nanog mailing list archives

RE: IPv4 Multicast


From: Jamie Sobczyk <lanson9 () cox net>
Date: Fri, 21 May 2010 10:52:02 -0400 (EDT)

Make sure you have
"ip multicast-routing"
on both routers.

On the router interfaces, make sure you have
"ip pim sparse-mode"

On both routers, make sure you have the same rp address assigned and that you can ping this ip address from both routers. (I prefer to make it a loopback interface)
"ip pim rp-address w.x.y.z"

Also, make sure that routing is setup on your routers so that your receiver can ping your sender.

On your routers you should be able to see the source unicast address and multicast address by typing "show ip mroute"
you should see something like this:
(*, 239.192.3.47), 7w0d/00:02:59, RP 10.31.0.1, flags: S
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    Port-channel15, Forward/Sparse, 7w0d/00:02:59, H

(10.5.9.51, 239.192.3.47), 4w5d/00:03:27, flags: TA
  Incoming interface: Port-channel15, RPF nbr 10.7.193.138
  Outgoing interface list:
    Port-channel17, Forward/Sparse, 4w5d/00:02:49, H

On your switches, with igmp snooping enabled, you should be able to type:
"show ip igmp snooping group" and see something like
Vlan      Group                    Type        Version     Port List
-----------------------------------------------------------------------
24        239.192.3.47             igmp        v2          Gi1/0/21
That port listed is the port of the requester.




-----Original Message-----
I have setup a lab for this multicast.

VLC receiver - 3560G - 1841 - 1841 - 4503 - VLC sender

The 2 switches only provide L2 access, they have IGMP snooping active

On both 1841's I have pim parse-mode & sap listen on all interfaces +
configured a static RP, the one closest to the sender.

With my VLC receiver I can see the channels via SAP, but when I join the
multicast group I don't receive anything.

Could someone help me to troubleshoot this?

Thanks in advance,

Rens




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