Please explain multiple APs, mesh, roaming, handoff, and broadcast frequencies

[snovvman]

Based on a lot of good advice already given here, I am considering implementing several APs in my house rather than using routers like AX86Us as mesh APs. SMB devices are obviously ideal options--Ubiquiti, Omada, and the like. Because I rather have desktop/tabletop APs, there are a few things I would like to better understand:

1) Some say that "mesh" is just a fancy term for a bunch of APs. Is this true? Don't mesh systems for home perform some type of coordination to better serve the clients as they move around?

2) I've read about the concept of "roaming assistant", which I believe is where one mesh node, which signal drops to a threshold, disconnects the client to "help" the client connect with another node--kind of like cellular handoff. Correct?

3) In a mesh network, I presume all the nodes are broadcasting on the same channels?

4) The most important questions: Not using a SMB system, can I use multiple APs, such as the TP-Link TL-WA3001 in the same house to make my own "mesh" network by using the same SSID? Since I do not believe that the 3001s do not coordinate with one another, will I end up with each AP on different channels? And how will roaming and handoff occur? Or, is the answer "you can't" or "you shouldn't", and "go with an SMB that can coordinate or a real mesh system"?

Thanks very much.

 

[tgl]

1) Some say that "mesh" is just a fancy term for a bunch of APs. Is this true? Don't mesh systems for home perform some type of coordination to better serve the clients as they move around?

"Mesh" is a marketing term with no solid technical meaning. IME what it usually means is a combination of wireless backhaul (i.e., only the central node has a wired connection) and single-point configuration (i.e., you do all management from the central node). The nodes might do something to improve roaming (see below) but I don't think that's inherent in the term.

2) I've read about the concept of "roaming assistant", which I believe is where one mesh node, which signal drops to a threshold, disconnects the client to "help" the client connect with another node--kind of like cellular handoff. Correct?

Yeah, what it usually does is boot the client off whichever node it's connected to, and hope that the client will reconnect to a better-chosen node. But the client is always in charge of where it will try to connect, so this doesn't work as well as you might hope.

3) In a mesh network, I presume all the nodes are broadcasting on the same channels?

I think that's typically true. Obviously, the wireless backhaul connections have to be on the same channel, but if the nodes have separate dedicated backhaul radios then in principle they could each use different channels for their client-facing radios. In practice this seems not to happen, perhaps because (a) single-point configuration discourages choosing a different channel per node (obviously you could do it, but it would complicate the GUI which most manufacturers don't want to do), and (b) there's not all that many separate channels available in either the 2.4GHz or 5GHz bands, and the backhaul radios are already eating one.

4) The most important questions: Not using a SMB system, can I use multiple APs, such as the TP-Link TL-WA3001 in the same house to make my own "mesh" network by using the same SSID? Since I do not believe that the 3001s do not coordinate with one another, will I end up with each AP on different channels? And how will roaming and handoff occur? Or, is the answer "you can't" or "you shouldn't", and "go with an SMB that can coordinate or a real mesh system"?

You can absolutely set up multiple non-communicating APs with the same SSID and password (better choose the same WPA level too), and then configure them with the same or different channels as you choose, and your client devices will think that's one network.

What you don't get in that kind of setup is 802.11k/v roaming. The k/v spec extensions allow APs to broadcast information about their neighbor APs that are broadcasting the same SSID, which allows clients that understand this info to make smarter roaming decisions. In practice that results in smoother-but-still-not-absolutely-perfect transitions as a device moves about the premises. (Note it's still the client in charge of its roaming decisions.) For pretty obvious security reasons, manufacturers don't enable k/v except between APs that have reason to trust each other, which in SMB gear normally means that they are being run by the same controller. In consumer mesh gear being part of the same mesh ought to be enough, but you still need to ask questions about whether the gear will do it at all.

802.11k/v is worth having: I noticed distinctly better roaming smoothness with my iPhone when I replaced a non-k/v collection of APs with a k/v-enabled setup. But it's not something that will completely kill you not to have, especially if you're not in the habit of walking around the house while on a wifi call.

 

[snovvman]

Thank you VERY MUCH, @tgl for taking the time to provide all the helpful information!

