Package isis
The XML API OSS interface uses the isis package to configure IS-IS. IS-IS is a
link state interior gateway protocol that uses the shortest path first algorithm to
determine routers. Routing decisions are made based on the link state information.
IS-IS entities are comprised of:
- networks, which are autonomous system routing domains
- intermediate systems, which are routers, such as the 7750 SRs
- end systems, which are network devices that send and receive PDUs
End systems and intermediate system protocols allow routers and nodes to identify
each other. IS-IS sends out link state updates periodically through the network, so
each router can maintain current network topology information.
Large networks, or autonomous systems, are supported by IS-IS using a two-level
hierarchy. This divides a large area into more manageable, smaller areas. The first
level (level 1) of routing is performed within an area. The second level (level 2) of
routing is performed between areas.