AI3 Tokyo, JP MeetingAI3 Tokyo, JP Meeting 11June 2003June 2003

UNIVERSITI SAINS MALAYSIA

IPv6 throughput over IPv6 throughput over Satellite links (update)Satellite links (update)

Data collection by: Ezrin, Bukhary, CH TangTat Chee Wan (tcwan@cs.usm.my)

Network Research GroupSchool of Computer SciencesUniversity of Science Malaysia

11800 Minden, Penang, Malaysia

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Satellite Link Expt SetupSatellite Link Expt Setup

• USM & Temasek Polytechnic via AI3 USM & Temasek Polytechnic via AI3 networknetwork– 2 hops2 hops– 512 kbps end-to-end (forward and reverse 512 kbps end-to-end (forward and reverse

links)links)

• Dual Stack native IPv4/IPv6 linksDual Stack native IPv4/IPv6 links

• FreeBSD 4.5FreeBSD 4.5

• Netperf for IPv6 supportNetperf for IPv6 support

• IPv4 and IPv6 TCP/UDP testsIPv4 and IPv6 TCP/UDP tests

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Satellite Link ConfigurationSatellite Link Configuration

512 kbps

512 kbps

512 kbps

1.5 Mbps

1.5 Mbps

512 kbps

1.5 Mbps

USM (4.5m) Temasek Polytechnic (4.5m)

512 kbps

end-to-end

JP (6.0m)

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Terrestrial Link Expt SetupTerrestrial Link Expt Setup

• Terrestrial Link tests done in NRG:Terrestrial Link tests done in NRG:– NRG leased-line to TMNet (512 kbps)NRG leased-line to TMNet (512 kbps)– USM leased-line to Jaring (4 Mbps) USM leased-line to Jaring (4 Mbps)

[Firewall blocks IPv6 traffic][Firewall blocks IPv6 traffic]• IPv4 tests between TMNet and JaringIPv4 tests between TMNet and Jaring• IPv6 tests using tunneling to MANIS IPv6 tests using tunneling to MANIS

(tunnel broker) via TMNet(tunnel broker) via TMNet• FreeBSD 4.7FreeBSD 4.7• Netperf for IPv6 supportNetperf for IPv6 support• TCP tests onlyTCP tests only

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UNIVERSITI SAINS MALAYSIATerrestrial Link Terrestrial Link

ConfigurationConfiguration

NRG

Jaring ISP

TMNet ISP

MANISIPv6 Tunnel Broker

Node BJaring IP

Node ATMNet IP

IPv6 Tunnelto MANIS

IPv4 Network

4 Mbps

512 kbps

USMNet

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Experiment ParametersExperiment Parameters

• Default FreeBSD 4.5 Buffer sizesDefault FreeBSD 4.5 Buffer sizes– TCP sendspace=32K, recvspace=64KTCP sendspace=32K, recvspace=64K

• Setting window size in FreeBSDSetting window size in FreeBSD– sysctl sysctl

net.inet.tcp.sendspace=<windowsize>net.inet.tcp.sendspace=<windowsize>– sysctl net.inet.tcp.recvspace=<windowsize>sysctl net.inet.tcp.recvspace=<windowsize>

• Results averaged from A->B & B->A Results averaged from A->B & B->A readingsreadings

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TCPv4 Performance over Two Hop Satellite Link (Averaged)

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TCPv6 Performance over Two Hop Satellite Link (Averaged)

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2M (TCPv6 Linux/Apr'02)

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UDPv4 Performance over Two Hop Satellite Link

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IPv4 (TP->USM)

IPv4 Linux/Apr '02(USM->TP)

IPv4 FreeBSD/Apr'02 (TP->USM)

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UDPv6 Performance over Two Hop Satellite Link

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IPv6 (TP->USM)

IPv6 Linux/Apr '02(USM->TP)

IPv6 FreeBSD/Apr'02 (TP->USM)

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TCPv4 Performance over Terrestrial Link (Averaged between 512 Kbps & 4 Mbps links)

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TCPv6 Performance over Tunneled Terrestrial Link (Averaged A->B & B->A over 512 kbps link)

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2M (TCPv4 Jaring->TMNet)

2M (TCPv6 Sat)

