Multicast

PIM sparse-dense mode:

  1. Enable multicast routing:
    ip multicast-routing
  2. Enable PIM on all required interfaces:
    ip pim sparse-dense-mode

For an RP using auto-RP:

  1. ip pim send-rp-announce Loopback0 scope [TTL] group-list [ACL]
  2. Set Lo0 as source for PIM register
    ip pim register-source Loopback0

For the mapping agent (may be the same router as the RP):

  1. ip pim accept-rp auto-rp [ACL]
    ip pim send-rp-discovery scope [TTL]
  2. Set Lo0 as source for PIM register
    ip pim register-source Loopback0

Scope = Multicast TTL (how big is the multicats domain?)
Group-list = allowed mcast groups server by this RP
Accept-rp ACL = limits the RPs that the mapping agent serves

Don’t forget to enable PIM on the loopbacks used for the RP and mapping agent.

CLI:
send-rp-announce – Auto-RP send RP announcement
send-rp-discovery – Auto-RP send RP discovery message (as RP-mapping agent)

PIM sparse-mode:

  1. Enable multicast routing:
    ip multicast-routing
  2. Enable PIM on all required interfaces:
    ip pim sparse-mode
  3. Point each Mcast router to the RP:
    ip pim rp-address 10.10.10.7

PIM dense-mode:

  1. Enable multicast routing:
    ip multicast-routing
  2. Enable PIM on all required interfaces:
    ip pim dense-mode

Join a group

So we can ping an Mcast address to test our Mcast config:

  • (config-if)# ip igmp join-group 239.2.3.9

Stop broadcasting Mcast

To everyone on NBMA networks:

  • (config-if)# ip pim nbma-mode

Gather Mcast statistics

R3(config)#ip multicast ?
__...
__cache-headers__Store IP multicast packet headers in circular buffer
__...

Use the following command to check the statistics:

R3(config-if)#do sh ip mpacket
IP Multicast Header Cache
25 packets received over 00:05:34, cache size: 1024 entries
Key: id/ttl timestamp (name) source group
0020/254 114300.012 (?) 12.1.5.5 225.0.0.99
0021/254 114302.008 (?) 12.1.5.5 225.0.0.99
0022/254 114304.008 (?) 12.1.5.5 225.0.0.99
0023/254 114306.008 (?) 12.1.5.5 225.0.0.99

Troubleshooting

auto-RP (External link to Cisco page by Liming Wei [4/2/99] ymmv)
Generic Cisco Multicast troubleshooting page

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