I've reviewed this document as an assigned ART reviewer. I'm not an expert in IPPM nor in security. I haven't seen any issue from the perspective of ART or i18n. However, I was struggling trying to understand the mapping between/implementation of appendix A.2 and the wire format described in section 3.3. For example, I'm not sure where and how security algorithms are negotiated. Maybe it is just me not understanding well the document. And I was wondering, maybe incorrectly, why there is yet another key exchange and algorithm negotiation mechanism, instead of maybe reusing one we already have. However, all these comments are related to security and I let the security reviewers and ADs to properly handle that perspective.