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 ADs. Document editors and WG chairs should treat these comments just like any other last call comments. This document describes how PPP can support TRILL. The security considerations section of this very short document says, in essence, that there are innumerable security considerations brought into play by the layering interactions between PPP and IS-IS, and that seems about right. I do not see any particular new security considerations for this particular mixture of the two. --Paul Hoffman