Networking advice

[ranbir sandhu]

Hi all,

I'm not a networking expert or even "the network guy",
and thus I am running into a problem figuring out how
to improve the network at my new office.

The business centre I'm in is sharing a DSL connection
with one dynamic IP between 19 tenants (simple
Linksys/Dlink type of router).  Besides the obvious
security problems, this makes it very difficult for
tenants to host their own servers, including me.

Along with changing the ISP to one that can provide
static IPs, here's what I'm thinking of suggesting:

Internet --> DSL Modem --> Hub/Switch
                           |        |
                        Router1   Router2
                          |          |
                        Switch      Tenant
                          |           That
                        Tenants      Cares
                         That
                      Don't Care

Router1 would have a static IP.  Like it says, tenants
that want a simple Internet connection would
essentially receive the same service they have now.

Router2 would be assigned another static IP. 
Additional tenants could easily be accommodated with
more static IPs and routers.  Firewalls etc. would be
the responsibility of the tenant.

The obvious problem with this is that if a simple
switch or even a hub is used after the DSL modem, the
business centre won't be able to control the traffic
(i.e. prioritize and/or control bandwidth use).  One
tenant could use up the entire pipe, for example.

I've considered dropping in a machine running mOnOwall
to help solve the traffic shaping issue. Also, I've
read that mOnOwall can transparently firewall/bridge:
this would make it very easy to assign static IPs to
those that want them. But, I don't know how many
routes it can accomodate.

Is the above approach a good one? How else would
something like this be handled? 

Incidentally, I've spent quite a bit of time reading
up on layer 2/3 switches, VLANs etc., but I still
haven't figured out if plugging the modem directly
into a switch is the right thing to do.

Thanks in advance for any tips.

Regards,

Ranbir
Linux Consultant
Systems Aligned Inc.
www.systemsaligned.com