Section 5.7.3 has been added to define the use of TLS in messaging associations
(and there have been minor editorial changes elsewhere to match):

5.7.3.  Protocol Definition: Transport Layer Security

   This defines the use of transport layer security as a basic channel
   security mechanism.  Support for this protocol is mandatory;
   associations using it can carry messages with the transfer attribute
   Secure=True.  For use with TCP, implementation of TLS1.0 [11] is
   REQUIRED and implementation of TLS1.1 [12] is RECOMMENDED.  (If an
   unreliable transport such as DCCP or UDP is defined for GIST
   messaging associations in the future, TLS would be implemented with
   it using DTLS [37].)  This specification makes no additional
   requirements on the TLS implementation (e.g. ciphersuites or
   authentication mechanisms) since these can be negotiated within TLS
   itself.

   No higher-layer-addressing format is defined for TLS.

with references:

Normative:

   [11]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
         RFC 2246, January 1999.

   [12]  Dierks, T. and E. Rescorla, "The TLS Protocol Version 1.1",
         draft-ietf-tls-rfc2246-bis-13 (work in progress), June 2005.

Informative:

   [37]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
         Security", draft-rescorla-dtls-05 (work in progress),
         June 2005.