Let's say I have three incoming internet connections (into the same building), and each one is hooked up to a wireless router. Is it possible for each router to broadcast the same SSID, with the same passwords, and for the computers connecting to these networks to seamlessly switch between them?

No. If a system switched to a different AP, any existing connections would fail to work. That said, if you're not concerned about long-term connections (that is, it's only intended for simple web browsing) it would probably work okay, with only the occasional glitch.

A better solution would probably be to aggregate all of the internet connections with a separate router that can handle that, and then just use the wireless routers as simple APs set up to do normal SSID sharing.

What Bitt said. If each router has its own DHCP server, then roaming is going to be a mess. Open connections will break when you switch routers. If the wireless boxes are just APs, then roaming should just magically work.

The key words to use if you want a router that can do this is "dual wan" or "multiple wan". I've used one of the Xincom routers when I had a cable modem and metro wireless service at home. It let me set my server to run only over the wireless wan connection, and everything else preferred the cable modem. If the cable modem was maxed out or down, connections would start going over the wireless. It offers a lot of various options to get whatever setup you need up and running.

Thanks for the input, guys. I suspected these issues, and wasn't sure how each DHCP server would handle a computer traveling between them. I figured at best it would drop the current connection, so they couldn't stream a movie and walk between floors.

Mostly, I needed confirmation that this wouldn't work so I could convince the client Thanks for the backup!

I was even assuming that you'd have a single DHCP server for the whole setup, and it still won't work then.

Yeah, I wish. I really need to give you some background:

Remember when I was getting help from you guys for designing a network for a building that was going up? Well, we ordered all the equipment, all totaling around 10 grand, but as the building was being completed, Comcast was still dragging their feet on getting us connected.

Long story short, after a month of constantly hounding them (they were well over their promised install date by about 45 days), they came back to tell us that there was a crushed conduit under the street and there was nothing they could do about it. Apparently that was the word from Verizon, and that was that. They canceled our contract and left us holding the $10,000 bag. We have this great network and nothing to connect it to.

After two weeks without TV and internet for 16 college students, which I can't fathom for a generation that grew up on the web, the program director decided to look into wireless as an option.

Currently, there is a Clear modem on each of the four floors of the building (students in three of them). They got three so there would at least be a little more bandwidth to share - about 6Mbps it total for each modem.

This will work for now, while there are 16 students in the building (though it's not great with 1Mbps upload), but there's going to be 25 students this summer and possibly the full capacity of 42 next fall. I'm trying to call everybody I can think of in order to get them a real internet connection in there. I have Verizon trying to sell me a $4,500 ethernet solution, and I suspect they wouldn't be able to get it into the building anyway! Fios was supposed to roll out in DC starting 3 years ago, but due to city politics I'd be surprised if it was in any homes yet.

I'm tearing my hair out over this. It's incredible to me that in a major metropolitan city, we can't get high speed internet. Here's a map of the location. The building is in the middle of that triangle, and while I admit that it's not exactly the center of DC, it takes about two minutes to drive to the heart of the business district of NW DC from there. This is just awful, and I don't seem to have any recourse...

You're going to have to put a single router in front of those wireless connections.

To do it properly with bonding of uplink and downlink, you're going to need the router on your end configured to do it and support from the ISP at the other end.

If you are happy to lock each client machines to a specific wireless interface then you don't need the ISP support. You'll want to force each machine to only use one wireless interface because you don't want connections from a single client coming from multiple public IPs.

Can you get line of sight to somewhere which can get a proper internet connection? I've no idea how much the permits and equipment necessary to do a point to point link for your situation would be though. I'd be guessing more than the 10K that has already been invested into this...

It's a new building? Did they tear down the whole block? Are there any neighbors left? If so, have you asked them what kind of internet access they have?

Nah, I'm just using them as-is, considering it's a temporary connection. I don't care if there are three networks in the building for now, it'll help spread the load anyway. Besides, I'm not sure how I'd do that, as these are modems/routers.


This is what has ended up pissing me off the most about Comcast. When we started everything, they told us there was service on our block (the rest of the block is not new, they just tore down a building right in the middle and built it back up). Sadly, it wasn't until after we found these problems that we went to the neighbors, who told us that they didn't get Comcast because they were told they couldn't get it. They all have DirecTV, and I'm not even sure what they do for internet. DSL, I was told, but I don't know how that's possible with this supposedly crushed conduit...

With Clear, you should definitely make sure you have a conversation with their technical people. I don't know the gory details of how they share their bandwidth, but it's not inconceivable that if you're banging away on all four Clear devices, that they'll each get 1/4 of the nearby base station's bandwidth. Conversely, they may be able to offer you "commercial" grade service at some higher price point, with a single base station from which you can service the whole building.

Meh, it works for now and the hope is that this is temporary anyway. Unless they can offer service at something around 50Mbps, which I don't think Clear's 4G can do, we don't plan on sticking with them.

Can you get line-of-sight to somewhere useful? You could always go with a laser solution. Also, while I've never looked into it, I wonder what it costs you to get yourself a chunk of real spectrum, dedicated to you, in a relatively small area.

Yikes, I don't know. The only buildings on the other blocks are hotels and apartment buildings. I suspect we'd have a hard time working something out with them, but it might be worth a shot...

If you have line of sight to nearby buildings, then perhaps you can use a narrow beam Ethernet radio links to do the inter-building link.

This stuff is often used to link nearby buildings in campus and business districts.

Each antenna is pointed at the other, and both have a very narrow field of view, so they only 'see' each other. Even if other gear in the area is using the exact same frequencies, it won't have much effect on your radio link.

Some of this gear isn't all that expensive, especially if it uses the unlicensed radio bands (some of the same frequencies that WiFi uses, plus some others like 900Mhz).

Essentially you plug an ethernet cable into each box, and the radio link acts link a long ethernet 'extension cord' between the two ends.

Connect one box to the Internet-connects-here port on your building's router, and plug the other radio box into the internet 'source' in the other building.

Maybe something from this site may be of use (as an example, I am sure this sort of thing will be available closer to home for you).