OSPF and IS-IS are both link-state protocols and are based on the Dijkstra algorithm of the Shortest Path First (SPF). In addition, they both have a two-level hierarchy.
OSPF tends to be deployed mostly as an enterprise solution, whereas Integrated IS-IS is used for IP routing in some ISP networks.
|IS-IS Terminology|OSPF Terminology |Area|Stub area |Area ID|Area ID |Backbone Area|Backbone Area |DIS (Designated Intermediate System)|Designated Router |Domain|Network |ES (End System)|Host |ES-IS (The Address Resolution feature of ES-IS)|ARP (Address Resolution Protocol) |IS (Intermediate System)|Router |ISO Routing Domain|Autonomous System |Level 1|Internal Nonbackbone Stub Area |Level 1-2|Area Border Router |Level 2|Backbone Router |LSP (Link-state Packet)|LSA (Link-state Advertisement) |CSNP and PSNP (Complete and Partial sequence number PDUs)|Link-state acknowledgement packet |PDU (Protocol Data Unit)|Packet |NET (Network Entity Title)|IP destination address (subnet and host), user in a similar way to Router ID |NSAP (Network Service Access Point)|IP Destination Address + IP Protocol Number
2 pages link to OSPFvsISIS:
