MOSPF Prunes

Document Type Expired Internet-Draft (mospf WG)
Last updated 1998-12-23
Stream IETF
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


MOSPF is a link-state multicast routing protocol, based on OSPF. Inside a single OSPF area, the delivery of multicast datagrams is restricted to group members only, by propagating the location of group members through group-membership-LSAs. However, group membership is not propagated across area and/or AS boundaries, relying instead on so-called wild-card multicast receivers. This means that in some cases multicast datagrams are transmitted further than necessary, wasting link and processor resources in the process. This document defines a way to prune these excess branches off the MOSPF delivery tree, using a new Prune-LSA. In concept these are similar to the prunes employed by the DVMRP protocol. However, to reuse the reliability mechanisms present in the base OSPF protocol, MOSPF prunes are implemented as local-scope Opaque-LSAs. As a result, inter-area and inter-AS multicast datagrams are forwarded by MOSPF using the broadcast-and-prune strategy employed by DVMRP.


John Moy (

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