Hosted Vici special considerations

[roger.milligan]

Hi

We are setting up a 300 agent Vici call centre which will be hosted in a remote data centre. The voice data connection to the call centre is 10Mbit fibre. I have 3 questions:

1. We plan to use Zoiper Biz softphones with G729 from the agents to the hosted Vici server and then G729 to connect to the VoIP provider. (We have allowed for 600 G729 licences.) What are the issues with this double G729 transcoding? Is it true that the quality will be worse than a single G729 transcoding? Is there a better way of doing this?
2. With the agent PC and browser being on a different site to the Vici server, do we need to do anything special with the time synchronisation of the PC clocks and the Servers? We don't want to get any issues with the clocks being out.
3. Is there anything else that we need to consider when using a hosted server? We have done a lot of Vici setups with the server on site, but never with a remote server.

Thanks very much

Roger
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ViciDial: VERSION: 2.12-480a BUILD: 150404-0932 DB schema: 1407 Scratch Install
Single Server: - 1 x Dell R730 Dual 10 Core 128GB RAM
Asterisk: v 1.8.28-cert5 MySQL: v 5.6.24 Apache: 2.2.15 CentOS: 6.6 Sangoma USB Timing

[mflorell]

Are all agents in one or two locations?

10Mb might not be enough bandwidth for 300 agents for both the agent audio using g729a and the vicidial web connection if they have to both fit through that pipe.

At the hosted location is bandwidth an issue? If not, you might want to avoid the g729a going out to your carrier and use a standard codec like g711a or 711u.

[roger.milligan]

Hi Matt

All 300 agents will be in one call centre location in Cape Town to start with, but we may add agents from another call centre in Johannesburg in the future. Why do you ask? Is there something that we should take into account with more than one agent location?

The 10Mbit fibre is only for the voice. We have another 10meg link for http traffic (Vici and their hosted CRM). Do you have any figures for the typical bandwidth requirement of a Vici web traffic per agent?

Bandwidth in South Africa is still very expensive - so we don't have the luxury a huge pipe. Our carrier is remote from our hosting centre - so we will need voice compression on this link. Are you suggesting G711 as a preference because there are known issues with the double G729 transcoding?

Thanks

[mflorell]

Typical agent bandwidth for the web interface alone should be at least 10kbps

As for ccodecs, G729a is very CPU intensive, so you will need about twice as many servers as you would with G711, unless you get transcoding cards like the kind Sangoma sells.

[bobchaos]

If bandwidth is a worry, see with your hosted service provider if it's possible to get digital lines (E1 or T1, whichever is in use in your country). You can then either halve your bandwidth requirements by making outbound go out digital lines or almost eliminate it by having the agents use digital lines themselves.

That said, you usually want to plan roughly 64kbps per SIP line, so 300 agents dialing at a 4to1 ration would fit a bit too tight for comfort inside a 100mbps pipe, probably leaving too little bandwidth for web traffic.

Regarding time, all your servers and clients will need to be sync to a single, common source. If that's a windows server that's been tweaked to serve NTP or a proper ntpd implementation is up to you but it needs to be the same for everyone involved.

*edit* final note: if your provider can work with IAX2, I've never benchmarked it myself but I hear its insanely efficient on bandwidth, you may want to look into that possibility.

*'nother edit*: You said 10mbps, not 100! Your 300 agents would likely require almost 20mbps to reach the servers, and the servers would need and extra 80mbps on top of that to call the clients!