comparison of wan igp protocols

Most companies with large WANs use either RSTP+flooding/learning or OSPFv2 for two purposes: to route around network link failures, and to automatically find the correct path to a destination address on a large network with many hops. Including RSTP in the comparison is a realistic acknowledgement of the way L2 switching is abused these days. Including OSI in the comparison should reveal some habitually irritating aspects of switched IP networks that are mere accidents of history, and others that are more fundamental.