HP 3500YL - Manual (Page 123)

PIM-SM (Sparse Mode)
Operating Rules and Recommendations
■ 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.
Operating Rules and Recommendations
Guideline for Configuring Candidate RPs and BSRs. Routers in a PIM­
SM domain should usually be configured as both candidate RPs and candidate
BSRs. Doing so can reduce some overhead traffic.
The Shortest-Path-Tree (SPT) Policy Should Be the Same for All RPs
in a Domain.
Allowing some RPs to remain configured to implement SPTs
while configuring other RPs in the same domain to force RPT use can result
in unstable traffic flows. (Use the
[ no ] ip pim-sparse spt-threshold command to
change between SPT and RPT operation on each router.)
Application of RPs to Multicast Groups. In a PIM-SM domain, a given
multicast group or range of groups can be supported by only one RP. (Typically,
multiple candidate RPs in a domain are configured with overlapping coverage
of multicast groups, but only one such candidate will be elected to support a
given group.)
Ensuring that the Candidate RPs in a PIM-SM Domain Cover All
Desired Multicast Groups.
All of the multicast groups you want to allow
in a given PIM-SM domain must be included in the aggregate of the multicast
groups configured in the domain’s candidate RPs. In most cases, all C-RPs in
a domain should be configured to support all RP groups (the default configu­
ration for a router enabled as a C-RP). This provides redundancy in case an
RP becomes unavailable. (If the C-RP supporting a particular multicast group
becomes unavailable, another C-RP is elected to support the group as long as
there is redundancy in the C-RP configuration for multiple routers. Note that
in cases where routers are statically configured to support a specific group or
range of groups, the C-RP prioritization mechanism allows for redundant
support.
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