1. 1 Achieving High Throughput on Fast Networks (Bandwidth Challenges and World Records) Les Cottrell & Yee-Ting Li Stanford Linear Accelerator Center Presented at ICTP “Optimization Technologies for Low Bandwidth Networks” workshop Trieste October 2006 Bandwidth Challenges and Internet World Records

2. 2 Driver: LHC Network Requirements CERN/Outside Resource Ratio ~1:2 Tier0/(  Tier1)/(  Tier2) ~1:1:1 Tier 1 Tier2 Center Online System CERN Center PBs of Disk; Tape Robot FNAL Center IN2P3 Center INFN Center RAL Center Institute Workstations ~150-1500 MBytes/sec ~10 Gbps 1 to 10 Gbps Tens of Petabytes by 2007-8. An Exabyte ~5-7 Years later. Physics data cache ~PByte/sec 10 - 40 Gbps Tier2 Center ~1-10 Gbps Tier 0 +1 Tier 3 Tier 4 Tier2 Center Tier 2 Experiment

3. 3  Product of distance * speed using TCP with routers  IPv4 Multi-stream record with FAST TCP: 6.86 Gbps X 27kkm: Nov 2004  PCI-X 2.0: 9.3 Gbps Caltech- StarLight: Dec 2005  PCI Express: 9.8 Gbps Caltech – Sunnyvale, July 2006 Internet2 Land Speed Records & SC2003-2005 Records Internet2 LSRs: Blue = HEP 7.2G X 20.7 kkm Throuhgput (Petabit-m/sec) H. Newman

4. 4 Internet2 Land Speed Record ’02-03: Outline Breaking the Internet2 Land Speed Record (2002/03) –Not be confused with: Rocket-powered sled breaks 1982 world land speed record, San Francisco Chronicle May 1, 2003 Who did it What was done How was it done? What was special about this anyway? Who needs it?

5. 5 Who did it: Collaborators and sponsors Caltech: Harvey Newman, Steven Low, Sylvain Ravot, Cheng Jin, Xiaoling Wei, Suresh Singh, Julian Bunn SLAC: Les Cottrell, Gary Buhrmaster, Fabrizio Coccetti (SISSA) LANL: Wu-chun Feng, Eric Weigle, Gus Hurwitz, Adam Englehart CERN: Olivier Martin, Paolo Moroni ANL: Linda Winkler DataTAG, StarLight, TeraGrid, SURFnet, NetherLight, Deutsche Telecom, Information Society Technologies Cisco, Level(3), Intel DoE, European Commission, NSF

6. 6 What was done? Beat the Gbps limit for a single TCP stream across the Atlantic – transferred a TByte in an hour WhenFromToBottle- neck MTUStrea ms TCPThru- put Nov ’02 (SC02) Amste rdam Sunny- vale 1 Gbps9000B1Stand ard 923 Mbps Nov ’02 (SC02) Balti- more Sunny- vale 10 Gbps 150010FAST8.6 Gbps Feb ‘03Sunny -vale Geneva2.5 Gbps 9000B1Stand ard 2.38 Gbps Set a new Internet2 TCP land speed record, 10,619 Tbit-meters/sec –(see http://lsr.internet2.edu/)http://lsr.internet2.edu/ With 10 streams achieved 8.6Gbps across US One Terabyte transferred in less than one hour

7. 7 Typical Components CPU –Pentium 4 (Xeon) with 2.4GHz cpu For GE used Syskonnect NIC For 10GE used Intel NIC –Linux 2.4.19 or 20 Routers –Cisco GSR 12406 with OC192/POS & 1 and 10GE server interfaces (loaned, list > $1M) –Cisco 760x –Juniper T640 (Chicago) Level(3) OC192/POS fibers (loaned SNV-CHI monthly lease cost ~ $220K) All borrowed & Off the Shelf Note bootees Earthquake strap GSR Heat sink Disk servers Compute servers

