topic Re: Multicast - Source-IP-VLAN in Switches, Hubs, and Modems

Multicast - Source-IP-VLAN

east — Sat, 09 Jan 2010 20:39:00 GMT

I currently have the settings below on a 5412zl to allow multicast traffic from VLAN 10 (Servers) to reach other devices on the network to stream video which works fine.

I will soon have another switch a 2910al with with a client device on VLAN 20 that will want stream multicast traffic also.

The config currently has "bsr-candidate source-ip-vlan 10" and "rp-candidate source-ip-vlan 10". What is the purpose of these commands and will I need to change them??

I read the manual but it says only one source-ip-vlan can be defined, does this mean that only one vlan can stream multicast traffic?

ip multicast-routing
router rip
exit
router pim
bsr-candidate
bsr-candidate source-ip-vlan 10
bsr-candidate priority 1
rp-candidate
rp-candidate source-ip-vlan 10
rp-candidate group-prefix 224.0.0.0 240.0.0.0
rp-candidate hold-time 150
exit
vlan 10
ip pim-sparse
ip-addr any
exit
exit
vlan 20
ip pim-sparse
ip-addr any
exit
exit

Re: Multicast - Source-IP-VLAN

Ralf Krause — Mon, 11 Jan 2010 08:31:41 GMT

As far as I understand, the source-ip-vlan command(s) is a configuration setting for the BSR- and/or RP-candidate advertisment conversation.

Meaning:
The router (or switch in this case) is going to advertise its role throughout the network. This is done by sending IP packets. When sending IP packets, each sending device mandatorily has to put an IP address into the IP header's source IP field.

The commands you are asking about are defining exactly this value.
The IP address configured on the according VLAN will be put here.
--> Theoretically, the router could advertise the services through any outgoing interface; usually based on the routing table entry for the destination network ...

The advantage with source-ip-vlan is, that with all BSR/RP-candidate protocol conversation, the router always uses the same source IP address. This avoids "confusion" at the partnering devices.

Best regards,
Ralf