Configuring IS-IS

IS-IS Overview

Intermediate System-to-Intermediate System (IS-IS) routing protocol is a link-state Interior Gateway Protocol (IGP). Link-state protocols are characterized by the propagation of the information required to build a complete network connectivity map on each participating device. That map is then used to calculate the shortest path to destinations.

The IS-IS protocol was developed in the late 1980s by Digital Equipment Corporation (DEC) and was standardized by the International Standards Organization (ISO) in ISO/IEC 10589. The current version of this standard is ISO/IEC 10589:2002.

For more information, refer Information About IS-IS.

How to Configure IS-IS

Enabling IS-IS

To configure IS-IS, you need to enable IS-IS on the device and interface.

To enable IS-IS as an IP routing protocol on the device at the global configuration mode, enter the following commands:

enable 
configure terminal 
router isis [area-tag] 
net network-entity-title 
end

Configuring IS-IS on BDI Interface

To enable IS-IS as an IP routing protocol on the BDI interface, enter the following commands:


enable
configure terminal
interface BDI<bdi-no>
ip address ip-address mask 
ip router isis [area-tag]
end

For more information, see Configuring IS-IS.

Configuring Loopback on IS-IS Interface

To configure loopback on IS-IS interface, enter the following commands:


interface loopback<loopback-no> 
ip address <ip-address > <subnet-mask>
ip router isis  area <area-tag>
end