Refer to the exhibit. Router RT-1 and router RT-2 both advertise network 131.25.0.0/16 to
router RT-3 via internal BGP. What is the reason that router RT-3 chose router RT-1 as its
best path to network 131.25.0.0/16.

A.
It has a better router ID.

B.
It advertises a lower autonomous system.

C.
It advertises the best AS-path.

D.
It advertises the best local preference.

E.
It advertises the best origin code.

F.
It advertises the best MED.

Explanation:
After BGP receives updates about different destinations from different autonomous systems,
it chooses the best path to reach a specific destination.
The following process summarizes how BGP chooses the best route on a Cisco router.
• Prefer the route with the highest weight. (The weight attribute is proprietary to Cisco
and is local to the router only.)
• If multiple routes have the same weight, prefer the route with the highest local
preference value. (The local preference is used within an autonomous system.)
• If multiple routes have the same local preference, prefer the route that the local
router originated. A locally originated route has a next hop of 0.0.0.0 in the BGP table.
• If none of the routes were locally originated, prefer the route with the shortest
autonomous system path.
• If the autonomous system path length is the same, prefer the lowest origin code (IGP
< EGP < incomplete).
• If all origin codes are the same, prefer the path with the lowest MED. (The MED is
exchanged between autonomous systems.) The MED comparison is made only if the

neighboring autonomous system is the same for all routes considered, unless the bgp
always-compare-med command is enabled
• If the routes have the same MED, prefer external paths to internal paths.
• If synchronization is disabled and only internal paths remain, prefer the path through
the closest IGP neighbor, which means that the router prefers the shortest internal path
within the autonomous system to reach the destination (the shortest path to the BGP next
hop).
• For EBGP paths, select the oldest route to minimize the effect of routes going up and
down (flapping).
• Prefer the route with the lowest neighbor BGP router ID value.
• If the BGP router IDs are the same, prefer the router with the lowest neighbor IP
address.
In this case, since everything else is equal the router ID will be used, and the specific router
ID that is chosen is 165.1.1.1 (lowest one), which is RT- 3.