You can configure summary prefixes to aggregate IS-IS IPv6 route information. Summary prefixes can enhance performance by reducing the size of the Link State database, reducing the amount of data the device needs to send to its neighbors, and reducing the CPU cycles used for IPv6 IS-IS. The following task configures a summary prefix 2001:db8::/32 for Level 1 routes.
Procedure
-
Enter the
configure terminal command to access global configuration mode.
device# configure terminal
-
Enter the
router isis command to enter IS-IS router configuration mode and enable IS-IS on the device.
device(config)# router isis
-
Enter the
address-family ipv6 unicast
command to enable ISIS address-family IPv6 unicast configuration mode.
device(config-isis-router)# address-family ipv6 unicast
-
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
