[muji/master] reword mixers sesion

[Sjoerd Simons]

---
 xep/muji.xml |   36 +++++++++++++++++++++---------------
 1 files changed, 21 insertions(+), 15 deletions(-)

diff --git a/xep/muji.xml b/xep/muji.xml
index bed9828..25ad0bd 100644
--- a/xep/muji.xml
+++ b/xep/muji.xml
@@ -225,20 +225,26 @@ streams.
   </p>
 </section1>
 
-<section1 topic='TODO' anchor='TODO'>
-<ul>
-  <li> Add support for relays. Not all participants might have the necessary
-       upstream bandwidth to stream to everyone. A relay can help by relaying
-       the RTP streams of on or more participants. The relay could either be a
-       specialised component or just another client. Participants will provide
-       relay services by advertising them in their MUC presence.
-  </li>
-  <li> Add support for mixers in a similar way. Not all participants might
-       have the CPU power to decode all streams or the downstream bandwidth to
-       receive all streams. A mixer could mix various media streams into one
-       media stream and relay that. Again the mixer could be a specialised
-       component or just another client.
-  </li>
-</ul>
+<section1 topic='relays and mixers' anchor='relaysmixer'>
+  <p>
+    When scaling to conferences with a big number of participants or when
+    clients it's no longer viable for all participants to have direct
+    connections.
+
+    On connections where upstream bandwidth is the limiting factor an RTP a
+    RTP relay which is able to relay the stream to multiple participants on
+    the behalf of the clients and which forwards the streams of other
+    participants back to the client can be used.
+
+    If the limiting factor is either CPU or downstream bandwidth then a mixer
+    can be used, which receives the media streams from other participants and
+    mixes them on behalf of the client, so that the client only has to deal
+    with receiving and decoding a single stream for each media type. On the
+    sending side a mixer acts like a relay and relays the clients stream to all
+    other participants.
+
+    Both these services can either be provided by dedicated services or by
+    other clients.
+  </p>
 </section1>
 </xep>
-- 
1.5.6.5