[Xorp-users] Questions on multicast routing

[Williams, Mark]

Well, looking at the diagram and details in the email, it looks like br1 on R1 was the rendezvous point for the multicast stream, and since you had a relatively high value of 1024000 (81 kbps with default interval value of 100) for switch-to-spt-threshold, a stream of only 64k would not trigger a switch to the shortest path. 

In any case, the register-stop message should have been sent from R1 to R2, but that didn't happen either. Was your fix related to this?

-Mark Williams

-----Original Message-----
From: xorp-users-bounces at xorp.org [mailto:xorp-users-bounces at xorp.org] On Behalf Of Ben Greear
Sent: Wednesday, July 01, 2009 11:16
To: xorp-users at xorp.org
Subject: Re: [Xorp-users] Questions on multicast routing

On 06/29/2009 04:51 PM, Ben Greear wrote:
> I am trying to figure out why multicast is taking the 'long' way through
> the
> network.
>
> My network diagram is attached. The xorp output below is from router 2
> (the top one).
>
> I am generating mcast traffic from Node2 interface to Node3. I would
> expect it to
> go through the link between R2 and R3, but instead it goes R2 -> R1 ->
> R3. My traffic
> flow is 64k, so I think it's using xorp user-space routing instead of
> setting up
> a kernel cache.
>
> I have hacked on multicast to support multiple routing tables, so it could
> be my bug, but I'd still appreciate any pointers to what might be going
> wrong
> if anyone has any ideas!
>
> I'll be happy to send any other information, just ask.

I think maybe I was confused on how multicast works..and I vaguely remember that this might
have happened to me before :P

Anyway, the real problem I was chasing was elsewhere, and the patch I sent to the mailing
list yesterday fixed it.

Thanks,
Ben

-- 
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc  http://www.candelatech.com

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