alexd wrote:[color=blue]
> [email]dilan.weerasinghe@gmail.com[/email] wrote:
>[color=green]
> >
> > alexd wrote:[color=darkred]
> >> [email]dilan.weerasinghe@gmail.com[/email] wrote:
> >>
> >> > We wish to implement VoIP to (primarily) communicate with overseas
> >> > offices,
> >> ...
> >> > The remote side will be implementing Cisco Express.[/color][/color]
>[color=green][color=darkred]
> >> My vote goes to Asterisk. If you don't already have people on your IT
> >> team with telephony experience, but they do have linux/unix expertise,
> >> then it's a no-brainer.[/color]
> >
> > They don't have linux/unix experience either! All of us are Windows
> > servers/ Cisco infrastructure guys really. :([/color]
>
> Oh well. I guess you need to work out what's going to be most cost effective
> in the long term. There are soft switches that run on Windows [eg Swyx],
> and Cisco make phone systems [as you've already mentioned], but replacing
> your phone system will most likely result in you having to replace all your
> Samsung handsets too. How far from the end of its life is your Samsung?
> What's the cost of a VoIP card for your Samsung vs. a new phone system?[/color]

The Samsung was installed about 2 years ago, so they're plenty of life
in it yet. Unfortunately, this place was run by a different IT team
then and they didn't pre-plan for
VoIP.
We can buy a VoIP card for the Samsung switch though, will probably
cost about £1500 (which is about what we pay per month for calls to
Nigeria).

[color=blue][color=green][color=darkred]
> >> > iii) One method of implementation is to insert a VoIP card into our
> >> > existing Samsung phone switch and use QoS on our existing
> >> > infrastructure.[/color][/color]
>
> It leverages what you've already got [in terms of infrastructure] and
> requires the least amount of upfront investment. If you end up with poor
> quality/dropped calls, then maybe it's time to start adding other things
> into the mix.
>[color=green]
> > The problem with purchasing an additional ADSL line would be that we're
> > already spending £x/month on just maintaining that line now. Given
> > that there are about 30 people in the London office, and the number of
> > concurrent VoIP calls to Nigeria will be maximum about 3, do you think
> > this is necessary?[/color]
>
> It depends on various factors:
>
> - What is the maximum that your link to Nigeria can carry in both
> directions? [And I don't mean how much are you paying for, I mean what's
> the most you get out of it].[/color]

The most we can get out of it is about 0.9 Mbs, I'd say.
[color=blue]
> - How much existing traffic is your link to Nigeria carrying? Are existing
> applications on the link going to suffer if VoIP traffic takes precedence
> over them?[/color]

The VPN is not used for anything else apart from HQ RDP'ing to our
servers in case of emergency and email. So, not much traffic at all.
There are no applications as such that run across the VPN.
[color=blue]
> - What [if any] voice compression codecs are you intending to use, in other
> words, how much bandwidth will each simultaneous call require?
>
> As 'one company' has already told you, QoS is hard to get right, as there
> are so many variables that need to be nailed down to guarantee call
> quality. If you can get it to work, then hats off to you, but you may find
> it a lot easier to get a dedicated circuit. You won't really know until
> you've implemented it and started making calls.[/color]

If we asked for a couple of pre-programmed IP phones and tested them
out using the VPN (and assuming the quality was good), would I be right
to infer that the this meant our existing link could cope and we don't
need to go down the seperate ADSL route?

[color=blue][color=green]
> > Initially, we're just looking at cutting down phone costs to Nigeria.
> > We are spending a hell of a lot per month on these.
> > We have a PIX-PIX VPN with them. Is it possible to just use on VoIP
> > card on our Samsung switch[/color]
>
> Shouldn't be a problem, so long as it's compatible with the phone system at
> the far end[s].
>[color=green]
> > and, utilising QoS on the switches, have
> > about 10 IP phones that would be used as well as our existing system,
> > for the users that speak to Nigeria the most?[/color]
>
> I'm not quite sure what you're aiming to achieve by adding IP handsets at
> the UK office. If it's just the phone systems in each office speaking to
> each other over your VPN, then the technology of the handsets themselves
> should be irrelevant.[/color]

To see if the existing link can carry the voice as well as data.

[color=blue]
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