15 Replies Latest reply: Jun 26, 2013 1:46 PM by bsheppard RSS

    Poor performance with Sling Pro-HD and fiber optic internet on both ends.




      I am seeking some advice from the community.  I have a Pro-HD that is located in the U.S.  I am watching it from the UK.  I have a 30mbps download connection at my viewing location in the UK.  This is realized performance, not just stated, as confirmed by speedtests on the fiber optic line.  I have a 15mbps upload connection at my Slingbox location in the U.S., also confirmed as realized by speedtests.  And yet, my actual realized performance throughput on watching the Slingbox in the UK NEVER goes higher than around 900kpbs.  How can this be?  What can I do to realize performance commensurate with my bandwidth availability?  Any help or advice would be appreciated.


      Many thanks,



        • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
          callanish Apprentice

          I'm guessing probably TCP latency is playing a big role in this. You could try turning off the port forwarding on the slingbox router side and run SNATT.  My speeds on the P.C went from 1.3 mb's to well over a 2mb stream going from the reverse ( U.K ( 5mb up) to West coast U.S (60 mb down). Waiting on Virgin's 12mb upload upgrade to happen in the next few months for me to see if it gives me a streaming speed boost.


          There's a lot of factors for why you're dealing with a limited stream speed even when you've got a lot of bandwidth to play with, but, for me, running the TCP protocol at long distances brings huge latency into the equation and would be something I'd at least test with the port forwarding either turned off on the router where your slingbox is located or block the port forwarding port on your router in the U.K forcing a SNATT stream from the slingbox. Should give you a speed boost. How much though is anyone's guess.

          • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
            test350 Novice

            The "official" answer to your query is this article: http://support.slingbox.com/get/KB-5000356.html


            Although technically accurate, IMO it misses the point:  Slinging real-time HD video over long distances requires software that can move data efficiently.  Slingmedia's solution lacks such software, relying primarily on TCP.  Their alternative methods, SNATT and Relay, do a great job getting around restrictive firewalls and improper forwarding, but don't really address the performance issue.  IMO, with proper software you should be able to stream at 10 Mbps+.  Unfortunately, none of the competing placeshifting systems, commercial or open source, address this issue properly.


            In addition to callanish's suggestion, try TCP and Relay as well; there are situations in which each method proves to be the fastest.  It's easiest to debug this on a Windows computer.  If running the web-based player, hold Ctrl and click in the video window to bring up the Statistics window.  What does it show for Stream Type?  Or, in the standalone player, hold Alt and Shift, then type I (for Info).  If Stream Type is not TCP and you have set up port forwarding correctly, provide details on your router(s) at Slingbox end and firewall(s) at viewing end.


            After trying TCP and SNATT, also try forcing Relay.  Usually, the easiest way is to block direct access to or from the public IP address of the Slingbox, using Windows Firewall or whatever other hardware or software firewall you may have.


            If all three methods are slow, it may be possible to rig an alternate path.  In what city is the Slingbox? ISP (if not FiOS)?  ISP in UK?


            (My own Slingbox is in New York on FiOS, with principal viewing locations in Paris and Bangkok.  The TCP path to Paris gives ~4 Mbps, which results in an adequate HD picture.  However, to Bangkok it varies from 1200 kbps down to 300 kbps!  I have some experimental software to address this issue and can move files at 5 Mbps+.)

              • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.

                Thanks both for your reponses.  I am not sure I am going to have much luck implementing anything at the source Slingbox site since it is back in the U.S. and I won't be back there for some time.  It is at my parent's house and I am not confident in their ability to make the changes suggested to their router setup. 


                Also, in response to a couple of the suggestions above, here are a few additional pieces of info.  I am on Macs only so do not have access to a Windows PC and therefore only use the web-player, not the standalone.  As far as ISP and locations go, the Sling is outside of Philadelphia, PA and the upload ISP is Verizon FiOS.  The ISP in the UK is Virgin Fiber Optic.


                I still think that I am going to have to physically be at the location of the Sling in Philly to be able to really implement any meaningful changes, do you agree? 


                Thanks again for your patience and help.



                  • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                    test350 Novice

                    Don't give up so easily.


                    First, find out what Stream Type you are getting now.  If it's TCP, you should be able to force both SNATT and Relay by changing firewall settings on your end.  I would guess that on a Mac, you open the Statistics window by holding CMD and clicking in the video window.  If that doesn't work, try the other modifier keys.  If still no luck, perhaps another member knows how, or use a Wireshark capture to see how and where you are connecting.


