RSTP-SP: Shortest path extensions to RSTP

Abstract

The spanning tree protocol is the component of the Ethernet architecture that establishes the network connectivity. Its plug-and-play property and ease of configuration have been some of the pillars of Ethernet's success. However, the new provider applications require improving the protocol capabilities such as response time, path optimality and path control. Optimal paths can be achieved if we deploy one tree rooted at each node. Nevertheless, this introduces the challenge of maintaining the path symmetry requirement of Ethernet networks. In this paper we propose RSTP-SP as an extension to RSTP that meets the performance objectives and keeps the bridging requirements. We evaluate RSTP-SP by means of a simulation analysis and we compare it to Shortest Path Bridging (SPB). Simulation results show that RSTP-SP outperforms SPB in terms of recovery time and outage experienced. In contrast, the message overhead introduced by RSTP-SP is higher than in the SPB case.