, may request either IPv4 or IPv6 PDN
addresses and to simplify, use only Default Bearers.
iii. To simplify, choose stateless data or no data at all. (Default bearers will still be
created.)
b. Set up Tester Port C to provide the S5 interface and configure the PDN GW Node of the
Visited Network.
2. Set up the Home Network:
a. Set up that same simulated MME S11 endpoint defined in (1), or a new one to load the
SGW with Session Requests for a PMIP S8 interface:
i. Set up a range of UEs, up to 1,000 for example (IMSI, ULI).
ii. The UEs perform session loading testing, may request either IPv4 or IPv6 PDN
addresses and to simplify, use only Default Bearers.
iii. To simplify, choose stateless data or no data at all. (Default bearers will still be
created.)
b. Set up an eNodeb S1-U interface simulation and assign it to Tester Port B.
c. Define the LMA characteristics including On-link prefix, GRE Key type.
d. Set up Tester Port C to provide the S8 interface and configure the PDN GW Node of the
Home Network.
3. Define the Session Loading parameters describing the traffic model followed by each of the
two types of subscribers: the local GTP-owned UEs and the visiting PMIP-owned UEs.
a. Local GTP-owned UEs: define:
i. Calls per second.
ii. Call duration.
MMEs
eNodeBs
PGW(PMIP)
PGW(GTP based)
SGW(DUT)
Test Port A (S11)
Test Port B (S1-U)
Test Port C (S8)
Test Port D (S5)
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iii. IDLE time.
iv. Ramp-up and Ramp-down periods.
b. Visiting PMIP-owned UEs: define:
i. Calls per second.
ii. Call duration.
iii. IDLE time.
iv. Ramp-up and Ramp-down periods.
4. Activate Wireshark traffic capture on both PDN GWs Control ports to be able to verify and
validate the message exchange with the SGW.
5. To execute:
a. Run the Visited Network elements first and establish the visited traffic.
b. Run the Home Visited UEs.
6. Automate Step 5 and change parameters as needed.
Control Variables & Relevance
Network Nodes and Interfaces
Variable Relevance Default Value
MME S5/S8 Protocol Protocol the MME signals the SGW to use in the S5/S8 interface.
GTP
S11 GTP Version GTP version to use in the S11 interface. 8.6.0
IMSI Range Visited Traceable range of GTP-owned UEs.
IMSI Range Home Traceable range of PMIP-owned UEs.
PMIPv6 Version PMIP version to use in the S5/S8 interface. 8.7.0
GTPv2 Version PMIP version to use in the S5/S8 interface. 8.6.0
Test Configurations
Variable Relevance Default Value
Subscribers Range Number of GTP or PMIP owned subscribers. 1
Transport Address Requested Network IP addressing (IPv4 or IPv6). IPv4
UE Home Address Requested PDN Address type assigned to the UE. IPv4
Default Bearers Number of Default Bearers per UE. 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Data Traffic Type Selection between Stateless, Stateful or none for control plane only testing.
None
Session Hold Time Duration of a UE session in seconds.
Session Pending Time Duration of the UE inactivity in seconds.
Activation Rate Number of Sessions/sec (generation). 1.0
Deactivation Rate Number of Sessions/sec (teardown). 1.0
Constant Session flag Maintain the generation rate throughout the test. uncheck
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Key Measured Metrics
Metric Relevance Metric Unit
PGW Creates Sessions Requests Received
Sessions attempts for the UEs belonging to the GTP network.
Sessions
PGW Proxy Binding Update Requests Received
Sessions attempts for the UEs belonging to the PMIP network.
Sessions
MME Create Sessions Request (GTP)
Number needed to obtain the global success rate for GTP-owned UEs.
Sessions
MME Create Sessions Request (PMIP)
Number needed to obtain the global success rate for GTP-owned UEs.
Sessions
PGW Creates Sessions Requests Received per second
SGW Session Generation rate for GTP-owned UEs. Sessions/second
PGW Proxy Binding Update Requests Received per second
SGW Session Generation rate for GTP-owned UEs. Sessions/second
Desired Result
If the DUT behaves correctly, it should:
1. Attach/Detach GTP sessions with the emulated GTP-PGW as indicated by the MME.
2. Attach/Detach PMIP sessions with the emulated PMIP-PGW as indicated by the MME.
3. Maintain session drop / failure < 0.2%.
Analysis
Using Wireshark:
1. Verify that as soon as the Visited Network MME issues Create Session Requests to the SGW
with a selection of a GTP S5/S8 interface, the SGW exchanges messages with the emulated
PGW using the GTPv2 protocol.
2. The message exchange should follow TS 23.401 interface for the Attach procedure.
3. If traffic is activated, packets should be exchanged in the default bearer.
4. Every time a session is ended by the emulated MME, the DUT should notify the emulated
PGW and implement the resource release procedure according to TS 23.401.
5. As soon as the Visited Network MME issues Create Session Requests to the SGW with a
selection of a GTP S5/S8 interface, the SGW should exchange messages with the emulated
PGW using the GTPv2 protocol.
6. The message exchange should follow TS 23.402 interface for the Attach procedure.
7. If traffic is activated, packets should be exchanged in the default bearer.
8. Every time a session is ended by the emulated MME, the DUT should notify the emulated
PGW and implement the resource release procedure according to TS 23.402.
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Using the test results:
1. Verify the average session generation rate (sessions/second) from the MME towards the
DUT is met and continuous in the S11 interface.
2. Verify the average session generation rate (sessions/second) from the SGW is continuous in
the GTP S5/S8 interface.
3. Verify the average session generation rate (sessions/second) from the SGW is continuous in
the PMIP S5/S8 interface.
4. The percentage of failure in any interface stays below 0.2 %.
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4G-EPC_005 PGW capacity and session loading with incremental
dedicated bearer allocation
Abstract
This test case determines whether a 4G PDN GW (DUT) is capable of handling a high density of
bearers. Attach Requests are issued toward the DUT and are followed by Dedicated Bearer
Activations requests. The user should use this validation method to guarantee nominal capacity
of the DUT.
Description
In LTE, the Packet Data Network Gateway (PDN GW) is the termination point of the packet data
interface toward the Packet Data Networks. As an anchor point for sessions toward the external
Packet Data Networks, the PGW is partly responsible for controlling resource allocation and
enforcement of quality of service for the data plane traffic. The traffic is carried over virtual
connections called service data flows (SDFs). These SDFs, in turn, are carried over bearers, virtual
containers with unique QoS characteristics. A fundamental role of a PGW is to manage the
creation and release of these bearers and the enforcement of the quality of service.
The PGW handles two types of bearers: default and dedicated.
Default Bearer
As part of the Attach procedure, the UE is assigned an IP address by the PGW and at least one
bearer is established. This is called the default bearer and it remains established throughout the
lifetime of the PDN connection to provide the UE with always-on IP connectivity to that PDN.
Default Bearers tend to be used for initial signaling of additional services or for services requiring
low or non-guaranteed quality of service.
Dedicated Bearers
Services such as VoIP, IMS, VoLGA and other real time streaming applications require some
guaranteed QoS. For this, additional bearers, called dedicated bearers, are established at any
time during or after completion of the Attach procedure. The PGW is responsible for filtering
user IP packets into the different QoS-based bearers. This is performed based on Traffic Flow
Templates (TFTs).
This test case validates and qualifies the performance of the PGW in two areas. The first step is
to find the maximum number of UEs that can be attached per second to the network, which
translates to the maximum number of UEs successfully assigned a default bearer per second.
The second step is to analyze the maximum number of dedicated bearers that can be allocated
to a UE and the maximum number of such UEs the PGW can handle per second. Although
specification 23.401 identifies a maximum of 11 bearers per UE (1 default and 10 dedicated),
observation of real world users seems to indicate that the majority of mobile terminals will
request between 1 to 3 dedicated bearers per session.
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Target Users
NEM load/performance testers.
Service provider load/performance and validation testers.
Target Device Under Test (DUT)
4G PDN Gateway (PGW)
Reference
3GPP 23.401 and 23.203
Relevance
The PGW is one of the concentration nodes for converged traffic in the LTE architecture. Being
able to determine its performance in terms of number of UEs and bearers is essential when
assuring quality of service.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [ ] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
SGW and S5/S8 interface simulation with Session Loading and Traffic modeling capabilities to
simulate the Attaches and Bearer Requests coming from the UEs.
Configurable PCRF Node Emulation that will be used to negotiate QoS with the PGW. The PCRF
should be configurable in such way that all Dedicated Bearer request should be accepted.
Network Host simulators that terminate user traffic at the PDN.
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Topology Diagram
Test Procedure
1. Set up the S5/S8 interface for a Session Loading test as follows:
a. Set up at least one simulated SGW S5/S8 endpoint and assign it to Tester Port A for
Control Plane. This endpoint simulates the SGW and loads the PGW with Session
Requests for a GTP S5/S8 interface:
i. Set up a range of UEs, up to 150,000 for example (IMSI, ULI).
ii. The simulated UEs behind the SGW perform session loading testing. They may
request either IPv4 or IPv6 PDN addresses and use up to 2 Dedicated Bearers for:
1. Video Streaming at 2Mbps MBR.
2. Conversational voice at 128 Kbps GBR.
iii. For each dedicated bearer, define:
1. Traffic Flow Templates (TFTs).
2. Bearers QoS parameters: QCI (3 or 1), GBR, MBR and ARP.
iv. To simplify, the test case uses only one default bearer per UE. The default bearer is
used among other signaling for HTTP transfers.
v. Define for Tester Port B the L3-L7 applications that use the dedicated bearers.
Establish the matching correlation between the transport layer protocols and ports
with the ones defined in the TFTs:
1. Set-up an RTSP client over udp for video streaming.
2. Set-up a SIP client over tcp for the voice call.
3. Set-up an HTTP client.
2. Test Port D terminates the SGi interface and builds as the reciprocal network hosts of the
above RTSP, SIP and HTTP clients.
3. Set up the Gx interface on Tester Port C.
a. Activate a PCRF Node Emulator to provide QoS information to the DUT.
b. The PCRF should be configured with at least the following information:
SGW
PCRFEmulated
Network Hosts
(FTP, HTTP, VoD
PGW(DUT)
Test Port A (S5/S8)Control
Test Port C (Gx)
Test Port D (SGi)
Test Port B (S5/S8)User Plane
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i. Gx interface.
ii. Identification based on IMSI with matching values to the ones configured in step
(1).
iii. Three rules per type of bearer for IPv4, IPv6 or both:
1. Rule for HTTP.
2. Rule for SIP.
3. Rule for RTSP.
iv. A total of 150,000 UE profiles matching identification information defined in Step 1
and QoS requirements.
4. Define the initial Session Loading parameters describing the traffic model followed by the
subscribers:
a. Activation Rate (sessions/second).
b. Session duration (seconds).
c. IDLE time (seconds).
d. Ramp-down rate (session).
5. Activate Wireshark traffic capture on PCRF GWs and SGW Control port.
6. Execute 3 types of test:
a. Session Loading with no dedicated bearer.
b. Session Loading with one dedicated bearer.
c. Session Loading with two dedicated bearers.
7. Change parameters in Step 4 as needed.
8. Add more Test Ports to scale the Test Case, such as 2x 300,000 UEs, 3x 600,000 UEs
Control Variables & Relevance
Network Nodes and Interfaces
Variable Relevance Default Value
Bearers Quality of Service QCI, GBR, MBR and ARP associated to each dedicated bearer that should be enforced by the PGW.
Default Bearer Quality of Service
QCI, MBR and ARP associated to the default bearer.
