The Deal:

1) Have Time Warner Turbo Cable Internet - supposedly > 10mb/s download speed

2) Am considering Vonage or other similar service - will obviously be working off the above service.

3) My employer wants to replace existing Home Office Land Line with a VOIP service working off the same Internet connection.

4) Family members rely on same connection for long distance learning, gaming and watch movies via Netflix off the same connection.


The Question(s):

1) Is it problematic to have more than one VOIP service running at the same time?

2) Are there ways to make the connection work smarter or faster in a high usage domestic environment?

Thanks in advance for your answers.

Your upload speed is going to be a way bigger issue than the download speed as the lines are generally asymmetric. You can control the bandwidth Vonage uses by changing the codec and you'll get some benefits in terms of reduced bandwidth usage but you still have the potential to run into troubles if someone is streaming a video while you're making a call.

Having two different VoIP services running on the same line should not be a problem; they'll each just register to their home server and run normally.

Good info - Thank you. ^

What would be a reasonable upload speed to assure excellent quality on two concurrent VOIP calls?

512kbps would be more than enough in theory. In practice, what is more relevant is how the traffic is prioritised, so that other (non-VoIP traffic) cannot flood the available capacity and cause the quality to drop dramatically.

What sort of router are you using?

It is a Belkin Pre-N MIMO router

My Vonage router insists it's the first thing in the chain.

We have multiple SIP based VOIP services and haven't had a problem. QOS (quality of service) is the bigger issue. Also learn the commands for call transfer. If a connection goes south on you, make an excuse and transfer it to your cell.

A G.711uLaw call (the basic highest bandwidth version of VoIP you'll get) consumes ~80Kbit. A G.729a call (the lowest bandwidth version you'll get) consumes ~32Kbit.

And while traffic priority/QoS is important it is also important to know that there really is no such thing on the internet. On a private network you can configure the infrastructure to prioritize the voice traffic and drop other packets if the lines get full. On the internet you have zero control of such things and you are stuck with a best-effort solution. That means that you are, for the most part, just going to have to deal with whatever you get in quality.

Voice consumes hardly any bandwidth as mentioned so I wouldn't be worried. And millions of people use Skype, Vonage, etc., without a problem in all well connected countries and even some not-so-well connected countries. QoS is not required nor feasible as mentioned.

You are partly right, but the prioritization of traffic at the edge (ie: on the router) makes a HUGE difference to performance. I have worked with many large (Global 2000) enterprises who are happily running VoIP in places like Africa over the Internet with the only prioritization being done on the edge router. The difference between it turned on and off is incredible.

So saying you have zero control over the traffic being dropped is only partially correct - on the network side, this is correct. But for the most part, the order of traffic you send out on a network link is the same as what you will receive at the far end, even over the Internet. Don't forget that the Internet backbones that providers operate are massively bigger than their private networks, so there is plenty of bandwidth to go around.

You are talking about physically being the device connected to the Internet connection, right? This is mainly so the VoIP calls can reach the router, due to Network Address Translation (NAT) issues.

You can very easily run Vonage (or similar) with another router "outside" it to prioritize the various traffic types. If you have loads of bandwidth this may not be an issue but if there is congestion it can make a big difference.

Actually HD codecs are much higher in quality and consume more bandwidth, and there are many tighter compression schemes that use 8 and even 4Kbps (plus IP headers)

my voip services, and we use 2-3 a day depending, are not really using more than 128kps or so OUTBOUND each. So, with the 750kps pip up we have, it works fine.

I DO use QOS on a linksys router, with the open source tomato software installed so I can PRIORITIZE any of the VOIP adaptors or protocols (skype is the third VOIP we use) above all other data traffic.

Since the INBOUND BW is 6MB, I don't alter the inbound (which is actually hard to do with QOS) so that the inbound VOIP has reserved bandwidth. But, it really hasn't ever been a problem unless a large download is going on.

With the buffalo, you MIGHT be able to change the software to a dd-wrt or tomato, which would allow you to setup QOS for VOIP properly.

Or, you could put ANOTHER router in the middle (they are pretty cheap, I just bought a refurb netgear for this) in between your modem and the buffalo.

I have no problems with conflict or call quality with three calls running in parallel.

And how many of those are used by consumer VoIP systems?? There are always going to be higher bandwidth codecs available, but they aren't the ones in use.

Again, how many are in commercial use? And the G.729a codec is only 8.9Kbit, I believe, plus the overhead for the headers.

Well I've been in the VoIP business for over a decade so I hear about it a lot. If you google "HD codec" or "HD Voip" you can see a lot. And we created a lot of low bitrate codecs back in the 90's that may not be quite as useful today, but still a heck of a lot in use around the world, especially on satellite links.

Plus Skype uses G.729 on Skype-Out calls.