What are three reasons a BGP route would be hidden? (Choose three.)
What are three reasons a BGP route would be hidden? (Choose three.)
A BGP route can be hidden for several reasons. First, if the AS Path contains a 0, the route is considered invalid since AS 0 is reserved and should not appear in a valid AS Path. Second, a damping policy can suppress a route if it is determined to be unstable, temporarily hiding it to maintain network stability. Lastly, if the next hop for the BGP route is unreachable, the route cannot be utilized or advertised, leading it to be hidden. These reasons are critical for ensuring reliable and stable BGP route management.
A. The AS Path contains a 0: BGP routes with an AS Path containing an AS number of 0 are considered invalid and are hidden. AS 0 is reserved and should not be used in the AS Path. B. It is suppressed by a damping policy: BGP route damping is a mechanism that suppresses unstable routes for a certain period of time. If a route flaps frequently, a damping policy may temporarily hide the route to avoid instability in the network. D. The next hop is unreachable: BGP routes with an unreachable next hop are considered hidden. A router will not use or advertise a route with an unreachable next hop, as it would not be able to forward packets along that path.
Thank you for the explanations.