How many users can a single Wi-Fi access point handle at one time? For example, can a single AP handle 100 concurrent users?
The 802.11 protocol can handle 2007 concurrent associations per AP. Note that if you have a simultaneous dual-band AP, it technically counts as two APs for the sake of this limit.
Individual AP implementations may have hard limits or soft/practical limits far below that. For example, if you have WPA or WPA2 enabled, the AP has to keep track of individual per-client encryption keys. The hardware crypto engines in some AP-side Wi-Fi radio chipsets only have hardware support for 50 or 64 keys. Such APs might have a hard limit (when WPA or WPA2 is on) of 50 or 64 clients. If you don't have wireless security enabled, you're not as likely to hit such a low hard limit on clients.
There are plenty of other ways that an underpowered or under-designed AP might not be able to handle the full 2007 client load. There's really no way to know what a given AP can do without testing it or reading it on a technical specifications document.
There are other practical limits like how much bandwidth each client needs. For example, if you were using an old 802.11g 54Mbps AP, and had 100 clients on it, and their average PHY (physical layer signaling) rate was, say, 24 mbps, then each client would only get 240kbps of bandwidth, if that. That's almost as bad as old dial-up modem speeds. Luckily network traffic tends to be "bursty", so not all 100 clients are going to try to do things all at the same time, but still, over time, each client would have much less than 1mbps of bandwidth. You wouldn't want anyone trying to watch videos over a connection like that.
Like others had said. It depends on the device. A lot of home routers with WiFi will not get past 15 or so. Some of the slightly more expensive boxes can get you 35 or more. I have seen 60 to 75 on professional boxes. Most of the low end boxes wont even tell you how many connections you can have at any one time.
As far as DHCP being a limitation this is probably due to having more network devices than the default configuration is set to allow. This however can be changed in almost all cases. Any standard subnet can allow for 250 networked devices. If the default is set to only allow for 25 devices you could run out of available IP addresses. You can either reduce the lease time or increase the pool.
antennas are simply a means of getting an existing signal to propagate in a certain direction/pattern and/or amplify the signal in order to transmit the signal further than other choices. Antennas are used by engineers to create desired signal coverage or a dependable signal at a distance being covered.
That said, I'll add this.... 802.11 wireless is half duplex and that alone creates limitations based on the overhead of the network, i.e. security measures used, types of traffic being placed on the wireless network, number of SSIDs on the network, and of course the modulation type being used by the access point depending on how far away from the access point certain devices are and the power settings of the access point as well.
The best case scenario is to have the access point set to a low power and high data rates only, but most all home access points do not allow this. The connection of multiple devices on a single access point can indeed climb to many many devices but it doesn't mean that they will have an adequate available source of band width to do anything once they are connected.
Going back to half duplex, this actually means that one client device is on a single transmitting radio at any given time. All other devices have to contend for access to the radio, and wait their turn. Of course this happens in micro seconds, but never the less the math adds up quickly when all of the other factors slowly chip away at time.
It takes time to process security, it takes time to send out and process beacons for every SSID on the access point, it takes time to process contention from every client device wanting to be on the network, and it takes time to process modulation types based on which modulation type is being used and that is relative to the RSSI, SNR, and noise floor of the signal.
The further away from the Access Point a device gets, rate shifting occurs and modulation types change. Eventually the "Heartbeat" of the network has to downshift its "Slot time" to the slowest device's slot time used so that contention for the network can continue to be in sync. All devices on the network sync up with the tempo of the slot time of the slowest data rate used by a device on the network.
The math supports that only 12 to 15 client devices utilizing VoIP over wireless can be on a single access point at any given time. VoIP standards require a minimum of -67dB signal received by the device and less than 50 milli-seconds (1/20th of a second) of interruption, and a noise floor of -92dB or less in order to avoid jitter, broken conversation or dropped calls. When more than 15 devices try to contend for the network at the same time, the contention window climbs above a 50 milli-second wait time and calls start getting effected significantly.
Streaming video is based on close to the same standards, yet it mainly depends on the resolution of the video watched. HDTV cuts way down on the amount of other users allowed.
So... What does all of this mean? Deciding what you are going to be using the access point for first helps determine your answer to how many users you can allow. The theoretical number of how many client devices can be on a single access point at any given time is irrelevant unless the actual network is designed and tuned up according to the specs given that will allow for those numbers. Just turning it on and plugging it into the internet will not yield those results.
CWNE, CCNP Wireless
Disclaimer: I am by no means an expert in WIFI signal area, I'm just a normal user trying to find some actionable guidance, and I hope my research based on STFW would give other normal people like me some ideas.
So, there are many different upper limits based on different aspects, and the actual upper limit will obviously be the smallest one of them.
- According to this answer, the 802.11 protocol can handle 2007 concurrent associations per AP. Note that if you have a simultaneous dual-band AP, it technically counts as two APs for the sake of this limit.
- Most consumer-grade home router creates a local network like this 192.168.1.x, which will allow up to 253 devices connecting to such network at the same time.
- Routers also come with a DHCP service to assign IPs to each new device. Default router has different DHCP setting on how much among those 253 IPs can be dynamically assigned. For example, my Arris SBG6580 allows all 253 of them to be used, but my another old Linksys router utilizes only 100 among them (ranging 100 to 199), though it is configurable.
- "Individual AP implementations may have hard limits or soft/practical limits far below that." Anecdote suggests:
For example, if you have WPA or WPA2 enabled, the AP has to keep track of individual per-client encryption keys. The hardware crypto engines in some AP-side Wi-Fi radio chipsets only have hardware support for 50 or 64 keys. Such APs might have a hard limit (when WPA or WPA2 is on) of 50 or 64 clients. If you don't have wireless security enabled, you're not as likely to hit such a low hard limit on clients.
- We don't usually find an official declaration about the limit, but I stumbled upon this Netgear knowledge base web page documents "NETGEAR home routers can accommodate up to 32 clients per wireless band. If your router is dual band, the total wireless clients your router can handle is 64 (32 for the 2.4GHz and 32 for the 5GHz). -- Last Updated:11/28/2016"
So now you have it, the actual upper limit of "how many clients you can connect wirelessly to a home router" is probably close to some 20~30-ish. And you can compare it to the number of devices you have. For example, a small family or a house shared by tenants may have 1 smartphone per member, a couple tablets, some laptops and/or desktops, several smart speakers or TV streaming devices (one per room?), smart switches, WiFi-based home videocam, etc..
The solution is simple. If one router can support 20~30ish clients, we just need to setup 2 (or even more) cascading routers. This is feasible. We don't even need to worry about multiple routers interfere with each other. For one, a normal household will probably need only 2 or 3 at most routers, and you can arrange them in channel 1, 6, 11. For two, I actually witnessed the small apartments in Hong Kong setup their own routers in a very high density, and they seemed to work well.
PS: This answer does not discuss about bandwidth. Because it is a separated issue in its own. Most normal network traffic is in spike, so it is NOT like 10 clients/devices sharing your say 20Mbps ISP plan would each have only 2Mbps speed. Nope. Clients/devices won't affect each other too much. But of course multiple simultaneous 4K video streaming and/or file downloading could be a problem. But then again, "how many concurrent 4k streaming can my ISP data plan handle" is a different question.
In theory what the guys have wrote is correct however, the bottleneck goes to a combination of:
- Wireless antennas used (default ones support around 10-15 simultaneous)
- Wireless dhcp is overloaded (this depends on how many devices connected over all time from last router restart)
What you can do if you have this problem at home is consider buying a longer wireless antenna, or better ask the shop there about the antenna's users capacity.