[Live-devel] RTCP RR reports do not reach to the server using UDP

[Muhammad Mohsin Abbasi]

Hi Ross,

Thanks for the earlier reply.

Can you please examine my following observation and provide your kind feedback on this. 

our server is a public server and for this I am using testRTSPClient on my local machine. I observed the RTCP packets on wireshark at both client and server end. What i saw is that when the Receiver reports are sent from the client, the destination IP shown in 'wireshark on client side' is the public IP of the server and the RTCP RR and SR reports work perfectly fine in this case. But when using UDP, the destination IP for RR shown in 'wireshark on client end' is the private IP of the server and the receiver packets are not reaching to the Server in this case. To confirm that this may be the cause, I just hack the client code in udp case and passed the public IP hard coded in MediaSubsession::setDestinations method. Now I can see in Wireshark that the destination IP for the Receiver Reports is the public IP of the server which i hardcoded. and now on the server I am receiving the receiver reports on the server and everything works fine. What is this behavior and how can I fix it?

Best Regards

Mohsin




 
________________________________________
From: live-devel <live-devel-bounces at ns.live555.com> on behalf of Ross Finlayson <finlayson at live555.com>
Sent: Tuesday, November 3, 2015 11:28 PM
To: LIVE555 Streaming Media - development & use
Subject: Re: [Live-devel] RTCP RR reports do not reach to the server using      UDP

> But we are having problem with UDP (REQUEST_STREAMING_OVER_TCP false) . First issue was that SR reports were sent by the server but were not reaching the client. the wireshark on the server shows the ICMP destination unreacheable (port unreachable) message from the client in response to SR reports. For testing purpose we fixed it with enabling port forwarding on our router. and now SR Reports reach to the client and there is no ICMP response. but now the problem is that RR reports are not reaching to the Server. What would be the possible cause for this?

The same thing.  You have a ‘middlebox’ somewhere between your client and your server that is either blocking these RTCP “RR” packets (from the client) from reaching the server.

To see what UDP ports are involved, look at the response to the RTSP “SETUP” command.  (If your stream contains both an audio track and a video track, then there will be one of these for each track.) For example, if response to a “SETUP command is:
        RTSP/1.0 200 OK
        CSeq: 4
        Date: Tue, Nov 03 2015 22:15:51 GMT
        Transport: RTP/AVP;unicast;destination=133.93.96.43;source=4.79.217.242;client_port=51384-51385;server_port=6970-6971
        Session: E3F2FB49;timeout=65
then:
        - RTP packets (from the server to the client) will be sent from port 6970 to port 51384
        - RTCP “SR” packets (from the server to the client) will be sent from port 6971 to port 51385
        - RTCP “RR” packets (from the client to the server) will be sent from port 51385 to port 6971

Note that RTSP/RTP cannot be expected to work if you have NAT (Network Address and/or Port Translation) happening between your client and server.  I.e., your client and server should be sharing the same address/port space.  However, if your ‘middlebox’ is only a firewall - not a NAT - then you should be able to get it to work by unblocking appropriate UDP ports.


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/


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