Network Troubleshooting: Stretching Performance Over the Network

1. Network Troubleshooting or …Is there any hope my Performance will be seen over the network? Bob Riddle – Technologist January 2005

2. What is a network geek doing at a New World Symphony seminar? • Did I come to share my musical talents? • I played the bassoon in elementary school & middle school • I taught myself to play a guitar, I now play it 1 week a year • My kids gave me a harmonica – want to hear me play? • No? then let’s look at some network stuff • using the network to “stretch” the stage & the auditorium • the kind of tools you need in your network “toolbox”? • how to “stack the deck” in your favor

3. Issues to consider when stretching the stage & the auditorium Things to think about when “stretching” the stage • Speed: do you need a freeway, city street, or a dirt road? (H.323 – HDTV) • Latency: is it a “telephone” call or a “movie”? (streaming or interactive) • Packet Loss: is there any “junk mail” you can throw away?

4. Issues to consider:Do you need adirt roador afreeway? • Determine the quality of the Experience • Mpeg1 ~= 1.5 – 3.0 mpbs • H.323 ~= 384 – 1.5 mbps kbps • Mpeg2 ~= 4 – 15 mbps • DV ~= 30 mbps • HDTV ~= 20 – 270 mbps; 1.5 gbps • Determine the type of Experience • One way? (streaming, broadcast) • Two way? (interactive voice, video) • Many way? (more than 2 end points) • Do the Math & check your “onramp”!

5. Issues to consider – unicast or multicast • can’t I get away with just unicast? (Real, QT) • Depends on the “ road” – 384 kbps or 30 mbps stream(s) • i.e. stats from earlier Victoria Secrets webcast • More than 1 million web hits during 1st hour • 283% increase in web traffic during event • Unicast delivery doesn’t cheaply scale! • think of multicast as “Broadcast TV” • If you have a “tuner” and your “antenna” is pointed in the right direction, just tune in the “channel” • If you’re on a Internet2 backbone, you’re ready! (well, almost ready …) • Do the math (stream * potential endpoints) • If there’s only 1 endpoint, use unicast • If it’s a “Victoria Secrets” type thing, use multicast

6. If the “math” works out – then go for a test drive Take a good look at your local “roads” • Run internal tests across your LAN • Make sure you’re testing what you plan to use! • Find a friend “next door” to test with • Learn about ping, traceroute, the Detective, ethereal, iperf, DVTS, VLC & what they can tell you about your network situation • Start thinking about the on-ramp, the freeway, and those other “local roads” at your endpoints and potential endpoints

7. Network Toolbox: Basic tools • Ping – can I get from here to there? • History of Ping • Web Page with Ping & other tools • Spend $24.95 for pretty pictures • Beware! ICMP packets are now often blocked • traceroute (tracert) – what roads do I travel • Web Page with Ping & other tools • Spend $24.95 for pretty pictures • When things good one direction but not the other, check for asymmetrical routes (then check for full duplex trouble!)

8. Network Toolbox: more tools • Internet2 Detective • check your on-ramp to Abilene • test your multicast capability • Test your “speed” (bandwidth) • Check you speed from here to there using “iperf” • Another “detective” • SurfNet – NAT, firewall tests, duplex test, IPv6 test, etc.

9. Network Toolbox: more tools • check out your network capability: • DVTS/DVGuide: readily available streams • MPEG2 example (using VLC client) • Research Channel 233.0.73.28 • University of Washington 233.0.73.29 • DVTS example (using DVTS WinXP client) • Research Channel 233.0.73.25 • University of Pennsylvania 233.0.55.10 • University of South Florida 233.22.29.128 • Internet2 Test Channel 233.45.17.50

10. Network Toolbox: great tools • ethereal – look at the traffic on your road • Powerful Multi-Platform Analysis • Useful for checking TTL, determining whether it’s a network problem or an endpoint problem • iperf – bandwidth measurement tool • Peer-to-peer tool for performance testing • Supports tcp, udp, multicast traffic • Supports uni-directional & bi-directional testing • Mailing lists • bigvideo@internet2.edu • wg-multicast@internet2.edu

11. Stack the deck in your favor • Use an early-warning system! • Wouldn’t it be nice if you could figure out if there was any hope your stuff would work without having to buy/borrow/steal another expensive device to ship to each end point? • Wouldn’t it be nice if you could use a cheap PC to determine if there was any hope? • Wouldn’t it be nice if you could use free (or almost free!) software to determine if there was any hope? • Think about building cakeboxes

12. Stack the deck using the cakebox • Criteria for the cakebox: • Small, inexpensive, easy to ship device • No operator, no monitor, keyboard, or mouse required • Just plug in a network cable & a power cable • Provide web interface for non-network geeks • http://envoy.internet2.edu/pioneer/ • What it will allow you to do: • Allows representative bandwidth testing • Shows you what “road” you’ll travel • Allows you to exercise “broadcast” (multicast) traffic • You can find out if there is any hope

13. Stack the deck using the cakebox • Cakebox built using freely available tools: • http://dast.nlanr.net/Projects/Iperf/ • http://dast.nlanr.net/Projects/Beacon/ • http://dast.nlanr.net/NPMT/ • Packaged on Linux Platform • “phone-home” to LDAP server • Secure access via SSL to web server • Secure access via SSH directly to cakebox

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