--- 1/draft-ietf-6man-ra-pref64-01.txt	2019-07-23 07:13:08.571457690 -0700
+++ 2/draft-ietf-6man-ra-pref64-02.txt	2019-07-23 07:13:08.595458297 -0700
@@ -1,18 +1,18 @@
 
 IPv6 Maintenance                                              L. Colitti
 Internet-Draft                                                J. Linkova
 Intended status: Standards Track                                  Google
-Expires: December 30, 2019                                 June 28, 2019
+Expires: January 23, 2020                                  July 22, 2019
 
               Discovering PREF64 in Router Advertisements
-                      draft-ietf-6man-ra-pref64-01
+                      draft-ietf-6man-ra-pref64-02
 
 Abstract
 
    This document specifies a Router Advertisement option to communicate
    NAT64 prefixes to clients.
 
 Status of This Memo
 
    This Internet-Draft is submitted in full conformance with the
    provisions of BCP 78 and BCP 79.
@@ -20,21 +20,21 @@
    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 December 30, 2019.
+   This Internet-Draft will expire on January 23, 2020.
 
 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
@@ -185,24 +185,24 @@
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |     Type      |    Length     |           Lifetime            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                                                               |
      +                                                               +
      |              Highest 96 bits of the Prefix                    |
      +                                                               +
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-     | Lowest bits (96-127) of the prefix (optional, if Length > 2)  |
-     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Prefix Length |                  Reserved                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+     |                           Reserved                            |
+     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 
                    Figure 1: NAT64 Prefix Option Format
 
    Fields:
 
    Type     8-bit identifier of the Pref64 option type as assigned by
             IANA: TBD
    Length   8-bit unsigned integer.  The length of the option (including
             the Type and Length fields) is in units of 8 octets. If the
             prefix length is 96 bits the sender MUST set the Length to 2
@@ -219,32 +219,30 @@
             which this NAT64 prefix MAY be used. The value of Lifetime
             SHOULD by default be set to lesser of  3 x MaxRtrAdvInterval
             or 65535 seconds.  A value of zero means that the prefix
             MUST no longer be used.
 
    Highest  96-bit unsigned integer. Contains bits 0 - 95 of the NAT64
    96 bits  prefix.
    of the
    prefix
 
-   Lowest   32-bit unsigned integer. Contains bits 96 - 127 of the NAT64
-   bits of  prefix.
-   the
-   prefix
-
-   Prefix   8-bit unsigned integer. The sender MUST set it only to one
-   Length   of the following values: 32, 40, 48, 56, 64 ([RFC6052]. The
-            receiver MUST ignore the Pref64 option if the prefix length
-            value is not set to one of those numbers.
+   Prefix   8-bit unsigned integer. Optional field which present only if
+   Length   the prefix length is not 96 bits. The sender MUST set it
+            only to one of the following values: 32, 40, 48, 56, 64
+            ([RFC6052]. The receiver MUST ignore the Pref64 option if
+            the prefix length value is not set to one of those numbers.
 
-   Reserved A 3-byte unused field.  It MUST be initialized to zero by
-            the sender and MUST be ignored by the receiver.
+   Reserved A 7-byte unused field.  It MUST be initialized to zero by
+            the sender and MUST be ignored by the receiver. This field
+            is optional and presents only if the prefix length is not 96
+            bits.
 
 6.  Handling Multiple NAT64 Prefixes
 
    In some cases a host may receive multiple NAT64 prefixes from
    different sources.  Possible scenarios include (but are not limited
    to):
 
    o  the host is using multiple mechanisms to discover Pref64 prefixes
       (e.g. by using PCP ([RFC7225]) and/or by resolving IPv4-only fully
       qualified domain name ([RFC7050]) in addition to receiving the