Dual RP's for multicast....

[TheJag]

I need some help.

I don't know what multicast is and how it benefits the network.

My boss told me to set up Dual RP's for multicast. I don't know what RP is or what multicast does.

Can anyone help explain?

 

[Dieselruss]

Hello Jag,

AUTO-RP
(with multiple RP's)

Sa(239.0.0.0/8) Sb(224.0.0.0/4)
| |
+-------+ +-------+
| RP1 | | RP2 |
+-------+ +-------+
| |
| |
+-------+ +-------+
|Router3| |Router4|
+-------+ +-------+
| |
-------------------------
|
receivers

Router RP1 configuration:

ip multicast-routing
ip pim send-rp-announce ethernet0 scope 16 group-list 1
ip pim send-rp-discovery scope 16

access-list 1 permit 239.0.0.0 0.255.255.255

Router RP2 configuration:

ip multicast-routing
ip pim send-rp-announce ethernet0 scope 16 group-list 1
ip pim send-rp-discovery scope 16

access-list 1 deny 239.0.0.0 0.255.255.255
access-list 1 permit 224.0.0.0 15.255.255.255


The access lists allow the RP's to only be an RP for the groups you want. If no access list is configured, then the RP's will be available as an RP for all groups.
If two RP's are announcing their availability to be RP's for the same group(s), the mapping agent(s) will resolve these conflicts using the highest ip address
wins rule. If you want to influence which router is the RP for a particular group, when two RP's are announcing for that group, you can configure each router with a
loopback address. Place the higher ip address on the preferred RP and then use the loopback interface as the source of the announce packets, ie 'ip pim send-rp-
announce loopback0'. When multiple mapping agents are used, they will listen to each others discovery packets and the mapping agent with the highest ip address
will win and be the only forwarder of 224.0.1.40.

 

[TheJag]

Thanks for the help. I have a couple of questions still...

What is RP?

What is multicast?