IS-IS

Technology & Computing abbreviation · Networking

IS-IS
Stands forIntermediate System to Intermediate System
CategoriesTechnology & Computing

IS-IS stands for Intermediate System to Intermediate System, a networking abbreviation.

A link-state interior routing protocol, similar in operation to OSPF, widely used inside large ISP and carrier backbones. Because it runs directly over layer 2 rather than over IP, it was easy to extend for IPv6 and MPLS traffic engineering.

Example: The backbone runs IS-IS as the IGP, with BGP carrying customer routes on top.

Usage notes

Originally designed for the OSI protocol suite and standardized as ISO/IEC 10589; RFC 1195 (1990) extended it to carry IP routes. In OSI vocabulary a router is an "intermediate system" and a host an "end system", which explains the name. Pronounced "eye-ess eye-ess".

More networking abbreviations

  • IMAP – Internet Message Access Protocol
  • IP – Internet Protocol
  • IPsec – Internet Protocol Security
  • IPv4 – Internet Protocol version 4
  • IPv6 – Internet Protocol version 6
  • IRC – Internet Relay Chat
  • iSCSI – Internet Small Computer Systems Interface
  • ISP – Internet service provider
  • IXP – Internet exchange point
  • L2TP – Layer 2 Tunneling Protocol
  • LAN – Local area network
  • LDAP – Lightweight Directory Access Protocol

See all 113 networking abbreviations →