[Live-devel] Live555 Proxy Server sometimes does not proxy source after connection loss

[Erik Montnemery]

Thanks Ross,

Regarding issue 1)
You might be right, I'll try to reproduce while recording network traffic.

Regarding issue 2)
> the state for the stream has timed out, and the proxy server then attempts to re-open a RTSP connection to the ‘back-end’ server. However, this appears to be hanging - again, apparently due to your ‘back-end’ server being broken.
The issue is triggered when there is network outage, and can be
reproduced by forcing the 'back-end' devices to repeatedly reconnect
to the WIFI.
After reproducing a few more times, I suspect the reestablishing of
network connection (sometimes) happens because there is a race
condition/timing issue:

Example 1)
Sep 05 18:24:18 ProxyServerMediaSubsession[(NULL),H264]::closeStreamSource()
Sep 05 18:24:18
ProxyServerMediaSubsession[(NULL),H264]::~ProxyServerMediaSubsession()
Sep 05 18:24:18
ProxyServerMediaSubsession[(NULL),MPEG4-GENERIC]::~ProxyServerMediaSubsession()
Sep 05 18:24:18 Opening connection to 192.168.0.126, port 554...
Sep 05 18:24:18 ProxyRTSPClient[rtsp://192.168.0.126/ch0_0.h264]: lost
connection to server ('errno': 115).  Resetting...
<----- "Reset" triggered in
ProxyRTSPClient::continueAfterLivenessCommand while reconnect to the
'back-end' is in progress

Example 2)
(Note, I added some additional debug prints)
Sep 05 19:53:16 StreamState::reclaim()
Sep 05 19:53:16 ProxyServerMediaSubsession[(NULL),H264]::closeStreamSource()
Sep 05 19:53:16
ProxyServerMediaSubsession[(NULL),H264]::~ProxyServerMediaSubsession()
Sep 05 19:53:16
ProxyServerMediaSubsession[(NULL),MPEG4-GENERIC]::~ProxyServerMediaSubsession()
Sep 05 19:53:16 Opening connection to 192.168.0.126, port 554...
Sep 05 19:53:16 Setting up BackhroundHandling for socket 7
Sep 05 19:53:16 ProxyRTSPClient[rtsp://192.168.0.126/ch0_0.h264]: lost
connection to server ('errno': 115).  Resetting...
<----- Again, "Reset" triggered in
ProxyRTSPClient::continueAfterLivenessCommand while reconnect to the
'back-end' is in progress

/Erik

2016-09-05 10:12 GMT+02:00 Ross Finlayson <finlayson at live555.com>:
>> Most of the time, the proxy server reconnects to the source after a
>> loss of connection to a source, but every now and then I observe one
>> of the following issues:
>
> In each case, the problem (from what I can tell) seems to be the fault of the ‘back-end’ server - i.e., it seems to be broken.
>
>
>> 1) The proxyserver reconnects to the source, but no data frames are
>> forwarded to the clients.
>
> If no data are forwarded to the (‘front-end’) clients, then that must mean that the ‘back-end’ server was not sending any data to the proxy server.  If the ‘back-end’ server appears responsive in spite of this (i.e., the RTSP connection remains open, and the server continues responding to “OPTIONS” requests from the proxy server), then it must be broken in some way…
>
>
>> 2) The proxy server does not reconnect to the source, and clients to
>> the proxy server are being told:
>> RTSP/1.0 404 File Not Found, Or In Incorrect Format
>> An example log of scenario 2) is pasted below
> […]
>> ProxyServerMediaSubsession[(NULL),H264]::~ProxyServerMediaSubsession()
>> Jul 26 20:25:44
>> ProxyServerMediaSubsession[(NULL),MPEG4-GENERIC]::~ProxyServerMediaSubsession()
>> Jul 26 20:25:44 Opening connection to 192.168.0.126, port 554…
>
> In this case the state for the stream has timed out, and the proxy server then attempts to re-open a RTSP connection to the ‘back-end’ server.  However, this appears to be hanging - again, apparently due to your ‘back-end’ server being broken.
>
> I suggest just replacing your ‘back-end’ servers (i.e., web cams or whatever).
>
>
> Ross Finlayson
> Live Networks, Inc.
> http://www.live555.com/
>
>
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