                    If it's not TCP, check whether the Sling servers believe that you have proper port forwarding -- see https://community.sling.com/message/90340#90340 .  If TCP is unavailable, you can still try both SNATT and Relay.  Also, if you can Remote Desktop into one of your parents' computers, you can run Safari from there and fix the router setting.  If Sling finds that TCP is available, you most likely have a firewall setting problem on the viewing end that is blocking a TCP connection.


                    Or, if you could provide me with temporary guest access to your Slingbox, I can check what modes are available and how fast it can stream to various locations.  To do this, since this forum does not have a direct PM feature, add me as a 'friend' and put the Slingbox ID and guest (view-only) password in the 'note' that gets sent with your invitation.  Also, let me know when it's ok to test (when you are not watching and, if the DVR also feeds a TV back home, when they won't be watching, either).

                      • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.



                        Thanks for the pep talk about not giving up and for the offer to help. I appreciate it!  Check your friend request as suggested.


                        I can't get anywhere with determining the type of feed.  When I alternate click, or cmd-click, or any other option I can think of in the Safari video window with sling.com, all I get is a link to About... which only gives version info for the SlingPlayer for Mac.  I can't seem to find any other window in Safari that gives me any statistics or anything unfortunately.


                        Here is one thing I have done on my end as I do not have access to the Sling location side yet, but may in the future.


                        On my end I went into the settings for the Slingbox and found the Home IP address and the Network port.  I then went into my router settings for my Virgin Media router and set up Port Blocking on that IP address and port using the TCP protocol.  I also set up Port Forwarding on that IP address and port using the UDP protocol.  Is that even close to the right thing to do?  To be fair, it hasn't really helped so maybe I am on the right track but haven't gotten it dialed in quite yet?  Any thoughts would be helpful. I am also investigating the proxy server route to see if I can find some service that will help.  Nothing decided on yet though.


                        Thanks for everyone's thoughts,



                          • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                            test350 Novice

                            Kyle, a couple of questions:


                            Is the Slingbox connected directly to the Actiontec router?  If not, please explain.


                            I went to try some other tests and noticed that TCP to the Slingbox appears to be blocked.  Did you do this intentionally, e.g. to test SNATT, or to start over with the config?  If not, and this is intermittent, it might be part of the problem.

                              • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.

                                I believe it is connected via Ethernet directly to the router.  Not sure what Actiontec is.  Is that the internal guts that so saw on a statistics report on your end?  Unless my dad has switched it out, I think it is a D-Link brand but that is probably netiher hear nor there.


                                On TCP blocking.  I did set up my router on my end in the UK to block the TCP port and forward the UDP port.  I did not do anything at the Sling location as I still do not have access.  I do think that the Sling has rebooted a couple of times so maybe it was reacting to the settings I have on my end?  Is that possible?


                                To be fair, I was getting over 2mbps throughput this morning in the UK so maybe I have done something right for once?  I maybe just a network traffic condition that showed me better throughput?  Maybe because everyone in the U.S. was asleep?  Do that have an affect on Sling traffic?


                                I also have a proxy server trial setup that I am going to try this evening.

                                  • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                                    test350 Novice

                                    Something has definitely changed on the source end.  TCP connections were previously possible, but aren't anymore.  I tried from three locations; the sparcs.slingmedia.com site shows "Supported but Failed" as well.  My first guess would be that something you did triggered a Slingbox or router reboot; when it came back up the private IP address had changed and the port forward no longer points to the correct address.  Although one can see the local IP address in the directory's Info page, I unfortunately failed to look before the change, so I can't confirm or deny the theory.


                                    I saw a credible post stating that holding Ctrl and clicking in the video window will bring up the Statistics window, even on a Mac.  If that's not the case, a Wireshark capture will tell you the stream type.  If most traffic is UDP, it's SNATT.  If TCP and the remote address is your Slingbox public IP, it's TCP.  If the remote address is in the Amazon cloud, it's Relay.


                                    I did not see anything on your system related to Actiontec (a make of router supplied by Verizon), though it is my impression that all FiOS installations come with such a router.  There is no technical or contractual requirement to use it, but it includes a MoCA bridge needed for VoD and PPV, so the vast majority of FiOS customers (that also have TV) hook it up.  Those who desire something different typically connect their router behind the Actiontec.


