ATOMIC_AGGREGATE is a well-known discretionary attribute. If a BGP speaker, when presented with a set of overlapping routes from one of its peers (see 9.1.4), selects the less specific route without selecting the more specific one, then the local system shall attach the ATOMIC_AGGREGATE attribute to the route when propagating it to other BGP speakers (if that attribute is not already present in the received less specific route). A BGP speaker that receives a route with the ATOMIC_AGGREGATE attribute shall not remove the attribute from the route when propagating it to other speakers. A BGP speaker that receives a route with the ATOMIC_AGGREGATE attribute shall not make any NLRI of that route more specific (as defined in 9.1.4) when advertising this route to other BGP speakers. A BGP speaker that receives a route with the ATOMIC_AGGREGATE attribute needs to be cognizant of the fact that the actual path to destinations, as specified in the NLRI of the route, while having the loop-free property, may traverse ASs that are not listed in the AS_PATH attribute.