1) Section 5 header should capitalize "messages"
2) The introduction says, "It is necessary to use the central control mode described in [RFC8283]". This reads like a mandatory constraint on implementers but is listed as an informative reference. If the I-D doesn't actually depend on RFC8283, but the authors are assuming this context, then the wording could be adjusted to describe the author's assumptions rather than describe it in (almost) normative style. Alternatively, it is a normative requirement that shouldn't exist in the introduction and the reference should move to the normative list.
3) Figure 16 - It isn't clear if TBD1 and TBD2 are gaps in the I-D that the WG has yet to complete vs. extension / extensibility properties that a subsequent I-D might define.
4) Section 10 "The communication of PCE and PCC described in this document should also follow the same procedures, treat the three newly defined objects (BPI, EPR, PPA) associated with the same symbolic path name as the attribute of the same path in the LSP-DB (LSP State Database)." The "should" in this sentence reads as though it is normative. Consider making it upper case. The sentence is potentially easily misread as it isn't clear which procedures is meant by "...the same procedures,...".