1. UNIVERSITI SAINS MALAYSIA AI3 Tokyo, JP Meeting 1 June 2003 IPv6 throughput over Satellite links (update) Data collection by: Ezrin, Bukhary, CH Tang Tat Chee Wan (tcwan@cs.usm.my) Network Research Group School of Computer Sciences University of Science Malaysia 11800 Minden, Penang, Malaysia

2. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting2 Satellite Link Expt Setup USM & Temasek Polytechnic via AI3 network USM & Temasek Polytechnic via AI3 network –2 hops –512 kbps end-to-end (forward and reverse links) Dual Stack native IPv4/IPv6 links Dual Stack native IPv4/IPv6 links FreeBSD 4.5 FreeBSD 4.5 Netperf for IPv6 support Netperf for IPv6 support IPv4 and IPv6 TCP/UDP tests IPv4 and IPv6 TCP/UDP tests

3. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting3 Satellite Link Configuration 512 kbps 1.5 Mbps 512 kbps 1.5 Mbps USM (4.5m)Temasek Polytechnic (4.5m) 512 kbps end-to-end JP (6.0m)

4. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting4 Terrestrial Link Expt Setup Terrestrial Link tests done in NRG: Terrestrial Link tests done in NRG: –NRG leased-line to TMNet (512 kbps) –USM leased-line to Jaring (4 Mbps) [Firewall blocks IPv6 traffic] IPv4 tests between TMNet and Jaring IPv4 tests between TMNet and Jaring IPv6 tests using tunneling to MANIS (tunnel broker) via TMNet IPv6 tests using tunneling to MANIS (tunnel broker) via TMNet FreeBSD 4.7 FreeBSD 4.7 Netperf for IPv6 support Netperf for IPv6 support TCP tests only TCP tests only

5. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting5 Terrestrial Link Configuration

6. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting6 Experiment Parameters Default FreeBSD 4.5 Buffer sizes Default FreeBSD 4.5 Buffer sizes –TCP sendspace=32K, recvspace=64K Setting window size in FreeBSD Setting window size in FreeBSD –sysctl net.inet.tcp.sendspace= –sysctl net.inet.tcp.sendspace= –sysctl net.inet.tcp.recvspace= –sysctl net.inet.tcp.recvspace= Results averaged from A->B & B->A readings Results averaged from A->B & B->A readings

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13. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting13 Observations/Comments (1) FreeBSD 4.5/4.7 has identical performance for TCP traffic over IPv4 and IPv6 via satellite link FreeBSD 4.5/4.7 has identical performance for TCP traffic over IPv4 and IPv6 via satellite link –TCPv4 for Linux (RH 7.1) appears to scale better (from previous results) –TCPv6 for Linux (RH 7.1) had worse performance compared with FreeBSD 4.5: immature IPv6 stack? UDP performance over satellite is too variable to draw any conclusion UDP performance over satellite is too variable to draw any conclusion

14. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting14 Observations/Comments (2) Firewall causes TCPv4 to have low throughput Firewall causes TCPv4 to have low throughput –TMNet->Jaring (firewall) low throughput (~150 kbps) –Jaring->TMNet high throughput (> ~500 kbps) –Averaged value (~350 kbps) for comparison purposes TCPv6 performance over terrestrial link still exceeds that for Satellite link TCPv6 performance over terrestrial link still exceeds that for Satellite link –Terrestrial IPv6 link is tunneled –Terrestrial & Sat links are both 512 kbps (end-to-end) –~400 kbps (terrestrial) vs ~150 kbps (satellite) UDP performance not tested for terrestrial link UDP performance not tested for terrestrial link

15. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting15 Conclusions FreeBSD 4.5/4.7 TCP protocol not affected by v4 vs. v6 transport FreeBSD 4.5/4.7 TCP protocol not affected by v4 vs. v6 transport Linux (RH 7.1) seem to have more aggressive TCPv4 performance Linux (RH 7.1) seem to have more aggressive TCPv4 performance TCPv6 performance over high latency links is very poor TCPv6 performance over high latency links is very poor

16. UNIVERSITI SAINS MALAYSIA AI3 Tokyo, JP Meeting 16 June 2003 Thank You Q&A

17. UNIVERSITI SAINS MALAYSIA AI3 Tokyo, JP Meeting 17 June 2003 Apr 2002 Presentation (Previous results)

18. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting18 Experimental Setup Linux RH 7.1 for USM Linux RH 7.1 for USM FreeBSD 4.3 for Temasek Polytechnic FreeBSD 4.3 for Temasek Polytechnic

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23. UNIVERSITI SAINS MALAYSIA June 2003AI3 Tokyo, JP Meeting23 Comments TCP Throughput in each direction is consistent for standard packet size (MTU < 1500 bytes) TCP Throughput in each direction is consistent for standard packet size (MTU < 1500 bytes) UDP Throughput: UDP Throughput: – for USM->TP is better for IPv6 (MTU>1500 bytes) – for TP->USM is better for IPv4 (MTU>1500 bytes) – Different IP Fragmentation setting in routers? IPv6 performance is not optimal over Satellite Links IPv6 performance is not optimal over Satellite Links – Need IPv6 stack optimization (KAME?) – TCP throughput is not improved with larger window size (> 32K): TCPv6 ssthresh not configured? – Support for jumbo frames?