Patent ID: 6278687
Filing Date: 2001-08-21
Classification: H04J,H04L,H04Q

Abstract:
A synchronous digital hierarchy (SDH) based communications network, comprising:a) a plurality of data communications channels embedded within the network;b) a plurality of intermediate systems (IS) divided between at least one non-IS--IS area and at least one IS--IS area within which a routing protocol forming part of a network layer of an open systems interconnection (OSI) is provided for routing a message from said at least one IS--IS area to a destination IS within said at least one non-IS--IS area, there being a plurality of connections between said at least one IS--IS area and said at least one non-IS--IS area;c) a plurality of manual adjacencies (MAs) constituting static routes at one of the IS within said at least one IS--IS area, for identifying routes to at least one network equipment (NE) within said at least one non-IS--IS area; andd) means for removing an identification of said at least one NE from which the message has been returned from the MAs after at least one of the connections to the destination IS within said at least one non-IS--IS area was broken, and for allowing routing of the message via alternative MAs.