PIM-SM (Sparse Mode)
PIM-SM Operation and Router Types
Supporting a Static-RP as Primary . A static-RP can be configured to
operate as either a secondary or primary RP. With the primary option, a
dynamic (C-RP) backup is recommended. The precedence of a static-RP over
a dynamic RP is determined by the following static-RP configuration options:
override enabled on the static-RP
a group mask on the static-RP that equals or exceeds the group mask
on the C-RP for the same multicast group(s)
For override configuration information, refer to "Statically Configuring an RP
To Accept Multicast Traffic" on page 4-42.
Operating Rules for Static RPs.
Static-RPs can be configured on the same routers as C-RPs.
Where a C-RP and a static-RP are configured to support the same multicast
group(s), the C-RP takes precedence over the static-RP unless the static-
RP is configured to override the C-RP. (Refer to "Supporting a Static-RP
as Primary", above.)
Any static-RP in a domain must be configured identically on all routers in
the domain. Otherwise, some DRs will not know of the static-RP and will
not forward the appropriate multicast traffic, and some routers will not
know where to send Joins for the groups supported by static-RP.
Up to four static-RP entries can be configured on a router. Each entry can
be for either a single multicast group or a range of contiguous groups.
Only one interface can be configured as the static RP for a given multicast
group or range of groups. For example, a properly configured PIM-SM
domain does not support configuring 10.10.10.1 and 10.20.10.1 to both
support a multicast group identified as 220.127.116.11.
Static-RPs are not included in the RP-set messages generated by the BSR,
and do not generate advertisements.
If a static-RP becomes unavailable, it is necessary to remove and/or
replace the configuration for this RP in all routers in the domain.
Configuration. Refer to "Statically Configuring an RP To Accept Multicast
Traffic" on page 4-42.