Appendix B. IS-IS Fundamentals

IS-IS (Intermediate System-to-Intermediate System) is a protocol standardized by the International Organization for Standardization (ISO) for use with Connectionless Network Service (CLNS) and other ISO routed protocols. The Internet Engineering Task Force (IETF) has integrated IP routing with IS-IS through a series of RFCs.

This appendix will give you a general overview of the IS-IS protocol. For more information, you should refer to the relevant ISO documents and RFCs.