Link Capacity Estimation in SDN-based End-hosts

Anees Al-Najjar, Farzaneh Pakzad ,Siamak Layeghy, and Marius Portmann

School of ITEE, The University of QueenslandBrisbane, Australia

Presented by Anees Al-NajjarThe 10th International Conference on Signal Processing and

Communication Systems, ICSPCS'2016

December 21st, 2016, The Gold Coast, Queensland, Australia

Paper Outline

1. Motivation

2. Background

3. Key Challenge

4. Methodology

5. Results

6. Conclusion

1

Motivation

End-Hosts have multiple network interfaces

Goal: Efficiently control the traffic in multi-interface end-hosts (e.g. smartphones with WiFi, and 4G interfaces)

2

Proposed Solution

Software Defined Networking (SDN) on the end-host

3

BackgroundWhat is Software Defined Networking

(SDN)?

Control Plane

Net. Device

Data Plane

Traditional Network SDN

SDN Switch Controller

SDN: it is a new paradigm in networking[1].

SDN Switch Controller

Benefits: Facilitate network management Enhance Network Efficiency Improve network programmability Empower innovation Reduce cost

4

BackgroundSDN Architecture

OpenFlow SwitchOpenFlow Switch

OpenFlow Switch

OpenFlow SwitchOpenFlow Switch

Southbound interface

Northbound interface

Application Layer

Control Layer(SDN Controller)Network Services

Applications

InfrastructureLayer

5

Key idea:Use unified interface (e.g. OpenFlow) to control

network traffic on end hosts.

SDN-based traffic control on end-hosts

Research HypothesisUsing SDN-based network traffic control on end-hosts can increase network efficiency,

performance.

6

Load balancing

Use Case (SDN based End-Host)

ServerGW Router

GW Router

Appl

icat

ions

OpenFlow Switch

SDN Controller

veth0

eth1

eth0

veth1

System Architecture

Appl

icat

ions

SDN Controller

veth0

eth1

eth0

OpenFlow Switch

Client

Simple Network interface load balancing[2]

In order to make optimal load balancing decisions, we need to know the characteristics of the different links, in particular the link capacity.

8

Key Challenge

Measuring link parameters from end-host via SDN, using only the OpenFlow interface.

Example of link parameters:

• Delay (transmission, propagation, jitter)

• Current flow

• Link capacity

9

Link Capacity Measurement

Traditional approaches [3]1. Packet Pair/Train probing

2. Trains of Packet Pairs

3. Self-Loading Periodic Streams (SLoPS)

4. Variable Packet Size (VPS) probing [4]

Require control on both ends of the link

Only requires control over one end of the link.It can be implemented via SDN Based End-Host

10

How does VPS work?

Transmission Time = RTT/2

Assuming there is no significant queuing delay Assuming we can ignore processing and propagation delay

VPS sends groups of probe packets (ICMP) with different packet size to

measure RTT

Assumption: Packet with minimum RTT value for each packet size

has experienced no or only minor queuing delay

11

1. Send n packets (ICMP packets) with different sizes x

2. Find the Minimum RTT for each packet size :

RTTx = (RTTi)3. Calculate linear Regression based upon step 2:

4. Estimate the Capacity based upon the slope ():

How does VPS work? (cont’d):

Y RTTx

X PKT sizeα y-intercept

y = x + α

12

Our Contribution:Adapting VPS to SDN (VPS-SDN)

VPS probing has not been implemented in SDNVPS-SDN

SDN controller Crafts the probing packets Computes the time difference (RTT) of the probing packets

13

Key Features of VPS-SDN

Only requires control over one side of connection

Is generic, works with all link types (e.g. WiFi, xG)

14

10Mbps

Testbed1. Two directly-connected PCs via

Ethernet2. Link capacity is limited to 10Mbps.3. Five Packet sizes

(64B, 128B, 256B, 512B, 1024B)4. 20 ICMP packets per size5. Probing packet delay 100ms6. Total experiment time is 25s7. No background Traffic

ResultsBasic Capacity Scenario (No background traffic)

=1176273 Byte 9.4 MbpsEstimated Capacity:

15

ResultsWith varying background traffic

Backlog Queue on the client 16

ResultsVPS-SDN with probe traffic prioritisation

Backlog Queue on the client

17

Conclusion

Presented VPS-SDN, an adaption of Variable Packet Size

probing to SDN

Implemented on end-host (client) only, without support from

network infrastructure

Demonstrated good performance, even in case of high levels of

background traffic, due to probe traffic prioritisation

Future work: Further evaluation of VPS-SDN on other links (WiFi, 4G, etc.)

Integration of VPS-SDN for end-host based traffic load balancing [2]

18

References

[1] Software-defined networking: The new norm for networks. Available: https://www.opennetworking.org/images/stories/downloads/sdn-resources/white-papers/wp-sdn-newnorm.pdf

[2] A. Al-Najjar, S. Layeghy, and M. Portmann, “Pushing sdn to the endhost, network load balancing using openflow,” in 2016 IEEE International Conference on Pervasive Computing and Communication Workshops (PerCom Workshops), IEEE, 2016, pp. 1–6

[3] R. Prasad, C. Dovrolis, M. Murray, and K. Claffy, "Bandwidth estimation: metrics, measurement techniques, and tools," IEEE network, vol. 17, pp. 27-35, 2003

[4] V. Jacobson, “Pathchar: A Tool to Infer Characteristics of Internet Paths,” ftp://ftp.ee.lbl.gov/pathchar/, Apr. 1997.

Questions ?