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saleemm
join:2014-03-16

saleemm

Member

[Other] GSM termination...

Hi all and thanks for reading,

I am trying to setup a VoIP GSM termination using 8 channels gsm gateway...

but my problem is that I only have the choice of having internet through 3g ... and VoIP is blocked on 3g connection ... so I am thinking of having a vpn router connected to the 3g router and connecting the gsm gateway to the vpn router ... but I am very concerned about the quality of the voice and I am afraid that the vpn will affect my quality I am not looking to have a quality as a regular call I will be using G723.1 codec but at least I dont want sound delays echo robotic sound etc... do you think 3g over vpn will work for me?... what is the bandwidth needed for 8 simultaneous G723.1 calls?... and how many mega bytes does a G723.1 one hour call consumes ?

toro
join:2006-01-27
Scarborough, ON

toro

Member

Usually the reports about VoIP quality over 3G are mixed due to high jitter.
There are too many variables (country, operator, how good is the signal in the are where you want to implement it, how congested is the network) for someone to give you an objective answer.
I don't think your problem here will be the VPN, I think it will be the actual Internet connection.
Why not try the quality on a smartphone, where you can set up VPN and a softphone ?

Trev
AcroVoice & DryVoIP Official Rep
Premium Member
join:2009-06-29
Victoria, BC

Trev to saleemm

Premium Member

to saleemm
You can find information on bandwidth and data transfer requirements with this website: »www.bandcalc.com/
saleemm
join:2014-03-16

saleemm to toro

Member

to toro
with respect to testing does it matter using a free vpn or a premium vpn?

mgraves1
Premium Member
join:2004-04-05
Houston, TX

mgraves1 to saleemm

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to saleemm
Do you have an 8 channel GSM gateway? An 8 channel GSM gateway should support 8 simultaneous voice calls.

The gateways that I use seen have one SIM card per port, providing one voice channel per port. They use the voice channels of the GSM service, not the data channel.

That is to say, the ones that I have used don't allow you to establish a data connection then run VoIP over that connection.

I'll admin that my experience with them is limited.
saleemm
join:2014-03-16

saleemm

Member

I have 8 channel goip gsm gateway ... what codec are you using?.. and have you ever tried voip over vpn ... my setup will be a 3g router then a vpn router then the gsm gateway .. do you think that is possible if the 3g connection is good? ... I tested Viber on my iphone on 3g while connected to a free vpn ... do you think that is enough for testing ?

mgraves1
Premium Member
join:2004-04-05
Houston, TX

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The "GoIP" gateways are manufactured by Hybertone. They are not unlike the Portech units that I have used in the past.

»www.hybertone.com/en/pro ··· proid=34

All of the details are there, as well as manuals.

This has nothing to do with 3G, Viber, etc. All of that is about cellular data. Using this sort of gateway you do not send calls over the data channel.

You send calls over the voice channel. One active call per SIM that is installed to the gateway.

You exchange calls with the gateway as if it were a SIP or H.323 device, like a multi-port FXO device.

The reference to VPN has to do with the wired network side of the device. It could be installed in the same location as a PBX, or installed remotely and connected to the PBX over a VPN.

I documented my use of a single-port gateway as a backup trunk for our SOHO PBX back when we had such a thing.

»www.mgraves.org/2008/12/ ··· -part-2/
saleemm
join:2014-03-16

saleemm

Member

thanks for the hybertone link very helpful...

yes I know it is a voice channel... the 3g has nothing to do with the gsm gateway except to connect the gateway with my voip server ... since both the gateway and the voip server are in two different countries ...

my only option for internet where the gateway will be located is 3g that's why im asking

mgraves1
Premium Member
join:2004-04-05
Houston, TX

mgraves1 to saleemm

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to saleemm
Ah, I see. I didn't understand at first. Clearly, G.729 is the tightest codec that it supports. A 3G data circuit may work, but it could be quite variable. I wonder if it will be acceptable in the end?

My installation had the gateway local to the PBX in one case. In a second case I had it registered to a hosted PBX. Both worked fine, but didn't face the kind of network bandwidth constraints that you have there.