Abstract: A system and method creates multiple, symmetric spanning trees within a network. Bridges within the network generate, send and process Spanning Tree Protocol (STP) control messages that are updated as they are propagated across the network to reflect the paths followed by the messages. The bridges, moreover, utilize the path indication value of received STP control messages to compute the spanning trees. The path indication values are preferably derived from the sum of Bridge Identifiers (IDs) corresponding to the bridges through which the STP control message has passed from the root bridge to the current bridge processing the STP control message. Each bridge also tags newly received messages with the Virtual Local Area Network (VLAN) identifier (VID) associated with the spanning tree for which the bridge is the root, thereby causing the messages to follow more optimal paths through the network.

Abstract: A technique shares a port (e.g., a physical port) among a plurality of virtual bridges on a switch in a computer network. According to the novel technique, two or more virtual bridges are established on the switch, and are each assigned respective sets of Virtual Local Area Networks (VLANs). Each virtual bridge has a virtual interface corresponding to the physical port (a “shared trunk”), the virtual bridges regarding the virtual interfaces as though they were physical ports. Control messages transmitted by the virtual bridges on the virtual interfaces are sent over the physical port and to each other virtual interface of the port (the shared trunk), such as, e.g., by a virtual hub of the shared trunk. Also, control messages received on the physical port are sent over each virtual interface to each virtual bridge (e.g., by the virtual hub).

Abstract: In one embodiment, a bridge may receive a first convergence proposal on a root port from an upstream adjacent bridge of a computer network, and in response, may transmit a second convergence proposal downstream on each non-edge designated port of the bridge without syncing the non-edge designated ports. The bridge may then return a convergence agreement to the adjacent bridge in response to the non-edge designated ports having received a returned convergence agreement (or in response to having only edge designated ports). Also, according to embodiments, the adjacent bridge blocks a link to the root port until the convergence proposal(s) and agreement(s) travel end-to-end.

Abstract: In one embodiment, a first port of a bridge is configured for a first spanning tree (ST) and not a second ST, while a second port of the bridge is configured for the second ST and not the first ST. A multiple ST (MST) bridge protocol data unit (BPDU) for the first and second STs is generated for the first and second ports having a first portion corresponding to the first ST and a second portion corresponding to the second ST. To translate MST instances, the second portion is stripped from the MST BPDU of the first port, and the first portion from the MST BPDU of the first port is associated with the second ST. Conversely, the first portion is stripped from the MST BPDU of the second port, and the second portion from the MST BPDU of the second port is associated with the first ST.

Abstract: A technique shares a port (e.g., a physical port) among a plurality of virtual bridges on a switch in a computer network. According to the novel technique, two or more virtual bridges are established on the switch, and are each assigned respective sets of Virtual Local Area Networks (VLANs). Each virtual bridge has a virtual interface corresponding to the physical port (a “shared trunk”), the virtual bridges regarding the virtual interfaces as though they were physical ports. Control messages transmitted by the virtual bridges on the virtual interfaces are sent over the physical port and to each other virtual interface of the port (the shared trunk), such as, e.g., by a virtual hub of the shared trunk. Also, control messages received on the physical port are sent over each virtual interface to each virtual bridge (e.g., by the virtual hub).