Nortel Networks Corporation

Jayne Brady

David Michael Goodman

James A Shields

Chris Murton

The SONET/SDH multiplexing hierarchy is extended to very high rates by creating new virtual containers of a higher capacity, and their associate pointers. The multiplexing hierarchy nests the pointers into the payload, so that the number of pointers on the high capacity line is importantly reduced, as the high rate spans of the network do not see the STS-1/STM-1 pointer granularity. Fewer pointers result in reducing the current complexity of pointer processing. The complexity of the multiplexing hierarchy is also reduced by the use of larger containers. The hierarchy may be extended to higher rates, as needed, and may also be used for other technologies, besides SONET/SDH.

Multiplex hierarchy for high capacity transport systems

An interface for converting a variety of incoming digital signals into SDH/SONET format for transmission on a synchronous digital network, by identifying the line code of the incoming digital signal, without identifying the information for OSI layer 2 or 3 processing, i.e. format of each packet. Headers are used to encapsulate incoming packets, and enable packets to be discriminated at the receiver. Advantages of performance monitoring capability and transparency are combined. Identifying line codes enables a greater degree of error detection, than a bit based interface. Also synchronisation can be simpler since line codes for padding can be added or deleted more easily than adding or subtracting bits. The interface is semi-transparent in the sense that identification of line codes limits the interface to those formats that use identifiable line codes, but without limiting to a particular OSI layer 2 or 3 frame format.

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Belfast, Ireland

Jayne Brady