8. 8 Challenges After a loss it can take over an hour for stock TCP (Reno) to recover to maximum throughput at 1Gbits/s –i.e. loss rate of 1 in ~ 2 Gpkts (3Tbits), or BER of 1 in 3.6*10 12 PCI bus limitations (66MHz * 64 bit = 4.2Gbits/s at best) At 10Gbits/s and 180msec RTT requires 500MByte window Slow start problem at 1Gbits/s takes about 5-6 secs for 180msec link, –i.e. if want 90% of measurement in stable (non slow start), need to measure for 60 secs –need to ship >700MBytes at 1Gbits/s Seconds Mbits/s Sunnyvale-Geneva, 1500Byte MTU, stock TCP

9. 9 What was special? 1/2 End-to-end application-to-application, single and multi- streams (not just internal backbone aggregate speeds) TCP has not run out of stream yet, scales from modem speeds into multi-Gbits/s region –TCP well understood, mature, many good features: reliability etc. –Friendly on shared networks New TCP stacks only need to be deployed at sender –Often just a few data sources, many destinations –No modifications to backbone routers etc –No need for jumbo frames Used Commercial Off The Shelf (COTS) hardware and software

10. 10 What was Special 2/2 Raise the bar on expectations for applications and users –Some applications can use Internet backbone speeds –Provide planning information The network is looking less like a bottleneck and more like a catalyst/enabler –Reduce need to colocate data and cpu –No longer ship literally truck or plane loads of data around the world –Worldwide collaborations of people working with large amounts of data become increasingly possible

11. 11 Who needs it? HENP – current driver –Multi-hundreds Mbits/s and Multi TByte files/day transferred across Atlantic today SLAC BaBar experiment already has almost a PByte stored –Tbits/s and ExaBytes (10 18 ) stored in a decade Data intensive science: –Astrophysics, Global weather, Bioinformatics, Fusion, seismology… Industries such as aerospace, medicine, security … Future: –Media distribution Gbits/s=2 full length DVD movies/minute 2.36Gbits/s is equivalent to –Transferring a full CD in 2.3 seconds (i.e. 1565 CDs/hour) –Transferring 200 full length DVD movies in one hour (i.e. 1 DVD in 18 seconds) Will sharing movies be like sharing music today?

12. 12 When will it have an impact ESnet traffic doubling/year since 1990 SLAC capacity increasing by 90%/year since 1982 –SLAC Internet traffic increased by factor 2.5 in last year International throughput increase by factor 10 in 4 years So traffic increases by factor 10 in 3.5 to 4 years, so in: –3.5 to 5 years 622 Mbps => 10Gbps –3-4 years 155 Mbps => 1Gbps –3.5-5 years 45Mbps => 622Mbps 2010-2012: –100s Gbits for high speed production net end connections –10Gbps will be mundane for R&E and business –Home broadband: doubling ~ every year, 100Mbits/s by end of decade (if double each year then 10Mbits/s by 2012)? –Aggressive Goal: 1Gbps to all Californians by 2010

13. 13 Impact Caught technical press attention –On TechTV and ABC Radio –Reported in places such as CNN, the BBC, Times of India, Wired, Nature –Reported in English, Spanish, Portuguese, French, Dutch, Japanese –Guinness Book of Reccords (2004)

14. 14 SC Bandwidth Challenge Bandwidth Challenge –Yearly challenge of SuperComputing show –‘The Bandwidth Challenge highlights the best and brightest in new techniques for creating and utilizing vast rivers of data that can be carried across advanced networks.‘ –Transfer as much data as possible using real applications over a 2 hour window

15. 15 BWC: History 2002: “Extreme Bandwidth” Caltech, SLAC, CERN –12.4Gbits/s peak, 2 nd place, LBNL video stream with UDP won 2003: “Bandwidth Lust” Caltech, SLAC, LANL, CERN, Manchester, NIKHEF –23 Gbits/s peaks (6.6 TBytes in < 1 hour), 1 st place 2004: “Terabyte data transfers for physics” Caltech, SLAC, FNAL + … –Achieved 101 Gbits/s, 1 st place 2005: “Global Lambda for Particle Physics” –Sustained > 100Gbits/s for many hours, peak > 150Gbits/s 1 st place

