摘要 |
The invention relates to auto-tunnelling in a heterogenous network, and more particularly in an IS-IS routing domain. The preferred embodiment provides a routing apparatus that enables network nodes which support incompatible network layer protocols, such as CLNP, IPv4 or IPv6 to be present in a single routing domain, e.g. IS-IS level-1 area or level-2 subdomain. The routing apparatus enables nodes automatically to tunnel one network layer protocol over another as required, provided that all of the nodes in the routing domain support IS-IS or Integrated IS-IS routing protocols. The routing apparatus does not necessarily try to route a data packet to its destination node but rather sends the data packet in a tunnel to a node in the path to the destination node, as appropriate. |