# Enabling and Configuring IS-IS for IPv6 Routing

When enabling IS-IS IPv6, you must create an IS-IS IPv6 routing process and assign it to specific interfaces rather than to networks. You can specify only a single IS-IS process per router.

To enable IS-IS routing, enter Global Configuration mode, and follow this procedure:

1. Access Global Configuration mode and specify an IPv6 license.
   host1(config)#license ipv6 license-value
2. Configure an IP address on the router to serve as the router ID.
   host1(config)#interface loopback0 host1(config-if)#ip address 10.6.5.4/32
3. Configure the lower-layer interfaces over which the IPv6 traffic flows.
   host1(config-if)#interface fastEthernet 1/0
4. Configure an IPv6 address on the interface.
   host1(config-if)#ipv6 address 2008::1/48
5. Specify the IS-IS IPv6 process to apply to the interface. Use the same tag name that you specify with the router isis command for the VR.
   host1(config-if)#ipv6 router isis floor12

   Repeat Steps 3–5 for all desired IPv6 interfaces.

6. Specify an IS-IS process globally for the VR. Use the same tag name that you specify with the ipv6 router isis command on the interface.
   host1(config)#router isis floor12
7. Configure a Network Entity Title (NET) for the routing process that specifies the ISO network address.
   host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
8. Create the IS-IS IPv6 address family for the interface.
   host1(config-router)#address-family ipv6 unicast
9. Configure any of the following desired IS-IS options for the address family: redistributing routes from other protocols, redistributing IS-IS IPv6 routes between levels, distributing level 2 routing information to level 1 routers throughout the IS-IS routing domain, summarizing IPv6 routes, applying a route map to modify routes before they are installed in the routing table,
   host1(config-router-af)#redistribute ospf level-1-2 host1(config-router-af)#redistribute isis level-2 into level-1 host1(config-router-af)#distribute-domain-wide host1(config-router-af)#summary-prefix 2001:2000::0/8 level-1 metric 10 tag 100 host1(config-router-af)#table-map ospfFilter
10. Exit the IS-IS IPv6 address family.
    host1(config-router-af)#exit-address-family

    | Note: Enabling IPv6 for the interface also enables IPv4 for that interface. However, this interface does not participate in IS-IS IPv4 routing.

address-family

- Use to configure IS-IS to exchange IPv6 addresses by creating the IPv6 address family.
- Use the unicast keyword to exchange unicast addresses. Use the multicast keyword to exchange multicast addresses. Use the unicast and multicast keywords together, or omit both of them to exchange both unicast and multicast addresses.
- Examples
  host1(config)#address-family ipv6 unicast
- Use the no version to disable the exchange of IPv6 addresses.
- See address-family

exit-address-family

- Use to exit Address Family Configuration mode and access Router Configuration mode.
- Example
  host1:vr1(config-router-af)#exit-address-family
- There is no no version.
- See exit-address-family

ipv6 router isis

- Use to configure an IS-IS routing process on an IPv6 interface.
- Before the IS-IS router process is useful, you must assign a NET with the net command, and enable some interfaces with IS-IS.
- Use the tag parameter to specify a meaningful name for a routing process. It must be unique among all IPv6 routing processes for a given router. If you choose not to specify a tag name, a null tag is assumed, and the process is referenced with a null tag. Use the same tag name for ipv6 router isis as you did for the router isis command.
- Example—Enables ISIS for IPv6 on an interface.
  host1(config-if)#ipv6 router isis bldg1
- Use the no version to disable IS-IS on the interface.
- See ipv6 router isis

## Summary Example

host1(config)#license ipv6 license-value host1(config)#interface loopback0 host1(config-if)#ip address 10.6.5.4/32 host1(config-if)#interface fastEthernet 1/0 host1(config-if)#ipv6 address 2008::1/48 host1(config-if)#ipv6 router isis floor12 host1(config)#router isis floor12 host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00 host1(config-router)#address-family ipv6 unicast host1(config-router-af)#redistribute ospf level-1-2 host1(config-router-af)#redistribute isis level-2 into level-1 host1(config-router-af)#distribute-domain-wide host1(config-router-af)#summary-prefix 2001:2000::0/8 level-1 metric 10 tag 100 host1(config-router-af)#table-map ospfFilter