4.4.2 Packet-Pair Bandwidth Estimation Using UDP

 The following sequence occurs between a client and server when conducting the packet-pair experiment over UDP:

  1. The client sends a Describe (section 2.2.7.2) request.

  2. The server sends a "200 OK:" response that includes the SDP record.

  3. The client sends a SelectStream (section 2.2.7.10) request by using the Setup method to establish an RTP session for a retransmission stream.

  4. The server responds with "200 OK".

  5. The client sends a UdpPacketPair (section 2.2.7.14) request with a content type of application/x-rtsp-udp-packetpair (section 2.2.6.3.3).

  6. The server sends a "200 OK" response with the message body empty.

  7. The server transmits two or three RTP packets with packet-pair data over UDP (sections 2.2.3.2 and 2.2.7.14).

The following illustration shows the sequence described above.

Packet-pair experiment sequence over UDP

Figure 13: Packet-pair experiment sequence over UDP

 The following example shows a client's packet-pair experiment request. Note that some headers extraneous to this example have been omitted for brevity.

 DESCRIBE rtsp://wms4708/test RTSP/1.0 
 User-Agent: WMPlayer/10.0.0.4332 
 Accept: application/sdp 
 CSeq: 5 
 Supported: com.microsoft.wm.srvppair, com.microsoft.wm.sswitch, 
 com.microsoft.wm.eosmsg, com.microsoft.wm.predstrm, 
 com.microsoft.wm.startupprofile 
  
 RTSP/1.0 200 OK 
 Content-Type: application/sdp 
 CSeq: 5 
 Server: WMServer/9.5.5732.6324 
 Supported: com.microsoft.wm.srvppair, com.microsoft.wm.sswitch, 
 com.microsoft.wm.eosmsg, com.microsoft.wm.fastcache, 
 com.microsoft.wm.packetpairssrc, com.microsoft.wm.startupprofile 
  
 v=0 
 ...
 m=application 0 RTP/AVP 96 
 a=rtpmap:96 x-wms-rtx/1000 
 a=control:rtx 
 a=stream:65536 
  
 SETUP rtsp://wms4708/test/rtx RTSP/1.0 
 User-Agent: WMPlayer/10.0.0.4332 
 CSeq: 6 
 Transport: RTP/AVP/UDP;unicast;client_port=3236-
 3237;ssrc=16a4ffff;mode=PLAY  
  
 RTSP/1.0 200 OK 
 Transport: RTP/AVP/UDP;unicast;server_port=5004-5005;client_port=3236-
 3237;ssrc=2f73682b;mode=PLAY 
 CSeq: 6 
 Session: 8134007897615700187;timeout=60 
 Server: WMServer/9.5.5732.6324 
 Supported: com.microsoft.wm.srvppair, com.microsoft.wm.sswitch, 
 com.microsoft.wm.eosmsg, com.microsoft.wm.fastcache, 
 com.microsoft.wm.packetpairssrc, com.microsoft.wm.startupprofile   
  
 SET_PARAMETER rtsp://wms4708/test RTSP/1.0 
 User-Agent: WMPlayer/10.0.0.4332 
 Accept-Language: en-US, *;q=0.1 
 Session: 8134007897615700187 
 Content-Type: application/x-rtsp-udp-packetpair;charset=UTF-8 
 CSeq: 7 
  
 type: high-entropy-packetpair
  
 RTSP/1.0 200 OK 
 Content-Type: application/x-rtsp-udp-packetpair;charset=UTF-8 
 CSeq: 7 
 Session: 8134007897615700187;timeout=60 
 Server: WMServer/9.5.5732.6324 
  
 type: high-entropy-packetpair
  
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