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 upstream on behalf of the host receivers and forward multicast traffic to the local LAN. When the optimal path of the local area network is on, there is a waste of network resources

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