CANOGA PERKINS 9175 Configuration Guide - Manual (Page 151)

CanogaOS Configuration Guide
24-9
At Router_E, eth-0-2 is the incoming interface of the (*, G) entry, and eth-0-1 is on the
outgoing interface list of the (*,G) entry. This means that there is a group member
through eth-0-1, and RP is reachable through eth-0-2.
The 0 position on this 32-bit index is for eth-0-1 (as illustrated in the interface display
above). The j on the 0 index indicates that the Join has come from eth-0-1.
Since Router_C is the RP, and the root of this multicast tree, the show ip pim
sparse-mode mroute command on Router_C shows RPF nbr as 0.0.0.0 and RPF idx as
none.
Router_C# show ip pim sparse-mode mroute
IP Multicast Routing Table
(*,*,RP) Entries: 0
(*,G) Entries: 1
(S,G) Entries: 0
(S,G,rpt) Entries: 0
(*, 224.0.1.3)
RP: 10.10.1.5
RPF nbr: 0.0.0.0
RPF idx: None
Upstream State: JOINED
Local ................................
Joined j...............................
Asserted ................................
Outgoing o...............................
Configuring RP dynamically
A static configuration of RP works for a small, stable PIM domain; however, it is not
practical for a large and not-sostable internetwork. In such a network, if the RP fails, the
network administrator might have to change the static configurations on all PIM routers.
Another reason for choosing dynamic configuration is a higher routing traffic leading to a
change in the RP.
We use the BSR mechanism to dynamically maintain the RP information. For configuring
RP dynamically in the above scenario, Router_C on eth-0-1 and Router_D on eth-0-1
are configured as Candidate RP using the ip pim rpcandidate command. Router_D on
eth-0-1 is also configured as Candidate BSR. Since no other router has been configured
as Candidate BSR, the Router_D becomes the BSR router, and is responsible for
sending group-to-RP mapping information to all other routers in this PIM domain.
The following output displays the complete configuration at Router_C and Router_D:
Router_D# show run
!
interface eth-0-0
!
interface eth-0-1
ip pim sparse-mode
!
interface eth-0-2
ip pim sparse-mode
!
ip pim bsr-candidate eth-0-1
ip pim rp-candidate eth-0-1 2
!
Router_C# show run
interface eth-0-0
!