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QoS@CERN

Explore QoS strategies & monitoring for high-speed file transfer on LANs. Understand intserv vs diffserv, ATM challenges, and security implications. Conclusion on CERN's connectivity.

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QoS@CERN

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  1. QoS@CERN • Quality of Service (QoS) • intserv versus diffserv • ATM • community versus public Internets • monitoring • High Speed file transfer • high performance LAN assumed • will remain problematic on high bandwidth*delay paths • could possibly conflict with strong security requirements • monitoring • Conclusions • CERN connectivity update Olivier Martin (Slide 1)

  2. Quality of Service (QoS) • Two approaches proposed by the IETF: • integrated services (intserv), • intserv is an end-to-end architecture based on RSVP that has poor scaling properties. • differentiated services (diffserv). • diffserv is a newer and simpler proposal that has much better chances to get deployed in some real Internet Service Providers environments, at least. • ATM is far from dead, but has serious scaling difficulties. • MPLS is promising. • In the meantime, community managed Internets will remain the best solution. Olivier Martin (Slide 2)

  3. Internet Access @CERN Canada ESnet Japan Abilene STARTAP vBNS MREN SURFNET Commodity Internet JANET TEN-155 DFN CERN PoP USA CERN CIXP Mission oriented Olivier Martin (Slide 3)

  4. QoS experience @CERN • Weighted Fair Queuing (WFQ) worked very well for Telnet style traffic on medium speed serial interfaces, not available on ATM. • CAR capable IOS versions installed, some bugs identified, capability disabled. • QoS mechanisms needed for: • VRVS (Virtual Room Videoconferencing System) • Considering to use RSVP or dedicated ATM VC • IP telephony (CERN, DESY, FNAL, SLAC) • Priority queuing adequate • Video on Demand services • iCAIR diffserv capable IBM Video Charger Olivier Martin (Slide 4)

  5. Maximum TCP throughput under periodic packet loss • Following formula proposed by Matt Mathis/PSC (“The Macroscopic Behavior of the TCP Congestion Avoidance Algorithm”) to approximate the maximum TCP throughput under periodic loss: • (MSS/RTT)*(1/sqrt(p)) • where MSS is the maximum segment size, 1460 bytes, in practice, because of Ethernet, and p is the packet loss rate. • The above formula shows the extreme sensitivity of achievable TCP throughputs in the presence of, even small, packet loss rates (i.e. less than 5%). Olivier Martin (Slide 5)

  6. QoS Monitoring • Various statistics available: • http://sunstats.cern.ch/mrtg • PINGER, Traceping • RIPE, NIMI & Surveyor probes installed. • Netperf & Tcptrace used for benchmarking & tuning • URL-GET (Web page access & Throughput). • statistics collected with SNMP polling and Netflow. Olivier Martin (Slide 6)

  7. Conclusions • It may well be that the QoS problem, having no solution, will never be solved! • Pragmatic solutions do exist, however, in: • well controlled environments • Can HEP afford them? • Monitoring is essential in order to: • see & understand the problem, • fix the problem, • tune the applications, • see & understand the problem, • etc, Olivier Martin (Slide 7)

  8. CERN connectivity update • Main Internet connections • Telecom Operators & ISPs • CERN Internet eXchange Point (CIXP) • CERN GigaPoP (August 1999) • C&W (Chicago) Colocation Status (August 99) • STAR TAP access model • STAR TAP Olivier Martin (Slide 8)

  9. Main Internet connections@CERN • RENATER (French Academic & Research Network). • SWITCH Next Generation (Swiss Academic & Research Network (supplied by diAx)). • TEN-155 (Trans-European Network - 155 Mb/s). • Combined CERN-SWITCH access (25% CERN, I.e. 40Mbps) • US Line consortium (USLIC) • CERN, US/HEP (via Caltech & DoE), Canada/HEP (via Carleton) • IN2P3 (CCPN Lyon). • World Health Organization (WHO). Olivier Martin (Slide 9)

  10. Telecom Operators & ISPs@CERN • France Telecom fiber installed 2*OC48 (2.4 Gbps). • Swisscom 2*OC12 (622 Mb/s) redundant SDH local loop installed. • New Telecom Operators DiaX, SIG/Thermelec, SUNRISE, MCI/Worldcom, Carrier1, Multilink(*), SmartPhone(*). • More Telcos expected to come (e.g. COLT) • 20+ Commercial Internet Service Providers (ISP) Olivier Martin (Slide 10)

  11. SWITCH EUnet FDDI FDDI CERN Internet eXchange Point (CIXP) Carrier1 Switched Ethernet FDDI AFstats RENATER GlobalOne IN2P3 Bloomberg Catalyst 5505 HP ISDnet USLIC IBM EBONE TEN-155 Sunrise/ BT Swisscom IP-Plus Petrel US Internet Fast Ethernet AT&T IProLink/ PSInet Transparent WEB Cache SKYcache ATM Test Beds Wisper INS Deckpoint Olivier Martin (Slide 11)

  12. CERN GigaPoP (August 1999) SWITCH NationalResearchNetworks RENATER 100 Mb/s 2Mb/s Mission Oriented Link IN2P3 6 Mb/s 2Mb/s WHO 39/155 Mb/s CERN TEN-155 Public 20Mb/s 100 Mb/s 2Mb/s C&W 155 Mb/s Commercial JEG (Japan) C-IXP Test SwissWAN Olivier Martin (Slide 12)

  13. Internet Access Models Canada ESnet Japan Abilene STARTAP vBNS MREN SURFNET Commodity Internet JANET TEN-155 DFN CERN PoP USA CERN CIXP Mission oriented Olivier Martin (Slide 13)

  14. C&W (Chicago) Colocation Status (August 99) C&W (Chicago) C&W Internet CERN (Geneva) T3 CERNH8 C&W CERN-USA LS1010 E3 T3 STAR TAP STM-1 LS1010 Olivier Martin (Slide 14)

  15. STAR TAP • STAR TAP (Science Technology & Research Transit Access Point) is one of three Internet eXchange Points provided by AADS (Ameritech Advanced Data Services) out of a huge ATM switch, namely: • Chicago NAP • MREN (Metropolitan Research and Education Network), the local Internet2 GigaPoP. • STAR TAP • A by-product is a full mesh of ATM VC with ALL the connected ISPs, thus making it easy to establish peerings and/ot to buy commercial Internet services (e.g. Exodus, NAP.NET). Olivier Martin (Slide 15)

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