Subject: Serious routing loop in UCLA

From: Bill Fenner <[email-masked]>
Date: Fri, 18 Oct 1996 12:43:46 PDT

It looks like there's a routing loop inside of UCLA.  I am receiving
27 copies of each packet that unagi.library.ucla.edu sends (mdups
output appended at end).  It looks like this is a PIM loop; mtrace
shows the traffic as being sourced from the souce subnet, so it looks
like there's an alternate path that's being taken from cbn6-f0.ucla.edu
or ucla-internet.LosAngeles.mci.net back to subnet 164.67.40 .  The total
length of the loop appears to be 2 routers.

Could someone please make unagi.library.ucla.edu (and fido too) stop sending
traffic and then fix the loop?

Thanks,
  Bill

mtrace output:

  Source        Response Dest    Overall     Packet Statistics For Traffic From
164.67.40.14    204.162.228.2    Packet      164.67.40.14 To 224.2.167.31
     |       __/  rtt  166 ms     Rate       Lost/Sent = Pct  Rate
     v      /     hop  211 s     -------     ---------------------
164.67.40.2    
164.67.128.202  cbn6-f0.ucla.edu 
     |     ^      ttl    1        30 pps       34/96   = 35%   9 pps
     v     |      hop   93 ms     29 pps      965/2829 = 34%   9 pps
164.67.128.80  
204.70.174.6    ucla-internet.LosAngeles.mci.net 
     |     ^      ttl   66         7 pps        0/62   =  0%   6 pps
     v     |      hop -211 s       8 pps        0/1864 =  0%   6 pps
204.70.170.45  
204.70.170.29   dec3800-1-fddi-0.LosAngeles.mci.net 
     |     ^      ttl   66       158 pps        0/62   =  0%   6 pps
     v     |      hop    0 ms    156 pps        0/1864 =  0%   6 pps
204.70.158.61   dec3800-2-fddi-0.SanFrancisco.mci.net 
     |     ^      ttl   68        16 pps        2/62   =  3%   6 pps
     v     |      hop  211 s      20 pps       56/1864 =  3%   6 pps
192.203.230.241 mbone.nsi.nasa.gov 
     |     ^      ttl   68       117 pps        0/60   =  0%   6 pps
     v     |      hop   62 ms    116 pps        0/1808 =  0%   6 pps
192.203.230.242 mbone2.nsi.nasa.gov 
     |     ^      ttl   70       117 pps        2/60   =  3%   6 pps
     v     |      hop -263 ms    116 pps       96/1808 =  5%   6 pps
192.52.195.128 
140.173.144.1   ames.dart.net  
     |     ^      ttl   70       126 pps        0/58   =  0%   5 pps
     v     |      hop   19 ms    124 pps        0/1712 =  0%   5 pps
140.173.144.2  
204.162.228.1   parc.dart.net  
     |      \__   ttl   70       130 pps        ?/58           5 pps
     v         \  hop -211 s     127 pps        ?/1712         5 pps
204.162.228.1   204.162.228.2
  Receiver      Query Source

mdups output:

