Mobile exterior gateway protocol: extending IP scalability

The mobile exterior gateway protocol (EGP) extends the two-tier hierarchical network concepts inherent within OSPF and IS-IS in order to create N-tier autonomous systems. It introduces the concept of an aggregated area border router (A-ABR), which behaves like traditional OSPF ABRst except that A-ABRs link together former autonomous systems (ASes) into an aggregated AS structure. These aggregated ASes can communicate with other ASes-or aggregated ASes-via AS boundary routers (ASBRs) using BGP in the traditional manner. This approach is currently being simulated by modifying John Moy's OSPF code and by Opnet modeling. The approach has been shown to converge without routing loops but an evaluation of its scaling promises will need to be deferred until we complete the porting of the code to an environment that can simulate thousands of routers. Mobile EGP seeks to address two specific problems: 1. To extend IP scalability in order to support the number of mobile ad hoc network (MANET) routers within a single AS that are currently being envisioned for emerging tactical military force structures. 2. To improve the inter-AS mobility attributes of joint and coalition operations by replacing the "well defined" pair-wise BGP interfaces of local mission deployments with meshed OSPF relation ships.