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Collaborations in Networking and Protocols HEP and Radio Astronomy

Collaborations in Networking and Protocols HEP and Radio Astronomy. Richard Hughes-Jones The University of Manchester www.hep.man.ac.uk/~rich/ then “Talks”. VLBI Proof of Concept at iGrid2002 European Topology: NRNs, Geant, Sites. SURFnet. Manchester Jodrell. iGrid 2002. JIVE.

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Collaborations in Networking and Protocols HEP and Radio Astronomy

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  1. Collaborations in Networking and ProtocolsHEP and Radio Astronomy Richard Hughes-Jones The University of Manchesterwww.hep.man.ac.uk/~rich/ then “Talks” Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  2. VLBI Proof of Concept at iGrid2002 European Topology: NRNs, Geant, Sites SURFnet Manchester Jodrell iGrid 2002 JIVE SuperJANET4 Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  3. Collaboration HEP, Radio Astronomy, Dante the NRNs, and Campus folks • Some results of the e-VLBI Proof of Concept Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  4. Dwingeloo DWDM link Jodrell BankUK MedicinaItaly TorunPoland e-VLBI at the GÉANT2 Launch Jun 2005 Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  5. e-VLBI UDP Data Streams • Collaboration HEP, Radio Astronomy, Dante the NRNs, and Campus folks • Good opportunity to test UDP Throughput:5 Hour run Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  6. ESLEA and UKLight • Exploiting Switched Lightpaths for e-Science Applications • EPSRC e-Science project £1.1M 11.5 FTE • Core Technologies: • Protocols • Control plane • HEP data transfers – ATLAS and D0 • e-VLBI • Medical Applications • High Performance Computing • Involved with Protocols, HEP and e-VLBI • Stephen Kershaw appointed as RA (joint with EXPReS) • Investigate how well the protocol implementations work • UDP flows, TCP advanced stacks, DCCP (developed by UCL partners) • Also examine how the Applications “use” the protocols • Also the effect of the transport protocol on what the Application intended! • Develop real-time UDP transport for e-VLBI – vlbi_udp Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  7. Reverse TCP ESLEA and UKLight • 6 * 1 Gbit transatlantic Ethernet layer 2 paths UKLight + NLR • Disk-to-disk transfers with bbcp • Seattle to UK • Set TCP buffer and application to give ~850Mbit/s • One stream of data 840-620 Mbit/s • Stream UDP VLBI data • UK to Seattle • 620 Mbit/s Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  8. TCP Congestion windowgets re-set on each Request • TCP stack RFC 2581 & RFC 2861 reduction of Cwnd after inactivity • Even after 10s, each response takes 13 rtt or ~260 ms • Transfer achievable throughput120 Mbit/s • Event rate very low • Application not happy! tcpmon: TCP Activity for remote Farms:Manc-CERN Req-Resp • Web100 hooks for TCP status • Round trip time 20 ms • 64 byte Request green1 Mbyte Response blue • TCP in slow start • 1st event takes 19 rtt or ~ 380 ms Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  9. ESLEA: ATLAS on UKLight • 1 Gbit Lightpath Lancaster-Manchester • Disk 2 Disk Transfers • Storage Element with SRM using distributed disk pools dCache & xrootd Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  10. Send times • Pause 695 μs every 1.7ms • So expect ~600 Mbit/s • Receive times (Manc end) • No corresponding gaps udpmon: Lanc-Manc Throughputnot quite what we expected !! • Lanc  Manc • Plateau ~640 Mbit/s wire rate • No packet Loss • Manc Lanc • ~800 Mbit/s but packet loss Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  11. EXPReS & FABRIC • EU Project to realise the current potential of eVLBI and investigate the Next Generation capabilities. • SSA • Use of GRID Farms for distributed correlation. • Linking Merlin telescopes to JIVE (present correlator) 4 * 1 Gigabit from Jodrell Links to 10 Service Challenge work. • Interface to eMERLIN – data at 30 Gbit/s • JRA - FABRIC • Investigate use of different IP Protocols • 10 Gigabit Onsala to Jodrell Links to 10 Gbit HEP work. • Investigate 4 Gigabit over GEANT2 Switched LightpathsUDP and TCP Links to Remote Compute Farm HEP work. • Develop 1 and 10 Gbit Ethernet end systems using FPGAsLinks to CALICE HEP work. Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  12. FABRIC 4 Gigabit Demo • Will use a 4 Gbit Lightpath between two GÉANT PoPs • Collaboration with Dante – Discussions in progress • Continuous (days) Data Flows – VLBI_UDP and multi-Gigabit TCP tests Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  13. Data Transfer CSR Access 2.8us 10 Gigabit Ethernet: UDP Data transfer on PCI-X • Sun V20z 1.8GHz to2.6 GHz Dual Opterons • Connect via 6509 • XFrame II NIC • PCI-X mmrbc 2048 bytes66 MHz • One 8000 byte packets • 2.8us for CSRs • 24.2 us data transfereffective rate 2.6 Gbit/s • 2000 byte packet, wait 0us • ~200ms pauses • 8000 byte packet, wait 0us • ~15ms between data blocks Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  14. Calice • Virtex 4 board from pld Applications • PCI-express development card • Using the FPGA to send and receive raw Ethernet frames at 1 Gigabit • Package data from internal memory or external source into Ethernet • Considering building a 10 Gigabit Ethernet add-on card • Take data in on the1Gig links, processing it, send results out on 10Gig link. • Using 2 boards (2nd is a data generator) we could produce a small scale Calice DAQ, take data in, buffer it to the DDR2 ram, and then read it out, Ethernet frame it and ship to PCs. • Ideas for an Ethernet packet monitor. From Slides of Marc Kelly Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  15. Backup Slides Further network & end host investigations Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  16. VLBI Work TCP Delay and VLBI Transfers Manchester 4th Year MPhys Project by Stephen Kershaw & James Keenan Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  17. VLBI Network Topology Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  18. Timestamp3 Timestamp4 Packet loss Timestamp5 Receiver Sender Data3 Data4 RTT ACK Segment time on wire = bits in segment/BW Time • Remember Bandwidth*Delay Product BDP = RTT*BW VLBI Application Protocol TCP & Network Sender Receiver Timestamp1 Timestamp2 Data1 Data2 ●●● • VLBI data is Constant Bit Rate • tcpdelay • instrumented TCP program emulates sending CBR Data. • Records relative 1-way delay Time Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  19. 1 way delay 100 ms 100 ms Message number 1-Way Delay 1 way delay – 10000 packets • 10,000 Messages • Message size: 1448 Bytes • Wait time: 0 • TCP buffer 64k • Route:Man-ukl-JIVE-prod-Man • RTT ~26 ms Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  20. = 1 x RTT 26 ms 1 way delay 10 ms = 1.5 x RTT 10 ms ≠ 0.5 x RTT Message number 1-Way Delay Detail • Why not just 1 RTT? • After SlowStart TCP Buffer Full • Messages at front of TCP Send Buffer have to wait for next burst of ACKs – 1 RTT later • Messages further back in the TCP Send Buffer wait for 2 RTT Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  21. Recent RAID Tests Manchester HEP Server Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  22. “Server Quality” Motherboards • Boston/Supermicro H8DCi • Two Dual Core Opterons • 1.8 GHz • 550 MHz DDR Memory • HyperTransport • Chipset: nVidia nForce Pro 2200/2050 • AMD 8132 PCI-X Bridge • PCI • 2 16 lane PCIe buses • 1 4 lane PCIe • 133 MHz PCI-X • 2 Gigabit Ethernet • SATA Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  23. Disk_test: • areca PCI-Express 8 port • Maxtor 300 GB Sata disks • RAID0 5 disks • Read 2.5 Gbit/s • Write 1.8 Gbit/s • RAID5 5 data disks • Read 1.7 Gbit/s • Write 1.48 Gbit/s • RAID6 5 data disks • Read 2.1 Gbit/s • Write 1.0 Gbit/s Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

  24. UDP Performance: 3 Flows on GÉANT • Throughput:5 Hour run • Jodrell: JIVE2.0 GHz dual Xeon – 2.4 GHz dual Xeon670-840 Mbit/s • Medicina (Bologna):JIVE 800 MHz PIII – mark6231.2 GHz PIII330 Mbit/s limited by sending PC • Torun:JIVE 2.4 GHz dual Xeon – mark5751.2 GHz PIII245-325 Mbit/s limited by security policing (>400Mbit/s  20 Mbit/s) ? • Throughput:50 min period • Period is ~17 min Collaboration Meeting , 4 Jul 2006, R. Hughes-Jones Manchester

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