Which three statements area true regarding BGP local preference? (Choose three.)
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A. B. C. D. E.ACD
A higher local preference value is preferred over a lower value. These values are not shared between autonomous systems, and can be altered by policy or configuration. you can use the local preference attribute to direct outbound traffic through a specific peer.
BGP (Border Gateway Protocol) uses a variety of attributes to determine the best path for traffic between autonomous systems. One of these attributes is local preference. Here are the explanations for each statement:
A. A higher value is preferred over a lower value This statement is true. The local preference is an optional, non-transitive BGP attribute that is used to indicate the preferred path to an external destination. The value of local preference is set by the network operator and is exchanged between BGP speakers within the same autonomous system (AS). When multiple paths exist to the same destination, the path with the highest local preference value is preferred.
B. A lower value is preferred over a higher value This statement is false. As stated above, the path with the highest local preference value is preferred. Therefore, a lower value is not preferred over a higher value.
C. Local preference is not shared between autonomous systems This statement is true. Local preference is an attribute that is only exchanged between BGP speakers within the same autonomous system (AS). Local preference is not shared with other ASes.
D. Local preference can be altered by policy or configuration This statement is true. The local preference value can be altered by policy or configuration. For example, a network operator can configure a local preference value for a particular prefix to influence the path selection process.
E. Local preference has a default value of 128 This statement is true. If a BGP speaker does not receive a local preference value for a particular route, it will assign a default value of 128 to the route. However, if a BGP speaker receives a local preference value from another BGP speaker for the same route, it will use the received value instead of the default value.