Forcing The Router To Use The Rp Tree Permanently; Changing An Interface's Dr Priority - HP 7102dl - ProCurve Secure Router Configuration Manual

Configuring Multicast Support with PIM-SM
Configuring PIM-SM
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13-36
The PIM-SM protocol automatically manages the transition to the SP tree,
keeping the RP tree active until convergence is complete. For more informa-
tion on this process, see "Switching from an RP to an SP Tree" on page 13-9.

Forcing the Router to Use the RP Tree Permanently

A router's SP tree is tailored to be the best connection between the router and
a specific source, and you should almost always allow your ProCurve Secure
Router to use this tree as soon as it can. However, if you need to tightly control
the flow of multicast traffic in your network, you can force routers to use the
RP tree rather than finding their own shortest paths.
Move to the PIM sparse configuration mode context and enter:
Syntax: spt-threshold infinity
The RP for a group always builds an SP tree to a registered source.
For more information on an SP tree versus an RP tree, see "Multicast Trees"
on page 13-4 and "Switching from an RP to an SP Tree" on page 13-9.
You should not force a router to use the RP tree permanently out of fear that
new hosts will not be able to join a group after routers switch to the SP tree.
PIM-SM automatically provides for this situation.

Changing an Interface's DR Priority

A multi-access network may include several PIM routers. However, only one
router should forward join/leave packets for the network. When a network
includes a source of multicast traffic, only one router should encapsulate this
traffic and send it to the RP. Routers in each subnet elect a DR to perform
these functions.
The router in the subnet with the highest DR priority becomes the DR. By
default, a ProCurve Secure Router's DR priority is 1. When multiple routers
have the same priority, the router with the highest IP address becomes DR.
If it is important that a specific router become DR, you can raise its priority.
If the router must not become DR, you should leave the priority at one and
raise another router's priority.