Tag :: AS_SET

In the BGP Update message’s AS_PATH, routers have the capability to perform route aggregation and combine the ASes an update has traversed, merging the discrete entries into an  AS_SET. Routers can also do this within the local confederation with member AS numbers, using an AS_CONFED_SET. Route aggregation can be problematic as it blurs the semantics of what it means to originate a route. RFC 6472 recommends not using AS_SET or AS_CONFED_SET in BGP, and further justifies reasoning as to why, as well as provides a recommended way to handle updates with these messages.

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