Reference Guide

Intermediate System to Intermediate System (IS-IS) | 921
isis circuit-type
e
Configure the adjacency type on interfaces.
Syntax
isis circuit-type {level-1 | level-1-2 | level-2-only}
To return to the default values, enter no isis circuit-type.
Parameters
Defaults
level-1-2
Command Modes
INTERFACE
Command
History
Usage
Information
Because the default establishes Level 1 and Level 2 adjacencies, you do not need to configure this
command. Routers in an IS-IS system should be configured as a Level 1-only, Level 1-2, or Level
2-only system.
Only configure interfaces as Level 1 or Level 2 on routers that are between areas (for example, a Level
1-2 router) to prevent the software from sending unused hello packets and wasting bandwidth.
isis csnp-interval
e
Configure the IS-IS complete sequence number PDU (CSNP) interval on an interface.
Syntax
isis csnp-interval seconds [level-1 | level-2]
To return to the default values, enter the no isis csnp-interval [seconds] [level-1 | level-2]
command.
level-1
You can form a Level 1 adjacency if there is at least one common area address between this
system and neighbors.
You cannot form Level 2 adjacencies on this interface.
level-1-2
You can form a Level 1 and Level 2 adjacencies when the neighbor is also configured as
Level-1-2 and there is at least one common area, if not, then a Level 2 adjacency is
established.
This is the default.
level-2-only
You can form a Level 2 adjacencies when other Level 2 or Level 1-2 routers and their
interfaces are configured for Level 1-2 or Level 2. Level 1 adjacencies cannot be
established on this interface.
Version 8.3.19.0 Introduced on S4820T
Version 8.3.12.0 Introduced on S4810