16. 16 BWC: Overview 2005 Distributed TeraByte Particle Physics Data Sample Analysis –‘Demonstrated high speed transfers of particle physics data between host labs and collaborating institutes in the USA and worldwide. Using state of the art WAN infrastructure and Grid Web Services based on the LHC Tiered Architecture, they showed real-time particle event analysis requiring transfers of Terabyte-scale datasets.’ In detail, during the bandwidth challenge (2 hours): –131 Gbps measured by SCInet BWC team on 17 of our 21 waves (15 minute average) - > 150Gbps on all 22 –95.37TB of data transferred. (3.8 DVD’s per second) –90-150Gbps (peak 150.7Gbps) On day of challenge –Transferred ~475TB ‘practising’ (waves were shared, still tuning applications and hardware) –Peak one way utlisation observed on a single link was 9.1Gbps (Caltech) and 8.4Gbps (SLAC) Also wrote to StorCloud –SLAC: wrote 3.2TB in 1649 files during BWC –Caltech: 6GB/sec with 20 nodes

17. 17 Participants Worldwide Caltech/HEP/CACR/ NetLab: Harvey Newman, Julian Bunn - Contact, Dan Nae, Sylvain Ravot, Conrad Steenberg, Yang Xia, Michael ThomasCaltech SLAC/IEPM: Les Cottrell, Gary Buhrmaster, Yee-Ting Li, Connie LoggSLAC FNAL Matt Crawford, Don Petravick, Vyto Grigaliunas, Dan YocumFNAL University of Michigan Shawn McKee, Andy Adamson, Roy Hockett, Bob Ball, Richard French, Dean Hildebrand, Erik Hofer, David Lee, Ali Lotia, Ted Hanss, Scott GerstenbergerUniversity of Michigan U Florida Paul Avery, Dimitri Bourilkov,U Florida University of Manchester: Richard Hughes-Jones ･University of Manchester CERN, Switzerland David FosterCERN, Switzerland KAIST, Korea Yusung Kim,KAIST, Korea Kyungpook Univserity, Korea, Kihwan Kwon,Kyungpook Univserity, Korea UERJ, Brazil Alberto Santoro,UERJ, Brazil UNESP, Brazil Sergio Novaes,UNESP, Brazil USP, Brazil Luis Fernandez LopezUSP, Brazil GLORIAD, USA: Greg Cole, Natasha BulashovaGLORIAD Sun & Chelsio Neterion ESnet

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19. 19 Networking Overview We had 22 10Gbits/s waves to the Caltech and SLAC/FNAL booths. Of these: –15 waves to the Caltech booth (from Florida (1), Korea/GLORIAD (1), Brazil (1 * 2.5Gbits/s), Caltech (2), LA (2), UCSD, CERN (2), U Michigan (3), FNAL(2)). –7 x 10Gbits/s waves to the SLAC/FNAL booth (2 from SLAC, 1 from the UK, and 4 from FNAL). The waves were provided by Abilene, Canarie, Cisco (5), ESnet (3), GLORIAD (1), HOPI (1), Michigan Light Rail (MiLR), National Lambda Rail (NLR), TeraGrid (3) and UltraScienceNet (4).

20. 20 Network Overview

21. 21 Hardware (SLAC only) At SLAC: –14 x 1.8Ghz Sun v20z (Dual Opteron) –2 x Sun 3500 Disk trays (2TB of storage) –12 x Chelsio T110 10Gb NICs (LR) –2 x Neterion/S2io Xframe I (SR) –Dedicated Cisco 6509 with 4 x 4x10GB blades At SC|05: –14 x 2.6Ghz Sun v20z (Dual Opteron) –10 QLogic HBA’s for StorCloud Access –50TB Storage at SC|05 provide by 3PAR (Shared with Caltech) –12 x Neterion/S2io Xframe I NICs (SR) –2 x Chelsio T110 NICs (LR) –Shared Cisco 6509 with 6 x 4x10GB blades

