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. I unfortunately was off-net for a few days and got to this assignment rather late. The document is long and covers a broad swath of material and I was not able to cover it deeply. This document is a product of the rrg IRTF working group. It summarizes 15 different proposals for a new routing and addressing architecture for the Internet, with short summaries, critiques and rebuttals for each, and gives a final recommendation to the IETF for future direction. With the breadth of scope of the document, there is no way for me to review each proposal's documents for security considerations. The security considerations of *this* document itself is quite terse: 20. Security Considerations All solutions are required to provide security that is at least as strong as the existing Internet routing and addressing architecture. Given the widely reported weakness of the "existing Internet routing and addressing architecture", this is a low bar indeed. There are attempts in progress to attempt to improve the security of the Internet routing and addressing architecture. I do not know what to suggest if these improvements leave the Internet with stronger security than is provided by these proposals. The summaries of the different proposals devote little attention to the infrastructure security ramifications of the proposal. Given the stated goal, perhaps no attention was necessary. Many of these proposals include an encapsulation system, presenting the expected difficulties with end system authentication, filtering systems at boundaries, etc. Some proposals addressed these concerns. I am not sure if the security considerations section meant that the proposals were required to avoid weakening the end-host security protections already provided (ipsec, NAT, whatever). The rrg wg came to consensus that a fundamental architectural feature is a separation of locator and identifier for any node. Many of the discussed alternatives include a mapping system that produce a locator for a given destination identifier. The mapping system would seem to be a very likely point of vulnerability, permitting traffic redirection for data exposure or blackholing, etc. Many proposals suggest a hierarchic architecture of the mapping system for scaling purposes. I would presume that an authorization scheme for the mapping system would be essential, and that the hierarchy would be an important aspect of that scheme. Of course, I can't tell much at this level of detail about how and if each proposals addresses this. (One of the recommendations suggests communicating mapping info through bgp - I can not say at this point whether the SIDR suggestions for improving bgp security would be applicable.) --Sandy Nits: PMTUD Path Maximum Transmission Unit Discovery: The process or mechanism that determines the largest packet that can be sent between a given source and destination with being either i) fragmented (IPv4 only), or ii) discarded (if not fragmentable) because it is too large to be sent down one link in the path from the source to the destination. It should say "*without* being either", right? A long sentence so I may have lost my place. Several of the comments start using terms that are part of the wg deliberations, I'm sure. But it makes reading the discussions and critiques obtuse. In particular, "Core-Edge Separation" and "Core-Edge Elimination" seems to a well understood concept in the wg. It needs to be defined somewhere. A web search found references in some conference papers and in rrg mailing lists.