All things related to multicast

[Gordon Rogier <>]

well here is the thing.  our attached sites are not getting certain sdr
announements reliably at all.  here is a couple of things we observed.

first our topology is site<-->gpn<-->abilene.  now we noticed that abilene
has sdr listen turned on to the interface to gpn.  interesting note here
is that from the perspective of the gpn<-->abilene connection, the sdr
connection is effectively dense; aka, gpn does not even need to do a msdp
triggered join to the respective sdr sources, their announcement will come
in regardless of our spt joins within the sdr 224.2.127.254 group.  this
is a little misleading, but understandable.

second, we noticed that the attached sites to gpn only had a subset of the
sdr list.  now, gpn does _not_ have sdr listen turned on to it's site
interfaces.   we did some digging and theorized about mroute prunning vs
msdp announcements, QED my prior question.

we have looked a little deeper and have a better issue.  it appears to us
that certain sdr announcers are not being advertised in msdp reliably or
even at all. eg. take the "NASA TV - Broadcast from NASA HQ" content.

here is how it looks in the "psuedo-dense" connected gpn router,

Session Name: NASA TV - Broadcast from NASA HQ
  Description: NASA TV Multicasting from NASA HQ
  Group: 0.0.0.0, ttl: 0, Contiguous allocation: 1
  Lifetime: from 11:36:16 CDT Jun 11 1999 until 10:36:16 CST Dec 11 1999
  Uptime: 3d21h, Last Heard: 00:01:20
  Announcement source: 131.182.10.250, destination: 224.2.127.254
  Created by: ellery 3132060082 3138107776 IN IP4 131.182.10.250
  Phone number: +202 651 8512
  Email: 

     (Ellery D. Coleman)
  URL: http://www.nasa.gov/ntv
  Media: audio 23748 RTP/AVP 0
    Media group: 224.2.203.38, ttl: 127
  Media: video 60068 RTP/AVP 31
    Media group: 224.2.203.37, ttl: 127
    Attribute: framerate:9
    Attribute: quality:8
    Attribute: grayed:0

and here are the related sdr source "131.182.10.250" msdp sa-cache
entries,

(131.182.10.250, 224.2.203.37), RP 198.10.80.1, MBGP/AS 24, 2w5d/00:05:07
(131.182.10.250, 224.2.203.37), RP 137.39.3.111, MBGP/AS 704, 1d18h/00:05:26
(131.182.10.250, 224.2.203.38), RP 198.10.80.1, MBGP/AS 24, 2w5d/00:05:07
(131.182.10.250, 224.2.203.38), RP 137.39.3.111, MBGP/AS 704, 1d18h/00:05:26
(131.182.10.250, 224.2.203.38), RP 128.32.0.89, MBGP/AS 25, 6d09h/00:05:42


why does not "131.182.10.250" have any msdp state for the sdr group ?? 

i know, i know, i could just fix the sdr group with the sdr listen config
on each interface like abilene is doing (i suspect although that putting
sdr listen on each interface was _not_ done my abilene as a work around to
this issue).  but, this does not do and will not do the trick for the
actual 'true' group active sources that apparently will also get
blackholed by this issue.


i have seen some other sdr sources i am suspicious of, including (with
some of my own quick notes relating to them),

(128.223.83.33, 224.2.127.254)          source mbp path is 11537 4600 3582    
  

(158.165.1.26, 224.2.127.254)           source mbp path 11537 24 10888 3701 
4222 6377
  >sh ip msdp sa-cache
   (158.165.1.26, 224.2.143.16), RP 137.39.3.111, MBGP/AS 704, 1d18h/00:05:09
   (158.165.1.26, 224.2.143.16), RP 158.165.0.2, MBGP/AS 6377, 2d16h/00:05:41
     = 224.2.143.16 is Session Name: 4J KRVM Radio Station

(169.229.12.35, 224.2.127.254)          source mbp path 11537 11423 25
  >sh ip msdp sa-cache
   (169.229.12.35, 224.2.132.110), RP 128.32.0.89, MBGP/AS 25, 
00:00:47/00:05:12

(140.109.13.249, 224.2.127.254)         source mbp path 11537 24 145 7539 9264

(131.243.2.71, 224.2.127.254)           source mbp path 11537 24 293 16

(171.69.248.71, 224.2.127.254)          source mbp path 11537 24 10888 109
  >sh ip msdp sa-cache
   (171.69.248.71, 224.2.188.149), RP 137.39.3.111, MBGP/AS 704, 
1d18h/00:05:43
   (171.69.248.71, 224.2.188.149), RP 171.69.10.13, MBGP/AS 109, 
5d16h/00:05:35
   (171.69.248.71, 224.2.145.19), RP 171.69.10.13, MBGP/AS 109, 5d16h/00:05:34
   (171.69.248.71, 224.2.127.254), RP 171.69.10.13, MBGP/AS 109, 
00:07:25/00:01:34

(210.200.32.189, 224.2.127.254)         source mbp path 11537 24 145 7539
  >sh ip msdp sa-cache
   (210.200.32.189, 224.2.172.238), RP 137.39.3.111, MBGP/AS 704, 
00:32:18/00:05:42
   (210.200.32.189, 224.2.172.238), RP 204.147.128.141, MBGP/AS 145, 
05:52:10/00:05:54
   (210.200.32.189, 224.2.189.51), RP 210.200.34.254, MBGP/AS 7539, 
06:10:50/00:05:59
   (210.200.32.189, 224.2.189.51), RP 137.39.3.111, MBGP/AS 704, 
00:32:18/00:05:40
   (210.200.32.189, 224.2.189.51), RP 204.147.128.141, MBGP/AS 145, 
06:10:49/00:05:54
   (210.200.32.189, 224.2.234.138), RP 210.200.34.254, MBGP/AS 7539, 
06:10:53/00:05:59
   (210.200.32.189, 224.2.234.138), RP 204.147.128.141, MBGP/AS 145, 
06:10:48/00:05:53


--*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*--
Gordon Rogier                        

            
Network Engineer                     785-864-0381wk 785-550-4468 cell
Great Plains Network                 785-864-9330 FAX

On Wed, 20 Oct 1999, Kevin C. Almeroth wrote:
> >>I am seeing an issue with the 'bursty' frequency of the sdr announcers and
> >>it's relationship to setting up and maintaining mroute state.  It appears
> >>to me that the mroute state is being torn down by a built in Cisco 
> >>IOS timeout of 3minutes; this coupled with that many sdr announcers are
> >>announcing with a greater than 3minutes separation is causing
> >>cascaded/edge sites to miss many sdr announcements.
> 
> As Bill points, given that MSDP is supposed to carry that first "n" data
> packets, can you explain what might be happening that would lead you
> to say MSDP is in fact NOT handling bursty sources correctly?