Configuring A Static Rp Set - HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual

Configuring Multicast Support with PIM-SM
Configuring PIM-SM
11-30
From the PIM sparse configuration mode context, you can:
specify static RPs
change the threshold for switching to an SP tree
force the router to use the RP tree permanently
change the interval at which the router sends periodic join/prune mes-
sages

Configuring a Static RP Set

An RP for a multicast group forms the root of that group's RP tree. The RP
tree is a unidirectional tree over which routers initially forward multicast
traffic to hosts in the associated group.
An RP must:
listen for join/prunes for groups
receive register packets, which encapsulate multicast traffic, from the DR
for a source
decapsulate register packets and forward the multicast packets along the
RP tree
send register-stops to a source's DR after the RP has joined an SP tree
keep track of routers that have switched to an SP tree so that it will not
forward multicasts to routers using an SP tree that differs from the RP tree
You must configure the same RP set on each router in the network. The RP
set consists of every router that you will allow to act as an RP and the
addresses of groups that you allow that router to support.
A PIM router does not actually match a potential RP to a group address until
it receives either an IGMP or a PIM join for that group. The router then
performs a hash function on multicast address and the IP address of each RP
that can support the group. The statically configured RP that produces the
highest hash value becomes the actual RP for the active group.
You do not need to take excessive care when deciding which router or routers
to add to the RP set. Because an RP tree is typically only briefly active, an RP
is not unduly burdened. However, you should be very careful to specify that
the same RPs support the same groups on each router in the PIM domain. You
must enter the configuration on each PIM router. Otherwise, the router will
not know how to forward join/prunes, will not join the RP tree, and will not
forward multicasts.