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VoIP implementation advise

 
 
dilan.weerasinghe@gmail.com
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      09-14-2006
Hi

We wish to implement VoIP to (primarily) communicate with overseas
offices, but at the same time reduce the phone bill for the office in
general. Our two offices (one in UK, the other in Africa) are connected
via a PIX-PIX VPN. More offices in Africa should be VoIP'ed up as the
year progresses.

We have a 1 MB leased line connecting to a Cisco 2501 router (ISP
managed), then a Cisco PIX 506e, through to four 3COM 4288g manageable
network switches. Number of users on London side is about 30.

The remote side will be implementing Cisco Express.

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).
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.
iii) One method of implementation is to insert a VoIP card into our
existing Samsung phone switch and use QoS on our existing
infrastructure. 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.

Would be grateful for pointers.

Cheers

 
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alexd
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      09-18-2006
http://www.velocityreviews.com/forums/(E-Mail Removed) wrote:

> We wish to implement VoIP to (primarily) communicate with overseas
> offices,

....
> The remote side will be implementing Cisco Express.


I would have thought it would be most sensible to answer the below questions
before deciding what one end is implementing!

> 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).


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.

> 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.


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

> iii) One method of implementation is to insert a VoIP card into our
> existing Samsung phone switch and use QoS on our existing
> infrastructure.


So long as it speaks the same VoIP protocols as the kit at the far end
[H.323 I'm guessing].

> 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.


That sounds like a fairly sensible idea, but it doesn't tick that
oh-so-fashionable "convergence" tickbox though

> Would be grateful for pointers.


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

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Daviey Walker
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      09-18-2006
alexd wrote:

> 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.
>



I believe much of Cisco kit uses the MGCP protocol, which Asterisk also
supports.
 
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dilan.weerasinghe@gmail.com
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      09-26-2006

alexd wrote:
> (E-Mail Removed) wrote:
>
> > We wish to implement VoIP to (primarily) communicate with overseas
> > offices,

> ...
> > The remote side will be implementing Cisco Express.

>
> I would have thought it would be most sensible to answer the below questions
> before deciding what one end is implementing!
>
> > 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).

>
> 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.
>
> > 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.

>
> 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


They don't have linux/unix experience either! All of us are Windows
servers/ Cisco infrastructure guys really.

>
> > iii) One method of implementation is to insert a VoIP card into our
> > existing Samsung phone switch and use QoS on our existing
> > infrastructure.

>
> So long as it speaks the same VoIP protocols as the kit at the far end
> [H.323 I'm guessing].
>
> > 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.

>
> That sounds like a fairly sensible idea, but it doesn't tick that
> oh-so-fashionable "convergence" tickbox though


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?

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 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?

> > Would be grateful for pointers.

>
> voip-info.org is a good start, if you want something biased towards
> Asterisk.
>
> --
> <http://ale.cx/> (AIM:troffasky) ((E-Mail Removed))
> 18:46:28 up 23 days, 2:51, 4 users, load average: 0.07, 0.09, 0.05
> This is my BOOOOOOOOOOOOOOOOOOOOOMSTICK


 
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alexd
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Posts: n/a
 
      09-27-2006
(E-Mail Removed) wrote:

>
> alexd wrote:
>> (E-Mail Removed) wrote:
>>
>> > We wish to implement VoIP to (primarily) communicate with overseas
>> > offices,

>> ...
>> > The remote side will be implementing Cisco Express.


>> 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.

>
> They don't have linux/unix experience either! All of us are Windows
> servers/ Cisco infrastructure guys really.


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?

>> > iii) One method of implementation is to insert a VoIP card into our
>> > existing Samsung phone switch and use QoS on our existing
>> > infrastructure.


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.

> 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?


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].

- 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?

- 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.

> 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


Shouldn't be a problem, so long as it's compatible with the phone system at
the far end[s].

> 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?


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.

--
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dilan.weerasinghe@gmail.com
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Posts: n/a
 
      09-28-2006

alexd wrote:
> (E-Mail Removed) wrote:
>
> >
> > alexd wrote:
> >> (E-Mail Removed) wrote:
> >>
> >> > We wish to implement VoIP to (primarily) communicate with overseas
> >> > offices,
> >> ...
> >> > The remote side will be implementing Cisco Express.

>
> >> 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.

> >
> > They don't have linux/unix experience either! All of us are Windows
> > servers/ Cisco infrastructure guys really.

>
> 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?


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).


> >> > iii) One method of implementation is to insert a VoIP card into our
> >> > existing Samsung phone switch and use QoS on our existing
> >> > infrastructure.

>
> 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.
>
> > 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?

>
> 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].


The most we can get out of it is about 0.9 Mbs, I'd say.

> - 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?


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.

> - 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.


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?


> > 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

>
> Shouldn't be a problem, so long as it's compatible with the phone system at
> the far end[s].
>
> > 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?

>
> 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.


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


> <http://ale.cx/> (AIM:troffasky) ((E-Mail Removed))
> 20:06:44 up 32 days, 4:12, 4 users, load average: 0.44, 0.29, 0.31
> This is my BOOOOOOOOOOOOOOOOOOOOOMSTICK


 
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