Currently the app RIB is an iBGP peer. This means that app RIB routes aren't sent to ODL's iBGP peers.

using eBGP from ODL means we can't "fake" the next-hop (a major use-case for app RIB)

setting an iBGP peer to be an rr-client means ODL will fill in cluster-ID and originator-ID (which is undesirable) - plus I'm currently seeing an issue where due to incorrect cluster-ID/originator-ID we're not advertising app RIB routes to RR clients (though sure, that one should be fixed anyhow).

So what I'd prefer is for the app RIB to be a modified form of rr-client where cluster-id and originator-id are not filled in when advertising routes to iBGP peers (or RR clients).