Patent ID: 7551571
Filing Date: 2009-06-23
Classification: H04L

Abstract:
1. A method for utilizing a Spanning Tree Protocol (STP) in an Ethernet network wherein a number of VLANs are defined and a plurality of Ethernet switching nodes are interconnected via their ports so that each of the ports is initially assigned to one or more VLANs, and each of the VLANs is intended to enable traffic between two or more edge ports, the method comprises: upon establishing a new STP topology related to one or more VLANs, initiating a pruning procedure of a broadcast domain of at least one of said one or more VLANs to obtain a sub-tree for each pruned VLAN in the new STP topology, wherein each said sub-tree being bound by the edge ports assigned to the corresponding pruned VLAN, thereby eliminating broadcast traffic of each said pruned VLAN to any Ethernet switch extending beyond the obtained corresponding sub-tree; the method comprising the following steps to be performed at each Ethernet switching node that is active in the new STP topology and with respect to each of said one or more VLANs: a ensuring that ports of the Ethernet switching node that is active in the new STP topology, are assigned to said one or more VLANs according to an initial VLANs configuration; b) counting forwarding ports assigned to a particular VLAN, being active according to the new STP topology; c) if a port assigned to a particular VLAN is a single forwarding port for said particular VLAN at said node, de-activating said port with respect to said VLAN, thereby pruning said VLAN at said port and said node; d) generating a de-activation message from each said single forwarding port of said node, the message indicating one or more VLANs de-activated at said port, and transmitting said de-activation message to a neighbor Ethernet switching node in the new STP topology; e) de-activating the port of the neighbor Ethernet switch, that has received said de-activation message, with respect to said one or more VLANs indicated in the message; f) repeating steps (b) to (e) at said neighbor node.