12:37:55.965147 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 2 deltatime 117 ms id 44585 ndups 1
12:37:55.970031 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 4 deltatime 122 ms id 44585 ndups 2
12:37:55.971012 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 6 deltatime 123 ms id 44585 ndups 3
12:37:55.977741 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 8 deltatime 130 ms id 44585 ndups 4
12:37:55.979077 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 10 deltatime 131 ms id 44585 ndups 5
12:37:55.981655 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 12 deltatime 134 ms id 44585 ndups 6
12:37:55.985616 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 14 deltatime 137 ms id 44585 ndups 7
12:37:55.988285 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 16 deltatime 140 ms id 44585 ndups 8
12:37:55.989624 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 18 deltatime 141 ms id 44585 ndups 9
12:37:55.991163 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 20 deltatime 143 ms id 44585 ndups 10
12:37:55.995142 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 24 deltatime 147 ms id 44585 ndups 11
12:37:55.996478 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 26 deltatime 148 ms id 44585 ndups 12
12:37:55.999038 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 28 deltatime 151 ms id 44585 ndups 13
12:37:56.005415 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 30 deltatime 157 ms id 44585 ndups 14
12:37:56.007164 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 32 deltatime 159 ms id 44585 ndups 15
12:37:56.008512 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 34 deltatime 160 ms id 44585 ndups 16
12:37:56.010067 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 36 deltatime 162 ms id 44585 ndups 17
12:37:56.013187 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 38 deltatime 165 ms id 44585 ndups 18
12:37:56.014653 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 40 deltatime 166 ms id 44585 ndups 19
12:37:56.015689 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 42 deltatime 168 ms id 44585 ndups 20
12:37:56.019959 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 44 deltatime 172 ms id 44585 ndups 21
12:37:56.021270 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 46 deltatime 173 ms id 44585 ndups 22
12:37:56.022839 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 48 deltatime 175 ms id 44585 ndups 23
12:37:56.023649 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 50 deltatime 175 ms id 44585 ndups 24
12:37:56.025750 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 52 deltatime 178 ms id 44585 ndups 25
12:37:56.027107 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 54 deltatime 179 ms id 44585 ndups 26
12:37:56.028329 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 56 deltatime 180 ms id 44585 ndups 27

---

From: Scott Burris <[email-masked]>
Date: Fri, 18 Oct 1996 20:44:11 +0000 ( )

I've taken UCLA temporarily off the MBONE until we fix this.

Scott Burris
UCLA Campus Network Services

> Could someone please make unagi.library.ucla.edu (and fido too) stop
> sending traffic and then fix the loop?
> 
> Thanks,
>   Bill
> 
> mtrace output:
> 
> 12:37:55.965147 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 2
> deltatime 117 ms id 44585 ndups 1 12:37:55.970031 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 4 deltatime 122 ms id 44585 ndups 2
12:37:55.971012 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 6 deltatime
123 ms id 44585 ndups 3
> 12:37:55.977741 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 8
> deltatime 130 ms id 44585 ndups 4 12:37:55.979077 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 10 deltatime 131 ms id 44585 ndups 5
12:37:55.981655 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 12 deltatime
134 ms id 44585 ndups 6
> 12:37:55.985616 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 14
> deltatime 137 ms id 44585 ndups 7 12:37:55.988285 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 16 deltatime 140 ms id 44585 ndups 8
12:37:55.989624 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 18 deltatime
141 ms id 44585 ndups 9
> 12:37:55.991163 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 20
> deltatime 143 ms id 44585 ndups 10 12:37:55.995142 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 24 deltatime 147 ms id 44585 ndups 11
12:37:55.996478 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 26 deltatime
148 ms id 44585 ndups 12
> 12:37:55.999038 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 28
> deltatime 151 ms id 44585 ndups 13 12:37:56.005415 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 30 deltatime 157 ms id 44585 ndups 14
12:37:56.007164 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 32 deltatime
159 ms id 44585 ndups 15
> 12:37:56.008512 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 34
> deltatime 160 ms id 44585 ndups 16 12:37:56.010067 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 36 deltatime 162 ms id 44585 ndups 17
12:37:56.013187 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 38 deltatime
165 ms id 44585 ndups 18
> 12:37:56.014653 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 40
> deltatime 166 ms id 44585 ndups 19 12:37:56.015689 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 42 deltatime 168 ms id 44585 ndups 20
12:37:56.019959 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 44 deltatime
172 ms id 44585 ndups 21
> 12:37:56.021270 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 46
> deltatime 173 ms id 44585 ndups 22 12:37:56.022839 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 48 deltatime 175 ms id 44585 ndups 23
12:37:56.023649 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 50 deltatime
175 ms id 44585 ndups 24
> 12:37:56.025750 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 52
> deltatime 178 ms id 44585 ndups 25 12:37:56.027107 unagi.library.ucla.edu
> 224.2.167.31 oTTL 118 delta 54 deltatime 179 ms id 44585 ndups 26
12:37:56.028329 unagi.library.ucla.edu 224.2.167.31 oTTL 118 delta 56 deltatime
180 ms id 44585 ndups 27