IMSI values Must match on both SGW and PCRF Emulators.
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Test Configurations
Variable Relevance Default Value
Subscribers Range Number of UEs. Should be set to at least 150,000. 1
Number of Default Bearers
Number of default bearers per UE. Always 1. 1
Number of Dedicated Bearers
Change the value to test: no bearer, one dedicated bearer, two dedicated bearers.
0
Session Hold Time Duration of a UE session in seconds. 100
Session Pending Time Duration of the UE inactivity in seconds. 100
Activation Rate Number of Sessions/sec (generation). 1.0
Deactivation Rate Number of Sessions/sec (teardown). 1.0
Constant Session flag Maintain the generation rate throughout the test. Clear
Key Measured Metrics
EPC Metrics
Metric Relevance Metric Unit
Attempted Session Connects Session activation attempts. Sessions
Attempted Session Disconnects Session deactivation attempts. Sessions
Attempted Dedicated Bearers Activate dedicated bearer attempts.
Actual Session Connects Number of active UEs.
Actual Dedicated Bearers Number of active bearers.
PGW Update Bearer Request Received
Number of bearers that have received a QoS modification from the network.
Actual Connection Rate Actual UE Activation rate. Sessions/second
Attempted Connection Rate Generation rate at the SGW. Sessions/second
Attempted Dedicated Bearers rate
Activate dedicated bearer attempts per second.
Bearers/second
Actual Dedicated Bearers rate Number of active bearers per second. Bearers/second
SGW Bearer Downlink Data Bytes Received
Total data sent in the downlink per bearer.
Bytes
SGW Bearer uplink Data Bytes Received
Total data sent in the uplink per bearer. Bytes
Session Errors Total number of session attempts that failed.
Sessions
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Failures (Sessions and Bearers)
Metric Relevance Metric Unit
All dynamic addresses occupied
Number of UEs that could not register due to unavailable PDN address.
No Memory Available UE or Bearer operation failure due to a limitation in the DUT’s memory.
No Resources Available
UE or Bearer operation failure due to a limitation in the DUTs or link resource.
L4-L7 Metrics
Metric Relevance Metric Unit
RTSP Maximum Receive Rate
Actual maximum downlink speed for the Video Streaming service requested vs defined in the Bearer Quality of Service field.
Bits per second
RTSP Average Receive Rate
Actual average downlink speed for the Video Streaming service requested vs defined in the Bearer Quality of Service field.
Bits per second
RTP Maximum bandwidth usage per stream
Actual maximum bandwidth for the Voice Call service requested vs defined in the Bearer Quality of Service field.
Bits per second
RTP Average usage per stream
Actual average bandwidth for the Voice Call service requested vs defined in the Bearer Quality of Service field
Bits per second
Desired Result
There are three types of desired results depending on the type of test:
No dedicated bearer. The user should see:
1. All the UEs attach without problems and are assigned a default bearer.
2. The Attach Rate matches the nominal value of the DUT or is within a 2%.
3. All user plane traffic uses the default bearer (Wireshark trace).
4. The QoS in default bearers is not guaranteed, so the bandwidth allocated per UE decrease as
the number of attached UEs increases rather than tearing down sessions or rejecting
attaches.
5. For a continuous session loading rate, the DUT should not change in behavior.
One Dedicated Bearer with GBR. The user should see:
1. The UEs attach without problems and are assigned a default bearer.
2. The Attach Rate matches the nominal value of the DUT or is within a 2%.
3. The DUT allows dedicated bearer activation as long as resources are available.
4. The DUT consults the PCRF prior to deciding on the dedicated bearer activation or rejection.
5. The default bearer carries HTTP traffic and the dedicated bearer carries video streaming
traffic.
6. As the number of active dedicated bearers increase almost to the nominal value of the DUT,
the PGW sends Update Bearer Request and Create Session Rejects to maintain QoS levels of
already accepted UEs and bearers.
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7. The GBR is respected in the dedicated bearers and the MBR is never reached.
8. For a continuous session loading rate, the DUT does not change in behavior.
Two Dedicated Bearer with GBR. The user should see:
1. The UEs attach without problems and are assigned a default bearer.
2. The Attach Rate matches the nominal value of the DUT or is within a 2%.
3. The DUT allows dedicated bearer activation as long as resources are available.
4. The DUT consults the PCRF prior to deciding on the dedicated bearer activation or rejection.
5. The default bearer carries HTTP traffic and the dedicated bearers carry video streaming
traffic and SIP traffic.
6. As the number of active dedicated bearers increase almost to the nominal value of the DUT,
the PGW sends Update Bearer Request and Create Session Rejects to maintain QoS levels of
already accepted UEs and bearers.
7. The GBR is respected in the dedicated bearers and the MBR is never reached.
8. For a continuous session loading rate, the DUT does not change in behavior.
Analysis
Use Wireshark to:
1. Verify that all User Plane traffic goes in the appropriate tunnels:
a. HTTP, RTSP and SIP use the default bearer tunnel.
b. HTTP and SIP use the default bearer tunnel and RSTP uses dedicated bearer 1.
c. HTTP uses the default bearer, RSTP uses dedicated bearer 1 and SIP uses dedicated
bearer 2.
2. Verify that the DUT consults the PCRF upon reception of a Bearer Resource Command from
the SGW.
Use the Measured Metrics:
No dedicated bearer
1. Use L3-L7 Metrics to see the impact of additional attached UEs in user plane traffic.
2. Use the EPC metrics to verify Connection Rate, Disconnection Rate.
3. Use EPC metrics to validate the maximum number of active UEs and percentage of failures
(<2%).
One Dedicated Bearer with GBR
1. Use the L3-L7 Metrics to see verify that MBR is never exceeded in the dedicated bearer and
that the GBR is maintained for each accepted UE.
2. Use the EPC metrics to verify that Attempts Dedicated Bearers number is close to UE
Activation, but that Actual Dedicated Bearer gap to Attempts Dedicated Bearers increases as
the number of Active UEs get closer to the nominal limit of the DUT.
3. Use Failures Metrics to identify the most common cause of a UE Attach or Bearer Reject.
4. Use EPC metrics to validate the maximum number of active UEs and percentage of failures
(<2%).
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Two Dedicated Bearer with GBR
1. Use the L3-L7 Metrics to see verify that MBR is never exceeded in the dedicated bearer and
that the GBR is maintained for each accepted UE.
2. Use the EPC metrics to verify that Attempts Dedicated Bearers number is close to UE
Activation, but that Actual Dedicated Bearer gap to Attempts Dedicated Bearers increases as
the number of Active UEs get closer to the nominal limit of the DUT.
3. Use Failures Metrics to identify the most common cause of a UE Attach or Bearer Reject.
4. Use EPC metrics to validate the maximum number of active UEs and percentage of failures
(<2%).
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4G-EPC_006 GGSN/PGW converged multi-RAT session loading test
Abstract
This test case determines the performance of a converged PGW and GGSN gateway. This is
achieved by issuing multiple Create Session Requests towards the DUT from one or several
simulated LTE SGW and from one or several simulated 3G SGSNs, simultaneously. The user
should use this validation method to guarantee convergence from the Gateway (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment while
managing existing 3G upgrades cost effectively and efficiently. Deploying an independent
Evolved Packet Core (EPC) can be costly due to the increased investment in new network
equipment and the increase in operational costs. One approach to addressing this issue is
deploying gateways that integrate legacy networks and EPC gateways onto a single box. One
example of such convergence is the PGW/GGSN Converged Gateway, which from a single device
can act as a GGSN, handling all the 3G sessions, and a PGW, handling all the LTE sessions.
This type of mobile gateway can simultaneously support the Layer 2/Layer 3 high-processing
capacities required for 3G/LTE data throughput, and handle millions of subscribers with a high
rate of mobility while delivering quality-of-experience sensitive applications and content to a
variety of mobile devices.
The purpose of this test is to validate the correct handling of 3G and LTE sessions within the same
piece of equipment with no mobility.
UEs
eNodeB
RNC
SGSN
SGW
GGSN/PGW
NodeB Gn
S5/S8
MME
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Target Users
NEM load/performance testers
Service providers load/performance and validation testers
Target Device Under Test (DUT)
A Converged GGSN/PGW Gateway
Reference
Standards 3GPP 23.401, 29.274, 29.060 and 23.060
Relevance
GGSN/PGW gateways are likely to become the LTE network element of choice among operators
due to their reduced cost compared to the investment and operational costs of stand-alone
GGSN and PGW nodes. Being able to determine the converged-gateway performance in terms of
number of UEs and mobility events that it can handle per radio access technology is key when
assuring quality of connection in the mobile core.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
SGW and S5/S8 interface simulation with session loading and traffic modeling capabilities, in
order to simulate the Create Session Requests coming from the LTE UEs.
SGSN and Gn interface simulation with session loading and traffic modeling capabilities, in
order to simulate the Create PDP Context Requests coming from the 3G UEs.
Topology Diagram
SGWsSGSNs
Converged GGSN/PGW
(DUT)
(S5/S8) (Gn)Test Port A – GTPC Test Port B – GTPv1
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Test Procedure
1. Set up the S5/S8 interface for a Session Loading type of test as follows:
a. Set-up at least one simulated SGW S5/S8 endpoint and assign it to Tester Port A for
Control Plane. This endpoint simulates the SGW and load the PGW with Session
Requests for a GTP S5/S8 interface:
i. Set up a range of UEs up to 600,000 for example (IMSI, ULI, ..etc..)
ii. The simulated UEs behind the SGW perform session loading testing, they may
request either IPv4 or IPv6 PDN addresses will only establish default bearers
iii. To simplify, the test case will not use traffic on the default bearers.
2. Set up the Gn interface for a Session Loading type of test as follows:
a. Set-up at least one simulated SGSN Gn endpoint and assign it to Tester Port B. This
endpoint simulates the SGSN and load the PGW with Create PDP Context Requests for a
GTP Gn interface:
i. Set up a range of UEs up to 600,000 for example and provide the IMSI, MSISDN,
IMEI (SV), …
ii. The simulated UEs behind the SGSN perform session loading testing, they may
request either IPv4 or IPv6 PDP addresses will only establish one primary context
iii. Set up the GTP layer: provide APN, authentication usage, authentication protocol,
password, direct tunnel indicator, teardown indication.
3. For both interfaces, define the initial Session Loading parameters describing the traffic
model followed by the subscribers:
a. Activation Rate (sessions/second)
b. Session duration (seconds)
c. IDLE time (seconds)
d. Ramp-down rate (session)
4. Activate Wireshark traffic capture on SGSN and SGW Control ports to be able to verify and
validate the message exchange with the GGSN/PGW Gateway.
