Message transmission method, network node and message transmission system

Embodiments of the invention disclose a message transmission method, a network node and a message transmission system. A centralized network node receives a message sent from a source edge route bridge through a transparent interconnection of lots of link (TRILL) unicast packaging way, wherein the message is a broadcast message or an unknown unicast message or a multicast message; the centralized network node determines a target edge route bridge set according to a multicast forwarding table, wherein the target edge route bridge set does not comprise the source edge route bridge, and the multicast forwarding table comprises identities of all edge route bridges of the network in which the centralized network node is; and the centralized network node sends the message to each route bridge in the target edge route bridge set through the TRILL unicast packaging way. Through adoption of the message transmission method, the network node and the message transmission system, multicast resource can be saved effectively, and the expansion performance of the system can be improved.