Tuesday, June 25, 2013

T1 and YouTube: A Not So Great Combination For A Hosted Voice Solution

Ok folks.  Simple scenario here.  A customer with a hosted voice solution, meaning the phone system is someone else other than your facility.  You also have your Internet traffic going out the same link hosted voice traffic.  In this case, its a T1.  1.544 Meg.  Not a lot, but enough for a small office.  I get a call complaining of voice quality problems.  Customer cant hear their customers.  Calls get hung up on.  You get the picture.  So, with that said, lets take a look at what is going on, on their circuit.  After all, none of the other hosted customers are complaining about voice quality. 
Oh, here is the problem.  See below.  You cant fill up a T1 and expect voice to be of good quality. 
So, notice that number circled 2234?  That is 2234 milliseconds.  Yeah, thats right.  2.2 SECONDS of delay at the most in that graph.  Id say that is enough to qualify for some voice quality issues, since 150 milliseconds of delay is the most you can have without noticing.   Also notice that 100% utilization.  Not good.

4 comments:

  1. Sounds like you need a Layer 7 Rate limiting product. I know something that can help. ;)

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    1. Yeah, you are right Jonathan. No doubt. Its all fun and games until... well their voice goes down.

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  2. Besides PingPlotterPro, what other tools do you keep in your toolbox?

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    1. Thanks Lyle for the question. I usually use the free stuff, with one exception. The one that helps me the most, in troubleshooting, is a program called Capsa, by Colasoft. Usually when trying to track down something quick. Other things I use are interface traffic indicator (for bandwidth monitoring, angry ip scanner, pt360, winmerge (for comparing cli configs), ping plotter pro (as you mentioned), and of course my terminal emulators (tera term, putty, and secure shell client). I also use Wireshark extensively as well. There are a few other things for special purpose stuff (like TFTP, etc), but these are the main ones I use. Im sure you could probably buy something that would do all this in one, but Im somewhat cheap I guess.

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