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Observations/Comments (1)Observations/Comments (1)

• FreeBSD 4.5/4.7 has identical performance FreeBSD 4.5/4.7 has identical performance for TCP traffic over IPv4 and IPv6 via for TCP traffic over IPv4 and IPv6 via satellite linksatellite link– TCPv4 for Linux (RH 7.1) appears to scale better TCPv4 for Linux (RH 7.1) appears to scale better

(from previous results)(from previous results)– TCPv6 for Linux (RH 7.1) had worse TCPv6 for Linux (RH 7.1) had worse

performance compared with FreeBSD 4.5: performance compared with FreeBSD 4.5: immature IPv6 stack?immature IPv6 stack?

• UDP performance over satellite is too UDP performance over satellite is too variable to draw any conclusionvariable to draw any conclusion

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Observations/Comments (2)Observations/Comments (2)

• Firewall causes TCPv4 to have low throughput Firewall causes TCPv4 to have low throughput – TMNet->Jaring (firewall) low throughput (~150 kbps)TMNet->Jaring (firewall) low throughput (~150 kbps)– Jaring->TMNet high throughput (> ~500 kbps)Jaring->TMNet high throughput (> ~500 kbps)– Averaged value (~350 kbps) for comparison Averaged value (~350 kbps) for comparison

purposespurposes

• TCPv6 performance over terrestrial link still TCPv6 performance over terrestrial link still exceeds that for Satellite linkexceeds that for Satellite link– Terrestrial IPv6 link is tunneledTerrestrial IPv6 link is tunneled– Terrestrial & Sat links are both 512 kbps (end-to-end)Terrestrial & Sat links are both 512 kbps (end-to-end)– ~400 kbps (terrestrial) vs ~150 kbps (satellite)~400 kbps (terrestrial) vs ~150 kbps (satellite)

• UDP performance not tested for terrestrial linkUDP performance not tested for terrestrial link

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ConclusionsConclusions

• FreeBSD 4.5/4.7 TCP protocol not FreeBSD 4.5/4.7 TCP protocol not affected by v4 vs. v6 transportaffected by v4 vs. v6 transport

• Linux (RH 7.1) seem to have more Linux (RH 7.1) seem to have more aggressive TCPv4 performanceaggressive TCPv4 performance

• TCPv6 performance over high latency TCPv6 performance over high latency links is very poorlinks is very poor

AI3 Tokyo, JP MeetingAI3 Tokyo, JP Meeting 1616June 2003June 2003

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Thank YouThank You

Q&AQ&A

AI3 Tokyo, JP MeetingAI3 Tokyo, JP Meeting 1717June 2003June 2003

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Apr 2002 PresentationApr 2002 Presentation

(Previous results)(Previous results)

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Experimental SetupExperimental Setup

• Linux RH 7.1 for USMLinux RH 7.1 for USM

• FreeBSD 4.3 for Temasek PolytechnicFreeBSD 4.3 for Temasek Polytechnic

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TCP v4 Stream Test with various Transfer Size

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TCP v6 Stream Test with various Transfer Size

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UDP Stream Test with 64KB Socket Buffer Size (USM->TP)

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UDP Stream Test with 64KB Socket Buffer Size (TP->USM)

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CommentsComments• TCP Throughput in each direction is consistent TCP Throughput in each direction is consistent

for standard packet size (MTU < 1500 bytes)for standard packet size (MTU < 1500 bytes)• UDP Throughput:UDP Throughput:

– for USM->TP is better for IPv6 (MTU>1500 bytes)for USM->TP is better for IPv6 (MTU>1500 bytes)– for TP->USM is better for IPv4 (MTU>1500 bytes)for TP->USM is better for IPv4 (MTU>1500 bytes)– Different IP Fragmentation setting in routers?Different IP Fragmentation setting in routers?

• IPv6 performance is not optimal over Satellite IPv6 performance is not optimal over Satellite LinksLinks– Need IPv6 stack optimization (KAME?) Need IPv6 stack optimization (KAME?) – TCP throughput is not improved with larger window TCP throughput is not improved with larger window

size size (> 32K): TCPv6 ssthresh not configured?(> 32K): TCPv6 ssthresh not configured?

– Support for jumbo frames?Support for jumbo frames?