Solution required

[rvanwyk]

hey guys

i need a voip solution

this is the setup. 10 locations in SA linked (via ADSL (VPN)) to a central location in JHB. each location will need 1 to 3 users (max, for now) and the central location 5 max.

which ever route i go, i dont want to go outside our network (ie. the internet) and only want to make calls within our network (for now) via the VPN connections to the various locations. (yes i know adsl is linked to the internet but i want to tunnel the voip through the vpn connections)

what free options do i have for the server side of things and then what kind of softphones works good?

also, what hardware based pc-less phones will work in "this" system that can be sourced locally and that could be used should we wish to later extend and break out to a provider?

there's just so many options out there and would like to know which is the better and more reliable free options available.

I hope someone can help. pretty new to this.

thanks in advance

 

[warwickw]

Asterisk in your main office, recomend using Trixbox from http://www.trixbox.org, configure for all your extention using IAX protocol NOT SIP. Port forward the IAX UDP port on your ADSL modem/firewall to the Asterisk server. Configure a dynamic dns name for your ADSL connection at the main site.

Get the ATCOM phones as they support IAX protocol so they will hapily connect over NAT'd connections to the central server. Configure them to connect to the central sites dynamic dns name. You can even use an IAX softphone on your PC suggest Zoiper http://www.zoiper.com

I wouldn't bother with VPN connections for voice, as the latency on the encryption and decryption of voice packets can lead to jitter on the call quality.

Warwick

 

[Big G SA]

VoIPSolution Required

Please send me a Private message with your details,
I have exactly what you are looking for, low cost, Onnet calls, SA phones.
Regards
Gary

 

[rvanwyk]

Asterisk in your main office, recomend using Trixbox from http://www.trixbox.org, configure for all your extention using IAX protocol NOT SIP. Port forward the IAX UDP port on your ADSL modem/firewall to the Asterisk server. Configure a dynamic dns name for your ADSL connection at the main site.

Get the ATCOM phones as they support IAX protocol so they will hapily connect over NAT'd connections to the central server. Configure them to connect to the central sites dynamic dns name. You can even use an IAX softphone on your PC suggest Zoiper http://www.zoiper.com

I wouldn't bother with VPN connections for voice, as the latency on the encryption and decryption of voice packets can lead to jitter on the call quality.

Warwick

thanks for the reply. you see, the thing is that the vpn connections are in place already and has been for some time. this is mainly for our accounting software and connection to the mail server and some other servers.

so basically, asterisk is the way to go?

 

[Big G SA]

VoIPSolution Required

Warickw is spot on regarding VoIP through a VPN, the end result will be jitter, latency, packet loss and overall poor quality. VoIP does not like to be authenticated!
Are you routing each branches ISP requirements through one central location, or does each branch have it's own ISP connectivity?
Would suggest looking at SIP based PBX for main branch, and SIP based phones for branches routing through ISP and connecting each office through unique 087 number range.
End result will be free onnet calls, and cost effective calls to PSTN and GSM providers locally.

 

[gmza]

I have to disagree about the comments re VPN disrupting call quality.

Any decent firewall can encrypt and decrypt a packet in under 2ms. Most decent phones (including the ATcoms suggested above) can easily cope with jitter well in excess of 20ms without introducing any perceptible additional delay. Asterisk's adaptive jitter buffer (on the PBX side) will cope with hundreds of ms of jitter (although delay is very perceptible at that level).

As for a VPN introducing packet loss, I'd be interested to understand how that conclusion comes about. That should only ever happen if there is network congestion. The only difference is that instead of having a 60-byte (typically) UDP-packet, you'll now have a ~110 byte IPsec packet. Sure, when links are congested, it's better not to double your per-call bandwidth usage, but provided the links are not congested in the first place, crypto is not going to magically introduce packet loss. If your links are sufficiently congested that packet loss is an issue, you're going to have a problem with or without crypto.

There is only one real problem with running VoIP through the VPN, and that is that you will approximately double* your per-call bandwidth requirement.

* This is not technically accurate in the case of an ADSL-based VPN, because ADSL runs on ATM technology and it is extremely inefficient to carry small IP packets in small ATM cells. With larger IP packets, the overhead introduced at the ATM layer, as a percentage, is smaller. Eg. Carrying a 60-byte IP packet in ATM requires two cells, total 106 bytes. Carrying a 120-byte IP packet takes 3 cells, total 159 bytes. So in this case, your ADSL bit-rate requirement rises from 42.4kbit/s to 63.6kbit/s which is only a 50% increase, despite the IP bit-rate doubling and despite your per-MB bandwidth usage bill doubling.

 

[Big G SA]

The crux of the matter!!

To help ryanvwk make a sound business decision.....
gmza - It's your business, do you push VoIP calls over the VPN?

 

[gmza]

Big_G_SA - point conceded: I'd only run the VoIP over VPN if I was working for SAPS or National Intelligence. For my own business, I see no benefit of using a VoIP over VPN; I'd be flattered if the competition went to such great lengths to try and snoop in on my conversations!

 

[warwickw]

Basically I've learnt to just take out any complexity when it comes to VOIP, to ensure a better a call quality at all times.

At the end of the day you want a clear conversation with someone, and when you are problem solving issues VPN's can sometimes cause more problems with VOIP than its worth.