Patent ID: 7519009

Claim:
An aggregation comprising: at least first and second autonomous systems (ASs); and a node between and linking the first and second ASs, the node having: a first channel physically linked with the first AS, and a first internal gateway protocol (IGP) instance operating on the first channel to provide a first IGP routing level between the first AS and the node, the first IGP instance configured on the node to receive, and to leak to a second IGP instance, topology information for link states internal to the first AS; and a second channel physically linked with the second AS, the second IGP instance operating on the second channel to provide a second IGP routing level between the second AS and the node, the second IGP instance configured on the node to receive, and to leak to the first IGP instance, topology information for link states internal to the second AS; the first IGP instance further configured to include the information leaked by the second IGP instance in external link state advertisements in the first AS; the second IGP instance further configured to include the information leaked by the first IGP instance in external link state advertisements in the second AS.