Subject: multicast routing loop near gopher.kornet.nm.kr

From: Van Jacobson <[email-masked]>
Date: Thu, 13 Jun 96 19:41:39 PDT

There seems to be a serious multicast routing loop somewhere around
router gopher.kornet.nm.kr.  I'm seeing around 200 packets/sec from
the Korea Telecom site on the mbone audio session socket.  Mtrace shows:

  Source                         Packet Statistics For     Only For Traffic
147.6.9.91       rtt  722 ms     All Multicast Traffic     From 147.6.9.91
     v                           Lost/Sent = Pct  Rate       To 224.2.0.1
147.6.9.103     h2o.kotel.co.kr 
     v            ttl   16    -1666/32   = --%   1 pps     0/8    = --%   0 pps
168.126.63.9    gopher.kornet.nm.kr 
     v            ttl  128      -16/487  = -2%  25 pps   949/1445 = 66%  76 pps
207.12.55.99    stk-mbone-1.sprintlink.net 
     v            ttl  129        0/514  =  0%  27 pps     0/496  =  0%  26 pps
192.203.230.241 mbone.nsi.nasa.gov 
     v            ttl  130        0/1374 =  0%  68 pps     0/496  =  0%  24 pps
192.203.230.242 mbone2.nsi.nasa.gov 
     v            ttl  131       -1/1385 =  0%  69 pps     0/496  =  0%  24 pps
192.52.195.128 
140.173.96.2    ames.dart.net  
     v            ttl  132        0/1507 =  0%  75 pps     0/496  =  0%  24 pps
140.173.96.1   
192.12.173.2    vee.ee.lbl.gov 
     v            ttl  133        2/1507 =  0%  75 pps     0/496  =  0%  24 pps
192.12.173.1   
131.243.1.64    vet.ee.lbl.gov 
     v            ttl  134          596         29 pps       496         24 pps
131.243.1.67    131.243.1.67
  Receiver      Query Source

The 8 packets from h2o.kotel.co.kr turning into 1445 at gopher.kornet.nm.kr
suggests that the loop is at or near this site.

 - Van