Patent ID: 8111613
Filing Date: 2012-02-07
Classification: H04L

Abstract:
1. A method of protecting Ethernet traffic in a communications network comprising a plurality of Ethernet nodes configured to implement a p-cycle, the communications network comprising a plurality of Ethernet nodes and interconnecting communications links along which Ethernet traffic is forwarded in a connection-oriented manner, the method comprising: at a said Ethernet node implementing said p-cycle in the communications network: mapping a plurality of said paths, each path being individually identified for the purpose of forwarding by a VLAN ID label having an original value and a destination address associated with a connection-oriented Ethernet path along one or more links in said communications network for which an entry exists in a forwarding table of an Ethernet switching apparatus at said Ethernet node, to another path identified for the purposes of forwarding by one or more reserved VLAN ID values, said path defining said p-cycle between logically adjacent nodes in said communications network, wherein each Ethernet node on the p-cycle has a mapping in memory between the original value and p-cycle connection value VLAN identifiers, and wherein said p-cycle is provisioned in the same layer as said Ethernet traffic by: modifying a connection-oriented Ethernet frame header of a failed Ethernet connection received with a said original VLAN ID value to a said reserved VLAN ID value, wherein said reserved VLAN ID value is unique for each Ethernet connection to be forwarded along said p-cycle; forwarding each Ethernet frame having said modified VLAN ID around the p-cycle using said reserved VLAN ID until the node adjacent to the link failure is reached and ignoring said destination address for the purposes of forwarding, and at that adjacent node, returning the modified VLAN ID value to the original VLAN ID value, and forwarding each Ethernet frame having a VLAN ID returned to the original value VLAN ID using said original value VLAN ID and destination address.