Abstract: The present invention discloses a method, an apparatus, and a system for forwarding a packet in a multi-topology network, relating to the field of communications technologies. The method includes: receiving, by an ingress node in the multi-topology network, a packet sent by a first network, and obtaining information of an ingress interface receiving the packet; where the first network is a network except the multi-topology network; obtaining a routing information base RIB or a forwarding information base FIB of a corresponding downlink topology according to the information of the ingress interface; and forwarding the packet to an egress node in the multi-topology network according to the RIB or the FIB of the corresponding downlink topology.

Abstract: The present invention discloses a method, an apparatus, and a system for forwarding a packet in a multi-topology network, relating to the field of communications technologies. The method includes: receiving, by an ingress node in the multi-topology network, a packet sent by a first network, and obtaining information of an ingress interface receiving the packet; where the first network is a network except the multi-topology network; obtaining a routing information base RIB or a forwarding information base FIB of a corresponding downlink topology according to the information of the ingress interface; and forwarding the packet to an egress node in the multi-topology network according to the RIB or the FIB of the corresponding downlink topology.

Abstract: The present invention provides a method for label distribution, including: receiving a Label Distribution Protocol packet that contains a first label and is distributed by a downstream node, in which the first label belongs to a downstream logical topology; searching for a second label that corresponds to the first label and belongs to an upstream logical topology, in which the upstream logical topology and the downstream logical topology are different logical topologies; and distributing, when an upstream node belonging to the upstream logical topology exists in a neighboring node, the second label to the upstream node. The present invention also provides a node device. Using the method or device disclosed in the present invention, a label may cross different logical topologies during distribution, so that in a newly established logical topology, it is not necessary to upgrade all common nodes, thereby reducing the cost for establishing the new logical topology.