Patent ID: 8724452
Filing Date: 2014-05-13
Classification: H04L

Abstract:
1. A method for protecting traffic in a Layer 2 (L2) communication network between a first and a second local nodes (CE 1 , CE 2 ) interconnected via a dual homed structure, wherein said structure comprises: four provider edge nodes PEs, four communication lines and four local connections, a first pair of the provider edge nodes (PEs A,C) being respectively connected by a first couple of local connections from among the four local connections (CE 1 -PEs A,C) to the first local node (CE 1 ), a second pair of the provider edge nodes (PEs B,D) respectively connected by a second couple of local connections from among the four local connections (CE 2 -PEs B,D) to the second local node (CE 2 ), two distant communication lines (P-PW) from among the four communication lines each interconnecting two provider edge nodes PEs belonging to different pairs, and two local communication lines (S-PW) from among the four communication lines each interconnecting two provider edge nodes PEs belonging to the same pair; the method comprising the steps of: a) in a fault-free state, carrying traffic from the first local node (CE b) in a faulty state, when a failure occurs in at least one element of a group comprising a local connection (CE propagating Layer 2 fault indications (L2 OAM tools) in the dual homed structure and processing thereof at the PEs so that as a result of said failure, the failed element, the remaining element of the group associated with it and also the local and the distant communication lines associated with said PE element of the group become blocked for said two traffic flows in the dual homed structure, while a specific one of said first and second local nodes CE performing switching at the local node being closer to the failure, so that both said two flows are directed to unblocked members of the dual homed structure, and rearranging said traffic flows based on the physical and said Layer 2 fault indications, so as to bypass all said blocked members of the dual homed structure by utilizing the remaining ones to carry both of said two flows, while both of the flows, arriving from the first local node (CE