PIM utilizes the unicast routing tables built by various unicast routing protocols to perform RPF checks, rather than maintaining a separate multicast routing table for multicast forwarding. It relies on the RPF mechanism to forward multicast packets. When a multicast packet arrives at the local device, an RPF check is first performed: if the RPF check passes, a corresponding multicast routing entry is created to forward the packet; if the RPF check fails, the packet is discarded.
1. To configure a router as a member of an HSRP standby group, use the following command in interface configuration mode:
router(config-if)# standby group-number ip ip-address
2. To enable a router to resume the role of forwarding router, in interface configuration mode:
router(config-if)# standy group-number preempt
3. The hello time and hold time parameters are configurable:
router(config-if)# standy group-number timers hellotime holdtime
4. Configuring HSRP tracking:
router(config-if)# standy group-number track type-number interface-priority
5. Use the command show ip igmp to determine the elected querier:
router# show standby type-number group brief
6. Enable IP multicast routing:
router(config)# ip muticast-routing
7. Enable PIM on an interface:
dalllasr1>(config-if)# ip pim {dense-mode|sparse-mode|sparse-dense-mode}
8. Enable PIM in sparse-dense mode:
router# ip multicast-routing
router# interface type number
router# ip pim sparse-dense-mode
9. Verify PIM configuration:
dallasr1># show ip pim interface[type number] [count]
10. Display PIM neighbors:
dallasr1># show ip neighbor type number
11. To configure the RP address, the command is as follows:
dallasr1># ip pim rp-address ip-address [group-access-list-number][override]
12. Select a default RP:
dallasr1># ip pim rp-address
13. Advertise the RP and the group ranges it serves:
dallasr1># ip pim send-rp-announce type number scope ttl group-list access-list-number
14. Advertise the RP address for administratively scoped groups:
dallasr1># ip pim send-rp-announce ethernet0 scope 16 group-list1
dallasr1># access-list 1 permit 266.0.0.0 0.255.255.255
15. Configure an RP mapping agent:
dallasr1># ip pim send-rp-discovery scope ttl
16. Verify group-to-RP mappings:
dallasr1># show ip pim rp mapping
dallasr1># show ip pim rp [group-name|group-address] [mapping]
17. Use the command ip multicast ttl-threshold ttl-value on a router interface to set the TTL threshold:
dallasr1>(config-if)# ip multicast ttl-threshold ttl-value
18. Use show ip pim neighbor to display the PIM neighbor table.
dallasr1>show ip mroute [group-name|group-address][scoure][summary][count][active kbps]