(Message inbox:48) Return-Path: tcpip-approval@cs.pdx.edu Delivery-Date: Tue Nov 11 09:42:44 2003 Return-Path: Received: from rigel.cs.pdx.edu (Majordomo@localhost [127.0.0.1]) by rigel.cs.pdx.edu (8.12.10/8.12.10) with ESMTP id hABHfua7029115 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Tue, 11 Nov 2003 09:41:57 -0800 (PST) Received: (from Majordomo@localhost) by rigel.cs.pdx.edu (8.12.10/8.12.3/Submit) id hABHfuZt029113 for tcpip-outgoing; Tue, 11 Nov 2003 09:41:56 -0800 (PST) X-Authentication-Warning: rigel.cs.pdx.edu: Majordomo set sender to owner-tcpip@cs.pdx.edu using -f Received: from sirius.cs.pdx.edu (root@sirius.cs.pdx.edu [131.252.208.57]) by rigel.cs.pdx.edu (8.12.10/8.12.10) with ESMTP id hABHfka7029092 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Tue, 11 Nov 2003 09:41:47 -0800 (PST) Received: from sirius.cs.pdx.edu (jrb@localhost [127.0.0.1]) by sirius.cs.pdx.edu (8.12.10/8.12.10) with ESMTP id hABHfk6B008104 for ; Tue, 11 Nov 2003 09:41:46 -0800 (PST) Message-Id: <200311111741.hABHfk6B008104@sirius.cs.pdx.edu> To: tcpip@cs.pdx.edu Subject: study question Date: Tue, 11 Nov 2003 09:41:46 -0800 From: Jim Binkley X-Virus-Scanned: by amavisd-new Sender: owner-tcpip@cs.pdx.edu Precedence: bulk X-Spam-Status: No, hits=-5.8 required=5.0 tests=BAYES_01,X_AUTH_WARNING version=2.55 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) Given the following traceroute from PSU to MIT ... which goes over I2, please give at least one reason (and try to be very very scientific please ... if you get this right, we will call you Mr. Science in class from now on ...) explain why: Givens: 1. Hop 7 is in Seattle and can be viewed as the entrance to the Abilene backbone (which is apparently an OC-192 Sonet link, but I'm not 100% sure about that) ( See http://abilene.internet2.edu/ for a map) 2. Hop 8 is in Denver and represents the other end of the Seattle to Denver link. So?: So give one reason why is there for example about a 25 ms time difference between hop 7 and hop 8? Compare this to hop 4 versus hop 5 (which is where to where?). Jim sh-2.02$ traceroute www.mit.edu traceroute to DANDELION-PATCH.mit.edu (18.181.0.31), 30 hops max, 40 byte packets 1 deepthot.seas.pdx.edu (131.252.208.2) 0.802 ms 0.653 ms 0.589 ms 2 fricka.dmz.pdx.edu (131.252.1.5) 0.520 ms 0.598 ms 0.556 ms 3 198.32.195.11 (198.32.195.11) 0.633 ms 0.693 ms 0.703 ms 4 core1-pdx-ge-1-1-0-0.pnw-gigapop.net (198.107.144.69) 0.841 ms 0.583 ms 0.549 ms 5 core1-wes-so-0-2-1-0.pnw-gigapop.net (198.107.144.17) 3.981 ms 3.989 ms 3.966 ms 6 hnsp2-wes-ge-1-0-1-0.pnw-gigapop.net (198.107.151.12) 3.978 ms 4.056 ms 4.363 ms 7 abilene-pnw.pnw-gigapop.net (198.107.144.2) 3.989 ms 4.047 ms 4.372 ms 8 dnvrng-sttlng.abilene.ucaid.edu (198.32.8.50) 29.682 ms 29.678 ms 30.119 ms 9 kscyng-dnvrng.abilene.ucaid.edu (198.32.8.14) 42.336 ms 40.394 ms 40.234 ms 10 * iplsng-kscyng.abilene.ucaid.edu (198.32.8.80) 343.354 ms 321.851 ms 11 chinng-iplsng.abilene.ucaid.edu (198.32.8.76) 58.035 ms 53.623 ms 55.249 ms 12 nycmng-chinng.abilene.ucaid.edu (198.32.8.83) 74.422 ms 73.294 ms 73.368 ms 13 ATM10-420-OC12-GIGAPOPNE.nox.org (192.5.89.9) 78.760 ms 78.526 ms 78.647 ms 14 192.5.89.90 (192.5.89.90) 78.671 ms 78.932 ms 78.650 ms 15 NW12-RTR-2-BACKBONE.MIT.EDU (18.168.0.21) 78.636 ms 78.751 ms 78.665 ms 16 * *^C sh-2.02$ exit script done on Tue Nov 11 09:26:12 2003