Hi, In context of traffic engineering it may be that Network A (customer of Network B) observes that performance is suboptimal between Network B and Network C. If Network B offers some kind of “Prepend to Network C” BGP community, network A will be able to utilize all of network B except the pieces that perform less well. (This is ofcourse assuming that Network C picks some alternative path because of the prepends) I think prepend communities are useful to empower customers to debug and perhaps even resolve issues without waiting for action from their supplier. Prepends are also slightly more graceful than “don’t export”, since if there are no alternative paths there still is _a_ path - and often any path is better than no path. Kind regards, Job