In section 2 (protocol overview), the reference to DTLS is wrong. It must be 
RFC4347 instead of RFC4346(which is the base TLS protocol itself). The updated 
text is:

<updated text>
2.  Protocol Overview

   The CAPWAP protocol is a generic protocol defining AC and WTP control
   and data plane communication via a CAPWAP protocol transport
   mechanism.  CAPWAP control messages, and optionally CAPWAP data
   messages, are secured using Datagram Transport Layer Security (DTLS)
   [RFC4347].  DTLS is a standards-track IETF protocol based upon TLS.
   The underlying security-related protocol mechanisms of TLS have been
   successfully deployed for many years.

</updated text>