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  • . # flows – currently a problem with the number of flows a router can keep track of . > 1 gbps – what happens to backbones (Abilene), switches, etc . IGMPv2 will not scale across routers, so how should one deploy SSM (directory services?)
  • ppt

    1. 1. Network Troubleshooting or … Is there any hope my Performance will be seen over the network? Bob Riddle – Technologist January 2005
    2. 2. What is a network geek doing at a New World Symphony seminar? <ul><li>Did I come to share my musical talents? </li></ul><ul><ul><li>I played the bassoon in elementary school & middle school </li></ul></ul><ul><ul><li>I taught myself to play a guitar, I now play it 1 week a year </li></ul></ul><ul><ul><li>My kids gave me a harmonica – want to hear me play? </li></ul></ul><ul><li>No? then let’s look at some network stuff </li></ul><ul><ul><li>using the network to “stretch” the stage & the auditorium </li></ul></ul><ul><ul><li>the kind of tools you need in your network “toolbox”? </li></ul></ul><ul><ul><li>how to “stack the deck” in your favor </li></ul></ul>
    3. 3. Issues to consider when stretching the stage & the auditorium <ul><ul><li>Speed: do you need a freeway, city street, or a dirt road? (H.323 – HDTV) </li></ul></ul><ul><ul><li>Latency : is it a “telephone” call or a “movie”? (streaming or interactive) </li></ul></ul><ul><ul><li>Packet Loss : is there any “junk mail” you can throw away? </li></ul></ul>Things to think about when “ stretching” the stage
    4. 4. Issues to consider: Do you need a dirt road or a freeway ? <ul><li>Determine the quality of the Experience </li></ul><ul><ul><li>Mpeg1 ~= 1.5 – 3.0 mpbs </li></ul></ul><ul><ul><li>H.323 ~= 384 – 1.5 mbps kbps </li></ul></ul><ul><ul><li>Mpeg2 ~= 4 – 15 mbps </li></ul></ul><ul><ul><li>DV ~= 30 mbps </li></ul></ul><ul><ul><li>HDTV ~= 20 – 270 mbps; 1.5 gbps </li></ul></ul><ul><li>Determine the type of Experience </li></ul><ul><ul><li>One way? (streaming, broadcast) </li></ul></ul><ul><ul><li>Two way? (interactive voice, video) </li></ul></ul><ul><ul><li>Many way? (more than 2 end points) </li></ul></ul><ul><li>Do the Math & check your “onramp”! </li></ul>
    5. 5. Issues to consider – unicast or multicast <ul><li>can’t I get away with just unicast? (Real, QT) </li></ul><ul><ul><li>Depends on the “ road” – 384 kbps or 30 mbps stream(s) </li></ul></ul><ul><ul><li>i.e. stats from earlier Victoria Secrets webcast </li></ul></ul><ul><ul><ul><li>More than 1 million web hits during 1 st hour </li></ul></ul></ul><ul><ul><ul><li>283% increase in web traffic during event </li></ul></ul></ul><ul><ul><li>Unicast delivery doesn’t cheaply scale! </li></ul></ul><ul><li>think of multicast as “Broadcast TV” </li></ul><ul><ul><li>If you have a “tuner” and your “antenna” is pointed in the right direction, just tune in the “channel” </li></ul></ul><ul><ul><li>If you’re on a Internet2 backbone, you’re ready! (well, almost ready …) </li></ul></ul><ul><li>Do the math (stream * potential endpoints) </li></ul><ul><ul><li>If there’s only 1 endpoint, use unicast </li></ul></ul><ul><ul><li>If it’s a “Victoria Secrets” type thing, use multicast </li></ul></ul>
    6. 6. If the “math” works out – then go for a test drive <ul><li>Take a good look at your local “roads” </li></ul><ul><ul><li>Run internal tests across your LAN </li></ul></ul><ul><ul><li>Make sure you’re testing what you plan to use! </li></ul></ul><ul><ul><li>Find a friend “ next door ” to test with </li></ul></ul><ul><ul><li>Learn about ping , traceroute , the Detective, ethereal , iperf , DVTS, VLC & what they can tell you about your network situation </li></ul></ul><ul><ul><li>Start thinking about the on-ramp, the freeway, and those other “local roads” at your endpoints and potential endpoints </li></ul></ul>
