My Slingbox 350 stops streaming at random times. The problem is easily reproduced. It occurs with various client computers and devices, both on the LAN and over the Internet, so it's quite certain the problem is not with my setup. I'm pretty sure that this is a firmware bug, and am willing to help Sling Media engineers isolate and fix the problem. It has plagued me since the box was new in November, 2012.
My environment (for the test case described below): Slingbox 350, running 1.1.52, fed with 1280x720p60 component video from a Motorola QIP-6416 DVR. Connected to Verizon FiOS (50 Mbps upload) in New York via stock Actiontec router. TCP port 5201 forwarded to Slingbox. WebSlingPlayer version 22.214.171.1245 is running in Paris on a Toshiba R835 laptop under Firefox 21.0 / Windows 8 Pro. Connected to Orange La Fibre (100 Mbps download) via stock Livebox router. TCP Streaming is (until the error) stable at about 4 Mbps.
The symptom: Video and audio are playing normally, then the sound suddenly stops and the picture freezes. The player appears to attempt a restart, but about one minute later it aborts with a W201 error. I have an old Slingbox PRO-HD connected to the 350's component outputs and have confirmed that there is no problem with the incoming video around the time of failure. There is also no problem with the network: pings from Paris to New York (and vice-versa) show no packet loss. Nor does the Slingbox OS crash or reboot -- pings over the LAN to the Slingbox IP also show no loss.
I took a Wireshark capture to see what is going wrong. Here is a summary; I can supply a capture file if desired. Packets are coming in on the stream connection and (after about 26,000,000 captured packets) suddenly cease. The last IP packet received properly completes a 3072-byte ASF packet and gets ACKed normally by Windows. Let's call this time t=0. At t=~9 (in this case), the player sends the next routine keep-alive (function 0x66) on the control connection, but that does not get ACKed. Windows does a series of TCP retransmissions, without any response, and at t=~30 sends a RST on the control connection. A second later, the player attempts to open a new control connection to the Slingbox, but gets a [RST, ACK] (connection refused) response, i.e. the Slingbox is not "listening" on TCP port 5201 anymore. However, the player keeps retrying at about one second intervals. At t=~61, the connection succeeds, i.e. the server process appears to have been restarted, and the player sends HTTP headers followed by a login (function 0x67). Unfortunately, the player tagged the login with the old Session ID, which the "new" server knows nothing about. The server's response, although 'success' (status code 0x00), is tagged with a new Session ID. The player appears to dislike the mismatch and closes the new control connection. About 100 milliseconds later, a RST comes in for the old stream connection. I don't know whether the player would have otherwise retried further, but at this point, it gives up and displays the W201 error code.
I hope that you have seen this problem before, or can reproduce it in your lab. If not, I'd be glad to perform further tests and/or provide captures as needed.
I'm also interested in hearing whether any other members have encountered this issue, and if any workaround is known.
Thanks in advance for your help,