Distributed directory services for locating network resources in a very large packet switching network

摘要

The present invention relates to a method and system of locating a network resource in a packet switching network divided in a backbone subnetwork connected to one or a plurality of access subnetworks. The access subnetworks comprise one or a plurality of access border nodes directly connected to the backbone subnetwork. The backbone subnetwork comprises one or a plurality of backbone border nodes directly connected to the access subnetworks. Border nodes of different subnetworks are connected by border links.;The method in access border nodes involves the steps of :receiving a query message comprising a resource name, the resource name including a prefix;comparing the resource name prefix with the prefixes stored in an access border node directory database, said access border node directory database comprising prefixes of the resources local to the access border node subnetwork;determining whether the resource name relates to a resource which is local to the access border node subnetwork or not;forwarding said query message to an adjacent backbone border node when the resource name relates to a resource which is not local to the access border node subnetwork.;The method in backbone border nodes involves the steps of :receiving a query message comprising a resource name, the resource name including a prefix;comparing the resource name prefix with the prefixes stored in one or a plurality of backbone border node directory databases. Each backbone border node directory database corresponds to an access subnetwork managed by the backbone border node;determining whether the resource name relates to a resource which belongs to an access subnetwork that the backbone border node manages or not;forwarding the query message to an adjacent access border node when the resource name relates to a resource which belongs to an access border node subnetwork managed by the backbone border.;Each access subnetwork has its own spanning tree and distributed topology, and interactions between access networks are limited to a minimum. The size of distributed topologies is kept small and the control traffic is mostly limited to subnetworks.