The Intermediate System-to-Intermediate System (IS-IS) routing protocol is an Interior Gateway Protocol (IGP) standardized by the Internet Engineering Task Force (IETF) and commonly used in large Service Provider networks. IS-IS may also be deployed in extremely large Enterprise networks. IS-IS is a link-state routing protocol, providing fast convergence and excellent scalability. Like all link-state protocols, IS-IS is very efficient in its use of network bandwidth.
Cisco is an active member of the IS-IS working group at the IETF, and is responsible for many of the ongoing enhancements to the protocol.
Technical Support and Documentation
Review additional information about Intermediate System-to-Intermediate System (IS-IS) in the Technical Support site area.