[cisco-voip] Multicast MoH Delay

[Tony Underwood]

If it's a delay in the route set up then you could try a static igmp join on the far end router.
ip igmp join-group group-address

Tony Underwood CCIE #7112
Sr. Network Engineer
Cambium Data Inc.
5050 So. 111th St.
Omaha, NE 68137
(402) 556-1388
http://www.cambiumdata.com<http://www.cambiumdata.com/>

From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of Daniel
Sent: Wednesday, June 24, 2009 1:46 AM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] Multicast MoH Delay

Hi All,

I've setup multicast routing for music on hold between our data centre network and building floor subnets. The setup is that the data centre is on a different subnet and gear to the floor subnets so multicast routing needs to be used to get MoH packets to the phones.

This consists of the following traffic flow,

MoH Server > Access Switch > Distribution Switch/router(RP) > Distribution Switch/router > Floor Switches > Phones

There are three routing hops (1) from vlan interface to routed interfaces of distribution switch (2) between Distribution and (3) from routed interface of distributionswitch  to phone vlan interface. Only the distribution switches are layer 3.

The first distribution switch is the RP for the group and only that group.The second distribution switch is accepting auto RP only. We are using sparse mode.

Multicast traffic is working, the RP mappings are there, the mroute is there, the problem is that when a call is placed on hold there is a 5 second delay before the music is heard. I assume this to be somewhat because of the join message and the delay of the route or path being setup.

Anyone know of a way to reduce the delay before music is heard? If not I guess its back to the lab.

regards,

Dan

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20090624/7a7d2fcc/attachment.html>