Classification of dynamic routing:
Classification according to scope (AS - autonomous system)
1. IGP - interior gateway protocol ---- mainly a routing protocol applied inside AS
------------- RIP, ospf, IS-IS, EIGRP, etc.
2. EGP—External Gateway Protocol——a routing protocol mainly used between ASs
———————BGP (Border Gateway Protocol)
BGP does not need an algorithm, it selects routes according to the rules
The IGP protocol is classified according to the algorithm
—distance vector protocol (DV)—to obtain routing information of unknown network segments by directly sending routing entry information. ---- Algorithm used: Bellman. Ford algorithm (Bellman-Ford algorithm) - also known as; "routing protocol based on rumors" (routing entry information is passed by the router one by one to tell the unknown routing entry information router)
---------------RIP
—Link State Protocol (LS)—transfers topology information (LSA—Link State Advertisement)—collects LSA information and finally completes the network The topology information is obtained. SPF - the shortest path first algorithm - this algorithm can convert the graph structure into a tree structure - and then calculate the local routing information to the unknown network segment according to the tree structure (the ultimate goal is to generate loop-free routing information, because the tree structure structure does not form a loop).
---------------- OSPF, IS-IS (equivalent to simplified OSPF)