: Implementing route reflectors, confederations, and using route maps for granular control over network traffic.
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Before BGP communities, route filtering was a mess of prefix-lists. Jeremy showed how tagging a route with a community (like 100:10 for "Customer A") allowed for scalable outbound filtering. The lab for this episode was famous: He created an ISP scenario with five customers, used route-maps to set communities as routes came in, and then used ip community-list to advertise only specific blocks back out. : Implementing route reflectors