I have reviewed this document as part of the security directorate's ongoing effort to review all IETF documents being processed by the IESG.  Document editors and WG chairs should treat these comments just like any other last call comments. The goal of this Informational draft is to suggest extensions of Happy Eyeballs (RFC 6555), originally targeted at IP protocol decisions in the a dual stack environment, to the more general case of multiple provisioning domains. The result is referred to as HE-MIF (Happy Eyeballs - Multiple Interfaces). From a security point of view, I believe this document needs a bit more in the Security Considerations section to be ready for publication. From a general text point of view, it would benefit from an English language review (see Editorials below). Security: The current Security Considerations section is the following sentence " The security consideration is following the statement in [ RFC6555 ]  and [ RFC6418 ]."  Having read the Security Considerations in those RFCs, I would say they are close to covering what should be mentioned in this document but there are two additional points that I think should be covered: (1) The dependence of the Happy Eyeballs interface and IP version choice on the results of generally unsecured connection attempts means that the interface and IP protocol used could be steered by an adversaries interference with such attempts. (2) To the extent that DNS query results affect HE-MIF decisions, DNSSEC should be used when available. I would also re-write the existing Securities Considerations sentence to be something more like: "For security considerations related to Happy Eyeballs, see [RFC6555]. For Security Considerations related to multiple provisioning domains, see [RFC6418]." Editorial: Section 1, 2nd sentence: "a issue" -> "an issue" Section 1, 2nd paragraph: Shouldn't some of these sentences that are questions end in a question mark? Section 1, 3rd paragraph: " defined in  [ RFC6555 ] necessary" -> " defined in  [ RFC6555 ] that are necessary"  Section 3: " scenarios the HE-MIF targeted to use" -> " scenarios targeted by  HE-MIF "  Section 4, 1st sentence: " This section provides input parameter proposal that HE-MIF should  catch." -> "This section describes the recommended input parameters to the HE-MIF decision process." Section 5, last sentence of the 2nd paragraph: " to proceed  the sort process." probably -> "on which to sort" Section 5.1: " mergence" -> "the merger"      " worth to note" -> "worthwhile to note" or "notable" Section 5.2.3, 1st paragraph: " receive certain next hop  in a RA message" First of all, should be "an RA". But next hop what? You could replace "next hop" with "next hop information" but that is a bit vague. If this means "receive the next hop address in an RA message", say that. Section 5.2.3, 2nd paragraph, 1st sentence: " When destination and source pairs are identified, it should be  treated with higher priority compared to others and choose to  initiate the connection in advance." does not really make sense. Probably should say something like "When destination and source pairs are identified, a connection should be initiated only to the highest priority pair or pairs." Section 5.2.3, last paragraph: " would initiate" -> "would be initiated"      " most fast" -> "fastest" or possible "most expeditious" Section 7.2, 1st paragraph: " in replied ICMP" -> "in an ICMP reply" Section 7.2, 2nd paragraph: " More optimal timer may be expected." -> "A more optimal timer for the circumstances is desirable."      " The memo didn't" -> " This memo doesn't" Section 7.2, 1st bullet item: " compensate the issues" -> "compensate for this issue"      " it leaves a" -> "this is left to a" Section 7.2, 2nd bullet item: " in the principle of" -> "based on" Section 7.3, 2nd bullet item: " cause messy" -> "cause confusion" Other editorial: Replace "WiFi" by "Wi-Fi" throughout. " out of the  document scope" -> "out of this document's scope" or "beyond the scope of this document" " beyond this document scope" -> "beyond the scope of this document" or "beyond this document's scope" Thanks, Donald ===============================  Donald E. Eastlake 3rd   +1-508-333-2270 (cell)  155 Beaver Street, Milford, MA 01757 USA   d3e3e3 at gmail.com