diff --git a/webrtc.html b/webrtc.html
index a83c41ba2..fc0644551 100644
--- a/webrtc.html
+++ b/webrtc.html
@@ -1758,21 +1758,35 @@ <h4>
                   <li>
                     <p id="remote-rid-reneg">
                       If <var>remote</var> is <code>true</code>, and
-                      <var>description</var> is of type {{RTCSdpType/"offer"}}
-                      and contains a request to receive simulcast, and applying
-                      <var>description</var> leads to modifying a
-                      transceiver <var>transceiver</var>, and
+                      <var>description</var> is of type
+                      {{RTCSdpType/"offer"}}, then for each
+                      [= media description =] requesting to receive simulcast
+                      that already has an existing {{RTCRtpTransceiver}} object,
+                      <var>transceiver</var>, associated with it, as described in
+                      <span data-jsep="applying-a-remote-desc">[[!RFC8829]]</span>,
+                      if none of the encodings in
                       <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[SendEncodings]]}}
-                      is non-empty, and not equal to the encodings that would
-                      result from processing <var>description</var>, the
-                      process of applying <var>description</var> fails. This
-                      specification does not allow remotely initiated RID
-                      renegotiation.
+                      [=map/contain=] a {{RTCRtpCodingParameters/rid}} member
+                      whose value matches any of the rids in the simulcast
+                      attribute, then [= description fails | fail =] the
+                      process of applying <var>description</var>.
+                      <div class="note">
+                        A change in rids values is tolerated in remote offers to
+                        receive simulcast as long as at least one rid matches a
+                        rid in the encodings that were previously negotiated, or
+                        the offer is to no longer receive simulcast.
+                        Mismatched or out-of-order rids result in layer removal,
+                        and layer expansion is prevented in user agent answers.
+                        This specification does not allow remotely initiated RID
+                        renegotiation.
+                      </div>
                     </p>
                   </li>
                   <li>
                     <p>
-                      If the process to apply <var>description</var> fails for
+                      If the <dfn data-lt="description fails"
+                      id="fail-description">process to apply
+                      <var>description</var> fails</dfn> for
                       any reason, then the user agent MUST queue a task that
                       runs the following steps:
                     </p>
@@ -2322,7 +2336,8 @@ <h4>
                               <li>
                                 <p>
                                   If the <var>description</var> is of type
-                                  {{RTCSdpType/"offer"}} and contains a request
+                                  {{RTCSdpType/"offer"}} and the
+                                  [= media description =] contains a request
                                   to receive simulcast, use the order of the
                                   rid values specified in the simulcast
                                   attribute to create an
@@ -2330,24 +2345,24 @@ <h4>
                                   each of the simulcast layers, populating the
                                   {{RTCRtpCodingParameters/rid}} member
                                   according to the corresponding rid value, and
-                                  let <var>sendEncodings</var> be the list
-                                  containing the created dictionaries.
-                                  Otherwise, let <var>sendEncodings</var> be an
-                                  empty list.
+                                  let <var>proposedSendEncodings</var> be the
+                                  list containing the created dictionaries.
+                                  Otherwise, let <var>proposedSendEncodings</var>
+                                  be an empty list.
                                 </p>
                               </li>
                               <li>Let <var>supportedEncodings</var> be the
                               maximum number of encodings that the
                               implementation can support. If the length of
-                              <var>sendEncodings</var> is greater than
+                              <var>proposedSendEncodings</var> is greater than
                               <var>supportedEncodings</var>, truncate
-                              <var>sendEncodings</var> so that its length is
+                              <var>proposedSendEncodings</var> so that its length is
                               <var>supportedEncodings</var>.
                               </li>
-                              <li>If <var>sendEncodings</var> is non-empty, set
-                              each encoding's
+                              <li>If <var>proposedSendEncodings</var> is non-empty,
+                              set each encoding's
                               {{RTCRtpEncodingParameters/scaleResolutionDownBy}}
-                              to <code>2^(length of <var>sendEncodings</var> -
+                              to <code>2^(length of <var>proposedSendEncodings</var> -
                               encoding index - 1)</code>.
                               </li>
                               <li>
@@ -2363,13 +2378,25 @@ <h4>
                               <li>
                                 <p>
                                   If a suitable transceiver was found
-                                  (<var>transceiver</var> is set) and
-                                  <var>sendEncodings</var> is non-empty, set
-                                  <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[SendEncodings]]}}
-                                  to <var>sendEncodings</var>, and set
-                                  <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[LastReturnedParameters]]}}
-                                  to <code>null</code>.
+                                  (<var>transceiver</var> is set), and
+                                  <var>proposedSendEncodings</var> is non-empty,
+                                  run the following steps:
                                 </p>
+                                <ol>
+                                  <li class="needs-test">
+                                    <p>
+                                      If the length of
+                                      <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[SendEncodings]]}}
+                                      is `1`, and the lone encoding
+                                      [=map/contains=] no
+                                      {{RTCRtpCodingParameters/rid}} member, set
+                                      <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[SendEncodings]]}}
+                                      to <var>proposedSendEncodings</var>, and set
+                                      <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[LastReturnedParameters]]}}
+                                      to <code>null</code>.
+                                    </p>
+                                  </li>
+                                </ol>
                               </li>
                               <li>
                                 <p>
@@ -2384,7 +2411,7 @@ <h4>
                                       [= Create an RTCRtpSender =],
                                       <var>sender</var>, from the [= media
                                       description =] using
-                                      <var>sendEncodings</var>.
+                                      <var>proposedSendEncodings</var>.
                                     </p>
                                   </li>
                                   <li data-tests=
@@ -2440,10 +2467,10 @@ <h4>
                                   </li>
                                   <li>
                                     <p>
-                                      If <var>description</var> rejects any of
-                                      the offered layers, then remove the
-                                      dictionaries that correspond to rejected
-                                      layers from
+                                      If <var>description</var> is missing any of
+                                      the previously negototiated layers, then
+                                      remove the dictionaries that correspond to
+                                      the missing layers from
                                       <var>transceiver</var>.{{RTCRtpTransceiver/[[Sender]]}}.{{RTCRtpSender/[[SendEncodings]]}}.
                                     </p>
                                   </li>