Patent ID: 8737270

Claim:
A method implemented by a network management system for avoiding a count-to-infinity problem in a network, the network having bridges with network interface ports emulated to be connected to a pseudo-root-bridge in an external network, the method comprising: configuring the network interface ports to have a same pseudoRootID; that pseudoRootID being superior to all bridge identifiers associated with the bridges within the network; wherein the pseudoRootID is an identification of the pseudo-root-bridge emulated to be within the external network; configuring the network interface ports to have different pseudoRootPathCosts, wherein the pseudoRootPathCosts is a pseudo path cost set for each of the network interface ports relative to the pseudo-root-bridge; the network interface ports including a first network interface port having a smallest pseudoRootPathCost and a second network interface port having a next smallest pseudoRootPathCost; relative to the external network, both: setting the first network interface port as forwarding to the external network; and setting all other network interface ports as blocked to the external network; thereafter, in response to failure of a link between the external network and the first network interface port, setting the second network interface port as forwarding to the external network; wherein the configuring the network interface ports to have different pseudoRootPathCosts comprises: determining an order of precedence of the network interface ports; configuring a pseudoRootPathCost which is to be used for a network interface port with highest precedence; iteratively determining if any of the network interface ports have not yet been configured to have pseudoRootPathCosts, and if any of the network interface ports have not yet been configured to have pseudoRootPathCosts then: selecting a network interface port to which the highest precedence is to be given from the non-configured network interface ports; calculating a smallest root path cost between the selected network interface port and the highest precedence network interface port; configuring the selected network interface port to have a pseudoRootPathCost that is greater than a sum of the smallest root path cost and a highest pseudoRootPathCost of any of the previously configured higher precedence network interface ports.