The ipv6 summary command configures IS-IS to generate IPv6 summarized routes.
The undo ipv6 summary command disables IS-IS from generating IPv6 summarized routes.
By default, IS-IS does not generate IPv6 summarized routes.
ipv6 summary ipv6-address prefix-length [ avoid-feedback | generate_null0_route | tag tag | [ level-1 | level-1-2 | level-2 ] ] *
undo ipv6 summary ipv6-address prefix-length [ level-1 | level-1-2 | level-2 ]
| Parameter | Description | Value |
|---|---|---|
| ipv6-address | Specifies the address range of IPv6 routes to be summarized. | - |
| prefix-length | Specifies the prefix length of an IPv6 route. | The value is an integer that ranges from 0 to 128. |
| avoid-feedback | Avoids learning summarized routes through SPF calculation. | - |
| generate_null0_route | Generates NULL0 routes to avoid routing loop. | - |
| tag tag | Specifies the administrative tag value. | The value is an integer that ranges from 1 to 4294967295. |
| level-1 | Indicates that only routes in Level-1 areas are summarized. If the level is not specified, level-2 is used by default. |
- |
| level-1-2 | Indicates that routes in Level-1 and Level-2 areas are
summarized. If the level is not specified, level-2 is used by default. |
- |
| level-2 | Indicates that only routes in Level-2 areas are summarized. If the level is not specified, level-2 is used by default. |
- |
The routes with the same prefix can be aggregated into one route. This can reduce the scale of the routing table, the size of the LSPs generated by the local switch, and the scale of the LSDB. The aggregated routes can be the routes discovered by IS-IS or the imported IPv6 routes. After the aggregation, the smallest cost among those of the routes that are aggregated is used as the cost of the aggregated IPv6 route.
The ipv6 summary command can take effect only after IPv6 is enabled for the IS-IS process by the ipv6 enable command.