The biggest advantage of OSPF is that it is efficient; OSPF requires very little network overhead even  in very large internetworks. The biggest disadvantage of OSPF is its complexity; OSPF requires  prop er planning and is more difficult to configure and administer.  
  OSPF uses a Shortest Path First (SPF) algorithm to compute routes in the routing table. The SPF  algorithm computes the shortest (least cost) path between the router and all the networks of the    internetwork. SPF-calculated routes are always loop-free. 
Instead of exchanging routing table entries like RIP routers, OSPF routers maintain a map of the  internetwork that is updated after any change to the network topology. This map, called the link state 
database, is synchronized between all the OSPF routers and is used to compute the routes in the  routing table. Neighboring OSPF routers form an adjacency, which is a logical relationship between 
routers to synchronize the link state database. 
C  hanges to internetwork topology are efficiently flooded across the entire internetwork to ensure that  the link state database on each router is synchronized and accurate at all times. Upon receiving  changes to the link state database, the routing table is recalculated. 
  OSPF using link cost information in determining routes instead of hop counts, overcoming the 16 hop limitation of RIP.  文章錄入：csh    責(zé)任編輯：csh