Handling Routed Traffic Over Ports Participating in Spanning Tree Protocol

The uplinks on the aggregation switches at the edge of the network transmit and receive both routed and bridged traffic. These uplinks are typically high capacity Ethernet links like gigabit Ethernet links. Network carriers run spanning tree protocol (STP) on these links to achieve device and link level redundancy. STP is a layer 2 control protocol and there are well defined forwarding mechanisms for handling bridged (layer 2) traffic over these STP enabled ports. But handling routed traffic (layer 3) over these STP enabled ports throws some challenges. This paper looks into the challenges faced while supporting routed traffic over STP enabled ports and proposes a simple and novel solution for efficient handling of routed traffic.