Is it possible to have multiple repeaters in a network with just 1 uniform SSID?

It is certainly possible to do what you ask. As a matter of fact, it is the default configuration for some range extenders, like the Tp-Link TL-WA850RE which I have installed at home. The same SSID is visible all over my house, and you switch seamlessly from one to the other.

Besides, this is the standard configuration which you find in most places large enough to be covered by many repeaters, like schools, universities, many private and public offices. In each of these places there is a unique SSID, and a unique Pre Shared Key (PSK).

I've spent quite some time recently looking into this problem.

There are two topics to consider:

1. What kind of WiFi network does a client see when they try to connect?
2. How do all the routers, access points, repeaters, switches, etc. talk to each other?

Let's start with topic 1:

There seem to be three options:

1. Assign a different SSID to each access point/repater:

   This way, your devices will see completely independent WiFi networks and as you walk around the location, you will need to manually tell the device to switch over to a different network as you get farther from the access point that you are currently connected to and closer to a different one.

   Pros:

   • Easy to set up with any WiFi hardware

   • You have full control over which access point/repeater you are connected to

   • There should be no possible issues (packet loss, etc.) due to auto-switching

   Cons:

   • If you walk away from one access point/repeater, you will eventually loose your connection even if another one is available, and then need to manually remedy the situation

   • Your network will take up a lot of frequency space and, depending on the size, you might end up with a lot of packet collisions

2. Assign the same SSID (and login credentials), but different channels to each access point/repeater:

   Your devices should (if they are built to standard) automatically assume that these different access points/repeaters belong to the same physical network and should automatically switch between channels as needed.

   Pros:

   • Easy to set up with any WiFi hardware

   • Your devices should automatically switch to a closer access point/repeater for a better signal

   Cons:

   • Some devices don't support the automatic switching and you will then need to reconnect to the network to trigger a switch

   • Many of the devices that do support auto-switching will do so only at the very last moment, when they almost lost signal to the other access point (or at least it's rarely configurable at which point they switch), leading to sub-optimal signal levels and thus lower bandwidth

   • In many cases, a switch will result in a short disconnection of the network and potential packet loss, which can interfere with things like VoIP connections or other streaming media

   • You have very little manual control over the time when a switch occurs

   • Your network will take up a lot of frequency space and, depending on the size, you might end up with a lot of packet collisions

3. Set up a system where the access points/repeaters handle all the switching:

   In this setup, there is only "one" network with a single SSID living on a single channel. All access points/repeaters will transmit and receive on the same frequency. The access points/repeaters talk to each other to make sure no packets are "received twice". The access points/repeaters also decide on which one should send packets destined for a device depending on who has the best connection. This way, your devices don't even know that they are talking to different access points/repeaters. They will simply see a strong signal wherever they go.

   Pros:

   • Automatic switching works for ANY client device without the device even knowing about it

   • If the system works well, no short disconnection or downtime should occur and no packets should be lost

   • Should work seamlessly even for VoIP connections, etc.

   • Your network only uses a single frequency range

   • If the access points/repeaters are smart, they can automatically avoid packet collisions (at least for the data they send)

   • Devices are switched over to the closer access point/repeater immediately, making sure that they always have optimal signal strength and thus bandwidth

   Cons:

   • Requires specialized hardware, but this is actually available for cheap now (see below)

   • You have no manual control over the timing of a switch, but since the system tries to guarantee no packet loss and no downtime, this shouldn't matter

   • Since your network only lives in one frequency range, you don't get the extra bandwidth available from using multiple frequency ranges, but this is only relevant for networks with tons of clients and traffic and can be remedied, for example, by having more access points and reducing their individual signal strength

Not sure if it's obvious yet, but I would DEFINITELY advocate option 3 over the other two by a landslide.

There should be several hardware choices out there (I believe EnGenius for example makes one*), but the one I went with is the UniFi line by Ubiquity Networks (I'm not affiliated in any way with them other than being a very happy customer).

They sell several different types of access points that support different WiFi standards (b/g/n, ac) and are meant for either indoor or outdoor use. The ones I use are the UniFi AP LR (the indoor long range b/g/n version), which sells for less than $90 these days (the non-long-range version even goes for only around $65).

