Routing With IS-IS Protocol - Part 5 (IS-IS versus OSPF) ⋆ IpCisco

IS-IS Protocol and OSPF have some similarities and differences.

Lets firstly check the similarities of these two protocol one by one:

– IS-IS Protocol and OSPF are both Link-State Interior Gateway Protocols.
– IS-IS Protocol and OSPF are both uses Dijkstra SPF (Shortest Path First) algorithm.
– These protocols have LSDBs and the LSDB similar structure
– Both support VLSM (Variable Length Subnet Mask)
– Both are very scalable protocols
– Both has a fast convergence time after changes
– Both are open standards
– Both have hierarchical structures, there are two hierarchy level
– Both protocols support LANs and point-to-point protocols in similar ways
– Both protocol use periodic Hello messages for neighbour establishment

Now let’s check the differences of these two important protocols: