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This is a very short and simple document, simply listing requirements.

This may be "too late" in the process to mention as an issue, but these requirements are missing any context as to "why" they are required.  Maybe these motivations are obvious to the WG participants, but it's not clear in reading the draft by itself whether there are specific operator needs, use cases, or other concerns that are driving these requirements.  If the authors have bandwidth, I would encourage them to provide a bit more context about how these requirements were determined.  Or maybe there are other documents for context that it would be useful to cite as references?

As an example, requirement 3 reads:
   3.   It SHOULD be possible to initialize a BIER OAM session from a
        centralized controller.
But there is no discussion about why this is a SHOULD rather than a MUST (e.g. why is this important?  under what conditions would it be acceptable to not support initializing BIER OAM from centralized controllers?).

A question: requirement 9 reads:
   9.   BIER OAM MUST support Path Maximum Transmission Unit discovery
        [RFC1191].
Is there any case of BIER transport where PLPMTUD (RFC 8899) would be relevant, and more desirable as an option?