SPBM overview

IEEE 802.1aq Shortest Path Bridging (SPB) enables multipath routing in an Ethernet mesh network by using IS-IS as the control protocol. The technology allows all paths to be active, supports equal cost paths, and provides shortest path forwarding in an Ethernet mesh network. IEEE 802.1aq SPB provides faster convergence, higher link efficiency, and larger Layer 2 topologies than conventional spanning tree protocols such as MSTP.

Shortest path bridging MAC mode (SPBM) is one bridging method of IEEE 802.1aq SPB. This method encapsulates Ethernet frames into MAC-in-MAC frames in compliance with IEEE 802.1ah PBB.