22. 22 Hardware at SC|05 Industrial fans to keep cool around back

23. 23 Software BBCP ‘Babar File Copy’ –Uses ‘ssh’ for authentication –Multiple stream capable –Features ‘rate synchronisation’ to reduce byte retransmissions –Sustained over 9Gbps on a single session XrootD –Library for transparent file access (standard unix file functions) –Designed primarily for LAN access (transaction based protocol) –Managed over 35Gbit/sec (in two directions) on 2 x 10Gbps waves –Transferred 18TBytes in 257,913 files DCache –20Gbps production and test cluster traffic

24. 24 Previous year (SC|04) BWC Aggregate Bandwidth

25. 25 Cumulative Data Transferred Bandwidth Challenge period

26. 26 Component Traffic Note instability

27. 27 In to booth Out from booth ESnet routed ESnet SDN layer 2 via USN Bandwidth Challenge period SLAC Cluster Contributions Router crashes

28. 28 Problems… Managerial/PR –Initial request for loan hardware took place 6 months in advance! –Lots and lots of paperwork to keep account of all loan equipment (over 100 items loaned from 7 vendors) –Thank/acknowledge all contributors, press release clearances Logistical –Set up and tore down a pseudo production network and servers in a space of week! –Testing could not begin until waves were alight Most waves lit day before challenge! –Shipping so much hardware not cheap! –Setting up monitoring

29. 29 Problems… Tried to configure hardware and software prior to show Hardware –NICS We had 3 bad Chelsios (bad memory) Neterions Xframe II’s did not work in UKLight’s Boston machines –Hard-disks 3 dead 10K disks (had to ship in spare) –1 x 4Port 10Gb blade DOA –MTU mismatch between domains –Router blade died during stress testing day before BWC! –Cables! Cables! Cables! Software –Used golden disks for duplication (still takes 30 minutes per disk to replicate!) –Linux kernels: Initially used 2.6.14, found severe performance problems compared to 2.6.12. –(New) Router firmware caused crashes under heavy load Unfortunately, only discovered just before BWC Had to manually restart the affected ports during BWC

30. 30 Problems Most transfers were from memory to memory (Ramdisk etc). –Local caching of (small) files in memory –Reading and writing to disk will be the next bottleneck to overcome

31. 31 SC05 BWC Takeaways & Lessons Substantive take-aways from this Marathon exercise: –An optimized Linux kernel (2.6.12 + FAST + NFSv4) for data transport; after 7 full kernel-build cycles in 4 days –Scaling up SRM/gridftp to near 10 Gbps per wave, using Fermilab’s production clusters –A newly optimized application-level copy program, bbcp, that matches the performance of iperf under some conditions –Extensions of SLAC’s Xrootd, an optimized low-latency file access application for clusters, across the wide area –Understanding of the limits of 10 Gbps-capable computer systems, network switches and interfaces under stress A Lot of Work remains, to put it this into production-use (for example Caltech/CERN/FNAL/SLAC/Michigan Collaboration)

32. 32 Conclusion Previewed the IT Challenges of the next generation Data Intensive Science Applications (High Energy Physics, astronomy etc) –Petabyte-scale datasets –Tens of national and transoceanic links at 10 Gbps (and up) –100+ Gbps aggregate data transport sustained for hours; We reached a Petabyte/day transport rate for real physics data Learned to gauge difficulty of the global networks and transport systems required for the LHC mission –Set up, shook down and successfully ran the systems in < 1 week –Understood and optimized the configurations of various components (Network interfaces, router/switches, OS, TCP kernels, applications) for high performance over the wide area network.

33. 33 What’s next? Break 10Gbits/s single stream limit, distance capped Evaluate new stacks with real-world links, and other equipment –Other NICs –Response to congestion, pathologies –Fairnesss, robustness, stability –Deploy for some major (e.g. HENP/Grid) customer applications Disk-to-disk throughput & useful applications –Need faster cpus (extra 60% MHz/Mbits/s over TCP for disk to disk), understand how to use multi-processors – Disk-to-disk Marks: 536 Mbytes/sec (Windows); 500 Mbytes/sec (Linux) –Concentrate now on reliable Terabyte-scale file transfers System Issues: PCI-X Bus, Network Interfaces, Disk I/O Controllers, Linux Kernel, CPU utilization Move from “hero” demonstrations to commonplace