5. To execute:
a. Run the LTE elements
b. Run the 3G elements
6. Change parameters in (3) as needed
7. Add more Test Ports to scale the Test Case.
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Control Variables & Relevance
Test Configurations for LTE
Variable Relevance Default Value
Subscribers Range for LTE Number of LTE subscribers 1
Transport Address Requested Network IP addressing (IPv4 or IPv6) IPv4
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Number Nodes Number of Simulated SGWs 1
Data Traffic Type Activated or Deactivated Deactivated
Session Hold Time Duration of a UE session in seconds
Session Pending Time Duration of the UE inactivity in seconds
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Constant Session flag Maintain the generation rate throughout the test uncheck
Test Configurations for 3G
Variable Relevance Default Value
Subscribers Range for 3G Number of 3G subscribers 1
PDP Type Address Requested PDP Address type assigned to the UE
IPv4
Number of Primary PDP contexts Number of Primary PDP Contexts per UE 1
Number of Secondary PDP contexts Number of Secondary PDP Contexts per UE 0
Data Traffic Type Activated or Deactivated Deactivated
Number Nodes Number of Simulated SGSNs 1
Session Hold Time Duration of a UE session in seconds
Session Pending Time Duration of the UE inactivity in seconds
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Constant Session flag Maintain the generation rate throughout the test
uncheck
Key Measured Metrics
S5 Metrics
Metric Relevance Metric Unit
Attempted Session Connects Indicates the session activation attempts Sessions
Attempted Session Disconnects
Indicates the session deactivation attempts
Sessions
Actual Session Connects Indicates the number of active UEs UEs
Actual Connection Rate Actual UE Activation rate Sessions/second
Attempted Connection Rate Generation rate at the SGW Sessions/second
Session Errors Indicates the total number of session attempts that failed
Sessions
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Gn Metrics
Metric Relevance Metric Unit
Attempted Context Connects Indicates the context activation attempts Contexts
Attempted Context Disconnects
Indicates the context deactivation attempts
Contexts
Actual Context Connects Indicates the number of active UEs UEs
Actual Connection Rate Actual UE Activation rate Contexts/second
Attempted Connection Rate Generation rate at the SGSN Contexts/second
Session Errors Indicates the total number of Context Creation attempts that failed
Contexts
Failures (Sessions)
Metric Relevance Metric Unit
All dynamic addresses occupied
Indicates number of UEs that could not register due to unavailable PDN address
No Memory Available Indicates a UE or Bearer operation failure due to a limitation in the DUT’s memory
No Resources Available Indicates a UE or Bearer operation failure due to a limitation in the DUTs or link resource
Failures (Contexts)
Metric Relevance Metric Unit
All dynamic addresses occupied
Indicates number of UEs that could not register due to unavailable PDN address
No Memory Available Indicates a UE or Bearer operation failure due to a limitation in the DUT’s memory
No Resources Available Indicates a UE or Bearer operation failure due to a limitation in the DUTs or link resource
Desired Result
The desired results are twofold:
1. The DUT is capable of providing the correct message exchange to establish/modify/end
sessions and contexts for both S5 and Gn interfaces, respectively.
2. The session and contexts drops/reject are below 2%, respectively.
Analysis
Using Wireshark, analyze the correctness of the message exchange on both signaling interfaces.
Once the behavior has been validated, use the counters to validate the performance in terms of
Actual Session/Context Rate and percentage of failure.
Use the Failure Metrics to understand the nature of the session and contexts that failed.
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4G-EPC_007 SGSN/MME converged multi-RAT session loading test
Abstract
This test case determines the performance of a converged SGSN and MME node. This is achieved
by simultaneously issuing multiple Attach Requests and default bearer setups towards the DUT
from one or several simulated LTE eNodeB as well as Attaches and PDP Activations from one or
several simulated 3G RNCs. The user should use this validation method to guarantee
convergence from the SGSN/MME network element (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment while
managing existing 3G upgrades cost effectively and efficiently. Deploying an independent
Evolved Packet Core (EPC) can result costly due to the increased investment in new network
equipment and the increase in operational costs. One approach to addressing this issue is
deploying gateways that integrate the legacy networks and EPC gateways onto a single device.
One example of such convergence is the MME/SGSN converged router, which from a single
device can act as an SGSN handling all the 3G sessions, as well as an MME handling all the LTE
sessions. This type of mobile network elements can simultaneously support high processing
capacities for 3G/LTE mobility events and handle millions of subscribers.
The purpose of this test is to validate the correct handling of 3G and LTE sessions within
equipment dingle device with no mobility.
Target Users
NEM load/performance testers
Service provider load/performance and validation testers
UEs
eNodeB
SGSN/MME
SGW
NodeB
S1-MME
Iu-PS
RNC
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Target Device Under Test (DUT)
A Converged SGSN/MME Node
Reference
Standards 3gpp 36.413, 24.301, 25.413, 25.412, 29.202
Relevance
The SGSN/MME converged nodes are likely to become the LTE network element of choice
among operators due to their reduced cost compared to the investment and operational costs of
stand-alone SGSN and MME nodes. Being able to determine their performance in terms of
number of UEs and mobility events that can handle per-radio access technology is key when
assuring quality of connection in the mobile core.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
eNodeB and S1 interface simulation with session loading and traffic modeling capabilities, in
order to simulate the Attach Requests and bearer setups coming from the LTE UEs.
RNC and Iu-PS interface simulation with session loading and traffic modeling capabilities, in
order to simulate the Attaches and PDP Context activation coming from the 3G UEs.
Topology Diagram
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Test Procedure
1. Set up the S1-MME interface for a Session Loading test as follows:
a. Set-up at least one simulated eNodeB S1-MME endpoint and assign it to Tester Port A
for Control Plane. This endpoint simulates the UEs/eNodeB and loads the SGSN/MME
with Attach Requests and bearer setups for a NAS/S1-AP interface:
i. Set up a range of UEs, up to 600,000 for example, and define: type of Attach, IMSI,
Location Information, APN, Keys, EMM Security Header.
ii. The simulated UEs behind the eNodeB perform session loading testing. They may
request either IPv4 or IPv6 PDN addresses.
iii. To simplify, the test case will not use traffic.
2. Set up the Iu-PS interface for a Session Loading test as follows:
a. Set-up at least one simulated RNC Iu-PS endpoint and assign it to Tester Port B. This
endpoint simulates the UE/NodeB/RNC and loads the SGSN/MME with Attach + Activate
PDP Context Requests for an Iu-PS interface:
i. Set up a range of UEs, up to 600,000 for example, and provide type of Attach,
IMSI,IMEI, Ciphering Algorithm Information, Authentication Parameters, Radio
Capabilities, Location and Routing Information, APN.
ii. The simulated UEs behind the RNC perform session loading testing. They may
request either IPv4 or IPv6 PDP addresses but only establish one primary context.
iii. Define the M3UA routing.
3. For both interfaces, define the initial Session Loading parameters describing the traffic
model followed by the subscribers:
a. Activation Rate (sessions/second).
b. Session duration (seconds).
c. IDLE time (seconds).
d. Ramp-down rate (session).
4. Activate Wireshark traffic capture on RNC and eNodeB ports to be able to verify validate the
message exchange with the SGSN/MME node.
5. To execute:
a. Run the LTE elements.
b. Run the 3G elements.
6. Change parameters in (3) as needed,
7. Add more test ports to scale the test case.
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Control Variables & Relevance
Test Configurations for eNodeB
Variable Relevance Default Value
Subscribers Range for LTE Number of LTE subscribers. Set it to 600,000 1
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Number Nodes Number of Simulated eNodeBs 1
Data Traffic Type Activated or Deactivated Deactivated
Session Hold Time Duration of a UE session in seconds
Session Pending Time Duration of the UE inactivity in seconds
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Constant Session flag Maintain the generation rate throughout the test uncheck
Test Configurations for UE/NodeB/RNC
Variable Relevance Default Value
Subscribers Range for 3G Number of 3G subscribers 1
PDP Type Address Requested PDP Address type assigned to the UE
IPv4
Number of Primary PDP contexts Number of Primary PDP Contexts per UE 1
Number of Secondary PDP contexts Number of Secondary PDP Contexts per UE
0
Data Traffic Type Activated or Deactivated Deactivated
PDP Activation Delay Delay between Attach accepted and PDP Activation Request
0 milliseconds
Number Nodes Number of Simulated SGSNs 1
Session Hold Time Duration of a UE session in seconds
Session Pending Time Duration of the UE inactivity in seconds
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Constant Session flag Maintain the generation rate throughout the test
uncheck
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Key Measured Metrics
S1-MME Metrics
Metric Relevance Metric Unit
Attempted Attach Indicates total attaches attempts Attaches
Attempted Detach Indicates total detaches attempts Attaches
Actual Attach Indicates the number of active UEs UEs
Actual Attach Rate Actual UE Activation rate Attaches/second
Attempted Attach Rate
Attempted Activation Attaches/second
Attach Failures Indicates the total number of Attaches attempts that failed
Attaches
Attempted InCtx-Setup Request
Indicates default bearer attempted
Actual InCtx-Setup Indicates default bearer active
Attempted InCtx-Setup Request Rate
Indicates default bearer creation rate attempted
Ctx-setup/second
Actual InCtx-Setup Request Rate
Indicates default bearer creation rate actual
Ctx-setup/second
InCtx-setup Failures Indicates the total number of InCtx-setup attempts that failed
Attaches
Iu-PS Metrics
Metric Relevance Metric Unit
Attempted PDP Context Activate
Indicates the context activation attempts Contexts
Attempted PDP Context Deactivate
Indicates the context deactivation attempts Contexts
Actual PDP Context Activate Indicates the number of active UEs UEs
Actual Activation Rate Actual UE Activation rate Contexts/second
Attempted Activation Rate Generation rate at the SGSN Contexts/second
Activation Errors Indicates the total number of Context Creation attempts that failed
Contexts
Attempted Attach Indicates total attaches attempts Attaches
Attempted Detach Indicates total detaches attempts Attaches
Actual Attach Indicates the number of active UEs UEs
Actual Attach Rate Actual UE Activation rate Attaches/second
Attempted Attach Rate Attempted Activation Attaches/second
Attach Failures Indicates the total number of Attaches attempts that failed
Attaches
Failures (S1-MME)
Metric Relevance Metric Unit
ESM Failure Indicates number of UEs that could set up ESM due to a DUT failure
Insufficient Resources
Indicates a UE attach or default bearer operation failure due to a limitation in the DUTs or link resource
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Failures (Iu-PS)
Metric Relevance Metric Unit
Insufficient Resources
Indicates a UE attach or default bearer operation failure due to a limitation in the DUTs or link resource
Desired Result
The DUT should be capable of providing the correct message exchange to establish/modify/end
sessions and contexts for both S1-MME and Iu-PS interfaces, respectively. The session and
contexts drops/reject should be below 2%, respectively.
Analysis
Using Wireshark, analyze the correctness of the message exchange on both signaling interfaces.
Once the behavior has been validated, use the counters to validate the performance in terms of
Actual Attach and Context Rates and percentage of failure.
Use the Failure Metrics to understand the nature of the Attaches and Contexts that failed.
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4G-EPC_008 Policy and Charging Rules Function (PCRF) 3GPP
session loading test
Abstract
This test validates the behavior of a PCRF (DUT) that is both connected to the PGW and AF,
analyze the derived PCC rules and categorize its performance in terms of sessions per second. To
do so, the DUT is loaded with multiple requests per second on the Gx and Rx interfaces. Without
this test, the user is not able to validate the correct behavior of the DUT both in terms of
compliance and performance, which may lead to a wrong management of resources in the EPC.
Description
The PCRF (Policy and Charging Rules Function) is the policy entity that forms the linkage between
the service and transport layers. The PCRF collates subscriber and application data, authorizes
QoS resources, and instructs the transport plane on how to proceed with the underlying data
traffic.
The PCRF is connected on its northbound Rx interface to the Application Function (AF), an
element residing on the service plane, which represents applications that require dynamic policy
and QoS control over the traffic plane behavior. On the traffic plane, connected to the PCRF via
the southbound Gx interface, is the Policy and Charging Enforcement Function (PCEF). The PCEF's
role encompasses applicable traffic detection and resultant policy enforcement. This entity is
typically located at a Gateway node, which varies by transport layer (e.g. a GGSN, PDG etc.).
