1. Börje Josefsson GRID Connections in

2. GigaSunet: GigaSunet: Nationwide 10 Gbit/s network Core network (22 cities): 5.270 km of lambdas. 27 inter-city segments with 10 Gbit/sec. 49 routers (Cisco 124xx). Access network (2,5 Gbit/s): 25 dark fiber rings. 3 segments of 2,5 Gbit/sec. lambda. 1 STM-1 connection. 70 routers (Cisco 10720).

4. Research networks in Europe

5. Local peering For future ideas… IPv6-network (via UTI) National research network (via UTI) GRID Production network (connected to University LAN). Suggested access scenario 4 * Gigabit Ethernet 8 * Fast Ethernet Uplink 2,5 Gbit/sec (redundant)

6. GRID-connection at the edge Fiber directly to SUNETs access router. –There are two access routers at each university. –1 Gbit/sec. [Gigabit Ethernet]. –IP version 4 supported today at this speed. –Avoid the local LAN-equipment if possible! –As ”straight” to Your hosts as possible ! Avoid (cheap) switches etc.!

7. GigaSunet Can handle the traffic we have today, and for several years into the future. Can be upgraded gradually. ”Always” available. ”All” bottlenecks are local.

8. Is GigaSunet fast enough? Hard to build a faster net today. For situations with many simultaneous users: –Can handle many concurrent flows with 10-100 Mbit/sec. –Not many computers can transfer 100 Mbit/sec or more over long distances.

9. But it is still slow?!? PathRTTMax speed Luleå - Umeå3 ms87,3 Mbit/sec Luleå - Lund32 ms8,2 Mbit/sec Luleå - Geneva70 ms3,7 Mbit/sec Luleå - Boston130 ms2,0 Mbit/sec Luleå - San Diego205 ms1,3 Mbit/sec For a single session, GigaSunet can be felt 1/ as slow! Speed of light and buffer sizes limits the speed. 1 / Unless You have tweaked Your computer and LAN. Theoretical maximum speed with 32 Kbytes buffer. Bw best = buffer / RTT

10. ”Fast-and-far” You have to think. Twice… Tweak Your OS parameters. Sweden is approx. 18 ms ”long”. –1 Gbit/sec * 36 ms RTT  4,5 megabyte buffer in the end hosts (usually it is 32 kilobyte…). This has nothing to do with the network itself, this is just how computer communication works. –It doesn’t help to have a “private” network!

11. Test results dino# ttcp -s -t -f m -l 61440 -n 20345 wilma.sunet.se ttcp-t: buflen=61440, nbuf=20345, align=16384/0, port=5001 tcp -> wilma.sunet.se ttcp-t: socket ttcp-t: connect ttcp-t: 1249996800 bytes in 10.35 real seconds = 966181102 bits/sec +++ ttcp-t: 20345 I/O calls, msec/call = 0.52, calls/sec = 1966.33 ttcp-t: 0.0user 1.6sys 0:10real 16% 0i+0d 0maxrss 0+341060pf 41346+4csw Luleå-Stockholm (approx. 1.000 km). Hosts connected to Gigabit Ethernet. 966,2 Mbit/sec. This is ”real” traffic, not counting the framing and packet overhead.

12. Hosts It is not enough to have a computer that is ”biggest in the world”, it also needs to: –Have Gbit/sec – network card with a lot of memory! –Have fast I/O-busses for the network. –Could be configured for large ”Window sizes” –Support ”jumbo frames” Otherwise You will be disappointed…

13. Can You spot the difference? Answer: a)0,001% more cable in ”B” (compared to total distance). b)More (expensive) equipment in ”B”. c)75-80% less performance in ”B”. Access router Core switch Data center switch Host Access router Core switch Data center switch Host Alt. A Alt. B

14. Conclusion SUNET and GigaSunet are ready to handle this. Now. The ”problems” are local at each university. We can help You with tuning guidelines and act as testing partners. –SUNET test hosts are connected directly to the core network, without LAN equipment in between. That helps us isolate “local” problems.

15. What You should do next.. Contact Your local network group. –Get a fiber connection from Your site to one of the SUNET access routers. –Have them 1 configure the router for Your connection. Connect the GRID equipment, as ”clean” as possible. Tune Your system! 1 / Done locally at each university, except Uppsala.

16. Questions? Börje Josefsson