What does the Junos command advertise-inactive allow?
A.
OSPF inactive routes to be advertised using BGP
B.
inactive and hidden BGP routes to be redistributed into OSPF
C.
the best BGP route to be re-advertised by BGP, even when it is not the best route
D.
the second-best BGP route to be re-advertised by BGP, to back up the best BGP route
C
Explanation:
Under normal circumstances, routes that are not being used to forward traffic—inactive routes—are not advertised to peers unless synchronization is enabled. For example, suppose a BGP speaker receives a route to a particular prefix, determines that it is the best route to the prefix, and stores the route in the IP routing table (sometimes known as the forwarding information base, or FIB). This route might not be used for forwarding to that prefix; for example, if you have configured a static route to the same destination prefix. Because static routes have better administrative distances than BGP received routes, IP will use the static route rather than the BGP received route for forwarding traffic to that prefix. The BGP received route is inactive and is not advertised to peers. You can use the bgp advertise-inactive command to enable the advertisement of inactive received routes.
bgp advertise-inactive
Use to enable the BGP speaker to advertise inactive routes—best routes in the IP forwarding table that are not being used to forward traffic. This feature is disabled by default.
Issuing this command does not affect the BGP rules for best route selection, or how BGP populates the IP forwarding table.
Example
host1(config-router)#bgp advertise-inactive
The new value is applied to all routes that are subsequently placed in the IP routing table.
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