In the case of LTE, the PDN Gateway (PGW), contains embedded the PCEF function. For each UE
willing to establish a data session with a PDN network, the PGW must first consult the PCRF and
obtain the rules of service to be applied for such session.
QoS control is applied per service data flow in the PCEF residing in the PGW. These service data
flows can be thought of as a set of packet flows, typically IP flows. The PCEF utilizes PCC (policy
and charging control) rules to classify traffic by service data flow. Rules can be pre-defined or
dynamically provisioned in the PCEF. Dynamic PCC rules are derived within the PCRF from
information supplied by the AF (such as requested bandwidth), PCEF data (such as requested QoS
at traffic level by user) and other Subscriber specific data if available
PCRF
PGW (PCEF)SGW
Application Services(e,g. IMS)Gx
Rx
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The purpose of this test is to validate the behavior of a PCRF that is both connected to the PGW
and AF, analyze the derived PCC rules and to categorize its performance in terms of sessions per
second.
Target Users
PCRF developers validation and performance testers
Service provider integration testers
Target Device Under Test (DUT)
A PCRF
Reference
Standards 3gpp 29.210, 29.211, 29.212, 29.213, 29.214 and IETF RFC 3588, RFC 4005, RFC 4006
Relevance
The PCRF is a key element to control, monitor and charge resources in the LTE Network. Knowing
how many sessions per second can handle without failing to provide the correct rules can be the
difference between a properly managed network and a disrupted one.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [ ] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
PCEF and Gx interface simulation with session loading and traffic modeling capabilities, in
order to simulate CC-requests generated by the activation of a session or a bearer at a specific
rate.
AF and Rx interface simulation with session loading and traffic modeling capabilities, in order
to simulate AA-requests generated by the activation of a session at a specific rate.
Correlated Gx and Rx interfaces.
Definition of PCC Rules for both interfaces, as well media subcomponents and requested QoS
for bearers.
Configurable host/realm.
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Topology Diagram
Test Procedure
1. Set up Gx Interface for a Session Loading test as follows:
a. Set-up at least one simulated PCEF endpoint and assign it to Tester Port A. This endpoint
simulates the PCEF residing in the PGW and loads the PCRF with CC-Requests at a
specific rate:
i. Set up a range of UEs up to 1,000,000 for example. (IMSI, MSISDN, NAI, IP, etc)
ii. The UEs perform session loading testing.
iii. To simplify, the PCEF uses the pull approach of the rules.
iv. Define the number of bearers per session to simulate and bandwidth requested for
each.
2. Set up Rx Interface for a Session Loading test as follows:
a. Set-up at least one simulated PCEF endpoint and assign it to Tester Port B. This endpoint
loads the PCRF with AA-Requests at a specific rate:
i. Set up a range of UEs up to 1,000,000 for example. (IMSI, MSISDN, NAI, IP, etc.)
ii. The users perform session loading testing.
iii. Define the Media Component Description, the number of media-subcomponents
per session to simulate and requested resources.
3. Define the session control for correlated interfaces. Three options to consider:
a. PCEF starts the sessions.
b. AF starts the sessions.
c. Combined.
4. For both interfaces, define the initial Session Loading parameters describing the traffic
model followed by the subscribers:
a. Activation Rate (sessions/second).
b. Session duration (seconds).
c. IDLE time (seconds).
d. Ramp-down rate (session).
5. To execute:
a. Run the PCEF.
b. Run the AF.
6. Change parameters in (4) as needed.
7. Add more test ports to scale the test case.
8. Automate and change parameters as needed.
PCEFAF
PCRF(DUT)
(Gx) (Rx)Test Port ADiameter
Test Port BDiameter
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Control Variables & Relevance
Variable Relevance Default Value
Subscriber Range PCEF Number of subscribers trying to access the PDN 1
Session Connect Rate PCEF Attempted Session Connect from the PGW 1.0
Session disconnect Rate PCEF Attempted Session Connect from the PGW 1.0
Session duration PCEF Duration of the session before attempting disconnect
100 seconds
Number PCEF How many PCEF simulated connecting to the PCRF
Number of Bearers per session How many bearers per session. The QoS requested impacts the PCC rule creation/modification
1
Subscriber Range AF Number of subscribers accessing IMS services 1
Session Connect Rate AF Attempted Session Connect from the AF 1.0
Session disconnect Rate AF Attempted Session Connect from the AF 1.0
Session duration AF Duration of the session before attempting disconnect
100 seconds
Number AF How many AF simulated connecting to the PCRF 1
Key Measured Metrics
Metric Relevance Metric Unit
Attempted Session Connect Rate
How many sessions per second attempted from both interfaces
Sessions/second
Actual Session Connect Rate How many sessions per second reached from both interfaces
Sessions/second
Attempted Session disconnect Rate
How many disconnect sessions per second attempted from both interfaces
Sessions/second
Actual Session disconnect Rate
How many disconnect sessions per second reached from both interfaces
Sessions/second
CCR initial sent CCR Session Initiation sent to the PCRF
CCR terminate sent CCR Session Termination sent to the PCRF
CCR update sent CCR Session Update sent to the PCRF
AAR sent AAR Session initiation sent to the PCRF
STR sent AAR Session Termination sent to the PCRF
Gx interface Actual Rate How many sessions per second in the Gx interface
Sessions/second
Rx interface Actual Rate How many sessions per second in the Rx interface
Sessions/second
Gx failures How many sessions failed in the Gx interface Sessions
Rx failures How many sessions failed in the Rx inteface Sessions
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Desired Result
The expected result is the following:
1. Standard compliance on both interfaces: The user should see the PCRF properly handling the
incoming requests from Gx and Rx.
2. Session endurance: The PCRF should be able to open, maintain and monitor the sessions
throughout the duration of the UE/Network Service lifetime, with no drops.
3. Session performance: The PCRF should guarantee the nominal performance rate, defined as
sessions (or transactions per second).
4. Session management: The PCRF should modify the PCC rules according to the resources
available in the system.
Analysis
Using the key metrics, verify the values of actual rate versus attempted rate and see if they both
converge. Also monitor the failures and determine the performance rate as the actual rate that
leads to a stable success percentage (> 98 %). Use the value obtained to compare to the nominal
performance.
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4G-EPC_009 Policy and Charging Rules Function (PCRF) 3GPP2
session loading test
Abstract
This test validates the behavior of a PCRF (DUT) that is both connected to the AGW and AF of a
3GPP2 based network categorizes its performance in terms of sessions per second. To do so, the
test ports send multiple requests per second to the Ty interface and Tx interfaces of the DUT to
derive the rules (OR QoS). Without this test, the user cannot validate the correct behavior of the
DUT both in terms of compliance and performance, which may lead to a wrong management of
resources in the EPC.
Description
3GPP2 is currently defining the all-IP core network Multimedia Domain (MMD), an architecture
closely based on the IMS network being standardized by 3GPP. Within the MMD model, control
of QoS is part of the Service Based Bearer Control mechanism. The policy decision point here is,
as in 3GPP, termed the Policy and Charging Rules Function (PCRF). This PCRF has a northbound
interface (Tx) to an Application Function (AF) that is responsible for application level service
decisions, whereas the southbound interface (Ty) connects the PCRF to the Access Gateway
(AGW) that is responsible for bearer resources policy enforcement.
The Service Based Control mechanism authorizes the use of bearer resources in the access
network based on negotiation between what the user requests and what the network can
support. The AGW applies QoS control per service data flow residing in the AGW. These service
data flows can be thought of as a set of packet flows, typically IP flows. The AGW utilizes PCC
(policy and charging control) rules to classify traffic by service data flow. Rules can be pre-defined
or dynamically provisioned in the AGW. The PCRF derives dynamic PCC rules from information
supplied by the AF (such as requested bandwidth), AGW data (such as requested QoS at traffic
level by user) and other Subscriber specific data if available.
This test validates the behavior of a PCRF that is connected to the AGW and AF, analyzes the
derived PCC rules, and categorizes its performance in terms of sessions per second.
PCRF
AGW (PCEF)
Application Services(e,g. IMS)Ty
Tx
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Target Users
PCRF developer validation and performance testers
Service provider integration testers.
Target Device Under Test (DUT)
A PCRF
Reference
Standards are IETF RFC 3588, RFC 4005, RFC 4006 and 3GPP2 X.S0013-012, X.S0013-013,
X.S0013-013
Relevance
The PCRF is a key element to control, monitor and charge resources in the LTE Network.
Knowing how many sessions per second can handle without failing to provide the correct rules
can be the difference between a properly managed network and a disrupted one.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
AGW and Ty interface simulation with session loading and traffic modeling capabilities to
simulate CC-requests generated by the activation of a session or a bearer at a specific rate.
AF and Tx interface simulation with session loading and traffic modeling capabilities to
simulate AA-requests generated by the activation of a session at a specific rate.
Correlated Ty and Tx interfaces.
Definition of PCC Rules for both interfaces, as WELL MEDIA SUBCOMPONENTS and requested
QoS for bearers.
Configurable host/realm.
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Topology Diagram
Test Procedure
1. Set up Ty Interface for a Session Loading test as follows:
a. Set-up at least one simulated AGW endpoint and assign it to Tester Port A. This
endpoint loads the PCRF with CC-Requests at a specific rate:
i. Set up a range of UEs, up to 1,000,000 for example. (IMSI, MSISDN, NAI, IP, etc)
ii. The UEs perform session loading testing.
iii. Define the number of flows per session to simulate and bandwidth requested for
each.
2. Set up a Tx Interface for a Session Loading test as follows:
a. Set-up at least one simulated AF endpoint and assign it to Tester Port B. This endpoint
loads the PCRF with AA-Requests at a specific rate:
i. Set up a range of UEs, up to 1,000,000 for example. (IMSI, MSISDN, NAI, IP, etc.)
ii. The users perform session loading testing.
iii. Define the Media Component Description, the number of media-subcomponents
per session to simulate and requested resources.
3. Define the session control for correlated interfaces. Three options to consider:
a. AGW starts the sessions.
b. AF starts the sessions.
c. Combined.
4. For both interfaces, define the initial Session Loading parameters describing the traffic
model followed by the subscribers:
a. Activation Rate (sessions/second).
b. Session duration (seconds).
c. IDLE time (seconds).
d. Ramp-down rate (session).
5. To execute:
a. Run the AGW.
b. Run the AF.
6. Change parameters in (4) as needed.
7. Add more test ports to scale the test case.
8. Automate and change parameters as needed.
AGWAF
PCRF(DUT)
(Ty) (Tx)Test Port ADiameter
Test Port BDiameter
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Control Variables & Relevance
Variable Relevance Default Value
Subscriber Range AGW Number of subscribers trying to access the PDN
1
Session Connect Rate AGW Attempted Session Connect from the AGW 1.0
Session disconnect Rate AGW Attempted Session Connect from the AGW 1.0
Session duration AGW Duration of the session before attempting disconnect
100 seconds
Number AGW How many AGW simulated connecting to the PCRF
Number of Bearers per session How many bearers per session. The QoS requested impacts the PCC rule creation/modification
1
Subscriber Range AF Number of subscribers accessing IMS services
1
Session Connect Rate AF Attempted Session Connect from the AF 1.0
Session disconnect Rate AF Attempted Session Connect from the AF 1.0
Session duration AF Duration of the session before attempting disconnect
100 seconds
Number AF How many AF simulated connecting to the PCRF
1
Key Measured Metrics
Metric Relevance Metric Unit
Attempted Session Connect Rate
How many sessions per second attempted from both interfaces
Sessions/second
Actual Session Connect Rate
How many sessions per second reached from both interfaces
Sessions/second
Attempted Session disconnect Rate
How many disconnect sessions per second attempted from both interfaces
Sessions/second
Actual Session disconnect Rate
How many disconnect sessions per second reached from both interfaces
Sessions/second
CCR initial sent CCR Session Initiation sent to the PCRF
CCR terminate sent CCR Session Termination sent to the PCRF
CCR update sent CCR Session Update sent to the PCRF
AAR sent AAR Session initiation sent to the PCRF
STR sent AAR Session Termination sent to the PCRF
Gx interface Actual Rate How many sessions per second in the Gx interface
Sessions/second
Rx interface Actual Rate How many sessions per second in the Rx interface
Sessions/second
Gx failures How many sessions failed in the Gx interface Sessions
Rx failures How many sessions failed in the Rx inteface Sessions
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Desired Result
The expected result is the following:
1. Standard compliance on both interfaces: The user should see the PCRF properly handling the
incoming requests from Gx and Rx.
