Refer to the Exhibit.
In the exhibit, the 172.32.1.0/24 prefix is being sent from Router A to Router B through BGP.
When the BGP announcement for 172.23.1.0/24 is sent from Router B and received by Router C, which two attributes will be changed by default? (Choose two.)
A.
AS path
B.
origin
C.
multiple exit discriminator (MED)
D.
next hop
Explanation:
Next-hop accessibilityIf the next hop is inaccessible, the local router does not consider the route. The router must verify that it has a route to the BGP next-hop address. If a local route to the next hop does not exist, the local route does not include the router in its forwarding table. If such a route exists, route selection continues.
Highest local preferenceThe local router selects the route with the highest local preference value. If multiple routes have the same preference, route selection continues. (For more information, see Local Preference.)
Shortest AS pathThe local router selects the route with the fewest entries in the AS path. If multiple routes have the same AS path length, route selection continues
AS Path
Routes advertised by BGP maintain a list of the ASs through which the route travels. This information is stored in the route advertisement as the AS path, and it is one of the primary criteria that a local router uses to evaluate BGP routes for inclusion in its forwarding table. Figure 61 shows how BGP creates an AS path.
Figure 61: BGP AS Path
