Which two statements about BGP facilitate the prevention of routing loops between two autonomous systems? (Choose two.)
Which two statements about BGP facilitate the prevention of routing loops between two autonomous systems? (Choose two.)
To prevent routing loops between two autonomous systems in BGP, EBGP routers will append their AS number when advertising routes to ensure that any router receiving the route can identify the origin AS and avoid routing loops (A). Additionally, EBGP routers will drop routes that contain their own AS number in the AS_PATH, as this indicates the route has already traversed that AS and would form a loop if readvertised (C). These mechanisms help maintain a loop-free routing environment between autonomous systems.
Prepending: Used to manipulate path preference by making a route less attractive. It increases the AS path length, which can influence other ASes to prefer alternative, shorter paths.
CD. If 192.168.2.0/24 is advertised in the order 65001 65002 65003, the route will look like this: 192.168.2.0/24 65003 65002 65001 I Therefore the answer is D(prepend)
A C are correct.
C,D are correct
AC is correct https://networklessons.com/bgp/bgp-prevent-transit-as
Pls read again, its AC. Append means it adds the ASPath to the route and this is done just from ebgp. Prepend is used when we want to influence the routes.
CD is correct
When a BGP router advertises a prefix, it will include its own AS number to the left of the AS path attribute - aka prepending. Therefore C and D is correct