UDP source port number is missing in the SETUP response message

Question

I am working on a Wifi Display Sink application in android and am facing an issue where the source is not sending the UDP server-port number in the RTSP SETUP message.

The SETUP RESPONSE is as below

  'RTSP/1.0 200 OK
   cseq: 2
   date: Tue, 11 Aug 2015 15:12:38 +0000
   server: Mine/1.0
   session: 1719935144;timeout=60
   transport: RTP/AVP/UDP;unicast;client_port=15550-15551;
  '

NOTE: I have figured out the server-port number using tcpdump in the source device. It is 16660. It doesnot look like any specifically assigned port number as well.Seems like a random port number hardcoded into the source device for Wifi Display Application.

Is there any other way to know the server-port number to which I should listen to for incoming UDP packets?

Answer 1

You should be listening on port 15550 and 15551 and the incoming UDP packets will contain their source port.