 

[coxhaus]

Mesh is a redundancy system. It has been changed by consumer router companies to mean wireless backhaul systems. It is no longer a redundancy system because they push the wireless to the limits and use it that way.
It needs to be on the same channel to support redundancy which does not work very well when you push it to the limits of the wireless.
Its kind of has lost its meaning.

Absolutely using wire out of a switch or switches for multiple APs is the best way to go.

I cannot stand not having roaming when I walk around my house especially when I am talking on my phone using WiFi calling which I do every day. Mobile devices are designed to be mobile and they should work that way.

 

[snovvman]

Absolutely using wire out of a switch or switches for multiple APs is the best way to go.

I cannot stand not having roaming when I walk around my house especially when I am talking on my phone using WiFi calling which I do every day. Mobile devices are designed to be mobile and they should work that way.

I've always used "mesh" with a wired backhaul. With multiple APs that are not coordinated , doesn't that make roaming less effective, as it is missing the 802.11k/v, as @tgl pointed out?

 

[coxhaus]

I've always used "mesh" with a wired backhaul. With multiple APs that are not coordinated , doesn't that make roaming less effective, as it is missing the 802.11k/v, as @tgl pointed out?

Yes. Roaming is not related to mesh. Wire or wireless is layer 1.

My guess is if you use Cisco wireless "mesh" then you will still have roaming. I have not tested it.

There are properties that go along with wire or wireless. One of them is wire is run out of a switch. Wireless allows only 1 communication per channel so it is a shared media with lots of latency, not like a fast switch making it much slower than wired.

 

[jaizan]

So assuming I have wired back haul, what exactly would the difference be between:
1 A wired backhaul mesh system
and
2 Two or more routers/APs with the same SSID ?

 

[degrub]

marketing

 

[coxhaus]

So assuming I have wired back haul, what exactly would the difference be between:
1 A wired backhaul mesh system
and
2 Two or more routers/APs with the same SSID ?

I have been pondering this for a while and the best answer I can come up with is if the system is mesh then it is using the same wireless channel. When I was taught networking back 40 years ago mesh was considered a redundant system so the only way I can see that marketing could have coined mesh is to use the same wireless channel. In actually running separate wireless channels works better.

 

[sfx2000]

1) Some say that "mesh" is just a fancy term for a bunch of APs. Is this true? Don't mesh systems for home perform some type of coordination to better serve the clients as they move around?

Some of the mesh systems have a level of coordination across the WLAN - but it's better to look at most of the offerings as AP's with a WiFi distribution system (and sometimes over ethernet).

Some may use a dedicated radio for the backhauls, and that radio may be a private SSID and not available for user devices (for example, this is how Orbi works)

2) I've read about the concept of "roaming assistant", which I believe is where one mesh node, which signal drops to a threshold, disconnects the client to "help" the client connect with another node--kind of like cellular handoff. Correct?

It's usually an action frame at the 802.11 layer, so it's not a disconnect..

It is not the same as Cellular handoffs, but the concept in similar - the key difference is who is really in charge - in 3GPP UMTS, LTE, 5G - the network is absolutely in charge, and the mobile must obey.

In WiFi - the client has a lot more say in the process - so the hints by Roaming Assist are suggestions, not required...

3) In a mesh network, I presume all the nodes are broadcasting on the same channels?

In many, yes, but is not required...

Single Channel and Single SSID does make searching for candidates faster (and there are some hints that can be set in the beacons), and the SSID should be common in any case, as the SSID shows that all of the AP's are in the same set - this is all part of the 802.11 specs there.

Some may prefer to use more that one SSID, and there is nothing to say that's not proper, but handing over from one AP to another, or from one band (2.4) to 5 or even 6GHz will be easier if everyone is on the same SSID - it's a layer 2 handoff, where as different SSID's it has to be a layer 3 with reauthication.

4) The most important questions: Not using a SMB system, can I use multiple APs, such as the TP-Link TL-WA3001 in the same house to make my own "mesh" network by using the same SSID?

Yes, absolutely... a well designed SMB platform with a controller and dedicated AP's over ethernet will offer a lot more flexibility, and generally better performance.

Many of the consumer oriented Mesh platforms hide a lot of the complexity as the typical user is not a wireless or network engineer - so the engineering challenge is to come up with something that "just works", and generally the solutions out there like Orbi, Eero, Google WiFi - they actually do just kind of work - but one does sacrifice some features that folks might prefer...