[TriLUG] OT: Relationship between Internet Speed and Video Latency

[Steven Tardy via TriLUG]

> On Apr 28, 2017, at 4:38 PM, Scott Chilcote via TriLUG <trilug at trilug.org> wrote:
> 
> Hello luggers,
> 
> We have an ongoing issue with receiving video over our internet
> connection.  It hasn't improved much, despite several changes and
> upgrades.  I'm hoping some of the more networking savvy members will
> share some insights.
> 
> By most yardsticks we have fairly decent cable broadband.  The service
> is 25X2. Recent online speed tests show above 40Mbps down, around 8
> going up. 
> 
> However, it's very rare that we are able to stream video without it
> being hitchy and lossy.  It's been that way for years.
> 
> I know that there are a beaucoup of contributing factors when it comes
> to getting video data from somewhere in the great cloud to a screen in
> one's house, but we've done our best to mitigate them. Changes made over
> the last couple of years include upgrading the entire path to our
> systems that display video to wired gigabit ethernet, including the
> firewall router, cat 6 cable, and network switches.  We also got TWCBC
> to replace the overheating refurb modem they originally dropped off with
> a new Arris DG1670.  I'm not saying that this was zero help, but not as
> much as hoped.  15-25% improvement is my guess. 
> 
> My biggest peeve is Google Hangouts, which my employer uses frequently
> for virtual staff meetings. 
> 
> It seriously does not help one's image to be the fellow at the meeting
> who stares back blankly after being asked a question, because the video
> came to a stop or started stuttering after the first syllable.  Or to
> get the first 1/3 of a set of instructions that two other people heard
> fine.  I've searched for help online many times, and tried several
> potential solutions. 
> 
> The only thing that helped so far is to pull the tab showing the video
> out of the browser window and to make it very small.  This reduces the
> amount of streamed data.  It provides a mild improvement, but not enough.
> 
> We also "cut the cord" and use video streaming for our modest TV needs. 
> We use amazon prime, and occasionally rent a package from a TV
> provider.  This often works better than Google Hangouts.  There have
> still been many programs where the streaming was too poor to make it
> worth the trouble.
> 
> We're not a high demand household.  When I'm working during the day I'm
> our only broadband user.  We don't have any devices that perform large
> downloads automatically.  I review our usage on the broadband router's
> logs, and it's typically very light. From what I've read, 25X5 should be
> plenty to support a single video stream - more likely two or three. 
> 
> I can't wait until Google Fiber shows up in our neighborhood, but
> they're keeping that a secret. 
> 
> Anyone have ideas regarding what might help?
> 
> Thanks as always,
> 
>   Scott C.
> 
> -- 
> Scott Chilcote
> scottchilcote at ncrrbiz.com
> Cary, NC USA

Scott it's not clear if their video stream to you is freezing or if your video stream to them is freezing.

My guess is their video to you is freezing. As strange as it may sound your 2Mb upstream bandwidth may be the culprit.

Most often home broadband latency/lag/stream-freezing is due to low upstream bandwidth combined with large buffer on your router/modem a condition coined "buffer bloat". 

In your case hangouts has sent you XkB of data and will not send more until your PC ACKs the data. If these ACKs from you PC is sitting behind other packets waiting to be graciously accepted by your ISP then the video you see will freeze.

The best solution I've found for this is to rate-limit/QoS your routers upstream bandwidth to be 90% of your actual upstream speed. What this does is prevent packets from sitting in the buffer for long periods (up to 2+ seconds) waiting to be sent out of your local router to your ISP. If your existing router can't rate-limit, putting another 30$ router with dd-wrt/tomato between your network and your ISP modem/router may do the trick.

Netflix/YouTube/etc almost always use "http chunking" instead of "video streaming". The player will grab minutes ahead and buffer locally.  A packet capture of this it would look like a square wave (20Mb followed by 0Mb) instead of a constant /stream/ (5Mb sustained). Comparing the two is useless/moot.

Hope that makes sense. Let us know how you resolve your issue!