Nortel Networks Corporation

Louis-Rene Pare

Peter William Phelps

David Charles Steele

Evert De Boer

Robert Caporuscio

Bruce E Dunn

Gary L Swinkels

Evert De Moer

A method and corresponding network element configuration for delivering communications services between first and second survivable rings, each comprising a respective plurality of network elements, at least two of which are common to both rings. For each particular service, one of the common network elements is designated as a primary gateway node and another as a secondary gateway node. A primary inter-ring connection is established for the particular service by a switch at the primary gateway node, but no inter-ring connection is established at the secondary gateway node. The secondary gateway node comprises a controller for monitoring the status of the primary gateway node and establishing a new inter-ring connection for delivery of the service upon detecting a failure of the primary gateway node. This provides survivable inter-ring traffic which is bandwidth-efficient and with a low switching delay.

Method and apparatus for ensuring survivability of inter-ring traffic

A method and corresponding network element configuration for delivering communications services between first and second survivable rings, each comprising a respective plurality of network elements, at least two of which are common to both rings. For each particular service, one of the common network elements is designated as a primary gateway node and another as a secondary gateway node. A primary inter-ring connection is established for the particular service by a switch at the primary gateway node, but no inter-ring connection is established at the secondary gateway node. The secondary gateway node comprises a controller for monitoring the status of the primary gateway node and establishing a new inter-ring connection for delivery of said service upon detecting a failure of the primary gateway node. This provides survivable inter-ring traffic which is bandwidth-efficient and with a low switching delay.

The present invention relates to a switching node for use in a synchronous optical network ring, where the ring is transporting data divided into first size blocks, for example OC-192 optical signals, characterized by data blocks of size 192. The switching node includes several primary receive and send connections, for receiving and transmitting inter-ring optical signals divided into second size blocks, for example OC-48 optical signals, characterized by data blocks of size 48. The switching node further includes a secondary receive and send connection for receiving and transmitting intra-ring optical signals divided into first size blocks. A critical component of the switching node is the main controller, responsible for routing incoming intra-ring first size blocks towards a primary send connection. The main controller divides a first size block into smaller second size blocks, observes the second size blocks for the presence of concatenated data and, in the case where there is presence of concatenated data, routes the second size block as a single unit towards the adjacent network ring. In the case where there is absence of concatenated data, the routing controller routes the group of data forming the second size block as independent data elements towards the adjacent network ring.

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Louis-Rene Pare