On 9/19/24 19:26, Sriram, Kotikalapudi (Fed) via NANOG wrote:

I know it makes sense for an AS to announce an aggregate less-specific prefix to transit providers and peers without NO_EXPORT while announcing some more-specific prefixes (subsumed under the aggregate) with NO_EXPORT towards customer ASes.  But are there good reasons when an AS might announce a prefix (route) to a transit provider with NO_EXPORT attached?  The IP address space in consideration here is meant to have global reachability.

An obvious use-case would be when there is on-net content or eyeballs in the transit network that you seek, but expressly require that they do not offer transit for your traffic toward their other eBGP neighbors.

Mark.