2. Session endurance: The PCRF should open, maintain and monitor the sessions throughout
the duration of the UE/Network Service lifetime, with no drops.
3. Session performance: The PCRF should guarantee the nominal performance rate, defined as
sessions (or transactions per second).
4. Session management: The PCRF should modify the PCC rules according to the resources
available in the system.
Analysis
Using the key metrics, verify the values of actual rate versus attempted rate and see if they both
converge. Also monitor the failures and determine the performance rate as the actual rate that
leads to a stable success percentage (> 98 %). Use the value obtained to compare it to the
nominal performance.
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4G-EPC_010 SGW/PGW converged gateway capacity test
Abstract
This test case determines the capacity of a converged SGW and PGW gateway in terms of
numbers of users handled simultaneously for a long period of time. This is achieved by issuing
and maintaining active multiple Create Session Requests towards the DUT from one or several
simulated LTE MMEs, activating user plane data from one or several eNodeBs and terminating
such traffic in one or several Network Hosts. The user should use this validation method to
guarantee convergence from the Gateway (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment cost
effectively and efficiently. Deploying an independent Evolved Packet Core (EPC) can be costly due
to the increased investment in new network equipment and the increase in operational costs.
One approach to addressing this issue is deploying gateways that integrate EPC gateways onto a
single device. One example of such convergence is the SGW/PGW Converged Gateway, which
from a dingle device can act as a SGW as well as a PGW, handling all the LTE sessions.
This type of mobile gateway can simultaneously support the Layer 2/Layer 3 high-processing
capacities for 3G/LTE data throughput, and handle millions of subscribers with a high rate of
mobility while delivering quality-of-experience sensitive applications and content to a variety of
mobile devices.
This tests validates the correct handling LTE sessions within a single device with no mobility.
Target Users
NEM feature validation and load/performance testers
Service provider load/performance and integration testers
Target Device Under Test (DUT)
A Converged EPC Serving Gateway (SGW)/PDN Gateway (PGW)
UEs
eNodeB SGW/PGW
MME
S11
S1-eNB
SGi
Network Hosts
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Reference
Standards are 3gpp 23.401, 29.274, 29.281
Relevance
SGW/PGW gateways are likely to become the LTE network element of choice among operators
due to their reduced cost compared to the investment and operational costs of stand-alone SGW
and PGW nodes. Being able to determine the converged gateway capacity in terms of number of
UEs and data throughput that can handle is key when assuring quality of connection in the
mobile core.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [ ] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
Capacity Test configuration
Multiple MME and UE/eNodeB simulation
S11, S1-U and SGi interfaces simultaneously
Low level security
Data plane throughput scalable from 10 Gbps to Tbps
IPv4 and IPv6 UEs and Nodes and IPv4 or IPv6 transport
Topology Diagram
MMEs
eNodeBs
Network Hosts
SGW/PGW(DUT)
Test Port A (S11)
Test Port B (S1-U)
Test Port C
(SGi)
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Test Procedure
1. Set up the S11 interface for a Capacity Test type of test as follows:
a. Set-up at least one simulated MME S11 endpoint and assign it to Tester Port A for
Control Plane. This endpoint simulates the MME and loads the SGW/PGW Converged
Gateway with Session Requests:
i. Set up a range of UEs, up to 1,000,000 for example. (IMSI, ULI, APN to access)
ii. The simulated UEs behind the eNodeB may request either IPv4 or IPv6 PDN
addresses and will only establish default bearers.
iii. To simplify, the test case uses UDP traffic on the default bearers.
2. Set up the S1-U interface as follows:
a. Set-up at least one simulated eNodeB endpoint and assign it to Tester Port B. This
endpoint is controlled by the simulated MMEs and sets up the user plane bearers with
the DUT on the S1-U interface.
3. Set up the L3-L7 traffic to be sent over the S1-U default bearers and SGi interface:
a. Define one or more Network Host Servers and assigned to Tester Port C.
b. To simplify, define the type of traffic as stateless UDP.
c. To stress the device under test, set up the packet size to 64 bytes.
d. Setup the transaction rate to 120 tr/second to reach line rate.
4. Define the initial Session Loading parameters describing the traffic model followed by the
subscribers:
a. Activation Rate (sessions/second).
b. Ramp-down rate (session).
5. Change parameters as needed:
a. Number of subscribers.
b. Size of packets.
c. Packets per second.
d. Activation Rate.
Control Variables & Relevance
Test Configurations
Variable Relevance Default Value
Subscribers Range Number of Subscribers simulated 1
Transport Address Requested Network IP addressing (IPv4 or IPv6) IPv4
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Data Traffic Type Selection between Stateless, Stateful or none for control plane only testing
None
Activation Rate S11 Number of Sessions/sec (generation) 1.0
Deactivation Rate S11 Number of Sessions/sec (teardown) 1.0
UDP Packet Size Size (in bytes) of the datagrams exchange between UEs and Networks Hosts
256
Transaction Rate Packets per second 1
Number of MME Number of MMEs simulated per S11 tester port 1
Number of NH Number of Network Hosts servers simulated per S11 tester port
1
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Key Measured Metrics
Control and User Plane metrics
Metric Relevance Metric Unit
Sessions Attempted Indicates the sessions attempts in the EPC Sessions
Actual Sessions Indicates the number of active sessions in the EPC Sessions
S1 User Plane Packets per Second
Number of packets per second sent in the user plane S1-U interface
Packets/second
SGi Packets per Second
Number of packets per second sent in the SGi interface
Packets/second
S1 User Plane bps Number of bps in the S1-U interface Bits per second
SGi bps Number of bps in the SGi interface Bits per second
Sessions Failed Number of session attempts that failed Sessions
Avg. Jitter Average jitter measured in the S1-U interface
Latency Average latency measured in the S1-U interface miliseconds
Loss Number of packets lost packets
Failures
Matric Relevance Metric Unit
All dynamic addresses occupied Indicates number of UEs that could not register due to unavailable PDN address
Sessions
No Memory Available Indicates a UE or Bearer operation failure due to a limitation in the DUT’s memory
Sessions
No Resources Available Indicates a UE or Bearer operation failure due to a limitation in the DUTs or link resource
Sessions
Timeout The DUT failed to respond to the request and all the retries
Sessions
Desired Result
The DUT should:
1. Create GTP sessions as indicated by the MME and Set up Default Bearers with the eNodeBs
for each session.
2. Process the user plane data received with low jitter, latency and loss.
3. Maintain a similar rate in the S1-U and SGi interface.
4. Maintain session drop / failure < 0.2% of the nominal value.
Analysis
1. Verify that as soon as the sessions are started, information flows (packets per second and
bits per seconds), in the user plane.
2. Verify the average session generation rate (sessions/second) from the MME toward the DUT
is met and continuous in the S11 interface.
3. Compare the SGi and S1-U user plane metrics to detect deviation in traffic throughput.
4. Verify that the percentage of failure in any interface stays below 0.2 %.
5. Use the failure metrics to detect possible bottlenecks in the DUT
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4G-EPC_011 GGSN/PGW converged gateway multi-RAT capacity
test
Abstract
This test case determines the capacity of a converged GGSN and PGW gateway in terms of
numbers of users and traffic handled simultaneously for a long period of time. This is achieved by
simultaneously issuing a maximum number of Create Session Requests toward the DUT from one
or several simulated LTE SGW as well as from one or several simulated 3G SGSNs. Such sessions
should remain open for the duration of the test. The user should use this validation method to
guarantee convergence from the Gateway (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment while
managing existing 3G upgrades cost effectively and efficiently. Deploying an independent
Evolved Packet Core (EPC) can be costly due to the increased investment in new network
equipment and the increase in operational costs. One approach to addressing this issue is
deploying gateways that integrate the legacy networks and EPC gateways onto a single device.
One example of such convergence is the PGW/GGSN Converged Gateway, which from a single
device can act as a GGSN handling all the 3G sessions, as well as a PGW handling all the LTE
sessions.
This type of mobile gateway can simultaneously support the Layer 2/Layer 3 high-processing
capacities for 3G/LTE data throughput, and handle millions of subscribers while delivering quality
of experience aware applications and content to a variety of mobile devices.
UEs
eNodeB
RNC
SGSN
SGW
GGSN/PGW
NodeB Gn
S5/S8
MME
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This test validates the correct handling of 3G and LTE simultaneously active sessions within a
single device with no mobility:
Maximum session creation
With default bearer activation
Target Users
NEM load/performance testers
Service provider load/performance and validation testers
Target Device Under Test (DUT)
A Converged GGSN/PGW Gateway
Reference
Standards 3GPP 23.401, 29.274, 29.060 and 23.060
Relevance
GGSN/PGW gateways are likely to become the LTE network element of choice among operators
due to their reduced cost compared to the investment and operational costs of stand-alone
GGSN and PGW nodes. Being able to determine the converged gateway capacity in terms of
number of UEs and user plane traffic that can handle per radio access technology is key when
assuring quality of service and network deployment with the lowest capital expenditure.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
SGW and S5/S8 interface simulation with capacity loading and traffic modeling capabilities to
simulate the Create Session Requests coming from the LTE UEs.
SGSN and Gn interface simulation with capacity loading and traffic modeling capabilities to
simulate the Create PDP Context Requests coming from the 3G UEs.
User plane traffic generation over the default bearer.
Gi and SGi interface and Network Host (client/server) emulation.
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Topology Diagram
Test Procedure
1. Set up the S5/S8 interface for a Capacity type of test as follows:
a. Set-up at least one simulated SGW S5/S8 endpoint and assign it to Tester Port A for
Control Plane. This endpoint simulates the SGW and loads the GGSN/PGW with Session
Requests for a GTP S5/S8 interface:
i. Set up a range of UEs up to 2,000,000 for example (IMSI, ULI, etc.)
ii. The simulated UEs behind the SGW perform session loading testing. They may
request either IPv4 or IPv6 PDN addresses and establish only default bearers.
iii. To simplify, the test case uses only UDP stateless traffic on the default bearers.
2. Set up the Gn interface for a Capacity type of test as follows:
a. Set-up at least one simulated SGSN Gn endpoint and assign it to Tester Port B. This
endpoint simulates the SGSN and loads the GGSN/PGW with Create PDP Context
Requests for a GTP Gn interface:
i. Set up a range of UEs up to 600,000 for example and provide the IMSI, MSISDN,
IMEI (SV).
ii. The simulated UEs behind the SGSN perform session loading testing. They may
request either IPv4 or IPv6 PDP addresses and establish only one primary context.
iii. Set up the GTP layer: Provide APN, authentication usage, authentication protocol,
password, direct tunnel indicator, teardown indication.
