What line speed is minimum required for VOIP

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planet-it-tree

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Hi

Just need some info regarding an VOIP system in my network at office. I want to implement 10 - VIOP phones, what can my minimum line speed requirement for clear & smooth line quality be?

Oh and I have 10 Computers connected to the network as well.

Thanks
Your help will be much appreciated:)
 
It depends on the codecs that will be supported by the handsets/softphones. It ranges from (what I remember) 8kbps to 64kbps. Just as important as bandwidth, probably even more, is QOS. Before you look at bandwidth, make sure you can provide QOS for said bandwidth, else it will be dead in the water for business use. It needs to stretch from your switch, all the way to your internet provider.
 
If you want to go VoIP then you need a dedicated line with something like vibe on to ensure QoS. Some people use ADSL which I wouldn't recommend for business use. There are a number of Diginet options which are actually well priced which give you really good service. If you plan to just deploy phones and not have your own PBX a hosted option like Telviva or similar products would work for you. If the VoIP provider can supply the link then they should also guide you on size and required codecs.
 
Diginet is quite pricy? if I am not mistaken.. I have 5 10Mbps ADLS lines combined in one pipe, would it work?
 
You'll absolutely need QOS on your network if you want to "share" this line with other users to guarantee at least 128kbps of bandwidth for VOIP use.

VOIP is actually very low on bandwidth, contrary to what many people believe, it's the fact that it needs to be 100% guaranteed which is the problem.

Otherwise just get a second ADSL like with the lowest speed you can get.
 
planet-it-tree said:
Diginet is quite pricy? if I am not mistaken.. I have 5 10Mbps ADLS lines combined in one pipe, would it work?
Click to expand...

As I said there are some really good prices at the moment. In fact IIRC at about 10 concurrent calls its cheaper to carry voice over Diginet than over the equivalent 5 ISDN lines.

Drop me a PM if you like and I'll get someone to contact you.
 
64kb/s will give you excellent quality for voice but you need QoS.

We used to do voice on Cisco kit (routers and call manager) back in the day without QoS support and we made it work with traffic prioritisation/shaping. This was on Martis & E1 circuits though.
 
Last edited:
Hi there,
Get the QoS right and you should be fine with a 1MB connection. I would have a separate one for the PC work in the office though it does take the headache out of the QoS as well. In terms of providers I use Otel for my VoIP at home and they have been very helpful. It would provide you with a virtual PABX but most importantly for me the support has been first rate.

Regards

Tim
 
Five 10mb bonded for 10 computers? You must be paying big bucks for that. You may get fibre or a dedicated wireless for less. Really. And with fibre or dedicated wireless you can easily run VOIP together with your data. The problem with ADSL and VOIP is the upload speed. You will hear your clients, but they will not 'clearly' hear you.
Fibre can give you simetrical speeds (same speed up & down). Dedicated wireless also can give you simetrical speed.
Get a 10mb fibre with neotel or microwave if no fibre is available.
Also you can contact EOH network solutions, for fibre or a dedicated wireless.
And last resource, a dedicated diginet 512kb with VIBE can easily run 15 concurrent conversations. And it goes for around R1000. But you need a local VOIP supplier, as it runs on the local loop (it only connect from your place to your voip supplier).
 
8kbps for g729

64kpbs for g711a

those are pretty much the standard atm
 
avert said:
8kbps for g729

64kpbs for g711a

those are pretty much the standard atm
Click to expand...

That is very simplistic.

G729 is 8kbps yes for the payload only, with headers etc it's just under 26kbps either direction.

Alaw/Ulaw is 64kbps for the payload only, with headers etc work on 96kbps either direction

See: http://www.asteriskguru.com/tools/bandwidth_calculator.php for a nice b/w calculator

The question you have to ask yourself is how many concurrent calls will be done, then determine the codec you want and multiply add a little for fat and you have a minimum required line for VOIP only.
 
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webtailor said:
Five 10mb bonded for 10 computers? You must be paying big bucks for that. You may get fibre or a dedicated wireless for less. Really. And with fibre or dedicated wireless you can easily run VOIP together with your data. The problem with ADSL and VOIP is the upload speed. You will hear your clients, but they will not 'clearly' hear you.
Fibre can give you simetrical speeds (same speed up & down). Dedicated wireless also can give you simetrical speed.
Get a 10mb fibre with neotel or microwave if no fibre is available.
Also you can contact EOH network solutions, for fibre or a dedicated wireless.
And last resource, a dedicated diginet 512kb with VIBE can easily run 15 concurrent conversations. And it goes for around R1000. But you need a local VOIP supplier, as it runs on the local loop (it only connect from your place to your voip supplier).
Click to expand...

Hi bud is it a R1000 for diginet 512kb line a month
Which ISP?
 
Dubai said:
Hi bud is it a R1000 for diginet 512kb line a month
Which ISP?
Click to expand...
I got that through my VOIP supplier, but it runs with SAINET internet. But is point to point. No internet traffic. It only connects from my Pbx to their system.
 
ADSL for mass VOIP is a really bad plan. The A stands for asymmetric. VOIP needs both upload & download so asymmetric is a bit of a problem.

Try to aim at a bonded service at the least.

Tim the Techxpert said:
Get the QoS right and you should be fine with a 1MB connection.
Click to expand...
For 10 VOIP phones and 10 computers?!?...dude you're insane.
 
SauRoNZA said:
You'll absolutely need QOS on your network if you want to "share" this line with other users to guarantee at least 128kbps of bandwidth for VOIP use.

VOIP is actually very low on bandwidth, contrary to what many people believe, it's the fact that it needs to be 100% guaranteed which is the problem.

Otherwise just get a second ADSL like with the lowest speed you can get.
Click to expand...

You know what you are talking about! +1
 
warwickw said:
That is very simplistic.

G729 is 8kbps yes for the payload only, with headers etc it's just under 26kbps either direction.

Alaw/Ulaw is 64kbps for the payload only, with headers etc work on 96kbps either direction

See: http://www.asteriskguru.com/tools/bandwidth_calculator.php for a nice b/w calculator
Click to expand...

The bandwidth you mentioned depends on the CODEC payload and number of concurrent calls. When we use a payload of 60ms I get 16Kbps in both direction for G729. If I use 20ms it goes up to 32Kbps in one direction and 16Kbps in the other because the upstream provider is transcoding the call. Multiple concurrent calls will have the 32Kbps rate on the first concurrent call but the rest will be at 16Kbps because the packet headers are sent with the first call. I have looked at our bandwidth monitors for a long time now and this is a fact - especially when using Mikrotik RB's

Same thing for ulaw and alaw.
 
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