Our office currently runs a few phones over a VoIP line. Through our VoIP provider, we have a virtual private server. We chose them as the VPS provider because the VPS came pre-loaded with all of the software that was necessary. However, I've discovered that I would rather manage the software myself and would prefer to work on a different platform.

The primary reason that we have stayed with them is because as our VoIP provider, I presume that there is some advantage in call quality because they have "direct access to the PSTN", which I would presume is an advantage when it comes to call termination and overall call quality.

My question boils down to:

What is better from a call quality perspective?

1) A server located 20ms closer to us (60ms), offered by a different company.

2) The current server at the VoIP/SIP provider (80ms)


You really don't provide enough details. Like how many phones in your office are there and how many concurrent calls do you typically have going on....

Remember that your VPS is probably a client to some SIP provider.

60ms seems high too. We typically see 60ms times with links going coast to coast in NA. Level3, NTT, QWest, and ATT... Looking Glass shows typical backbone speeds with no hand offs much lower of course.

So your mileage will vary... need more details: Who's you're provider, your relation to them, BW speed, CODECS in use, number of SIP stations, etc...

  • We only have two phones in our office. We use G729.a – user60921 Nov 20 '10 at 23:47

There is a lot more you need to check other than just what the latency is. The QoS for the connection delivering the SIP trunks to you is going to be critical. You should insure the providers offer some type of SLA on the QoS for the SIP trunks.

At the end of the day you should evaluate the two services and choose whhich service provider offers better service. You can use some of the different applications found here to help evaluate the different providers: http://www.pernau.at/kd/voip/bookmarks-sip-test.html

  • QoS does you no good against in-bound traffic, keep in mind. It's good to have but it's not a complete solution by itself. The answer, however, to #1 should be obvious. Lower latency is always better. – Kilo Feb 18 '11 at 16:48
  • Not to uselessly argue with you, but why do you think latency is more important in a VoIP environment than QoS? – kernelPanic Mar 25 '11 at 19:02

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