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I have a warehouse that I want to cover with WiFi. My thoughts are to use some kind of WDS (repeaters). WDS is a common feature now in many SOHO routers. In the end the warehouse will be split in cells, each cell cover by a WiFi repeater.

My problem is that I will have clients with tablets walking across the warehouse. What is going to happen when the tablet moves from one cell to another? Would this have impact over my client-server application? Are there other options I should consider?

Chris S
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garzanti
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    `"Would this have impact over my client-server application?"` I'd say that's impossible to answer, considering you haven't told us a thing about the application. – MDMarra Nov 15 '11 at 20:55
  • @MarkM You are right it depends from application to application, some recover on link-loss some not. The warehouse manager will have a tablet and using some webforms from an intranet webserver, fills some data. – garzanti Nov 15 '11 at 21:58
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    If its just HTTP, then it should be pretty resilient. – MDMarra Nov 15 '11 at 22:16

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Considering that most warehouses I've supplied IT services into are full of metal racking, all kinds of goods and badly shielded power lines, I don't think that a wireless mesh would make me super happy if reliability was important and I certainly wouldn't be looking at the sort of... uh, under-specified shall we say... wireless implementations that appear in most SOHO routers if I wanted to implement WDS and count on it working because my users were trying to do stock control with it, not just read their email and dilbert on the move.

I'd look at a more formal wireless "mesh" system with wired access points - you have to run cable of some kind to every place you want a wireless access point because you need to power the SOHO box, so why not run a network cable instead. and use decent wireless access points that support POE?

-- edit to address comment --

I assume by a wireless mesh (and you mention WDS) you're talking about access points that act as both local access points to their area and repeaters to spread to signal to other wireless access points? With only the access points at some of the "edges" connected to the wired network?

When I talk about a mesh system I'm thinking more about systems like the aruba / trapeze (who have apparently been purchased by juniper since I last looked, hmm...) / meru (& other vendors are out there too) system where, yes, you have an ethernet backbone with WAPs connected to it with some kind of centralised management system (most of them use a dedicated "wireless controller" appliance) to handle how the WAPs integrate with each other & any authentication system you implement to provide good coverage and seamlessly hand off client devices to each other as the user walks around.

I've implemented both the aruba and trapeze systems campus wide in education (large indoor sports halls are like warehouses in terms of delivering wired and wireless services, without the racking issue but with the added problem of people hitting the WAPs with balls or whatever in the course of sporting events), and advised / helped people implement them in business areas, including warehouses. These sorts of implementations are obviously more expensive than a bunch of SOHO WAPs, but if "works reliably" is more important than "doesn't cost much" then its money well spent.

Rob Moir
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    Maybe the "mesh" word is not technically correct, this is how I saw it. So, your suggestion would be to start thinking for an ethernet back-bone, and to place WAPs where is need it. – garzanti Nov 15 '11 at 22:05
  • @garzanti - started to type in a long reply here and realised it would be too long, so edited the answer to address your comment. – Rob Moir Nov 15 '11 at 22:32
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You've got two options:

  1. Cheap SOHO routers with WDS. When users switch form one WAP to the next they'll lose any active connections they have going. Some application can recover gracefully, others not so much.
  2. Get WAPs that can coordinate to gracefully roam clients from one AP to the next. These aren't nearly as cheap and are more complicated to configure and install. These units usually require some sort of central coordination unit or gateway; but not all implementations.
Chris S
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Please see great answer to this question in this post: https://superuser.com/questions/122441/multiple-access-points-for-the-same-ssid

Generally it is not true that you need some great intelligence behind the multiple AP network. You just need to have them configured the same way except for channel and make sure you are running only one DHCP server across the network (so disable built-in DHCP server in all AP except one if you have no dedicated DHCP server on the network)

Switching between APs is seamless and at most you can experience 1 packet loss. I'm sure this is not going to break any established connection. I've got this type of configuration setup at home with two APs (same SSID, encryption type and password) and I enjoy full wireless signal in every room.

Generally I suggest running ethernet connection from POE enabled switch to POE enables APs across the warehouse which I believe will greatly improve performance in comparison to WDS. If performance isnt the main goal and you just need wifi coverage then WDS solution would be easier and cheaper.

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ne7runner
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    +1 but... While that answer is good in theory, and would work well in practice for smaller deployments, I find it works badly if you have to have lots of WAPs in a relatively small geographic area, which is quite possible in a warehouse environment because of all the stuff you find in it (see MRC's comment/answer - they've nailed the issue I would worry about). With the greatest of respect, there's a big difference between providing wireless support in a warehouse environment for a business and providing wireless support in a home. – Rob Moir Nov 15 '11 at 22:59
  • @Robert, you are right and possibly I was to hasty with suggestions. My understanding was this network would be to support few people with tablets as garzanti described it so just wanted to give him an option if he would like running into rather big and expensive project. – ne7runner Nov 17 '11 at 21:47
  • This doesn't work in even the simplest of setups. Devices will connect to the first AP they encounter and not let go until the device can no longer hear the AP. What they want is roaming or hand-off, going base station to base station as they move through the building, maximising performance. A great way to experience this problem first-hand is to go to a hotel. In almost every hotel they deploy uncoordinated APs in the building and it is very annoying when combined with a crappy authentication system. – Cameron Lowell Palmer May 03 '17 at 14:13
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802.11k, 802.11r and 802.11v

The specific technologies you're looking for in a Wi-Fi system are 802.11k, 802.11r, and 802.11v. Professional grade systems offer it. Clients must also support this technology and Apple's iOS is an example of a client device that does. A demonstration video is available on Cisco's blog called Wi-Fi Roaming 101 that demos a model train they step up with 4 access points and compare their implementation with a competitors.

In the land of consumer grade equipment I know Eero supports 802.11r.

Cameron Lowell Palmer
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