3. Set up the L3-L7 traffic to be sent over the S5/S8 default bearers, Gn Primary PDP Contexts
and Gi/SGi interfaces:
a. Define one or more Network Host Servers and assigned to Tester Port C.
b. To simplify, define the type of traffic as stateless UDP.
c. To stress the device under test, set up the packet size to 64 bytes.
d. Setup the transaction rate to 120 tr/second to reach line rate.
4. For both interfaces, define the initial capacity parameters and the activation model followed
by the subscribers:
a. Number of LTE subscribers and Number of 3G subscribers.
b. Activation Rate (sessions/second).
c. Ramp-down rate (session).
5. Activate Wireshark traffic capture on SGSN and SGW Control ports to verify and validate the
message exchange with the GGSN/PGW Gateway.
SGWsNetwork
Hosts
GGSN/PGW(DUT)
Test Port A (S5/S8)
Test Port B (Gn)
Test Port C
(Gi/SGi)
SGSNs
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6. To execute:
a. Run the LTE elements.
b. Run the 3G elements.
7. Change parameters in (3) as needed.
8. Add more test ports to scale the test case.
Control Variables & Relevance
Test Configurations for LTE
Variable Relevance Default Value
Subscribers Range for LTE Number of LTE subscribers 1
Transport Address Requested Network IP addressing (IPv4 or IPv6) IPv4
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Number Nodes Number of Simulated SGWs 1
Data Traffic Type Activated or Deactivated Activated
UDP Packet Size Size (in bytes) of the datagrams exchange between UEs and Networks Hosts
256
Transaction Rate Packets per second 1
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Test Configurations for 3G
Variable Relevance Default Value
Subscribers Range for 3G Number of LTE subscribers 1
PDP Type Address Requested PDP Address type assigned to the UE IPv4
Number of Primary PDP contexts
Number of Primary PDP Contexts per UE 1
Number of Secondary PDP contexts
Number of Secondary PDP Contexts per UE 0
Data Traffic Type Activated or Deactivated Activated
UDP Packet Size Size (in bytes) of the datagrams exchange between UEs and Networks Hosts
256
Transaction Rate Packets per second 1
Number Nodes Number of Simulated SGSNs 1
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
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Key Measured Metrics
S5/S8 Metrics
Metric Relevance Metric Unit
Attempted Session Connects Indicates the session activation attempts Sessions
Attempted Session Disconnects
Indicates the session deactivation attempts Sessions
Actual Session Connects Indicates the number of active UEs. This is the main metric S5/S8
UEs
S5/S8 User Plane Packets per Second
Number of packets per second sent in the user plane S5/S8 interface
Packets/second
SGi Packets per Second Number of packets per second sent in the SGi interface
Packets/second
S1 User Plane bps Number of bps in the S1-U interface Bits per second
SGi bps Number of bps in the SGi interface Bits per second
Sessions Failed Number of session attempts that failed Sessions
Avg. Jitter Average jitter measured in the S1-U interface
Latency Average latency measured in the S1-U interface
miliseconds
Loss Number of packets lost packets
Gn Metrics
Metric Relevance Metric Unit
Attempted Context Connects
Indicates the context activation attempts Contexts
Attempted Context Disconnects
Indicates the context deactivation attempts Contexts
Actual Context Connects Indicates the number of active UEs UEs
Gn User Plane Packets per Second
Number of packets per second sent in the user plane Gn interface
Packets/second
Gi Packets per Second Number of packets per second sent in the Gi interface
Packets/second
Gn User Plane bps Number of bps in the S1-U interface Bits per second
Gi bps Number of bps in the SGi interface Bits per second
Contexts Failed Number of session attempts that failed Sessions
Avg. Jitter Average jitter measured in the S1-U interface
Latency Average latency measured in the S1-U interface miliseconds
Loss Number of packets lost packets
Failures (Sessions)
Metric Relevance Metric Unit
All dynamic addresses occupied Indicates number of UEs that could not register due to unavailable PDN address
No Memory Available Indicates a UE or Bearer operation failure due to a limitation in the DUT’s memory
No Resources Available Indicates a UE or Bearer operation failure due to a limitation in the DUTs or link resource
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Failures (Contexts)
Metric Relevance Metric Unit
All dynamic addresses occupied Indicates number of UEs that could not register due to unavailable PDN address
No Memory Available Indicates a UE or Bearer operation failure due to a limitation in the DUT’s memory
No Resources Available Indicates a UE or Bearer operation failure due to a limitation in the DUTs or link resource
Desired Result
1. The DUT provides the correct message exchange to establish/modify/end sessions and
contexts for both S5 and Gn interfaces.
2. The number of UEs (3G and LTE) active per blade is close to the nominal and throughput
reaches line rate.
3. The DUT processes the user plane data received with low jitter, latency and loss.
4. The DUT maintains a similar throughput in all interfaces.
Analysis
Using Wireshark:
Analyze the correctness of the message exchange on both signaling interfaces. Once the behavior
has been validated, increment the control variables to scale the test.
Using the test results:
1. Verify that as soon as the sessions start, information flows (packets per second and bits per
seconds) in the user plane.
2. Verify the average session generation rate (sessions/second) from the SGSNs and the SGWs
towards the DUT is met and is continuous.
3. Compare the SGi and S5/S8 user plane metrics to detect deviation in traffic throughput.
4. Compare the Gi and Gn user plane metrics to detect deviation in traffic throughput.
5. As the number of UEs ramps up, the percentage of failure in any interface should stay below
0.2 %. Once it surpasses this margin, the capacity is determined.
6. Use the Failure Metrics to understand the nature of the session and contexts that failed to
detect possible bottlenecks in the DUT.
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4G-EPC_012 SGSN/MME converged node multi-RAT capacity test
Abstract
This test case determines the capacity of a converged SGSN and MME node. This is achieved by
simultaneously issuing a maximum number of Attach Requests and default bearer setups toward
the DUT from one or several simulated LTE eNodeB, as well as a maximum number of Attaches
and PDP Activations from one or several simulated 3G RNCs. The user should use this validation
method to guarantee convergence from the SGSN/MME network element (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment while
managing existing 3G upgrades cost effectively and efficiently. Deploying an independent
Evolved Packet Core (EPC) can be costly due to the increased investment in new network
equipment and the increase in operational costs. One approach to addressing this issue is
deploying gateways that integrate the legacy networks and EPC gateways onto a single device.
One example of such convergence is the SGSN/MME Converged router, which from a single
device can act as an SGSN handling all the 3G Contexts, as well as an MME handling all the LTE
Sessions. This type of mobile network element can simultaneously support high-processing
capacities for 3G/LTE mobility events and handle millions of subscribers.
This test validates the correct handling of the maximum number of 3G and LTE sessions within a
single device with no mobility.
Target Users
NEM load/performance testers
Service provider load/performance and validation testers
UEs
eNodeB
SGSN/MME
SGW
NodeB
S1-MME
Iu-PS
RNC
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Target Device Under Test (DUT)
A Converged SGSN/MME Node
Reference
Standards 3gpp 36.413, 24.301, 25.413, 25.412, 29.202
Relevance
SGSN/MME converged nodes are likely to become the LTE network element of choice among
operators due to their reduced cost compared to the investment and operational costs of stand-
alone SGSN and MME nodes. Being able to determine their capacity in terms of number of UEs
and sessions that can handle per radio access technology is key when assuring quality of
connection and network deployment with the lowest capital expenditure.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [X] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting:
eNodeB and S1 interface simulation with capacity testing capabilities to simulate the Attach
Requests and bearer setups coming from the LTE UEs.
RNC and Iu-PS interface simulation with capacity testing capabilities to simulate the Attaches
and PDP Context activation coming from the 3G UEs.
(Optional) SGW and GGSN simulation to terminate the S11 and Gn interfaces respectively.
Topology Diagram
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Test Procedure
1. Set up the S1-MME interface for a Capacity Testing type of test as follows:
a. Set-up at least one simulated eNodeB S1-MME endpoint and assign it to Tester Port A
for Control Plane. This endpoint simulates the UEs/eNodeB and loads the SGSN/MME
with Attach Requests and bearer setups for a NAS/S1-AP interface:
i. Set up a range of UEs up to 2,000,000 for example and define: type of Attach, IMSI,
Location Information, APN, Keys, EMM Security Header.
ii. The simulated UEs behind the eNodeB perform session loading testing. They may
request either IPv4 or IPv6 PDN addresses.
iii. To simplify, the test case does not use traffic.
2. Set up the Iu-PS interface for a Capacity Testing type of test as follows:
a. Set-up at least one simulated RNC Iu-PS endpoint and assign it to Tester Port B. This
endpoint simulates the UE/NodeB/RNC and loads the SGSN/MME with Attach + Activate
PDP Context Requests for a Iu-PS interface:
i. Set up a range of UEs, up to 1,000,000 for example, and provide type of Attach,
IMSI,IMEI, Ciphering Algorithm Information, Authentication Parameters, Radio
Capabilities, Location and Routing Information, APN.
ii. The simulated UEs behind the RNC perform session loading testing. They may
request either IPv4 or IPv6 PDP addresses will establish only one primary context.
iii. Define the M3UA routing.
3. For both interfaces, define the initial Session Loading parameters describing the traffic
model followed by the subscribers:
a. Activation Rate (sessions/second).
b. Ramp-down rate (session).
4. Activate Wireshark traffic capture on RNC and eNodeB ports to be able to verify and validate
the message exchange with the SGSN/MME node.
5. To execute:
a. Run the LTE elements.
b. Run the 3G elements.
6. Increase the number of subscribers until the percentage of failure is > 2%.
7. Add more test ports to scale the test case.
Control Variables & Relevance
Test Configurations for eNodeB
Variable Relevance Default Value
Subscribers Range for LTE
Number of LTE subscribers. Main variable. Set it to 2,000,000
1
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Number Nodes Number of Simulated eNodeBs 1
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
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Test Configurations for UE/NodeB/RNC
Variable Relevance Default Value
Subscribers Range for 3G
Number of 3G subscribers. Main variable. Set it to 1,000,000
1
PDP Type Address Requested PDP Address type assigned to the UE IPv4
Number of Primary PDP contexts
Number of Primary PDP Contexts per UE 1
Number of Secondary PDP contexts
Number of Secondary PDP Contexts per UE 0
Number Nodes Number of Simulated SGSNs 1
Activation Rate Number of Sessions/sec (generation) 1.0
Deactivation Rate Number of Sessions/sec (teardown) 1.0
Key Measured Metrics
S1-MME Metrics
Metric Relevance Metric Unit
Attempted Attach Indicates total attaches attempts Attaches
Actual Attach Indicates the number of active UEs UEs
Attach Failures Indicates the total number of Attaches attempts that failed
Attaches
Attempted InCtx-Setup Request
Indicates default bearer attempted Contexts
Actual InCtx-Setup Indicates default bearer active Contexts
InCtx-setup Failures Indicates the total number of InCtx-setup attempts that failed
Contexts
Iu-PS Metrics
Metric Relevance Metric Unit
Attempted PDP Context Activate Indicates the context activation attempts Contexts
Attempted PDP Context Deactivate
Indicates the context deactivation attempts
Contexts
Actual PDP Context Activate Indicates the number of active UEs UEs
Actual Activation Rate Actual UE Activation rate Contexts/second
Attempted Activation Rate Generation rate at the SGSN Contexts/second
Activation Errors Indicates the total number of Context Creation attempts that failed
Contexts
Attempted Attach Indicates total attaches attempts Attaches
Attempted Detach Indicates total detaches attempts Attaches
Actual Attach Indicates the number of active UEs UEs
Actual Attach Rate Actual UE Activation rate Attaches/second
Attempted Attach Rate Attempted Activation Attaches/second
Attach Failures Indicates the total number of Attaches attempts that failed
Attaches
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Failures (S1-MME)
Metric Relevance Metric Unit
ESM Failure Indicates number of UEs that could set up ESM due to a DUT failure
Insufficient Resources
Indicates a UE attach or default bearer operation failure due to a limitation in the DUTs or link resource
Failures (Iu-PS)
Metric Relevance Metric Unit
Insufficient Resources
Indicates a UE attach or default bearer operation failure due to a limitation in the DUTs or link resource
Desired Result
The DUT should provide the correct message exchange to establish/modify/end sessions and
contexts for both S1-MME and Iu-PS interfaces. The number of UEs (3G and LTE) active per blade
should be close to the nominal.
