Scalable Multi-Region Routing at Inter-Domain Level

DTIA (Dynamic Topological Information Architecture), an inter-domain routing architecture, assumed the existence of "regions of domains" to offer a scalable solution for the Internet. The way regions can be connected and how traffic flow amongst them is not a trivial aspect and can jeopardize the solution proposed for intra-region traffic. This paper covers the inter-region case showing that it can be performed by using a smaller set of valid paths than for the intra-region case in the source region, but still featuring multipath to the destination and taking advantage of multi-homing. The routing is based on a monotone algebra to converge without the need to change the IP headers or introduce additional signaling or state in the network. The overall system complies with the current business model of the Internet, and it also features one tendency that has been increasingly used: the fact that Autonomous Systems (ASes) are each time more connected with direct (or semi-direct) links instead of in a pure hierarchical structure up to tier-1 ASes.