Reference Guide

● Configuring the IS-IS Metric Style
● Configuring IS-IS Cost
● Changing the IS-Type
● Controlling Routing Updates
● Configuring Authentication Passwords
● Setting the Overload Bit
● Debuging IS-IS
Enabling IS-IS
By default, IS-IS is not enabled.
The system supports one instance of IS-IS. To enable IS-IS globally, create an IS-IS routing process and assign a NET address.
To exchange protocol information with neighbors, enable IS-IS on an interface, instead of on a network as with other routing
protocols.
In IS-IS, neighbors form adjacencies only when they are same IS type. For example, a Level 1 router never forms an adjacency
with a Level 2 router. A Level 1-2 router forms Level 1 adjacencies with a neighboring Level 1 router and forms Level 2
adjacencies with a neighboring Level 2 router.
NOTE: Even though you enable IS-IS globally, enable the IS-IS process on an interface for the IS-IS process to exchange
protocol information and form adjacencies.
To configure IS-IS globally, use the following commands.
1. Create an IS-IS routing process.
CONFIGURATION mode
router isis [tag]
tag: (optional) identifies the name of the IS-IS process.
2. Configure an IS-IS network entity title (NET) for a routing process.
ROUTER ISIS mode
net network-entity-title
Specify the area address and system ID for an IS-IS routing process. The last byte must be 00.
For more information about configuring a NET, refer to IS-IS Addressing.
3. Enter the interface configuration mode.
CONFIGURATION mode
interface interface
Enter the keyword interface then the type of interface and slot/port information:
● For a 1-Gigabit Ethernet interface, enter the keyword GigabitEthernet then the slot/port information.
● For the Loopback interface on the RPM, enter the keyword loopback then a number from 0 to 16383.
● For a port channel, enter the keywords port-channel then a number.
● For a SONET interface, enter the keyword sonet then the slot/port information.
● For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port information.
● For a VLAN, enter the keyword vlan then a number from 1 to 4094.
4. Enter an IPv4 Address.
INTERFACE mode
ip address ip-address mask
Assign an IP address and mask to the interface.
The IP address must be on the same subnet as other IS-IS neighbors, but the IP address does not need to relate to the NET
address.
5. Enter an IPv6 Address.
INTERFACE mode
ipv6 address ipv6-address mask
● ipv6 address: x:x:x:x::x
Intermediate System to Intermediate System
411