                                    The present address is 192.168.0.x, which is the default subnet for D-Link routers.  Actiontec, Linksys, Netgear and most others default to 192.168.1.x.


                                    For most folks, poor streaming performance over a long distance is usually caused by one congested hop in the path, so throughput varies dramatically with time of day.  However, I suspect your case may have another cause, as I have not seen much variation between tests many hours apart.


                                    If you can arrange remote access to a computer on the Slingbox LAN, it would be interesting to see how fast you can transfer a big file across that link.

                                      • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.

                                        Hey there,


                                        I've been spending all this time trying to figure out what I was doing wrong and what settings I had wrong and how I could tweak things and dial in the right settings and pay for premium services and this and that.  Then I left my house today and took my laptop to another location.  A location that had a DSL line with 15mpbs download speed.  I did nothing, no port forwarding, no force UDP vs TCP, nothing.  Just turned it on and connected to slingbox.com.  Boom, HD picture, 3+mbps throughput.  So it's Virgin.  And other than spending my life on hold talking with people who know less about this than I do, I don't know what I am going to do.  I think I will read some books instead!





                                          • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                                            test350 Novice

                                            I don't think it's as simple as you imply.  Before you tried the DSL, you had (indirectly) made a change at the Slingbox location that forced connection in UDP.  And, after the change, you observed 2+ Mbps on your Virgin connection.


                                            From your FiOS to my Orange connection here, I got only 1.4 Mbps (TCP) but 3.5 Mbps (UDP).  So, while it does appear that the route from your FiOS to the DSL provider is superior to the FiOS -> Virgin route, it's nearly certain that there is at least one other significant factor involved.


                                            If you're not locked into a contract with Virgin and can get a DSL line at your home that's fast enough to also satisfy your non-Sling requirements, that may be an easy solution for you.  If you can get the DSL without a contract or with a 30-day guarantee, you could run both services for a month and see how they stack up.


                                            OvCollyer had suggested running speed tests to a server near Philadelphia.  If you get poor results with Virgin, that's another strike against them.  On Orange, I get quite high speeds, far beyond what a Slingbox can do.



                            • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                              OvCollyer Apprentice

                              I think you should be able to get more than 900k streaming from the East coast to the UK. I can get 4mbps streaming from NYC to London.


                              Where in the UK are you streaming to?


                              I'd be interested in the results of a speedtest run from your location in the UK but if you select a server in Philadelphia. Post both your ping and speedtest, but run it a few times to see how much it varies.


                              Using a proxy server or a VPN can sometimes have surprising benefits even when it seems somewhat illogical. I stream from the UK to Istanbul and have found that routing my connection through a London based VPN server stabilises my stream at certain times such as evenings. More recently, I have connected to a proxy server, also in London, and seen my streaming speed from London to Istanbul jump from around 3mbps to 4mbps. Not exactly sure why either solution works - maybe it changes the routing, or maybe by using different ports it circumvents some ISP throttling or prioritisation or something. Perhaps if you connect to a proxy server in the same city/close to your Slingbox it somehow makes the Slingbox believe it can stream at a higher speed (could it be that the TCP ACK packets are received more regularly by the Slingbox from the proxy server, since it is nearer, and this allows for a faster stream?), I really don't know, but the effect has been quite dramatic.


                              It's not a one off either, I also stream from a NYC based Slingbox. I was getting about 2mbps, not enough for HD and also with a fair bit of fluctuation, However, once I connected to a proxy server in Paris, it stabilised at 3-3.5mbps, which gives me an HD picture, which isn't bad considering I'm streaming across the Atlantic and pretty much all of Europe. All by routing through an intermediate server.

                                • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                                  test350 Novice

                                  I don't yet understand what is going wrong, but here's what I've found so far:


                                  1. Your router is correctly configured, the Sling servers believe that your PRO-HD can stream TCP, and it actually can stream TCP.  Unless there is a networking issue on your end, your stream probably is TCP.  Unless Sling or another member can tell us how to get the Statistics window on a Mac, use Wireshark to see what kind of stream you have.




                                  2. When I connect straightforwardly as above, i.e. in TCP with no proxy or relay, I get ~1400 kbps.  This is somewhat better than to your location, but puzzling, because my box on FiOS gets about three times that rate.  It's only a little closer, and I would expect that the routing would be the same, except for links within Verizon, which I assume would have plenty of capacity.  (Click in the image to see full size.)



