[email]dilan.weerasinghe@gmail.com[/email] wrote:
[color=blue]
> We wish to implement VoIP to (primarily) communicate with overseas
> offices,[/color]
....[color=blue]
> The remote side will be implementing Cisco Express.[/color]

I would have thought it would be most sensible to answer the below questions
before deciding what one end is implementing!
[color=blue]
> A couple of questions -
>
> i) Is it recommended we implement Cisco Express too, for compatibility
> issues, or can we use any system (e.g. Avaya).[/color]

No Idea. If the Cisco speaks a VoIP standard like SIP or H.323 then you
should in theory be able to use pretty much anything. But bear in mind some
PBX manufacturers seem to take sadistic pleasure in using H.323 but
bastardising it in some subtle way to make it impossible to use with
anything else.
[color=blue]
> ii) We will outsource the implementation to external companies, but
> wish to manage the maintenance. Given that none of the of the IT
> department has
> experience in either Cisco Express or Avaya etc, what is the most
> straighforward application to learn.[/color]

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. Such a no-brainer in fact, that if that was the case you
probably wouldn't even be asking. If Management insist on Cisco, give 'em
Cisco handsets and use Asterisk on the back end ;-)
[color=blue]
> 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]

So long as it speaks the same VoIP protocols as the kit at the far end
[H.323 I'm guessing].
[color=blue]
> Another would be to leave for the existing
> infrastructure for data only and use a SIP gateway and seperate ADSL
> line for voice (which one company is advising). Any thoughts? Their
> claim is that QoS can only go so far, and a seperate ADSL
> line/dedicated hardware is what is needed.[/color]

That sounds like a fairly sensible idea, but it doesn't tick that
oh-so-fashionable "convergence" tickbox though ;-)
[color=blue]
> Would be grateful for pointers.[/color]

voip-info.org is a good start, if you want something biased towards
Asterisk.

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