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How to tell if a line is qualified for VoIP?

I plan on using VoIP overseas for my family. Both locations will have broadband. The bandwidth will be provisioned enough but it's the latency that I'm worried about.

How do I test if the line is good enough for VoIP?

I pinged the other end, using 1500 byte size, and repeat 10 times. The results were average of 300 ms.

Am I using the right ping values, and does 300 ms look good enough for VoIP (and possibly video too)?

This is for personal use.


Re: How to tell if a line is qualified for VoIP?

We are doing VOIP over satellite links with round trip times of 550-600 ms. Cisco says latency should not exceed 150ms one way, but that is not always practical. The problem this poses for VOIP is the same one it poses for traditional circuit switched calls. There is a 2 way radio effect, where talkers need to take turns because of the long lag.

A bigger problem than static delay when dealing with the Internet is lack of any QOS. If you are on a call, and there is congestion somewhere, it will cause the latency to vary greatly, this high jitter can exceed the range of the buffers, and cause severe quality problems. Packet loss can also occur due to congestion.

Your best bet is to try it and see how it works.

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