                                  As you can see, forcing SNATT was a huge improvement -- 2.5 times as fast.  This is not typical.  Although SNATT has that potential, Sling''s implementation is generally pretty lame, which is why they set TCP as the first choice.


                                  3. Forcing Relay (it went through Ireland) gave worse performance than TCP.  Likewise for a couple of personal relays, via New York and Chicago.  I tried a few other tests/measurements, with puzzling and inconsistent results.


                                  4. Though I hope to do some additional investigation and understand what is happening, you may be able to get a big improvement by simply forcing SNATT.  I'm not sure how to do this on a Mac.  I found this: http://www.ibiblio.org/macsupport/ipfw/ .  I'm guessing that you can just issue:


                                  sudo /sbin/ipfw add 00050 deny tcp from any to any 5001 out


                                  Before and after, do:


                                  sudo /sbin/ipfw list


                                  to confirm that the rules are modified as expected.  If you can't get a Statistics window, use Wireshark to confirm that you are getting SNATT, i.e. that the video packets are UDP.


                                  Let me know if you get SNATT running and how it performs.  I'll post another message if/when I better understand what is happening.

                                    • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                                      callanish Apprentice

                                      Just a few things to add to the discussion.


                                      My understanding is that if you're using the sling web player to watch your slingbox ( mac or pc ), holding ctrl on the keyboard and clicking the streaming video on the screen should allow you to see the streaming statistics including stream type.


                                      Needed to read your reply again as I must have skipped over the section where you tried port blocking, but it didn't make any difference. I noticed with my Virgin superhub, after changing settings using port forwarding, or in your case port blocking, I need to reboot the Virgin router for it to take effect. You shouldn't have to mess with port forwarding on your router in the U.K to block TCP in order to get a SNATT stream. I'd just focus on Port blocking.


                                      Also, see if your Verizon router in the U.S has remote access capabilities.


                                      Negatives to using SNATT, and only if this matters is, if you're using any of the connected devices with your slingbox, they'll all run in 'Relay'. You'll never get a SNATT stream with a connected device, thus missing out on the speed boost that SNATT can give. It's either TCPwan or Relay, and Relay is the worst of all protocols for streaming speed at a distance, but this would only matter if you were thinking about a connected device down the road.


                                      Other options I use for direct access to my slingbox is I keep a laptop at the P.C location with the free service logmein installed ( I pay extra for the ability to turn it on remotely ) allowing me to change settings or re-run the setup if anything drastically goes wrong. Might be a long shot with non-tech savvy parents, but a laptop hooked up to your network ( wirelessly or through ethernet ) running logmein could be a life saver when it comes to you accessing your slingbox from a far away location. You'd just need to setup a free account with logmein. You'd send them the link to download the logmein software. They'd have the logmein software installed on their computer running in the background which would give you access to the slingbox and your verizon router remotely. Also couldn't hurt to adjust the MTU settings, if possible, on the router in Philadelphia to try to get maximum efficiency out of the stream. Probably gave me an extra 150 kbps on top of my viewing speeds by doing this.


                                      Just random thoughts. Test350 seems to be providing you with the best help.

                                  • Re: Poor performance with Sling Pro-HD and fiber optic internet on both ends.
                                    bsheppard Newbie

                                    Sounds like a very similar situation I have  (except Slinging from UK via Virgin media internet to the US on Verizon Fios). After quite a bit of testing and process of elimination it appears that Virgin has a poor transatlantic link that suffers during peak times. It starts to fall off evening UK time to around 2,000kbps (from a normal 3,500) and then flops to about 1000 US evening. Rather anoying considering the high speed connections I have either side. I have 10 up, 15 down. Virgin admits that in their stride to increase speeds their network cant cope well during peak times.  My trouble has been going on since getting the superhub July last year (but if it was the superhub router why does it work great some of the time?). Seems to be particualtly prone to peak time traffic. Just hope Virgin sorts itself out. May try a different UK provider. It has got better than a few months back.


                                    My testing included getting US and European sling support (based in Holand I beleive) to connect to my box. The dutch could connect with a great speed of 7,000kbps several times over!! US support at about the same time (few mins apart from contacting Euro support) got the same slow speed as me. Running a VPN has improved things some of the time but need to look for a better more reliable VPN. I will test the SNATT, TCP suggetsions - although using slingcatcher that uses just TCP - that is not much use. But could be fine for Boxee Box that I view on as well. It use to be really bad with gettingjust 734kps while the Euro support could still get 7,000!