Networking advice

[Kanwar Ranbir Sandhu]

On Sat, 2005-22-01 at 13:47 -0800, Nifty Hat Mitch wrote:
> Since they want to put in Asterisk soon to replace the
> > old, existing PBX, any tenant not connected to the local LAN will not
> > have access to the PBX.
> 
> Ouch...

Yeah, I'll say.  This is one thing that I very clearly understand. They
should have planned at least 2 runs to each office, but then I didn't
know the owner at that time: the business centre only opened up in
September 2004.  I moved in on the first of this month.

> > Any tenants plugged into the first HUB/Switch (in order to receive one
> > of the public IPs) in your diagram won't be able to use Asterisk, which
> > would be located behind the firewall....

[snip]
> It is clear that you will need a serious managed router/ switch at some
> point in the future.  You will need bandwidth for the PBX equivalent
> as well as bandwidth for generic TCP/IP.  

Yes.  It's why I've been considering that a layer 3 switch should be
made a part of the solution right from the beginning.

> I have never seen an 'office'
> with a single phone line: Main line, private line, fax, answering
> machine.
> I think the part that is most unclear to me is "What a tenant is".

Perhaps I should explain what a business centre is.  Instead of
purchasing or leasing office space at a considerable cost (in this area,
generally starting at CDN$18,000/yr to lease), business centres offer
the chance to license an office on a month-to-month basis (or yearly,
but that's up to you).  There is no lease tying you down for 3, 5 or
more years.  

Business centres also provide other services, such as a shared
receptionist to answer phones and greet your clients, shared fax line,
photo copiers, kitchens, shared conference rooms (with projectors etc.),
fully furnished offices and so on.  This saves the individual businesses
in the business centre a ton of start up and recurring costs.

So the "tenants" in this case are all separate businesses, all working
out of the same building.  Every business has the same physical mailing
address, but individual telephone numbers (fax is shared and available,
if required).

This is why Leonard suggested that it is important to partition the
network.  Each business should be on its own separate network.

> You should be able to bootstrap things with a good multiport hub and a
> linux box as a firewall+NAT+proxy+squid network management resource
> but if you have only one link into each office you will need
> eventually high bit rates and a small but possibly smart hub in each
> office.

Right now the network seems fine.  The only foreseeable problem is the
Internet link, but that can be easily upgraded.  

I don't think the business centre will have to worry about moving from a
100 Mbps to 1000 Mbps LAN for a long time, if ever.  A good layer 3
switch will be able to handle QoS, so when Asterisk gets thrown in,
priority for SIP can at least be provided.

> Of interest the old phone line wires may be usefull for some low speed
> IP traffic.

I've been wondering if they used Cat5 for the phone lines.  Easy enough
to find out.

In any case, I wouldn't have even bothered delving into proposing a
network upgrade if I didn't need to host servers.  As it is, I have to,
and I want to stay in that office, so an upgrade is necessary.  The cool
part is that not only will my small business benefit, but the business
centre owner will be able to offer additional and improved services to
his clients.

It's a good thing that he's interested.  He's just waiting for me to
tell him what the plan is and how much it's going to cost.

Regards,

Ranbir

-- 
Kanwar Ranbir Sandhu
Linux Consultant
Systems Aligned Inc.
www.systemsaligned.com