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.

This document discussions use of RADIUS over TLS (over TCP).  This document is being considered for publication as an Experimental RFC.

This document does not discuss the particulars of how TLS is to be used.  It seems left to draft-ietf-radext-radsec, which this document only informatively references.  It may be appropriate to elevate the reference to draft-ietf-radext-radsec to normative status.

I suggest inclusion of text in the Security Considerations section that specifically refer the reader to draft-ietf-radext-radsec for RADIUS over TLS specific security considerations, as well as RFC 5246 for general TLS security considerations.

Beyond this, I have no security concerns with transport details this I-D discusses.

Regards, Kurt