Nortel Networks Corporation

Derek Gilmore

Terence Canning

Philip Christian

Allen Houston

In the preferred embodiment, the invention provides a modified Shortest Path First routing algorithm for use in a heterogeneous network. The routing algorithm is modified to include predetermined heterogeneous characteristics of the network nodes and to take these characteristics into account when calculating the shortest paths. For example, information may be included in the algorithm which identifies heterogeneous network nodes as it calculates shortest paths. Once a node has been identified as heterogeneous, i.e., capable of supporting at least two protocol sets, this information is carried over into subsequent path entries created by the routing algorithm. The algorithm then uses the encapsulation capability identifier in the calculation of the shortest paths by including the cost of auto-tunneling between heterogeneous nodes to be taken into account when determining the short path.

Routing method and apparatus for optimising auto-tunnelling in a heterogeneous network

The invention relates to a routing apparatus for routing data packets in a network comprising a sub-network, in particular a broadcast sub-network. The routing apparatus is included in a first network element of the sub-network, the first network element being arranged to support first and second protocol sets, for example OSI protocols and IP protocols. Upon designation of the first network element to represent the other network elements in the sub-network in respect of the first and second protocol sets, the routing apparatus is arranged to create a respective routing data packet for each protocol set and to cause the routing data packets to be propagated through the network. Upon resignation of the first network element as representative in respect of one of the protocol sets, the routing apparatus is arranged to cause the respective routing data packet for that protocol set only to be purged from the network.

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Antrim, United Kingdom

Derek Gilmore