Is buffering bad or good?

Aug 28 2012
By Fred Hoot - Google+

If you were expecting an answer of either ‘yes’ or ‘no’ just toss that idea out in the trash.  In the world of networking, buffering is the Gemini.  It has both good and bad properties as far as visual enjoyment of video and music goes.

Any time you have two different throughput speeds, you need a buffer to prevent packets of data from being dropped.  An ISP providing a video for streaming has a lot of bandwidth.  The video stream may need a 2.5 to 3 Mbps bandwidth to be viewed by your media player. If the video is HD, it will require between 5 and 10 Mbps.  If you have a DSL connection, you may get1.5 Mbps download speed, so you can see a problem developing here.

Buffering In Action

When you start the video, you may experience a delay before the video starts as the buffer on your computer video player downloads enough video data to start displaying the video.  Your player may be smart enough to be able to figure out how much of the video to buffer so you will experience few interruptions.

There is also another buffer at work and that is at your ISP.  When the 3 Mbps stream gets converted to match your 1.5 Mbps line, the rest of the data has to be stored somewhere or else it would be lost, so the ISP will start filling a buffer.  This is good buffering as it prevents video loss.

An example of this is a camp shower out in the middle of a forest.  A small pump fills up a storage tank (the buffer) with water from a stream.  As long as there is water in the tank, you can enjoy your shower.  If you use up the water in the tank, you will only get a trickle of water from the pump, so you turn off the shower, wait for more water to fill the tank and continue your shower.

Video streaming is like that, as soon as the buffer empties, the video player waits for the buffer to fill to a certain level and then continues.  You may see a buffering message or just no video.  This is that infamous bad buffering.

If you want to view the video without hiccups, you can start the player at the beginning, pause and wait for all of the video to download.  Then you should be able to view it without interruptions.

Ideal Situation

The perfect situation would be to be located in the same area as your video source and be connected to the same ISP.  You would have a 30 Mbps download speed and you could view your video without interruption.  The video source would not have any bottlenecks to push through so your video player would be fed a constant stream of data.

There is still buffering involved, but like the water tank that still has enough water in it to allow you to finish your shower, you will not notice it.  We can solve the camp shower problem by installing a huge gasoline-powered pump to feed the water tank, but that would be too expensive to be practical.  Your ISP should not have this problem.

More Buffers Than You Can Imagine

Now take that ideal situation: you have a 30 Mbps download speed and the video provider has a humongous amount of bandwidth to feed you video data.  The only difference is that they are in the UK and you are in the US.

There may be up to 30 different hops your video goes through to get to you.  Every one of those points has buffers.  More important is the fact that any one of those hops could be in a congested state.  Sounds ominous, right?

I traced a video packet from BBC to Cupertino, California and it took 16 hops.  Two hops were in the UK.  Three hops for the trans-Atlantic cable and handoff nodes.  Then the video packet passed through Ashburn, Virginia (two hops in this city); Marietta, Georgia; Dallas Texas; and finally a whirlwind tour through California passing through Los Angeles, Sacramento, Oakland and Santa Clara before arriving in Cupertino, California.

Just think of all the possibilities for that video stream to be delayed, packets dropped or even lost.  At any point in the data path problems can develop and a buffer could run dry.  Add to this dynamic routing at any of the ISPs handling the video stream and you can possibly have different paths being taken by each packet.  There is one other thing that some ISPs do and that is giving different priorities to different sources of data.  Several ISPs have admittedly given lower priority to video sources with the exception of their own, like Comcast does with their Xbox video.

Real Life Example Of Buffering Put To The Test

You might wonder why I picked the UK and the US to see how many hops a video made to reach me: Summer Olympics.

Google supplied the streaming technology and infrastructure to support an expected record breaking amount of video streaming.  Fifty (50) simultaneous streams of video with many if not all in HD is a lot of video.  Now imagine 13.2 million viewers looking at the video streams.  Swimming was popular with 943,000 viewers.

Google set up three different data pipes to make sure they could meet the video demand.  Jason Gaedtke, Google’s Director of Software Engineering was in charge of the video streaming.  Even with a seemingly limitless supply of funds, equipment and resources available at his fingertips, Jason still ran into buffering problems.  He said “I do believe any issues are highly localized,” but “We can’t create bandwidth where there is none.”

Yes, even one of the most experienced companies in the world of networking ran into buffering problems.

ISP Claims

Speaking of the Summer Olympics, Usain Bolt, one of the fastest men in the world, made some commercials for Virgin Media and other companies.  Virgin Media, based in the UK, used the super-fast Usain to support Virgin’s super fast Internet service.  Great commercials, but a statement that claims “say bye-bye to buffering” is way over the line.  Just ask some Virgin customers who spent a lot of time watching the Olympics and see how many times they experienced buffering issues.

It is very ironic that in the United States there were many complaints of missing Usain Bolt’s record finish due to buffering issues!  Any ISP who can claim eliminating buffering issues is playing with smoke and mirrors.

 

Summary

As you can see all buffering is good until the buffers closest to you run out of data and have to be refilled; then good buffering turns into bad buffering!

Here are a couple short, quick tests to isolate and determine where the buffering is taking place.

• Take your computer to a neighbor who has a different ISP and see if the problem goes away.  If you still have the problem, your computer is at fault.  If you do not have a buffering problem, your router or ISP could be at fault.
• Try connecting your neighbor’s computer to your network and compare the performance.
• Resetting your router and computer often clears up some local buffering problems.
• Make sure your router is secure.  A neighborhood kid who is using your router to stream his own videos and movies will degrade your video viewing experience immensely.
• When all else fails, call your ISP and have them help you resolve the problem.

Usain Bolt photo via usainbolt.com

Serengeti Shower photo via Flickr by Ameeeer

Circle Fred on Google+

Follow Broadband Expert on Twitter

Circle Broadband Expert on Google+