ORFs are a challenging feature and haven't gotten a lot of deployment for a number of reasons.
At a high level, they're a very coarse filter. Since each new ORF type adds to the logical AND condition, you start having to be more and more permissive in what you permit in the policy. Since a significant amount of common ISP policies require matching things in tuples, this doesn't translate super well into many types of automatically generated ORFs.
The ext-community-orf feature was effectively supplanted by Rt-Constrain (RFC 4684).
The as-path ORF was challenging because different vendors have different ideas about what "regex" means and what the input tokens are. Consider for example Juniper vs. Cisco regex matching. The abstract fix would have been to define a regex that is for the feature. I half suspect if people pushed on this these days, they'd want PCRE. :-)
The RD-ORF work is part of some ongoing discussion about how to deal with VRF overwhelm (prefix-limit exceed).
-- Jeff (IDR co-chair)
Hello!
I also found a recent draft(expires Novembre 2021) about using Route Distinguisher as a Value on ORF.
--
Douglas Fernando Fischer
Engº de Controle e Automação