An enhanced DVMRP method for regulating multicast traffic in a
destination-based forwarding router is disclosed. As a plurality of
neighbor multicast routers are detected and route reports exchanged, the
enhanced DVMRP router transmits one or more restricted route reports,
each of the restricted route reports omitting the routes associated with
one or more of its branch interfaces. With the exception of the neighbor
router detected on a given interface, a route report omits reference to
other branch interfaces to prevent branch-to-branch routing of multicast
streams that may cause a destination-based forwarding router in a
multi-access network to transmit duplicate packets to a group member. The
enhanced DVMRP method also employs flash updates indicating that some
branch interfaces are inaccessible in order to prevent multicast routing
through newly-detected neighbor multicast routers.