If you install the beta-release of their (free) controller software (which I've found to be very stable already), the access points will communicate with each other to handle the automatic device switching to implement what they call "Zero Handoff Roaming". And it works fantastically*. I can watch in the controller as other clients are being passed between APs while maintaining perfectly fluid skype calls, etc. And the clients are entirely unaware of what is happening. All they see is a single wireless network with perfect signal anywhere.

BTW: The controller software is only needed to configure the APs and update their firmware. Once the system is up and running, you can shut down the software and everything still works. So you don't need any other dedicated hardware to implement this system, just a bunch of APs sprinkled across your site.

Now, to topic 2 from the very beginning, i.e. how to have the APs/repeaters talk to each other:

There are two options here:

1. Wired

2. Wireless

The Pros and Cons should be obvious: Wired is faster, more reliable, and probably more secure, but it might not be feasible because it involves running wires... So, choose it if you can and go wireless if you have to.

Luckily, the UniFi APs also support both modes*. For the initial configuration, you need to hook them up to a wire once to provision them, but then you can tell all but one of them to simply up-link wirelessly to their nearest neighbor, unplug them from the network and move them to their final location. Note: I have NOT tried this yet, so I don't know how well it works. Also, I don't know if the system supports multiple hops or if each AP using a wireless uplink needs to be close to an AP that is wired.

Note also: I've only tested their system in a fairly small network (3 APs with around 20 devices). In this setup, it works beautifully and provides much better stability and performance than our previous setup. But the v3 software (which is needed for zero handoff to work) IS still in beta and officially not recommended for production use. Maybe a different manufacturer has a solution that is no longer in beta already... Not sure.

*UPDATE:

A couple of things I researched over the weekend:

• The EnGenius WiFi APs do not seem to offer zero-handoff (or any equivalent). So far, the only ones I've come across are the UniFi APs, but there probably are other solutions out there.
• Zero-handoff only seems to be supported with b/g/n-networks so far and not ac, i.e. no support yet for the UAP-AC (I have NOT tried this).
• The UniFi APs do not support zero-handoff and wireless uplinks at the same time (I tried it and it says so here). So, if you'd like to use zero-handoff with these units, you must connect all of your APs with a wire. Maybe, in the distant future, both features will be available simultaneously, but I haven't found any indication that this is even on their road-map, so I wouldn't wait for it.

You can run into issues with setup like this. I have router and 3 extenders. The side effect is that the extender might not always take the router as source and can therefor end up being not functional or running at low performance. In my case it was connecting like this:

Router -> extender -> extender -> extender This resulted in very bad performance for the last router in the chain.

Also when i had a power drop the extenders only connected to to other extenders (none of them connected to the router leaving them not working.

To fix the issues above i enabled to SSID's on the router my main SSID and a hidden SSID just for the extenders. The extenders will connect to the hidden SSID making sure they only connect to the router not other extender but the extenders is still broadcasting the main SSID. I would recommend configuring wireless channel on the router and extenders to avoid that they switch.

As Markus said there is no zero handoff between the devices and you might get drops when they switch over but for me it's hardly noticeable and fully works for my need.

First of all, use Access Points and connect them to your switch. Then, when you install your AP's, make sure that they are located af far as possible with low intersection zones (intersection zones should be there to avoid loosing the signal, but should not be large). Then, configure each AP to use different frequency and make sure that frequencies don't repeat (AP1 with Freq.x intersects with AP2 with Freq.y, and AP2 intersects with AP3 Freq.z and AP3 intersects with AP4 with Freq.x) Set all AP's with the same SSID. Read Google about setting your frequencies; there are really only 3 options there and it is must know information. IMHO very important thing to know.

A detailed answer to original question was already provided by Markus A. However in his answer a keyword is missing, which currently describes the option (3) of 1st topic in the answer : "Mesh" https://en.wikipedia.org/wiki/Wireless_mesh_network

Currently even cheap Routers and WLAN-Repeaters (i.e. TP-LINK RE305) are supporting the Mesh-Mode. Unfortunately the suppliers have different implementation of Mesh functionality, so Fritz!Repeater would not support Mesh mode of TP-Link Router and vice versa. I think in close future it will be improved, but currently you need to plan - which HW-supplier is more suitable for you. Some suppliers (like Netgear) are making repeaters supporting also mesh mode from other suppliers, but such HW might cost more than a replacement from a single "cheap supplier".

So if someone likes to organize a single "joined" network as described in the question above - the fastest and cheapest way would be to get a WLAN Router and compatible Repeater(s) supporting same Mesh mode.