Every owner of a modern router has experienced at least one situation: the internet is lightning fast in the morning, but by evening, when the whole family is home, video conferences turn into slide shows. This isn't magic or a trick of the ISP, but a fundamental principle of wireless network operation based on resource sharing.
Imagine your internet connection as a wide pipe carrying water (data). When the tap is open for just one person, the pressure is at its maximum. But if several more taps are opened at once, the pressure in the system inevitably drops, and each person receives only a portion of the flow.
However, in the world Wi-Fi It's a bit more complicated than simply dividing bandwidth. Time factors and the physical limitations of the radio channel, which can't transmit all the data to all devices simultaneously, come into play. Understanding these mechanics will help you configure your equipment correctly and avoid annoying delays.
Time-sharing principle and throughput
The main reason for the drop in speed is technology. TDM (Time Division Multiplexing) is a term used to describe time-division multiplexing. A router is unable to transmit data packets to all connected devices simultaneously at maximum speed; instead, it switches between them at a tremendous, but finite, rate.
When one device starts downloading a large file or watching a 4K video, it takes up the lion's share of the airtime. Other devices have to wait their turn, which is visually perceived as a sharp drop in response time or buffering.
⚠️ Attention: Wireless interface bandwidth is always divided by the number of active users. If your ISP plan offers 100 Mbps and you have 10 devices actively consuming traffic connected to the router, ideally each device will only receive about 10 Mbps, but in reality, the numbers will be lower due to overhead.
The situation is exacerbated by the fact that modern routers, even dual-band ones, have limitations in how much the processor can process requests. As the number of clients increases, the load on CPU router bandwidth increases exponentially, resulting in increased ping and packet loss.
Factors Affecting Connection Stability
The number of users isn't the only enemy of speed. The type of traffic and the communication standards your equipment supports also play a significant role. Older devices can slow down the entire network, forcing the router to switch to slower data transfer protocols.
Frequency range is also critical. In a congested airwaves with dozens of neighboring networks, each new connected client adds noise and competition for available channels. This is especially true for the 2.4 GHz band.
- 📡 Airtime congestion: The more neighboring networks there are around, the more difficult it is for the router to find clear time to transmit data to your devices.
- 💻 Type of activity: One device downloading torrents can paralyze the work of ten others simply scrolling through social media feeds.
- 📶 Signal level: Devices located far from the router transmit data more slowly, taking up more airtime than devices located nearby.
It is important to take into account channel widthSetting the 2.4 GHz band to 40 MHz will increase the speed for a single device, but will significantly reduce the stability of the entire network in an apartment building due to interference with neighboring devices.
The difference between the 2.4 GHz and 5 GHz bands
Modern routers are often dual-band, and distributing users between the 2.4 GHz and 5 GHz frequencies is key to network survival with a large number of connections.
Range 2.4 GHz It has excellent penetration, but it's extremely narrow and congested. It has only three non-overlapping channels. When you connect multiple devices here, they start to interfere with each other, creating a "traffic jam" effect.
Range 5 GHz Offers significantly more available channels and higher throughput. It handles multiple connections better because it can transfer more data per unit of time, minimizing request queues.
| Characteristic | 2.4 GHz band | 5 GHz band |
|---|---|---|
| Penetration ability | High (breaks through walls) | Low (walls muffle the signal) |
| Maximum speed | Up to 300-450 Mbps (actually less) | Up to 1300 Mbps and higher |
| Number of channels | 3 non-overlapping | Up to 25 non-overlapping |
| Susceptibility to interference | High (microwaves, Bluetooth) | Low |
For maximum efficiency, it is recommended to switch all devices that support 5 GHz (smartphones, laptops, TV set-top boxes) to this frequency, leaving only older equipment and smart home devices that consume little traffic in 2.4 GHz.
MU-MIMO and OFDMA Technologies: A Smart Home Rescue
If you have more than 10-15 active devices in your home, older routers will start to choke. Modern technologies like MU-MIMO (Multi-User Multiple Input Multiple Output) and OFDMA (Orthogonal Frequency-Division Multiple Access).
Traditional routers use SU-MIMO technology, which allows them to communicate with only one device at a time, albeit very quickly. MU-MIMO Allows the router to transmit data to multiple devices simultaneously using different antennas.
What is the difference between MU-MIMO and OFDMA?
