State Refresh in PIM-DM

Document Type Expired Internet-Draft (pim WG)
Authors Dino Farinacci  , Isidor Kouvelas  , Kurt Windisch 
Last updated 2000-11-28
Stream IETF
Intended RFC status (None)
Expired & archived
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Stream WG state WG Document
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IESG IESG state Expired
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This proposal extends the PIM-DM [1] protocol specification by intro- ducing the PIM State-Refresh control message. When an (S,G) entry is created in a router for a directly connected source, if the interface directly connected to the source is the incoming interface for the entry, a new timer is started: the State- Refresh-Timer [SRT(S,G)]. The State-Refresh-Timer controls periodic transmission of the PIM State-Refresh message, which is propagated hop-by-hop down the (S,G) RPF tree. When received by a router on the RPF interface, the State-Refresh message causes existing prune state to be refreshed. Addition of this heartbeat message solves many of the current prob- lems with PIM-DM. It prevents the periodic timeout of prune state in routers, greatly reducing the re-flooding of multicast traffic down the pruned branches that expire periodically. It also causes topology changes to be realised quicker than the traditional 3 minute timeout.


Dino Farinacci (
Isidor Kouvelas (
Kurt Windisch (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)