Subject: Missing Mbone routes, sources, ...

From: [email-masked]
Date: Wed, 18 Feb 1998 11:40:48 -0800 (PST)

At the moment, I am seeing only 16 sdr announcements, and, I am
also seeing only one session consistently in places all over the
world - the UWM parking lot.  The NYU source is appearing and
disappearing with regularity, and, most of the other sources
(I saw 7-8 yesterday evening) have disappeared completely.

One question is, are there really only 16 global sdr announcements:

>show ip sdr
SDR Cache - 16 entries
  Best Bitch Session
  Best Elite Corps of Whiteboard Artists
  cisco Beta
  Clark's Aural Abuse
  Diesel Combustion Collaboratory
  IMJ -- Channel 1
  MBone RTP Audio
  OCC Beacon
  U(S)C-LA-LBNL(Private)
  UO Presents KKXO Memories 1450 AM
  UO Presents KMGE Magic 94 FM
  UO Presents KRVM Alternative Radio
  UO Presents KWAX Classical Radio
  UO Presents KWVA Campus Radio
  USC-CS dgroup VR conference room (private)
  VINT (private)

Another question is, are there only one or two "Places ..." sources?

It could be that is all there is at the moment.

Or, is there a big routing problem somewhere in my vicinity?
The reason I am asking is that recently there were a lot more
"Places ..." senders, and, if I'm only seeing two, it could
be that something is broken, or, it could be that activity
is low at the moment.

-Hugh LaMaster

  Hugh LaMaster, M/S 258-5,     ASCII Email:  [email-masked]
  NASA Ames Research Center     Or:           [email-masked]
  Moffett Field, CA 94035-1000  No Junkmail:  USC 18 section 2701
  Phone:  415/604-1056          Disclaimer:   Unofficial, personal *opinion*.

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From: Bill Fenner <[email-masked]>
Date: Wed, 18 Feb 1998 15:52:43 PST

Well, you can answer your first question yourself - the Precept IP/TV
Program Guide (http://www.precept.com/cgi-bin/iptv/iptvmain.pl) shows
around 30 sessions - not all of them are global, but you can compare
their list to yours.

When I run vic on the "Places" session, I see 6 video streams.
However, (my locally-modified) rtpmon shows that some people see a 7th
source that I don't see (and it also shows that most people don't see
the UWM Parking Lot Cam).

In the UWM Parking Lot Cam case, it appears that maew-mbone.nsn.nasa.gov
isn't forwarding traffic to mbone.idt.net .  Although this is only one
sample point, perhaps maew-mbone is malfunctioning (seems a logical choice
since it's near enough to you that its failure would heavily affect you).

  Bill

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From: Bill Fenner <[email-masked]>
Date: Wed, 18 Feb 1998 16:16:28 PST

maew-mbone's problem is that mbone.idt.net is a cisco, and maew-mbone's
tunnel is configured in DVMRP mode.  Cisco says that DVMRP tunnels
between two ciscos don't work.  Interestingly enough, the route
exchange works, since maew-mbone is pointing 5042 routes towards
mbone.idt.net ("show ip dvmrp route tunnel14").  However, multicast
forwarding fails to work and so apparently any route going over this
tunnel will simply blackhole.

(Interestingly enough, "mrinfo" on both ends of the tunnel show it
to be down.  I can't imagine why a router might accept routes pointing
to a down tunnel.)

Configuring PIM over a GRE tunnel is the accepted way to tunnel two
Ciscos together.

  Bill