Which statement describes the role of local preference in the BGP route selection process?
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A. B. C. D.A
BGP (Border Gateway Protocol) is an inter-domain routing protocol that is used to exchange routing information between different Autonomous Systems (AS). BGP allows the exchange of network reachability information along with various attributes that influence the selection of the best path for routing packets.
One such attribute is Local Preference, which is a value that is assigned to a route by a BGP router to indicate the degree of preference for that route within the local AS. The local preference value is an arbitrary value and is used to influence the selection of the best path for outgoing traffic from the local AS.
The role of Local Preference in the BGP route selection process is to determine the preferred exit point from the local AS for a given destination. In other words, Local Preference is evaluated early in the BGP route selection process and results in the route with the highest numerical Local Preference being selected. Therefore, the answer is A.
Local Preference is an attribute that is only used within the local AS and is not propagated to other AS. It is used to influence the routing decisions within the local AS, but it does not affect the routing decisions of remote AS. Therefore, Local Preference is not used to break ties when all other received BGP attributes are otherwise equal (option C).
Option D is incorrect because Local Preference is not sent by an EBGP speaker to a neighboring AS. It is an attribute that is used within the local AS only to influence the path selection for outgoing traffic from the local AS.
In conclusion, Local Preference is evaluated early in the BGP route selection process and is used to select the best path for outgoing traffic from the local AS. The route with the highest numerical Local Preference is preferred over other routes.