Analysis
Using Wireshark:
Analyze the correctness of the message exchange on both signaling interfaces. Once the behavior
has been validated, increment the control variables to scale the test.
Using the test results:
1. Verify the average session generation rate (sessions/second) from the RNCs and the
eNodebs towards the DUT is met and is continuous.
2. As the number of UEs ramps up, the percentage of failure in any interface stays below 0.2 %.
Once it surpasses this margin, the capacity is determined.
3. Use the Failure Metrics to understand the nature of the session and contexts that failed to
detect possible bottlenecks in the DUT.
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4G-EPC_013 SGW/PGW converged gateway session performance
test
Abstract
This test case determines the performance of a converged SGW and PGW gateway in terms of
numbers of user events per second handled simultaneously for a long period of time. This is
achieved by issuing, maintaining and deleting multiple sessions towards the DUT from one or
several simulated LTE MMEs and eNodeBs, while terminating user traffic in one or several
Network Hosts. The user should use this validation method to guarantee convergence and
performance from the Gateway (DUT).
Description
A major challenge for mobile operators is preparing for future 4G/LTE deployment cost
effectively and efficiently. Deploying an independent Evolved Packet Core (EPC) can be costly due
to the increased investment in new network equipment and the increase in operational costs.
One approach to addressing this issue is deploying gateways that integrate EPC gateways onto a
single device. One example of such convergence is the SGW/PGW Converged Gateway, which
from a single device can act as a SGW as well as a PGW, handling all the LTE sessions.
This type of mobile gateways can simultaneously support the Layer 2/Layer 3 high-processing
capacities for LTE data throughput, and handle millions of subscribers with high rate of mobility
while delivering quality of experience aware applications and content to a variety of mobile
devices.
This test validates the correct handling of a high rate of LTE sessions events such as:
Creations per second
Modification per second
Teardown per second
Target Users
NEM feature validation and load/performance testers
Service provider load/performance and integration testers
UEs
eNodeB SGW/PGW
MME
S11
S1-eNB
SGi
Network Hosts
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Target Device Under Test (DUT)
A Converged EPC Serving Gateway (SGW)/PDN Gateway (PGW)
Reference
Standards are 3gpp 23.401, 29.274, 29.281
Relevance
SGW/PGW gateways are likely to become the LTE network element of choice among operators
due to their reduced cost compared to the investment and operational costs of stand-alone SGW
and PGW nodes. Being able to determine the converged gateway performance in terms of
number of UE events per second that can handle is key when assuring quality of connection in
the mobile core.
Version
1.0
Test Category
4G-EPC
PASS
[X] Performance [ ] Availability [ ] Security [ ] Scale
Required Tester Capabilities
The tester should be capable of supporting
Session Loading Test configuration
Multiple MME and UE/eNodeB simulation
S11, S1-U and SGi interfaces simultaneously
Low level security
Data plane throughput
IPv4 and IPv6 UEs and Nodes and IPv4 or IPv6 transport
Topology Diagram
MMEs
eNodeBs
Network Hosts
SGW/PGW(DUT)
Test Port A (S11)
Test Port B (S1-U)
Test Port C
(SGi)
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Test Procedure
1. Set up the S11 interface for a Session Loading Test type of test as follows:
a. Set-up at least one simulated MME S11 endpoint and assign it to Tester Port A for
Control Plane. This endpoint simulates the MME and loads the SGW/PGW Converged
Gateway with Session Requests. Then it will hold the session opened for certain amount
of time before stopping traffic for a UE and issuing the Delete Session Request:
i. Set up a range of UEs, up to 2,000,000 for example. (IMSI, ULI, APN to access)
ii. The simulated UEs behind the eNodeB may request either IPv4 or IPv6 PDN
addresses and will establish only default bearers.
iii. To simplify, the test case uses UDP traffic on the default bearers.
2. Set up the S1-U interface as follows:
a. Set-up at least one simulated eNodeB endpoint and assign it to Tester Port B. This
endpoint is controlled by the simulated MMEs and sets up the user plane bearers with
the DUT on the S1-U interface.
3. Set up the L3-L7 traffic that will be sent over the S1-U default bearers and SGi interface:
a. Define one or more Network Host Servers and assigned to Tester Port C.
b. To simplify, define the type of traffic as stateless UDP.
c. To stress the device under test, set up the packet size to 64 bytes.
4. Define the initial Session Loading parameters describing the traffic model followed by the
subscribers:
a. Session Hold (seconds).
b. Sessions Idle (seconds).
c. Activation Rate (sessions/second).
5. Change parameters as needed:
a. Number of subscribers (up to 8 Million, for instance).
b. Session Hold.
c. Activation Rate (in the order of 30,000 Sessions/sec).
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Control Variables & Relevance
Test Configurations
Variable Relevance Default Value
Subscribers Range Number of Subscribers simulated. It should be high enough to allow a sustained session creation/deletion
1
Transport Address Requested Network IP addressing (IPv4 or IPv6) IPv4
UE Home Address Requested PDN Address type assigned to the UE IPv4
Default Bearers Number of Default Bearers per UE 1
Dedicated Bearers Number of Dedicated Bearers per UE 0
Data Traffic Type Selection between Stateless, Stateful or none for control plane only testing
None
Activation Rate S11 Number of Sessions/sec (generation) 1.0
Deactivation Rate S11 Number of Sessions/sec (teardown) 1.0
UDP Packet Size Size (in bytes) of the datagrams exchange between UEs and Networks Hosts
256
Transaction Rate Packets per second 1
Number of MME Number of MMEs simulated per S11 tester port 1
Number of NH Number of Network Hosts servers simulated per S11 tester port
1
Key Measured Metrics
Control and User Plane metrics
Metric Relevance Metric Unit
Session Rate Attempted Indicates the sessions attempts per second in the EPC
Sessions/second
Actual Session Rate Indicates the number of successful session per second established in the EPC
Sessions/second
Sessions Failed Number of session attempts that failed Sessions
Session Disconnect Rate Attempted
Indicates the sessions Disconnect attempts per second in the EPC
Sessions/second
Actual Session Disconnect Rate
Indicates the number of successful session Disconnect per second established in the EPC
Sessions/second
Total Session Attempts Total number of session establishment attempted
Sessions
Sessions Disconnect Failed Number of session attempts that failed Sessions
Failures
Metric Relevance Metric Unit
Timeout The DUT failed to respond to the request and all the retries Sessions
Undefined Indicates a UE event failure due to an unknown situation in the DUT’s memory
Sessions
Rejected Indicates a UE or Bearer operation rejected due to a limitation in the DUTs or link resource
Sessions
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Desired Result
The DUT should;
1. Create GTP sessions as indicated by the MME and Set up Default Bearers with the eNodeBs
for each session, with no loss in rate.
2. Maintain the session opened and processes the user plane data received with low jitter,
latency and loss.
3. Maintain a similar rate in the S1-U and SGi interfaces.
4. Maintain session drop/failure < 0.2% of the nominal value.
Analysis
Using the test results:
1. Verify the average session generation rate (sessions/second) from the MME toward the DUT
is met and continuous in the S11 interface.
2. The percentage of failure in any interface stays below 0.2 % for any Session Attempts rate
below the nominal value.
3. Use the failure metrics to detect possible bottlenecks in the DUT.
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Appendix A – Telecommunications
Definitions
APPLICATION LOGIC. The computational aspects of an application, including a list of instructions that tells a
software application how to operate.
APPLICATION SERVICE PROVIDER (ASP). An ASP deploys hosts and manages access to a packaged application by
multiple parties from a centrally managed facility. The applications are delivered over networks on a
subscription basis. This delivery model speeds implementation, minimizes the expenses and risks incurred
across the application life cycle, and overcomes the chronic shortage of qualified technical personnel
available in-house.
APPLICATION MAINTENANCE OUTSOURCING PROVIDER. Manages a proprietary or packaged application from
either the customer's or the provider's site.
ASP INFRASTRUCTURE PROVIDER (AIP). A hosting provider that offers a full set of infrastructure services for
hosting online applications.
ATM. Asynchronous Transport Mode. An information transfer standard for routing high-speed, high-
bandwidth traffic such as real-time voice and video, as well as general data bits.
AVAILABILITY. The portion of time that a system can be used for productive work, expressed as a
percentage.
BACKBONE. A centralized high-speed network that interconnects smaller, independent networks.
BANDWIDTH. The number of bits of information that can move through a communications medium in a
given amount of time; the capacity of a telecommunications circuit/network to carry voice, data, and
video information. Typically measured in Kbps and Mbps. Bandwidth from public networks is typically
available to business and residential end-users in increments from 56 Kbps to 45 Mbps.
BIT ERROR RATE. The number of transmitted bits expected to be corrupted per second when two computers
have been communicating for a given length of time.
BURST INFORMATION RATE (BIR). The rate of information in bits per second that the customer may need over
and above the CIR. A burst is typically a short duration transmission that can relieve momentary
congestion in the LAN or provide additional throughput for interactive data applications.
BUSINESS ASP. Provides prepackaged application services in volume to the general business market,
typically targeting small to medium size enterprises.
BUSINESS-CRITICAL APPLICATION. The vital software needed to run a business, whether custom-written or
commercially packaged, such as accounting/finance, ERP, manufacturing, human resources and sales
databases.
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BUSINESS SERVICE PROVIDER. Provides online services aided by brick-and-mortar resources, such as payroll
processing and employee benefits administration, printing, distribution or maintenance services. The
category includes business process outsourcing (BPO) companies.
COMMERCE NETWORK PROVIDER. Commerce networks were traditionally proprietary value-added networks
(VANs) used for electronic data interchange (EDI) between companies. Today the category includes the
new generation of electronic purchasing and trading networks.
COMPETITIVE ACCESS PROVIDER (CAP). A telecommunications company that provides an alternative to a LEC
for local transport and special access telecommunications services.
CAPACITY. The ability for a network to provide sufficient transmitting capabilities among its available
transmission media, and respond to customer demand for communications transport, especially at peak
usage times.
CLIENT/DEVICE. Hardware that retrieves information from a server.
CLUSTERING. A group of independent systems working together as a single system. Clustering technology
allows groups of servers to access a single disk array containing applications and data.
COMPUTING UTILITY PROVIDER (CUP). A provider that delivers computing resources, such as storage, database
or systems management, on a pay-as-you-go basis.
CSU/DSU. Channel Server Unit/Digital Server Unit. A device used to terminate a telephone company
connection and prepare data for a router interface.
DATA MART. A subset of a data warehouse, intended for use by a single department or function.
