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9.6 | ![]() |
BGP Attributes | |
9.6.1 | ![]() |
Controlling BGP routing with attributes |
Traffic inside and outside an AS always flows according to the road
map laid out by routes. If the routes are altered, the traffic behavior
will be affected. The following are among the questions that organizations and service
providers ask about controlling routes:
Through the use of attributes, BGP provides the answer to all these questions and more. A BGP speaker can receive updates from multiple autonomous systems that describe different paths to the same destination. It must then choose the single best path for reaching that destination. Once chosen, BGP propagates the best path to its neighbors. The decision is based on the value of attributes, such as Next Hop or Local Preference, that the update contains and other configurable BGP factors. The following sections provide an overview of these key attributes that BGP uses in the decision making process:
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