Method and system for determining network characteristics using routing protocols

Abstract

A method and system are described herein for obtaining IGP network information useful in determining network routing topologies. The method involves querying a router for its router identifier and all its area identifiers, counting the router's number of area identifiers to determine whether the router is an ABR or an ASBR, and querying the router's link state database for the lowest area identifier on the router. The method further involves importing all Type 1 and Type 2 LSAs for that area into the database of a network discovery software engine, importing from the router's link state database only those networks outside the router's autonomous system that are also directly connected to an ASBR, then moving to the next highest area identifier in the router's database to repeat importing Type 1 and Type 2 LSAs for that area into the database. Next, the method involves importing from the router's link state database only those networks outside the router's autonomous system that are also directly connected to an ASBR. This process is repeated until there are no more areas on the router that have not been processed. Then, starting with the lowest area identifier discovered, all networks in the area making LSAs other than Type 1 or Type 2 are swept. The entire process is repeated for every router discovered.