Hello,

I have reviewed this document as part of the security directorate’s ongoing
effort to review all IETF documents being processed by the IESG. These
comments were written primarily for the benefit of the security area
directors. Document editors and WG chairs should treat these comments just
like any other last call comments.

Summary: Ready

I have no particular secdir-related comment for this document.
The "Security Considerations" section is well documented and understandable.


However I have a few extra comments for this ID, totally disconnected from this secdir review:

- s/is/are/ in: "Existing security concerns documented in [RFC8362] is applicable"
- s/is/are/ in: "both BIER and OSPF layer is under a single administrative domain"
- Question: in section 2.2, only the lowest 20 bits of the "Label" field are used ("The 4 leftmost bits MUST be ignored."), whereas there is an extra 4-bit field, "BS Len". Why not shrinking a bit field "Label" and moving "BS Len" there to save 4 extra bytes in this sub-TLV? There's probably a good reason not to do so, but nothing is said.
- Comment: field "Reserved" is discussed in section 2.2, but nothing is said about "Reserved" in section 2.1.

Regards,    Vincent