Patent ID: 7792099
Filing Date: 2010-09-07
Classification: H04L

Abstract:
1. A method of multicast label switching in which label switching routes are established for multicast distribution from a multicast source node to a group of multicast leaf nodes, the method comprising the steps of: establishing a point-to-multipoint label switching route of a first layer from the multicast source node to the group of multicast leaf nodes; establishing a plurality of label switching routes of a second layer that configure partial trees of the label switching route of the first layer using second layer labels for respective subgroups of leaf nodes, the subgroup of leaf nodes being extracted as destinations from the group of leaf nodes for which the point-to-multipoint label switching route of the first layer has been established; allocating traffic addressed to a destination leaf group corresponding to the second layer labels to corresponding hierarchical labels using the first layer label switching route and the second layer label switching routes by an input label edge router; label-switching packets in accordance with a label pair of the first layer and the second layer by a relay label switch router; if a relay node is designated as a branching node of the point-to-multipoint label switching route of the first layer, copying the traffic for each output branch and replacing input label pair with output labels corresponding to a plurality of output branches; switching the traffic to an output line by an output label edge router, and identifying the group of the input hierarchical labels and removing the labels; and label-switching traffic of each second layer subgroup using the point-to-multipoint label switching routes of the second layer forming the first layer partial tree and forming different destination subgroups of the first layer leaf group nodes in the point-to-multipoint label switching routes with the first layer label switching route shared.