Performance Evaluation of L3 Transport Protocols for IEEE 802.21 (2nd round)Richard Rouil, Nada Golmie and David Griffith

National Institute of Standards and Technology

http://www.antd.nist.gov/seamlessandsecure.shtml

Outline

• MIH transport issues investigated

• Simulation scenarios

• Performance evaluation results– UDP without MIH ACK (for reference)– UDP with MIH ACK– TCP evaluation

• Conclusions

MIH Transport Issues Investigated• Transport protocol type

– UDP– TCP

• PoS Location– RTT between the MIH nodes

• Message parameters– Size– Rate

• Network conditions– Link congestion

• Priority queuing• Retransmission timeout• Fragmentation• Congestion & rate control

Mobility scenariosVarying the RTT between the MN and the MoS

addresses all 4 scenarios identified in draft-xxx-mipshop-mstp-solution-00:– S1: Home Network MoS, the MN and the services are

located in the home network. – S2: Visited Network MoS, MN is in the visited network

and mobility services are also provided by the visited network.

– S3: Roaming MoS, MN is in the visited network and all services are provided by the home network.

– S4: Third party MoS, MN is in home or visited network and services are provided by a 3rd party network.

Network Topology

MN

AP(co-located PoS)

PoS (not co-located) CN

Variable link delay

and packet loss

Background traffic to CN for congestion

MIH message exchange to PoS

Simulation parametersIEEE 802.11

Data rate (Mb/s) 11Mb/s

Coverage area – radius (m) 50

Links

Speed (Mb/s) 100

Delay (s) 0.01

UDP

Max packet size (byte) 1000

Header size (bytes) 8

TCP

Maximum segment size (bytes) 1280

Min RTO (s) 0.2

Max retransmission Unlimited

Queue size Unlimited

Header size (bytes) 20

IP header

IPv6 header (bytes) 40

MIH Function

Transaction timeout (s) none

Maximum number of retransmission

2

Background traffic

Traffic type cbr over udp

Packet size (bytes) 500

Inter-arrival rate (s) 0.005

Simulation variables

Transport protocol UDP no ACK, UDP ACK, TCP

PoS Location Co-located, Remote

Variable link Delay (s) 0.01-0.5

Variable network packet loss (%) 0-50

MIH message Indication, Request/Response

MIH packet size (byte) 50-1000

MIH packet inter-arrival (s) Exp distribution w/ varying mean in [ 0.1 2]

MIH request processing time (s) 0-0.2

MIH message timeout (xRTT) (s) 0.5-2

Number of background traffic nodes 0-10

Rate limiting bucket size (packet) 1-20

Rate limiting token rate (packet/s) 1-20

Rate limiting queue size (packet) 10-50

Transport protocol performance evaluation

Performance metrics:– Transaction success rate (i.e. indication or

response received)– Delay to complete a transaction– Network load– Overhead created by the MIH

acknowledgement mechanisms and the transport layer

– Transport throughput

UDP (no ACK) Performance

UDP (with ACK) Performance

TCP Performance