    7. 7. Network Toolbox: Basic tools <ul><li>Ping – can I get from here to there? </li></ul><ul><ul><li>History of Ping </li></ul></ul><ul><ul><li>Web Page with Ping & other tools </li></ul></ul><ul><ul><li>Spend $24.95 for pretty pictures </li></ul></ul><ul><ul><li>Beware! ICMP packets are now often blocked </li></ul></ul><ul><li>traceroute (tracert) – what roads do I travel </li></ul><ul><ul><li>Web Page with Ping & other tools </li></ul></ul><ul><ul><li>Spend $24.95 for pretty pictures </li></ul></ul><ul><ul><li>When things good one direction but not the other, check for asymmetrical routes (then check for full duplex trouble!) </li></ul></ul>
    8. 8. Network Toolbox: more tools <ul><li>Internet2 Detective </li></ul><ul><ul><li>check your on-ramp to Abilene </li></ul></ul><ul><ul><li>test your multicast capability </li></ul></ul><ul><ul><li>Test your “speed” (bandwidth) </li></ul></ul><ul><ul><li>Check you speed from here to there using “iperf” </li></ul></ul><ul><li>Another “detective” </li></ul><ul><ul><li>SurfNet – NAT, firewall tests, duplex test, IPv6 test, etc. </li></ul></ul>
    9. 9. Network Toolbox: more tools <ul><li>check out your network capability: </li></ul><ul><ul><li>DVTS/DVGuide: readily available streams </li></ul></ul><ul><ul><li>MPEG2 example (using VLC client ) </li></ul></ul><ul><ul><ul><li>Research Channel </li></ul></ul></ul><ul><ul><ul><li>University of Washington </li></ul></ul></ul><ul><ul><li>DVTS example (using DVTS WinXP client ) </li></ul></ul><ul><ul><ul><li>Research Channel </li></ul></ul></ul><ul><ul><ul><li>University of Pennsylvania </li></ul></ul></ul><ul><ul><ul><li>University of South Florida </li></ul></ul></ul><ul><ul><ul><li>Internet2 Test Channel </li></ul></ul></ul>
    10. 10. Network Toolbox: great tools <ul><li>ethereal – look at the traffic on your road </li></ul><ul><ul><li>Powerful Multi-Platform Analysis </li></ul></ul><ul><ul><li>Useful for checking TTL, determining whether it’s a network problem or an endpoint problem </li></ul></ul><ul><li>iperf – bandwidth measurement tool </li></ul><ul><ul><li>Peer-to-peer tool for performance testing </li></ul></ul><ul><ul><li>Supports tcp, udp, multicast traffic </li></ul></ul><ul><ul><li>Supports uni-directional & bi-directional testing </li></ul></ul><ul><li>Mailing lists </li></ul><ul><ul><li>[email_address] </li></ul></ul><ul><ul><li>wg-multicast@internet2.edu </li></ul></ul>
    11. 11. Stack the deck in your favor <ul><li>Use an early-warning system! </li></ul><ul><ul><li>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? </li></ul></ul><ul><ul><li>Wouldn’t it be nice if you could use a cheap PC to determine if there was any hope? </li></ul></ul><ul><ul><li>Wouldn’t it be nice if you could use free (or almost free!) software to determine if there was any hope? </li></ul></ul><ul><li>Think about building cakeboxes </li></ul>
    12. 12. Stack the deck using the cakebox <ul><li>Criteria for the cakebox: </li></ul><ul><ul><li>Small, inexpensive, easy to ship device </li></ul></ul><ul><ul><li>No operator, no monitor, keyboard, or mouse required </li></ul></ul><ul><ul><li>Just plug in a network cable & a power cable </li></ul></ul><ul><ul><li>Provide web interface for non-network geeks </li></ul></ul><ul><li>http://envoy.internet2.edu/pioneer/ </li></ul><ul><li>What it will allow you to do: </li></ul><ul><ul><li>Allows representative bandwidth testing </li></ul></ul><ul><ul><li>Shows you what “road” you’ll travel </li></ul></ul><ul><ul><li>Allows you to exercise “broadcast” (multicast) traffic </li></ul></ul><ul><ul><li>You can find out if there is any hope </li></ul></ul>
    13. 13. Stack the deck using the cakebox <ul><li>Cakebox built using freely available tools: </li></ul><ul><ul><li>http:// dast.nlanr.net/Projects/Iperf / </li></ul></ul><ul><ul><li>http:// dast.nlanr.net /Projects/Beacon/ </li></ul></ul><ul><ul><li>http:// dast.nlanr.net /NPMT/ </li></ul></ul><ul><li>Packaged on Linux Platform </li></ul><ul><ul><li>“ phone-home” to LDAP server </li></ul></ul><ul><ul><li>Secure access via SSL to web server </li></ul></ul><ul><ul><li>Secure access via SSH directly to cakebox </li></ul></ul>
    14. 14. <ul><li>? </li></ul>