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
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
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.