Multicast flow forwarding method and multicast router in local area network

Abstract

The invention relates to a multicast flow forwarding method and a multicast router in a local area network. The method comprises the following steps of: enabling a non-DR (Designated Router) to enter a delay waiting state when a non-DR local access interface detects multicast flow forwarded by a DR; if the delay waiting overtimes, transmitting a PIM (Protocol Independent Multicast) access message to an upstream router in the RP (Rendezvous Point) or S (Source) direction; after the multicast flow is received from an RPT (Rendezvous Point Tree) or SPT (Shortest Path Tree), forwarding the multicast flow to the local area network; receiving an Assert message sent by the DR when the DR detects the multicast flow at a downstream outbound interface; and competing with the DR to forward the multicast flow according to the Assert message and a local routing metric value. In the invention, by introducing a non-DR local access interface principle and expanding the disposal to the non-DR local access interface type in the Assert process, when the non-DR competes with the DR to forward the multicast flow according to the Assert message and the local routing metric value to realize that a downstream multicast router does not exist in the local area network, a host receiver still receives the multicast flow from the router on the optimal path from the RP or S to the local area network, and therefore, the optimizing utilization to network resources is achieved.

Description

technical field [0001] The invention relates to the field of communication technology, in particular to a multicast traffic forwarding method in a local area network and a multicast router for realizing that a host receiver receives multicast traffic from a data source to a multicast router on an optimal path of the local local area network. Background technique [0002] Multicast is a bandwidth saving technology. In multicast technology, the data source only sends a copy of traffic, and all and only host receivers that join the multicast group can receive the same traffic. At present, the widely used three-layer multicast technology includes PIM-SM (Protocol Independent Multicast-Sparse Mode, independent multicast protocol sparse mode), PIM-SSM (Protocol Independent Multicast-Source Specific Multicast, independent multicast protocol source specific group broadcast) and IGMP (Internet Group Management Protocol, Internet Group Management Protocol), wherein, PIM is used betwee...

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Problems solved by technology

[0008] Therefore, when there is no router among the downstream host receivers, the existing multicast routing technology limits that only the DR can send PIM join messages upstr

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