Combined ARP-Path&RSTP Bridges for Smooth Migration to Robust Shortest Path Bridging

Rapid Spanning Tree Protocol (RSTP) is a layer 2 protocol that blocks redundant links to avoid loops. Due to its well-known limitations, diverse solutions have been proposed to replace it, but scarcely adopted, such as Transparent Interconnection of Lots of Links (TRILL) and Shortest Path Bridging (SPB). To overcome the constraints of RSTP, while keeping its advantages, we propose to combine the fast and proven reconfiguration mechanisms of RSTP with the shortest path capabilities and load balancing of ARP-Path bridging in the same device. The combined bridges are self-configuring and allow full miscibility of combined bridges in legacy RSTP networks. This enables a smooth migration path from standard 802.1D bridges to ARP-Path shortest path bridges. This paper presents a preliminary proposal: full validation, simulation, implementation and evaluation are ongoing.