isis circuit-type [level-1 | level-1-2 | level-2-only]
no isis circuit-type
level-1 (Optional) Configures a router for Level 1 adjacency only. level-1-2 (Optional) Configures a router for Level 1 and Level 2 adjacency. level-2-only (Optional) Configures a router for Level 2 adjacency only.
To configure the type of adjacency, use the isis circuit-type command in interface configuration mode. To reset the circuit type to Level l and Level 2, use the no form of this command.
By default, a Level 1 and Level 2 adjacency is established.
Normally, this command need not be configured. The proper way is to configure a router as a Level 1-only, Level 1-2, or Level 2-only system. Only on routers that are between areas (Level 1-2 routers) should you configure some interfaces to be Level 2-only to prevent wasting bandwidth by sending out unused Level 1 hello packets. Note that on point-to-point interfaces, the Level 1 and Level 2 hellos are in the same packet.
A Level 1 adjacency may be established if there is at least one area address in common between this system and its neighbors. Level 2 adjacencies will never be established over this interface.
A Level 1 and Level 2 adjacency is established if the neighbor is also configured as level-1-2 and there is at least one area in common. If there is no area in common, a Level 2 adjacency is established. This is the default.
Level 2 adjacencies are established if the other routers are Level 2 or Level 1-2 routers and their interfaces are configured for Level 1-2 or Level 2. Level 1 adjacencies will never be established over this interface.
In the following example, other routers on Ethernet interface 0 are in the same area. Other routers on Ethernet interface 1 are in other areas, so the router will stop sending Level 1 hellos.Router(config-if)# interface ethernet 0 Router(config-if)# ip router isis Router(config-if)# interface ethernet 1 Router(config-if)# isis circuit-type level-2-only
� Cisco Systems, Inc. 2001, 2002, 2003
World Wide Education
|Converted from CHM to HTML with chm2web Pro 2.85 (unicode)|