7 Replies Latest reply: Feb 3, 2012 11:08 AM by wxforcaster RSS

    Extremely Slow Bandwidth Remotely From PRO-HD

    wxforcaster

      I am baffled and at wits end, so hopefully someone here can help me.

       

      I've had a PRO-HD installed at my folks' house in Rhode Island since March 2011 and it's worked GREAT -- until a few weeks ago.

       

      A little background.

      The PRO-HD is setup with the default settings using input from a dedicated cable box.

      I have Time Warner cable and am located here in Kansas City, and average about 20 Mbps download. My folks have Verizon FIOS and average about 23 Mbps upload. Way more than enough to support HD output. In fact, I could leave the Slingbox running for hours on end without so much as a hiccup of HD signal.

       

      For the past few weeks, without reason, I cannot pull more than 300-400 kbps from their Slingbox. I have gone so far as to replace the router, try both direct LAN connections and wireless. I have utilized the old SlingPlayer windows app, slingbox.com, facebook app, and the app for my droid tablet. They're all identical.

       

      To verify the bandwidth I went to speakeasy.net and again, no problems on either end.

       

      So tonight, I had my folks re-seat all the cables into the slingbox. Then I went to remotely access my folks' PC and use slingbox.com to see what happens when THEY watched the slingbox. In pure amazement, the stream was so strong is was pulling 8-9Mbps on Auto setting!!! (My dad was watchig the screen while I was in control of his desktop and said the signal actually looked better through my dedicated FIOS box than the one on his TV!!!).

      OK I thought. So I closed down his browser and re-connected from here.

       

      Wouldn't you know, max signal 200-300 kbps.

       

      I'm at a total and complete loss. We both have 10 fold the necessary bandwidth for this to work...and it DID work. Who/what is at fault and who can I contact to get it resolved? I'm willing to try anything and am pretty technically savvy.

       

      Thanks for all your help,

      Evan

        • Re: Extremely Slow Bandwidth Remotely From PRO-HD
          beadon

          Bandwidth is the rating of delivered bits per second.  This is impacted by the transit time of packet to and from the endpoints.  I suspect that the device you're watching *from* has had some network setting changed -- or the route from the sender to the receiver has gotten longer.  This is increased round trip time (RTT) and as a result you're left with less available bandwidth.  This could be as simple as an additional hop between you and the sender, or as drastic as now consuming data across a problematic Wifi network.

           

          I am assuming that this is a TCP/IP stream.

           

          To counteract the effects of a problem with latency you will need to modify TCP options on the receiver, increasing the TCP window size significantly to improve performance would be my first optimization step.  This allows more packets to be in-flight while the ACK travels back to verify that packets were delivered.  These settings can be defined at the endpoints which manage the connection, but at no point between.

           

          For further technical discussion, this looks like it addresses all the relevant details :

          http://packetlife.net/blog/2010/aug/4/tcp-windows-and-window-scaling/

           

          Do a little math here to see how large the window size should be given the current and worst case scenario RTT.

           

          Let us know how you get on with this.

            • Re: Extremely Slow Bandwidth Remotely From PRO-HD
              wxforcaster

              I appreciate the response, but I don't think this is it.

               

              1.) Ping times to the destination are ~30ms. You're not going to beat that.

              2.) Speakeasy.net and speedtest.net both give me bandwidth download speeds 10x what is necessary to receive an HD signal. -- On both ends.

              3.) Results are the same from here regardless of wether I am directly connected to the router via CAT6 cable, or using our Wireless N (which has an outstanding signal strength)

               

              I'm fairly certain any applicable settings in my router are already optimized by the firmware, but if you (or anyone else) has something specific, please let me know. I visited the site you posted, and it's informational (nothing I wasn't already familiar with).

               

              Evan

                • Re: Extremely Slow Bandwidth Remotely From PRO-HD
                  beadon

                  Examine the network stream in transit to see if there are packets which indicate window shortening (wireshark, tcpdump)  or TCP window size renegotiation going on.  If this is not occuring then you can not blame bandwidth and must target higher in your OSI stack.  In fact, I'd start higher on the stack - log files ,etc.

                    • Re: Extremely Slow Bandwidth Remotely From PRO-HD
                      wxforcaster

                      Beadon,

                       

                      I really appreciate the response,  but it reads like cryptic chinese to me, and I'm pretty technically savvy. Put it this way, if you gave that response to your grandparents, think of the glossed over look you'd get.

                       

                      I downloaded Wireshark and will launch it shortly. What is OSI? What log files (where)?

                       

                      Evan

                        • Re: Extremely Slow Bandwidth Remotely From PRO-HD
                          wxforcaster

                          Conspiracy theory? I think not.

                           

                          Obviously the test on my folks' system was to be expected since he was essentially watching the SlingBox internal to his own network.

                           

                          I think people tend to forget that SlingBox (the company and not the device) IS an intermediary through this whole process.

                           

                          So, anyone else find it "mildly coincidental" that I've been dealing with this issue for weeks, and found NUMEROUS posts from other users on this and other forums with the same exact problem, and as soon as I post here it magically is resolved this morning when I went to launch Wireshark to trace the problem?

                           

                          Funny. Especially considering there has been no change to either network overnight (we were both sleeping).

                          • Re: Extremely Slow Bandwidth Remotely From PRO-HD
                            beadon

                            Calling yourself technical, shooting me down for addressing you casually and stating there are a few places to look with a technical article and then coming back saying that I'm being too technical is poor form.

                             

                            OSI - http://en.wikipedia.org/wiki/OSI_model

                             

                            Choose netstat as your option to track window sizes.  Use Linux or OSX since the windows one appears deficient for these options :

                             

                               Local Address        Remote Address    Swind Send-Q Rwind Recv-Q  State

                             

                            Track on the Swind and Rwind.

                              • Re: Extremely Slow Bandwidth Remotely From PRO-HD
                                wxforcaster

                                Having a technical background does mean (in my mind) that I have a PhD in system administration and networking

                                 

                                Like I said, your posts have been most helpful and appreciative, but the intended audience should be *anyone* using this forum, from the ley person on up. My desire for more specific instructions/details was so that everyone, including myself, could benefit from your wealth of knowledge. I'm not sure where I "knocked you down" and that surely wasn't my intention. Apologies if there was any indication as such.