White Paper Abstract:
OSPF is the routing protocol of choice for almost all large IP networks. No other Interior Gateway Protocol (IGP) provides the combination of speed, scalability, reliability, and flexibility of OSPF. And because OSPF is an open standard, it is an essential component of large, scalable, innovative networks. Yet many network operators have locked themselves into the proprietary Extended Interior Gateway Routing Protocol (EIGRP). As their networks grow large, this once simple protocol begins to present scaling problems that can be increasingly disruptive to the network and are notoriously difficult to troubleshoot. Interestingly, the very characteristics that make EIGRP simple to use in small networks are the same characteristics that become liabilities in large networks: No requirements to build
an ordered or hierarchical network, thus allowing the network to expand in random patterns; no inherent capabilities to break a network into manageable areas without resorting to multiple EIGRP processes; no need to think about your network topology. And, stuck in active (SIA) conditions, regularly encountered in larger EIGRP networks, cause abrupt, unpredictable adjacency drops that can have severe effects throughout the network.