MU-MIMO allows data to be transmitted to multiple devices simultaneously using spatial streams. OFDMA, on the other hand, divides a single transmission channel into smaller subchannels, allowing small data packets (such as instant messaging messages) to be transmitted to multiple devices in a single transmission cycle, dramatically reducing latency.
Technology OFDMA, which comes from the Wi-Fi 6 standard, is even more efficient. It allows the transmission channel to be broken down into smaller chunks and data to be sent to different clients within a single time slot. This is ideal for scenarios where many devices send small amounts of data (smart light bulbs, sensors, phone notifications).
⚠️ Attention: For MU-MIMO and OFDMA to work, both the router and the client device (smartphone or laptop) must support these technologies. If the router is new and the phone is old, the connection will use older, less efficient protocols.
How to optimize a network with a large number of users
As the number of devices grows, it's necessary to move from passive monitoring to active equipment configuration. The first step should always be an audit of connected devices and bandwidth limitation for non-core traffic.
Many modern routers allow you to configure QoS (Quality of Service). This feature prioritizes certain types of traffic. For example, you can tell the router that video calls or online games are more important than background app updates or file downloads.
- 🚀 QoS settings: Give maximum priority to work devices or gaming consoles.
- 🔒 Guest network: Separate guest devices into a separate network with speed limits so that they do not interfere with the main channel.
- 🔄 Firmware update: Manufacturers frequently release patches that improve stability when working with multiple clients.
It's also worth considering installing a mesh system. Unlike simple repeaters, which cut speeds in half, mesh systems create a single, seamless network, intelligently distributing the load between nodes and clients.
☑️ Network optimization check
When is it time to change equipment?
There's a limit beyond which software settings become ineffective. If your router was purchased 5-7 years ago, its hardware simply isn't designed to handle the 20+ devices typical in the average home today.
Signs that the router can't handle the number of users include not only a drop in speed, but also periodic connection breaks, the need to reboot the device once a day, and the case becoming very hot even when idle.
The modern Wi-Fi 6 (802.11ax) standard can effectively handle up to 200-250 connected devices simultaneously without a critical drop in performance, while older standards began to choke after just 15-20 active clients.
When choosing new equipment, pay attention not only to the stated speed (AC1200, AX3000), but also to the RAM capacity and processor power. These parameters determine how many simultaneous connections the device can handle without freezing.
The Impact of Background Processes and Smart Devices
Users often forget that a smart home consists of dozens of devices. Light bulbs, outlets, vacuum cleaners, and speakers constantly exchange data with manufacturers' servers. Although each device consumes little bandwidth, their combined number creates a constant background noise.
Moreover, smartphone and computer operating systems tend to update when you least expect it. Background photo syncing to the cloud or downloading Windows updates can silently eat up your bandwidth.
⚠️ Attention: Router settings interfaces and provider mobile apps frequently change. If you can't find the features described (QoS, device prioritization), check the official manual for your specific model or the software version in your personal account.
To diagnose such issues, use your router's built-in traffic monitors. They'll show you which device is consuming the most data right now, allowing you to quickly identify the culprit.
Why might a smart light bulb slow down the internet?
A light bulb itself consumes negligible power. But if there are 50 of them, all trying to send a status report or receive a command at the same time, and the router is old and can't properly queue them (bufferbloat), then data packets are lost, and the internet lags on all devices.
How many devices can a typical router support?
Theoretically, up to 255, as this is a DHCP protocol limitation. However, in practice, budget models begin to operate unstable after only 10-15 active devices. Mid-range models support 30-50 connections, while high-end Wi-Fi 6 models support over 100.
Why does the speed drop even if no one is downloading?
Even when idle, devices exchange service packets, check email, and update widgets. With a large number of clients, these small requests create a queue, increasing ping (latency), which is felt as lag in games and video calls.
Will a signal booster (repeater) help under heavy load?
More likely no than yes. Cheap repeaters often cut speeds in half and create additional competition for airtime. If you have a large number of users, it's better to buy a powerful router or mesh system rather than a repeater.
Does the antenna type affect the number of connections?
The number of antennas affects signal stability and MIMO support, but not the router's processing power. Multiple antennas won't help if the device's processor is weak and can't handle requests from dozens of clients.
What is AirTime Fairness and should it be enabled?
This feature limits the amount of time a slow device can spend on the air. This protects fast devices from being slowed down by older devices. It's recommended to enable this feature if you have a variety of devices on your network.