End-to end inter-domain routing

Abstract

According to a first aspect of the present invention there is provided a method of constructing an end-to-end routing path across multiple packet switched domains. The method comprises generating a domains topology identifying all possible domains, the border elements of those domains and the inter-domain links. When a request is received for computation of a path from a source entity in a first domain to a destination entity in a second domain, all domains and inter-domain links that cannot or are unlikely to feature in the requested path are removed from the domains topology. Candidate intra-domain paths for each remaining domain are then computed, with each candidate intra-domain path being mapped to a logical link defined by its two ends, at least one end being a border element and the other being a border element or the source or destination entity. Attributes for each logical link are determined, together with attributes of the remaining inter-domain links. A virtual network topology is generated by combining the logical links and their associated attributes with the remaining inter-domain links and their associated attributes. This allows a best end-to-end route to be determined by analyzing the virtual network topology.