--- 1/draft-ietf-mboned-driad-amt-discovery-04.txt	2019-04-25 15:13:14.195728772 -0700
+++ 2/draft-ietf-mboned-driad-amt-discovery-05.txt	2019-04-25 15:13:14.271730682 -0700
@@ -1,19 +1,19 @@
 
 Mboned                                                        J. Holland
 Internet-Draft                                 Akamai Technologies, Inc.
-Updates: 7450 (if approved)                               April 22, 2019
+Updates: 7450 (if approved)                               April 25, 2019
 Intended status: Standards Track
-Expires: October 24, 2019
+Expires: October 27, 2019
 
                       DNS Reverse IP AMT Discovery
-                draft-ietf-mboned-driad-amt-discovery-04
+                draft-ietf-mboned-driad-amt-discovery-05
 
 Abstract
 
    This document updates RFC 7450 (Automatic Multicast Tunneling, or
    AMT) by extending the relay discovery process to use a new DNS
    resource record named AMTRELAY when discovering AMT relays for
    source-specific multicast channels.  The reverse IP DNS zone for a
    multicast sender's IP address is configured to use AMTRELAY resource
    records to advertise a set of AMT relays that can receive and forward
    multicast traffic from that sender over an AMT tunnel.
@@ -26,21 +26,21 @@
    Internet-Drafts are working documents of the Internet Engineering
    Task Force (IETF).  Note that other groups may also distribute
    working documents as Internet-Drafts.  The list of current Internet-
    Drafts is at https://datatracker.ietf.org/drafts/current/.
 
    Internet-Drafts are draft documents valid for a maximum of six months
    and may be updated, replaced, or obsoleted by other documents at any
    time.  It is inappropriate to use Internet-Drafts as reference
    material or to cite them other than as "work in progress."
 
-   This Internet-Draft will expire on October 24, 2019.
+   This Internet-Draft will expire on October 27, 2019.
 
 Copyright Notice
 
    Copyright (c) 2019 IETF Trust and the persons identified as the
    document authors.  All rights reserved.
 
    This document is subject to BCP 78 and the IETF Trust's Legal
    Provisions Relating to IETF Documents
    (https://trustee.ietf.org/license-info) in effect on the date of
    publication of this document.  Please review these documents
@@ -378,21 +378,22 @@
    Eyeballs algorithm is a useful one, and so this section provides the
    following normative definition:
 
    o  An AMT connection is completed successfully when the gateway
       receives from a newly discovered relay a valid Membership Query
       message (Section 5.1.4 of [RFC7450]) that does not have the L flag
       set.
 
    See Section 2.5.5 of this document for further information about the
    relevance of the L flag to the establishment of a Happy Eyeballs
-   connection.
+   connection.  See Section 2.5.4 for an overview of how to respond if
+   the connection does not provide multicast connectivity to the source.
 
 2.4.  Optimal Relay Selection
 
 2.4.1.  Overview
 
    The reverse source IP DNS query of an AMTRELAY RR is a good way for a
    gateway to discover a relay that is known to the sender.
 
    However, it is NOT necessarily a good way to discover the best relay
    for that gateway to use, because the RR will only provide information
@@ -530,24 +531,27 @@
    above, a Happy Eyeballs algorithm for AMT MUST use the Destination
    Address Selection defined in Section 6 of [RFC6724], as required by
    [RFC8305].
 
    Among relay addresses that still have an equivalent preference after
    the above orderings, a gateway MUST make a non-deterministic choice
    for relay preference ordering, in order to support load balancing by
    DNS configurations that provide many relay options.
 
    The gateway MAY introduce a bias in the non-deterministic choice
-   according to network topology or timing information obtained out of
-   band or from a historical record.  The collection of this information
-   is out of scope for this document, but a gateway in possession of
-   such information MAY use it to prefer topologically closer relays.
+   according to information obtained out of band or from a historical
+   record about network topology, timing information, or the response to
+   a probing mechanism, that indicates some expected benefits from
+   selecting some relays in preference to others.  Details about the
+   structure and collection of this information is out of scope for this
+   document, but a gateway in possession of such information MAY use it
+   to prefer topologically closer relays.
 
    Note also that certain relay addresses may be excluded from
    consideration by the hold-down timers described in Section 2.5.4.1 or
    Section 2.5.5.  These relays constitute "unusable destinations" under
    Rule 1 of the Destination Address Selection, and are also not part of
    the superseding considerations described above.
 
    The discovery and connection process for the relay addresses in the
    above described ordering MAY operate in parallel, subject to delays
    prescribed by the Happy Eyeballs requirements described in Section 5