DATA WAREHOUSE. A database containing copious amounts of information, organized to aid decision-
making in an organization. Data warehouses receive batch updates and are configured for fast online
queries to produce succinct summaries of data.
DEDICATED LINE. A point-to-point, hardwired connection between two service locations.
DEMARCATION LINE. The point at which the local operating company's responsibility for the local loop ends.
Beyond the demarcation point (also known as the network interface), the customer is responsible for
installing and maintaining all equipment and wiring.
DISCARD ELIGIBILITY (DE) BIT. Relevant in situations of high congestion, it indicates that the frame should be
discarded in preference to frames without the DE bit set. The DE bit may be set by the network or by the
user; and once set cannot be reset by the network.
DS-1 OR T-1. A data communication circuit capable of transmitting data at 1.5 Mbps. Currently in
widespread use by medium and large businesses for video, voice, and data applications.
DS-3 OR T-3. A data communications circuit capable of transmitting data at 45 Mbps. The equivalent data
capacity of 28 T-1s. Currently used only by businesses/institutions and carriers for high-end applications.
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ELECTRONIC DATA INTERCHANGE (EDI). The electronic communication of business transactions (orders,
confirmations, invoices etc.) of organizations with differing platforms. Third parties provide EDI services
that enable the connection of organizations with incompatible equipment.
ENTERPRISE ASP. An ASP that delivers a select range of high-end business applications, supported by a
significant degree of custom configuration and service.
ENTERPRISE RELATIONSHIP MANAGEMENT (ERM). Solutions that enable the enterprise to share comprehensive,
up-to-date customer, product, competitor and market information to achieve long-term customer
satisfaction, increased revenues, and higher profitability.
ENTERPRISE RESOURCE PLANNING (ERP). An information system or process integrating all manufacturing and
related applications for an entire enterprise. ERP systems permit organizations to manage resources
across the enterprise and completely integrate manufacturing systems.
ETHERNET. A local area network used to connect computers, printers, workstations, and other devices
within the same building. Ethernet operates over twisted wire and coaxial cable.
EXTENDED SUPERFRAME FORMAT. A T1 format that provides a method for easily retrieving diagnostics
information.
FAT CLIENT. A computer that includes an operating system, RAM, ROM, a powerful processor and a wide
range of installed applications that can execute either on the desktop or on the server to which it is
connected. Fat clients can operate in a server-based computing environment or in a stand-alone fashion.
FAULT TOLERANCE. A design method that incorporates redundant system elements to ensure continued
systems operation in the event of the failure of any individual element.
FDDI. Fiber Distributed Data Interface. A standard for transmitting data on optical-fiber cables at a rate of
about 100 Mbps.
FRAME. The basic logical unit in which bit-oriented data is transmitted. The frame consists of the data bits
surrounded by a flag at each end that indicates the beginning and end of the frame. A primary rate can be
thought of as an endless sequence of frames.
FRAME RELAY. A high-speed packet switching protocol popular in networks, including WANs, LANs, and
LAN-to-LAN connections across long distances.
GBPS. Gigabits per second, a measurement of data transmission speed expressed in billions of bits per
second.
HOSTED OUTSOURCING. Complete outsourcing of a company's information technology applications and
associated hardware systems to an ASP.
HOSTING PROVIDER. Provider who operates data center facilities for general-purpose server hosting and
collocation.
INFRASTRUCTURE ISV. And independent software vendor that develops infrastructure software to support
the hosting and online delivery of applications.
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INTEGRATED SERVICES DIGITAL NETWORK (ISDN). An information transfer standard for transmitting digital voice
and data over telephone lines at speeds up to 128 Kbps.
INTEGRATION. Equipment, systems, or subsystem integration, assembling equipment or networks with a
specific function or task. Integration is combining equipment/systems with a common objective, easy
monitoring and/or executing commands. It takes three disciplines to execute integration: 1) hardware, 2)
software, and 3) connectivity – transmission media (data link layer), interfacing components. All three
aspects of integration have to be understood to make two or more pieces of equipment or subsystems
support the common objective.
INTER-EXCHANGE CARRIER (IXC). A telecommunications company that provides telecommunication services
between local exchanges on an interstate or intrastate basis.
INTERNET SERVICE PROVIDER (ISP). A company that provides access to the Internet for users and businesses.
INDEPENDENT SOFTWARE VENDOR (ISV). A company that is not a part of a computer systems manufacturer
that develops software applications.
INTERNETWORKING. Sharing data and resources from one network to another.
IT SERVICE PROVIDER. Traditional IT services businesses, including IT outsourcers, systems integrators, IT
consultancies and value added resellers.
KILOBITS PER SECOND (KBPS). A data transmission rate of 1,000 bits per second.
LEASED LINE. A telecommunications line dedicated to a particular customer along predetermined routers.
LOCAL ACCESS TRANSPORT AREA (LATA). One of approximately 164 geographical areas within which local
operating companies connect all local calls and route all long-distance calls to the customer's inter-
exchange carrier.
LOCAL EXCHANGE CARRIER (LEC). A telecommunications company that provides telecommunication services
in a defined geographic area.
LOCAL LOOP. The wires that connect an individual subscriber's telephone or data connection to the
telephone company central office or other local terminating point.
LOCAL/REGIONAL ASP. A company that delivers a range of application services, and often the complete
computing needs, of smaller businesses in their local geographic area.
MEGABITS PER SECOND (MBPS). 1,024 kilobits per second.
METAFRAME. The world's first server-based computing software for Microsoft Windows NT 4.0 Server,
Terminal Server Edition multi-user software (co-developed by Citrix).
MODEM. A device for converting digital signals to analog and vice versa, for data transmission over an
analog telephone line.
MULTIPLEXING. The combining of multiple data channels onto a single transmission medium. Sharing a
circuit - normally dedicated to a single user - between multiple users.
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MULTI-USER. The ability for multiple concurrent users to log on and run applications on a single server.
NET-BASED ISV. An ISV whose main business is developing software for Internet-based application services.
This includes vendors who deliver their own applications online, either directly to users or via other
service providers.
NETWORK ACCESS POINT (NAP). A location where ISPs exchange traffic.
NETWORK COMPUTER (NC). A thin-client hardware device that executes applications locally by downloading
them from the network. NCs adhere to a specification jointly developed by Sun, IBM, Oracle, Apple and
Netscape. They typically run Java applets within a Java browser, or Java applications within the Java
Virtual Machine.
NETWORK COMPUTING ARCHITECTURE. A computing architecture in which components are dynamically
downloaded from the network onto the client device for execution by the client. The Java programming
language is at the core of network computing.
ONLINE ANALYTICAL PROCESSING (OLAP). Software that enables decision support via rapid queries to large
databases that store corporate data in multidimensional hierarchies and views.
OPERATIONAL RESOURCE PROVIDER. Operational resources are external business services that an ASP might
use as part of its own infrastructure, such as helpdesk, technical support, financing, or billing and payment
collection.
OUTSOURCING. The transfer of components or large segments of an organization's internal IT infrastructure,
staff, processes or applications to an external resource such as an ASP.
PACKAGED SOFTWARE APPLICATION. A computer program developed for sale to consumers or businesses,
generally designed to appeal to more than a single customer. While some tailoring of the program may be
possible, it is not intended to be custom-designed for each user or organization.
PACKET. A bundle of data organized for transmission, containing control information (destination, length,
origin, etc.), the data itself, and error detection and correction bits.
PACKET SWITCHING. A network in which messages are transmitted as packets over any available route rather
than as sequential messages over circuit-switched or dedicated facilities.
PEERING. The commercial practice under which nationwide ISPs exchange traffic without the payment of
settlement charges.
PERFORMANCE. A major factor in determining the overall productivity of a system, performance is primarily
tied to availability, throughput and response time.
PERMANENT VIRTUAL CIRCUIT (PVC). A PVC connects the customer's port connections, nodes, locations, and
branches. All customer ports can be connected, resembling a mesh, but PVCs usually run between the
host and branch locations.
POINT OF PRESENCE (POP). A telecommunications facility through which the company provides local
connectivity to its customers.
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PORTAL. A company whose primary business is operating a Web destination site, hosting content and
applications for access via the Web.
REMOTE ACCESS. Connection of a remote computing device via communications lines such as ordinary
phone lines or wide area networks to access distant network applications and information.
REMOTE PRESENTATION SERVICES PROTOCOL. A set of rules and procedures for exchanging data between
computers on a network, enabling the user interface, keystrokes, and mouse movements to be
transferred between a server and client.
RESELLER/VAR. An intermediary between software and hardware producers and end users. Resellers
frequently add value (thus Value-Added Reseller) by performing consulting, system integration and
product enhancement.
ROUTER. A communications device between networks that determines the best path for optimal
performance. Routers are used in complex networks of networks such as enterprise-wide networks and
the Internet.
SCALABILITY. The ability to expand the number of users or increase the capabilities of a computing solution
without making major changes to the systems or application software.
SERVER. The computer on a local area network that often acts as a data and application repository and that
controls an application's access to workstations, printers and other parts of the network.
SERVER-BASED COMPUTING. A server-based approach to delivering business-critical applications to end-user
devices, whereby an application's logic executes on the server and only the user interface is transmitted
across a network to the client. Benefits include single-point management, universal application access,
bandwidth-independent performance, and improved security for business applications.
SINGLE-POINT CONTROL. One of the benefits of the ASP model, single-point control helps reduce the total
cost of application ownership by enabling widely used applications and data to be deployed, managed
and supported at one location. Single-point control enables application installations, updates and
additions to be made once, on the server, which are then instantly available to users anywhere.
SPECIALIST ASP. Provide applications which serve a specific professional or business activity, such as
customer relationship management, human resources or Web site services.
SYSTEMS MANUFACTURER. Manufacturer of servers, networking and client devices.
TELECOMS PROVIDER. Traditional and new-age telecommunications network providers (telcos).
THIN CLIENT. A low-cost computing device that accesses applications and and/or data from a central server
over a network. Categories of thin clients include Windows-Based Terminals (WBT, which comprise the
largest segment), X-Terminals, and Network Computers (NC).
TOTAL COST OF OWNERSHIP (TCO). Model that helps IT professionals understand and manage the budgeted
(direct) and unbudgeted (indirect) costs incurred for acquiring, maintaining and using an application or a
computing system. TCO normally includes training, upgrades, and administration as well as the purchase
price. Lowering TCO through single-point control is a key benefit of server-based computing.
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TOTAL SECURITY ARCHITECTURE (TSA). A comprehensive, end-to-end architecture that protects the network.
TRANSMISSION CONTROL PROTOCOL/INTERNET PROTOCOL (TCP/IP). A suite of network protocols that allow
computers with different architectures and operating system software to communicate over the Internet.
USER INTERFACE. The part of an application that the end user sees on the screen and works with to operate
the application, such as menus, forms and buttons.
VERTICAL MARKET ASP. Provides solutions tailored to the needs of a specific industry, such as the healthcare
industry.
VIRTUAL PRIVATE NETWORK (VPN). A secure, encrypted private connection across a cloud network, such as
the Internet.
WEB HOSTING. Placing a consumer's or organization's web page or web site on a server that can be
accessed via the Internet.
WIDE AREA NETWORK. Local area networks linked together across a large geographic area.
WINDOWS-BASED TERMINAL (WBT). Thin clients with the lowest cost of ownership, as there are no local
applications running on the device. Standards are based on Microsoft's WBT specification developed in
conjunction with Wyse Technology, NCD, and other thin client companies.
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Appendix B – MPEG 2/4 Video QoE
The following information is a typical pattern for MPGE2TS based video streams with a normalized MOS-
AV schedule.