You configured an aggregate route of 192.168.8.0/21 and committed the updated configuration. Using an operational show command, you notice that the newly configured route is not present in the output.
What would explain this behavior?
A.
The next hop is not resolvable.
B.
The next hop is not reachable.
C.
There are no active contributing routes.
D.
An aggregate route will not show up in the local table; it will be shared only with BGP neighbors.
Explanation:
Configuring Aggregate Routes
Route aggregation allows you to combine groups of routes with common addresses into a single entry in the routing table. This decreases the size of the routing table as well as the number of route advertisements sent by the router.An aggregate route becomes active when it has one or more contributing routes. A contributing route is an active route that is a more specific match for the aggregate destination. For example, for the aggregate destination 128.100.0.0/16, routes to 128.100.192.0/19 and 128.100.67.0/24 are contributing routes, but routes to 128.0.0.0./8, 128.0.0.0/16, and 128.100.0.0/16 are not.
A route can contribute only to a single aggregate route. However, an active aggregate route can recursively contribute to a less specific matching aggregate route. For example, an aggregate route to the destination 128.100.0.0/16 can contribute to an aggregate route to 128.96.0.0/13.
When an aggregate route becomes active, it is installed in the routing table with the following information:
* Reject next hopIf a more-specific packet does not match a more-specific route, the packet is rejected and an ICMP unreachable message is sent to the packets originator.
* Metric value as configured with the aggregate statement.
* Preference value that results from the policy filter on the primary contributor, if a filteris specified.
* AS path as configured in the aggregate statement, if any. Otherwise, the path is computed by aggregating the paths of all contributing routes.
* Community as configured in the aggregate statement, if any is specified.