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Currently we have a T1 which we use for both our voice and data.
We are looking at getting a bonded T1 but have been told by the provider that it would be a bad idea to run both voice and data on a bonded T1 (Multilink PPP) and that we should either:

A) Put in a bonded T1 for data only and have a 2nd non-bonded T1 for voice, or
B) Put in a 2nd T1 for data only and make the current T1 voice only

We don't use the voice as much and the reason we looked into a bonded T1 is for more internet speed, but obviously we still need to keep voice services with good quality and reliability. Unfortunately T1 is the only thing available to us since all the lines here are copper.

I am not familiar with bonded T1s. Tried googling about bonded T1s and having both data and voice on it but couldn't come up with anything helpful. So my question is, will we lose service quality by getting a bonded T1 and putting both voice and data on it?

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up vote 2 down vote accepted

By voice, do you mean 1.) you're using a MUX to split channels out of the current T1 for voice, or 2.) you've got VOIP as part of your data traffic?

  1. I don't think there would be any difference whether your link was 1 T1 or a MPPP link, as long as all of your MUX and termination equipment supported MPPP. You'd have to confirm that it would work though, so that may be what the mean. Maybe your existing equipment doesn't and they're trying to save you the cost of an upgrade.

  2. If it's all data (VOIP is just data) then it doesn't make a lick of difference what the link is. As long as you're giving priority to the VOIP, you could be using T1, T3, dial-up, cable modems, ham radio, ISDN, carrier pigeons, smoke signals - you just want to give priority to VOIP and ensure that you don't fill the pipe. Of course, you do also need to concern yourself with latency, jitter, etc - but those factors are independent of what the pipe is (although some will be less suitable.)

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Unfortunately I don't know the exact answer to what voice means in this scenario since it is managed by the provider. They send it across the wire and then we have X amount of standard analog lines that we plug into our PBX. I suspect the correct answer is #2 and they probably just want us to spend more money. I spoke with the service provider a few minutes ago and they said they could make the scenario work but they wouldn't guarantee voice quality. Understandably the business group doesn't like that answer so we are probably sticking with a single T1 for now. – Nate Pinchot Mar 10 '10 at 19:07
In scenario 2, I don't see how you could double the available bandwidth and have worse performance compared to what you have now. Are you having problems now? If not, then I don't see how more bandwidth could hurt you - assuming you don't anticipate an increase in voice usage. If you are seeing problems, then more bandwidth would help, not hurt, regardless. It might not help as much as separating them into different links, but proper QOS would help as well and you can do that on any link. – mfinni Mar 10 '10 at 19:15
Get more details from the provider. Don't let them snow you. – mfinni Mar 10 '10 at 19:15
+1 - VoIP over smoke signals... heh heh. – Evan Anderson Mar 23 '10 at 14:54

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