34. 34 Press and PR SC|05 11/8/05 - Brit Boffins aim to Beat LAN speed record from vnunet.comBrit Boffins aim to Beat LAN speed record SC|05 Bandwidth Challenge SLAC Interaction Point.SC|05 Bandwidth Challenge Top Researchers, Projects in High Performance Computing Honored at SC/05... Business Wire (press release) - San Francisco, CA, USATop Researchers, Projects in High Performance Computing Honored at SC/05... 11/18/05 - Official Winner AnnouncementOfficial Winner Announcement 11/18/05 - SC|05 Bandwidth Challenge Slide PresentationSC|05 Bandwidth Challenge Slide Presentation 11/23/05 - Bandwidth Challenge Results from SlashdotBandwidth Challenge Results 12/6/05 - Caltech press releaseCaltech press release 12/6/05 - Neterion Enables High Energy Physics Team to Beat World Record Speed at SC05 Conference CCN Matthews News Distribution ExpertsNeterion Enables High Energy Physics Team to Beat World Record Speed at SC05 Conference High energy physics team captures network prize at SC|05 from SLACHigh energy physics team captures network prize at SC|05 High energy physics team captures network prize at SC|05 EurekaAlert!High energy physics team captures network prize at SC|05 12/7/05 - High Energy Physics Team Smashes Network Record, from Science Grid this Week.High Energy Physics Team Smashes Network Record Congratulations to our Research Partners for a New Bandwidth Record at SuperComputing 2005, from Neterion.Congratulations to our Research Partners for a New Bandwidth Record at SuperComputing 2005

35. 35 How was it done: Typical testbed 12*2cpu servers 4 disk servers GSRGSR 6*2cpu servers Sunnyvale 6*2cpu servers 4 disk servers OC192/POS (10Gbits/s) 2.5Gbits/s (bottleneck) T640T640 Sunnyvale section first deployed for SC2002 (Nov 02) (EU+US) Geneva Chicago 76097609 76097609 SNV CHIAMS GVA > 10,000 km

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37. 37 SLAC/UK Contribution ESnet/USN layer 2 UKLight In to booth Out from booth ESnet routed

38. 38 SLAC-ESnet FermiLab-HOPI SLAC-ESnet-USNFNAL-UltraLight UKLight Out from booth SLAC-FermiLab-UK Bandwidth Contributions In to booth SLAC-ESnet routed

39. 39 SLAC/Esnet Contribution Mbps Hosts Aggregate

40. 40 SLAC/FNAL Booth Aggregate Mbps Waves

41. 41 HOPI USN FermiLab Contribution UltraLight

42. 42 Conclusion Products from this the exercise –An optimized Linux (2.6.12 + NFSv4 + FAST and other TCP stacks) kernel for data transport; after 7 full kernel-build cycles in 4 days –A newly optimized application-level copy program, bbcp, that matches the performance of iperf under some conditions. –Extensions of Xrootd, an optimized low-latency file access application for clusters, across the wide area –Understanding of the limits of 10 Gbps-capable systems under stress. –How to effectively utilize 10GE and 1GE connected systems to drive 10 gigabit wavelengths in both directions. –Use of production and test clusters at FNAL reaching more than 20 Gbps of network throughput. Significant efforts remain from the perspective of high-energy physics –Management, integration and optimization of network resources –End-to-end capabilities able to utilize these network resources. This includes applications and IO devices (disk and storage systems)

43. 43 More Information Internet2 Land Speed Record Publicity –www-iepm.slac.stanford.edu/lsr/www-iepm.slac.stanford.edu/lsr/ –www-iepm.slac.stanford.edu/lsr2/www-iepm.slac.stanford.edu/lsr2/ 10GE tests –www-iepm.slac.stanford.edu/monitoring/bulk/10ge/www-iepm.slac.stanford.edu/monitoring/bulk/10ge/ –sravot.home.cern.ch/sravot/Networking/10GbE/10GbE_test.htmlsravot.home.cern.ch/sravot/Networking/10GbE/10GbE_test.html