Subject: serious multicast routing loop a uoregon

From: Van Jacobson <[email-masked]>
Date: Thu, 21 Mar 96 23:46:23 PST

David,

There seems to be a serious multicast routing loop somewhere in
the UOregon PIM cloud.  Appended is the result of one session
packet set from riley-net170-164.uoregon.edu to the NASA Shuttle
video session.  For me, mtrace always fails at either
univ-of-oregon.Sacramento.mci.net (204.70.166.42) or
mci-gw.transit.uoregon.edu (198.107.238.250) so I don't know how
to debug this.  But it seems there have been a lot of PIM
related multicast loops recently so perhaps Dino knows what
caused them & how to fix them (I see the loops appear then
disappear but never find out the cause or the fix).

 - Van
--------------------
23:23:24.454456 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 116, id 8615)
23:23:24.455648 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 114, id 8615)
23:23:24.457218 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 112, id 8615)
23:23:24.458745 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 110, id 8615)
23:23:24.460290 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 108, id 8615)
23:23:24.462545 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 106, id 8615)
23:23:24.464284 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 104, id 8615)
23:23:24.465816 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 102, id 8615)
23:23:24.467376 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 100, id 8615)
23:23:24.469204 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 98, id 8615)
23:23:24.470730 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 96, id 8615)
23:23:24.472451 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 94, id 8615)
23:23:24.474050 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 92, id 8615)
23:23:24.475495 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 90, id 8615)
23:23:24.476905 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 88, id 8615)
23:23:24.478983 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 86, id 8615)
23:23:24.480399 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 84, id 8615)
23:23:24.481983 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 82, id 8615)
23:23:24.483490 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 80, id 8615)
23:23:24.484888 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 78, id 8615)
23:23:24.486343 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 76, id 8615)
23:23:24.487622 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 74, id 8615)
23:23:24.488661 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 72, id 8615)
23:23:24.490258 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 70, id 8615)
23:23:24.492717 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 68, id 8615)
23:23:24.494076 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 66, id 8615)
23:23:24.495116 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 64, id 8615)
23:23:24.496634 128.223.170.164.1132 > 224.2.135.224.54673: udp 144 (ttl 62, id 8615)

---

From: "David M. Meyer 503/346-1747" <[email-masked]>
Date: Fri, 22 Mar 1996 06:35:44 -0800 (PST)

Sorry all. I believe that this is due to some students
	we have here in our dorms. I'll shut down their interface
	until I can understand what is happening here.

	BTW, no changes in software (Cisco images) or 
	topology recently, so I don't know what to
	attribute this to.

	Dave