Question : Cisco 1841 - VLAN and Broadband Internet

We were contacted by a client of ours to provide the following solution:

A large office building will be divided in to smaller offices for businesses. He wants to use a single internet connection and share it with up to 15 tenants (seperate networks), without them being able to access each others networks. The separate networks need to be secure from security threats from with in the building and from external threats via the internet.

We originally looked at using the Cisco 1711 but the Cisco tech support recommended the Cisco 1841. I cannot find any documentation online that says how many VLAN's the 1841 will support .

I also need to know if the 1841 that supports DSL/Cable modem internet connections because I do not believe the client is ready to purchase a T1 at this time since the offices will not be filled immediately. Do I need an expansion card to support this?

Thanks in advance to everyone for your help.

Answer : Cisco 1841 - VLAN and Broadband Internet

Depending on budget, you might consider getting a Catalyst 3550 or 3750 switch - they support more than enough VLANs (>1000, something like 1008 or 1024?), & up to 48 ports on both models.  This way, all you need is a router that supports DSL, & your internal network can be subdivided into many VLANs, & the layer 3 switch can be configured to block traffic wherever necessary, while still allowing the individual VLANs to access the Internet.
  I've setup a 3550 in the past for just this type of scenario: internally there were >18 separate businesses in an office building, each with their own VLAN, & they weren't allowed to access anything in their neighbor's subnets, but they were able to access the Internet.  If budget permits, I highly recommend getting a switch with the "EMI" software image, which supports the EIGRP routing protocol - vastly superior to RIP & is scales quite well.  A layer 3 switch will also allow you to do such things as QoS directly on the switch, without having to make your border router do all the work; with a "shared bandwidth" environment such as this, being able to do it directly on your switch is a major plus.

cheers