Configuring summary prefixes

1. Enter the configure terminal command to access global configuration mode.
   

   device# configure terminal

2. Enter the router isis command to enter IS-IS router configuration mode and enable IS-IS on the device.
   

   device(config)# router isis
   

3. Enter the address-family ipv6 unicast command to enable ISIS address-family IPv6 unicast configuration mode.
   

   device(config-isis-router)# address-family ipv6 unicast
   

4. Enter the summary-prefix command with the level-1 parameter, specifying an IPv6 address and network mask, to configure a summary prefix and network mask for Level 1 routes.
   

   device(config-router-isis-ipv6u)# summary-prefix 2001:db8::/32 level-1
   

Example

The following example configures asummary-prefix of 2001:db8::/32 for Level 1 routes.

device# configure terminal
device(config)# router isis
device(config-isis-router)# address-family ipv6 unicast
device(config-router-isis-ipv6u)# summary-prefix 2001:db8::/32 level-1