To establish adjacencies and establish dynamic routing, enable routing on one or
more interfaces.
You can configure only one IS-IS routing process to perform Level 2 routing. A
level-1-2
designation performs Level 1 and Level 2 routing at the same time.
Related
Commands
•
net
— configures an IS-IS network entity title (NET) for the routing process.
•
is-type
— assigns a type for a given area.
isis circuit-type
Configure the adjacency type on interfaces.
Syntax
isis circuit-type {level-1 | level-1-2 | level-2-only}
To return to the default values, use the
no isis circuit-type
command.
Parameters
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, a Level 2 adjacency is established.
This setting 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.
Defaults
level-1-2
Command
Modes
INTERFACE
Command
History
Version 9.2(0.0)
Introduced on the MXL 10/40GbE Switch IO Module.
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 must 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.
810
Intermediate System to Intermediate System (IS-IS)
