Extensions to the Path Computation Element Communication Protocol (PCEP) for Route Exclusions
RFC 5521

The Manageability Consideration section includes a reference to a PCEP MIB document: 

  'A MIB module for management of the PCEP is specified in a separate
  document. This MIB module allows examination of individual PCEP
  messages, in particular requests, responses and errors.

  The MIB module MUST be extended to include the ability to view the
  route exclusion extensions defined in this document.'

Actually right now there is no PCEP MIB in works. The WG is indeed working on a MIB document http://www.ietf.org/internet-drafts/draft-ietf-pce-disc-mib-02.txt but the approach taken there is to manage the PCE Discovery process and results, without reference to a PCEP. If a PCEP MIB will be the object of future work the text needs to be changed accordingly to avoid confusion.

Section 1, third paragraph:

In order to achieve path computation for a
   secondary (backup) path, a PCE may act as a PCC to request another

Incomplete sentence.

The security considerations section notes that 

   The new exclude route mechanisms defined in this document allow
   finer and more specific control of the path computed by a PCE. Such
   control increases the risk if a PCEP message is intercepted,
   modified, or spoofed. Therefore, the security techniques described
   in [PCEP] are considered more important.

The phrase "increases the risk" begs the question "what risk?"  After reviewing
pce-pcep-12, I would hazard a guess that the increases in risk are limited to
PCEP Privacy (section 10.2 of pce-pcep) and possibly the DOS attacks described
under Request Input Shaping/Policing (section 10.3.2 of pce-pcep).  If my analysis
is correct, it would be nice to expand on "risk" and explicitly identify the concerns.
If other risks are impacted by this specification, that would be very helpful as well.