Wireless network with 6 routers

Question

I have 5 internal Wi-Fi routers (DrayTek Vigor2110n).

These routers are intended to supply Internet connectivity for visitors of the site within the open area, without aloowing access to the internal network. (Please refer to the below diagram.)

The location of the units, as in the diagram below is: 4 routers in the windows of building A and a 5th router located in the building B, which also transmits a signal to the open area.

My suggested configuration is:

1. To configure the routers as APs, with the same SSID.
2. The routers will be connected to a switch, which will assign a dedicated VLAN to them and their wireless clients.
3. Add 2 wireless repeaters (blue circles) in order to strengthen the signal from units 2 and 4.

My questions are:

1. Does this plan look right in general?
2. Will this kind of router able to provide roaming for the wireless clients?
3. Is it possible to assign a VLAN which will give Internet access without access to the internal network?
4. What will happen if there are 70 clients connected to AP number 3 which is physically able to handle a maximum of 50 clients? Will 20 clients automatically migrate to another AP?

Thank you in advance.

Answer 1

Does my suggestion is right in general?

Truth is, there are many ways to create Wireless LANs. But yes, your suggestion will work.

Does this kind of router able to provide a roaming for the clients?

The best way to answer that is by doing more research on test cases where it has worked. In general, you want to setup the SSID to be the same, but the BSSID needs to be the same as well. Some Wireless Access Points support moving from one AP to another. However, this is a Wireless Router, which means each one has it's own brain for making decisions on how to transmit traffic--and typically do not have extra support for WLAN sharing.

Does it possible to assign such VLAN which will give an Internet access without the access to internal network?

Yes, but this is dependent on your LAN Router. If you have VRF on your router, create your own VRF, put the VLAN in there, and make it's only route point to the internet. If you don't, I would create an ACL or access list disallowing that subnet to your other LAN subnets.

What will happen if there are 70 clients connected to AP number 3 which is physically able to handle maximum 50 clients? Will 30 clients automatically migrate to another AP?

Again, this depends on DrayTek. It's best to ask the manufacturer about this configuration if possible.

NOTE that this router does mention a feature called WDS (wireless distribution) as well as Wireless ACLs controlled by the router itself, so you can use that as well to filter traffic.

Answer 2

Does this plan look right in general?

From the scale you gave, it sounds like you won't need one of AP2 or AP3 (or you could move one to the other building), and the wireless repeaters are probably not needed either. I've never used that brand of wireless gear before, but I have trouble imagining a wireless unit that needs a repeater after ~15 meters.

Having too many wireless units in a small area can lead to channel congestion and increase interference, which will actually decrease performance and make the wireless access seem slow. So it will probably be best to install units 1, 4 and 5 first, see how your signal strength is and then probably install either 2 or 3 (but not both). And again, I can't imagine you needing repeaters in such a small space. Even with stock antennas on a normal enterprise AP, I can throw a usable signal almost half a mile across an open space.

Will this kind of router able to provide roaming for the wireless clients?

Need to check with the manufacturer. You're using all the same manufacturer, so I'd think it should work, but them being wireless routers and not actual APs makes it hard to say. On that note, why are you using wireless routers instead of proper APs? Seems like it's going to add unwanted complications into the mix.

Is it possible to assign a VLAN which will give Internet access without access to the internal network?

Absolutely, but that's set on the networking gear in place at the office (into which you'll be plugging these wireless routers/APs).

What will happen if there are 70 clients connected to AP number 3 which is physically able to handle a maximum of 50 clients? Will 20 clients automatically migrate to another AP?

That's actually determined by the client computers. As one AP/router gets more congested, your client devices should prefer a different AP/router, and associate with it instead. You shouldn't see the clients all swamping one AP unless something goes wrong, bu again, clients determine which AP they associate with, and your AP will generally do its best to serve as many clients as try to connect to it.