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Protocols Progress with Current Work.

Protocols Progress with Current Work. Richard Hughes-Jones The University of Manchester www.hep.man.ac.uk/~rich/ then “Talks”. vlbi_udp: UDP on the WAN. iGrid2002 monolithic code Convert to use pthreads control Data input Data output Code branch for Simon’s file transfer tests

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Protocols Progress with Current Work.

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  1. ProtocolsProgress with Current Work. Richard Hughes-Jones The University of Manchesterwww.hep.man.ac.uk/~rich/ then “Talks” ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  2. vlbi_udp: UDP on the WAN • iGrid2002 monolithic code • Convert to use pthreads • control • Data input • Data output • Code branch for Simon’s file transfer tests • Work on vlbi_recv: • Output thread polled for data in the ring buffer – burned CPU • Input thread signals output thread when there is work to do – else wait on semaphore – packet loss at high rate, variable thoughput • Output thread uses sched_yield() when no work to do – CPU used • Add code for:MarkV card and PCEVN interface • Measure: throughput, packet loss, re-ordering, 1-way delay • Multi-flow Network performance – being set up Nov/Dec06 ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  3. vlbi_udp: B2B UDP Tests • Kernel 2.6.9 • vlbi_recv sched_yield() • Wait 12 us • Stable throughput • 999 Mbit/s variation less than 1 Mbit/s • No packet loss • Inter-packet time • Processing time • mean 0.1005 sigma 0.1438 • CPU load: • Cpu0 : 0.0% us, 0.0% sy, 0.0% ni, 99.7% id, 0.3% wa, 0.0% hi, 0.0% si • Cpu1 : 11.3% us, 88.7% sy, 0.0% ni, 0.0% id, 0.0% wa, 0.0% hi, 0.0% si • Cpu2 : 0.3% us, 0.0% sy, 0.0% ni, 99.3% id, 0.3% wa, 0.0% hi, 0.0% si • Cpu3 : 9.3% us, 15.6% sy, 0.0% ni, 37.5% id, 0.0% wa, 1.3% hi, 36.2% si ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  4. vlbi_udp: Multi-site Streams Gbit link Chalmers University of Technology, Gothenburg Metsähovi OnsalaSweden Jodrell BankUK Gbit link TorunPoland DedicatedGbit link Dwingeloo DWDM link MedicinaItaly ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  5. TCP & Network Sender Receiver Timestamp1 Timestamp2 Timestamp3 Data1 Timestamp4 Packet loss Data2 Timestamp5 Data3 Data4 ●●● Number of packets Time n bytes  And now with Packet Loss time Wait time TCP: tcpdelay How does TCP move CBR data? • Want to examine how TCP moves Constant Bit Rate Data • VLBI Application Protocol • tcpdelay a test program: • instrumented TCP program emulates sending CBR Data. • Records relative 1-way delay • Web100 Record TCP Stack activity ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  6. Delay in stream Packet loss Expected arrival time at CBR TCP: tcpdelay Visualising the Results Stephen Kershaw • If Throughput NOT limited by TCP buffer size / Cwnd maybe we can re-sync with CBR arrival times. • Need to store CBR messages during the Cwind drop in the TCP buffer • Then transmit Faster than the CBR rate to catch up Arrival time Message number / Time ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  7. TCP: tcpdelay JB-Manc • Message size: 1448 Bytes • Wait time: 22 us • Data Rate: 525 Mbit/s • Route: JB-Man • RTT ~1 ms • TCP buffer 2MB • Drop 1 in 10,000 packets • ~2.5-3 ms increase in timefor about 2000 messagesie ~ 44 ms • Classic Cwnd behaviour • Cwnd dip corresponds to ~ 1.2M bytes data “Delayed” (~810 packets) • Peak Throughput ~ 620 Mbit/s ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  8. Arrival Times: UKLight JB-JIVE-Manc Presented at the Haystack Workshop • Message size: 1448 Bytes • Wait time: 22 us • Data Rate: 525 Mbit/s • Route:JB-UKLight-JIVE-UKLight-Man • RTT ~27 ms • TCP buffer 32M bytes • BDP @512Mbit 1.8Mbyte • Estimate catchup possible if loss < 1 in 1.24M • Data needed forJIVE-Manc ~27msChicago-Manc ~120 ms • Have ~30 GBytes!!! Stephen Kershaw ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  9. TCP: TCP Stacks, Sharing, Reverse Traffic • Delayed by Provision of UKLight link Manc - Starlight • PC installed in Starlight and Manchester Sep06 • Udpmon tests Good • Plateau ~990 Mbit/s wire rate • No packet Loss • Same in both directions • TCP studies: Work Now in progress ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  10. DCCP: The Application View • Stephen & Richard with help from Andrea • Had problems with Fedora Core 6 using stable kernel 2.6.19-rc1 • DCCP data packets never reached the receiving TSAP ! • Verify with tcpdump • Using 2.6.19-rc5-g73fd2531-dirty • Ported udpmon to dccpmon • Some system calls don’t work • dccpmon tests • Plateau ~990 Mbit/s wire rate • No packet Loss • Receive system crashed! • Iperf tests • 940Mbps, back-to-back • Need more instrumentation in DCCP • Eg a line in /proc/sys/snmp ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  11. 10 Gigabit Ethernet Lab • 10 Gigabit Test Lab now set up in Manchester • Cisco 7600 • Cross Campus λ <1ms • Neterion NICs • 4 Myricom 10 Gbit NICs – delivery this week • Chelsio being purchased • Boston/Supermicro X7DBE PCs • Two Dual Core Intel Xeon Woodcrest 5130 2 GHz • PCI-e and PCI-X • B2B performance so far • SuperMicro X6DHE-G2 • Kernel (2.6.13) & Driver dependent! • One iperf TCP data stream 4 Gbit/s • Two bi-directional iperf TCP data streams 3.8 & 2.2 Gbit/s • UDP Disappointing • Installed Fedora Core5 Kernels 2.6.17 & 2.6.18 (+web100 + packet drop) & 2.6.19 on the Intel dual-core PCs ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  12. ESLEA-FABRIC:4 Gbit flows over GÉANT • Set up 4 Gigabit Lightpath Between GÉANT PoPs • Collaboration with Dante • GÉANT Development Network London – Amsterdamand GÉANT Lightpath service CERN – Poznan • PCs in their PoPs with 10 Gigabit NICs • VLBI Tests: • UDP Performance • Throughput, jitter, packet loss, 1-way delay, stability • Continuous (days) Data Flows – VLBI_UDP and • multi-Gigabit TCP performance with current kernels • Experience for FPGA Ethernet packet systems • Dante Interests: • multi-Gigabit TCP performance • The effect of (Alcatel) buffer size on bursty TCP using BW limited Lightpaths ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  13. Options Using the GÉANT LightPaths • 10 Gigabit SDH backbone • Alkatel 1678 MCC • Node location: • Budapest • Geneva • Frankfurt • Milan • Paris • Poznan • Prague • Vienna • Can do traffic routingso make long rtt paths • Ideal: London Copenhagen • Set up 4 Gigabit Lightpath Between GÉANT PoPs • Collaboration with Dante • PCs in Dante PoPs ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  14. Network/PC Booking System • Based on Meeting Room Booking System • Divide into Links and End systems • Hard work by Stephen Kershaw • Tesing with VLBI ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  15. Any Questions? ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

  16. Backup Slides ESLEA PMB, Manchester, 23 Nov 2006, R. Hughes-Jones Manchester

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