Merge pull request #34 from cdh4u/cdh4u-reliability-note

Note added regarding reliable and ordered transmission

draft-ietf-mmusic-t140-usage-data-channel.xml

@@ -129,6 +129,17 @@
         <c>Label</c>
         <c>See <xref target="sec.sdp.dcmap"/> and <xref target="sec.gw"/></c>
       </texttable>
+      <t>
+        NOTE: T.140 requires the transport channel to provide transmission of real-time text without
+        duplication and in original order. Therefore, T.140 does not specify reliable and ordered
+        transmission of T.140 data on the application layer. Instead, when RTP based transport is used,
+        the RTP sequence number is used to detect packet loss and out-of-order packets, and a redundancy
+        mechanism using the RTP timestamp is used to achieve reliable delivery of T.140 data. By using
+        the WebRTC data channel reliable and in-order transmission features <xref target="I-D.ietf-rtcweb-data-channel"/>
+        for the T.140 data channel, there is no need for a redundancy mechanism or a mechanism to detect
+        data loss and out-of-order delivery on the application level. The latency characteristics of the
+        T.140 data channel is also regarded to be sufficient to meet the application requirements of T.140.
+      </t>
     </section>
 
     <section anchor="sec.sdp" title="SDP Considerations">
@@ -841,7 +852,7 @@ Answer:
       <t>
         Thomas Belling provided useful comments on the initial (pre-submission) version
         of the draft. Gunnar Hellstrom provided comments and text on the draft. Paul
-        Kyzivat provides comments on the draft.
+        Kyzivat and Bernard Aboba provided comments on the draft.
       </t>
     </section>
   </middle>