Subject: mrouted 3.9-beta3 strangness...

From: "Craig M. Votava" <[email-masked]>
Date: Thu, 06 Aug 1998 16:20:17 -0500

Folks-

I have mrouted3.9b3 running on an O2 with IRIX 6.3, with
two network interfaces, and I'm seeing some strange things.

Maybe someone could help me.

A workstation on network A gets an audio and a video
session fine.

A PC on network B gets the same video session fine, but
doesn't get the audio session at all.

An mtrace on the audio session from the source to the
destination shows that the O2 is "Not forwarding" the
session on to that interface. An mtrace on the video
shows everything normal.

A USER1 signal sent to the mrouted shows a group
host for the PC on the video session, but not on
the audio session.

It almost seems as if mrouted is ignoring the request
from the PC, to subscribe to the audio session, but
processes the request for the video session just fine.

Is this an mrouted problem, or is something else
causing the problem? Any help is appreciated!

Thanks

-Craig

	()_()	Craig Votava
	 (_)	Lucent Technologies
		[email-masked]

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From: Bill Fenner <[email-masked]>
Date: Thu, 6 Aug 1998 15:33:41 PDT

Try running "mrouted -d igmp,membership", or snooping IGMP on the
interface with the PC, to see if you can see what's going on.

  Bill

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From: "Thomas M. Kendall <tkendall>" <[email-masked]>
Date: Thu, 6 Aug 1998 22:14:09 -0400 (EDT)

Craig,

I have an open case with SGI on the IRIX 6.3 multicast routing 
implementation.  My case number is 0917087 and has been open
since March, with no current resolution.  Our multicast configuration
was a little different than yours (we only had one interface and one tunnel),
but the results were similar.  We replaced the O2 with an Indy running 
IRIX 6.2 and it works as expected.

Tom Kendall

>causing the problem? Any help is appreciated!

-------------------------------------------------------------------------------
Thomas M. Kendall		U. S. Army Research Laboratory
410-278-9195			Corporate Information and Computing Center
410-278-9199 (FAX)		Attn: AMSRL-CI-HC
[email-masked]		Aberdeen Proving Ground, MD  21005-5067
-------------------------------------------------------------------------------

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From: "Craig M. Votava" <[email-masked]>
Date: Fri, 07 Aug 1998 10:38:26 -0500

Bill-

Thanks for the suggestion. I ran mrouted as you said, then tried
to start the video session (224.2.171.134/49798) on the PC. It
worked fine, and here's what the debug log showed:

08:10:51.731 RECV V1 member report   from 135.185.106.253 to
224.2.171.134
08:10:51.731 group 224.2.171.134 joined on vif 1
08:11:01.548 RECV V1 member report   from 135.185.106.253 to
224.2.171.134

Then I tried to start the audio session on the PC. It didn't work, and
there
were no messages printed in the debug log.

This made me wonder if there's something wrong in the SGI protocol
stack, that drops some igmp messages on the floor. So I ran the
following command on the SGI:

# netsnoop -iec1 -y -s -vvv -x IGMP ip.src=135.185.106.253

This command (as I understand) will display all IGMP messages seen
on interface ec1 from the given source (although if the protocol
stack is dropping messages, this running on the same machine probably
wouldn't help any).

For some reason, at this point. The video session stopped coming up on
the PC. Every time I restarted it, I saw the following debug message
from netsnoop, and now, didn't see anything in the mrouted debug log.

0028:   len   60   time 10:23:21.933254
    ether:  src 0:80:c7:d2:5:9a           dst 1:0:5e:2:ab:86/IP-mcast  
            type ip    
    ip:     v 4       hl 5      tos 0     len 28    id 39425  off 0
            ttl 1     p igmp    sum 0xa19f
            src il0015craig2.ih.lucent.co dst 224.2.171.134            
    igmp:   version 1           type REPORT         unused 0   
            cksum 0x6276        group 224.2.171.134

Also, when I tried to bring up the audio session again, I saw no
messages either the mrouted debug log or the netsnoop log.

Any further help, or guesses on what this means, would be appreciated!

Thanks

-Craig

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From: Bill Fenner <[email-masked]>
Date: Sat, 8 Aug 1998 12:36:36 PDT

Craig,

  If you have a third machine on the subnet, try snooping from it, to see
if the message that the SGI doesn't see is on the network at all (i.e. is
the PC sending it and the SGI dropping it, or is the PC just not sending
it?)

  Bill