A method and system are disclosed, for using Intermediate System to Intermediate System, IS-IS, as control plane for Shortest Path Bridging, SPB, in a network comprising at least a Service Provider Network, SPN (101), and at least two Backbone Edge Bridges, BEBs (121i), connected to the SPN (101). The method comprises, and the BEBs are configured to: forming adjacency between BEBs through LAN Hellos, electing one of the BEBs as a Designated IS, DIS, and an emulated pseudonode, all BEBs creating and flooding non-pseudonode level-1 LSPs, the DIS creating and flooding a Pseudonode level-1 ESP, and periodically sending Complete Sequence Number PDUs, CSNPs, to the other BEBs, and running Shortest Path First, SPF, to calculate the shortest path in the network between BEBs.