Update Opus RTP payload

Addresses comments from several months ago

doc/draft-ietf-payload-rtp-opus.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
 <!ENTITY rfc2119 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml'>
+<!ENTITY rfc3389 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3389.xml'>
 <!ENTITY rfc3550 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3550.xml'>
 <!ENTITY rfc3711 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3711.xml'>
 <!ENTITY rfc3551 PUBLIC '' 'http://xml.resource.org/public/rfc/bibxml/reference.RFC.3551.xml'>
@@ -17,7 +18,7 @@
 <!ENTITY nbsp "&#160;">
   ]>
 
-  <rfc category="std" ipr="trust200902" docName="draft-ietf-payload-rtp-opus-01">
+  <rfc category="std" ipr="trust200902" docName="draft-ietf-payload-rtp-opus-02">
 <?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
 
 <?rfc strict="yes" ?>
@@ -60,17 +61,17 @@
       <organization>Mozilla</organization>
       <address>
         <postal>
-          <street>650 Castro Street</street>
-          <city>Mountain View</city>
+          <street>2 Harrison Street</street>
+          <city>San Francisco</city>
           <region>CA</region>
-          <code>94041</code>
+          <code>94105</code>
           <country>USA</country>
         </postal>
         <email>jmvalin@jmvalin.ca</email>
       </address>
     </author>
 
-    <date day='14' month='January' year='2014' />
+    <date day='30' month='June' year='2014' />
 
     <abstract>
       <t>
@@ -189,7 +190,7 @@
 	    The bitrate can be changed dynamically within that range.
 	    All
 	    other parameters being
-	    equal, higher bitrate results in higher quality.
+	    equal, a higher bitrate results in higher quality.
 	  </t>
 	  <section title='Recommended Bitrate' anchor='bitrate_by_bandwidth'>
 	  <t>
@@ -247,14 +248,22 @@
             the Opus encoder may be set to use discontinuous
             transmission (DTX), where parts of the encoded signal that
             correspond to periods of silence in the input speech or audio signal
-            are not transmitted to the receiver.
+            are not transmitted to the receiver. A receiver can distinguish
+            between DTX and packet loss by looking for gaps in the sequence
+            number, as described by Section 4.1
+            of&nbsp;<xref target="RFC3551"/>.
           </t>
 
           <t>
             On the receiving side, the non-transmitted parts will be handled by a
             frame loss concealment unit in the Opus decoder which generates a
             comfort noise signal to replace the non transmitted parts of the
-            speech or audio signal.
+            speech or audio signal. Use of <xref target="RFC3389"/> Comfort
+            Noise (CN) with Opus is discouraged.
+            The transmitter MUST drop whole frames only,
+            based on the size of the last transmitted frame,
+            to ensure successive RTP timestamps differ by a multiple of 120 and
+            to allow the receiver to use whole frames for concealment.
           </t>
 
           <t>
@@ -346,8 +355,9 @@
         therefore no padding is required. The payload MAY be padded by an
         integer number of octets according to <xref target="RFC3550"/>.</t>
 
-        <t>The marker bit (M) of the RTP header is used in accordance with
-	Section 4.1 of <xref target="RFC3551"/>.</t>
+        <t>The timestamp, sequence number, and marker bit (M) of the RTP header
+        are used in accordance with Section 4.1
+        of&nbsp;<xref target="RFC3551"/>.</t>
 
         <t>The RTP payload type for Opus has not been assigned statically and is
         expected to be assigned dynamically.</t>
@@ -914,6 +924,7 @@
   <back>
     <references title="Normative References">
       &rfc2119;
+      &rfc3389;
       &rfc3550;
       &rfc3711;
       &rfc3551;