How Many Devices is Too Many for a Router? [WiFi Dropping Fix]
Most consumer-grade routers are set to assign DHCP IP addresses to connected devices. Most routers will be set to a Class C network, typically 192.168.1.x. There are 254 addresses in a Class C network, including 1 for the router; therefore, a router could be connected simultaneously to up to 253 devices (unless the IP range and subnet mask were modified). The actual connection ability would depend on the router itself. In general, the total session count is limited by the router’s network assignment capability. So 254 devices would be too many.
In terms of stable performance, the number of devices a router can serve depends more on the amount of data being transferred to each device and the capability of the router, and less on the number of devices connected. For example, three users with 5GB connections pushing one or two Terabits of data will be much more impactful on the router’s capability that ten users streaming Netflix or 200 users reading e-mail.
As noted, a consumer home router may be able to handle hundreds of devices — but a Cisco enterprise product that costs multiples more in price, can easily handle a million concurrent connected devices. Remember that the defining factor is not how many clients are connected to the router, it is how much data is being streamed at once between devices via the router.
Can Too Many Devices Cause WiFi Modem/Router to Drop Connections?
Indirectly, having too many devices connected to your WiFi router can cause some devices to lose their connections. But it may not be for obvious reasons.
Having many devices connected to WiFi will not hinder the connection speed very much, but the amount of data exchanged across the devices on that network will affect network stability, speed, and overall performance:
- The more devices that are downloading or transferring data over that WiFi does affect speed of all devices connected to the router. The cause of this slow-down is because the router can only deliver a finite amount of data per second. This amount of data has to be shared amongst all users.
- Interference from other devices or appliances on the same frequency, corrupt or obsolete router firmware, and WiFi limitations itself are other contributing factors to an increase in the number and frequency of dropped device connections.
Why Does the Router WiFi Drop Connections?
Interference. Dropped WiFi connections are sometimes the result of radio frequency interference: the router’s proximity to too many other WiFi routers, or interference from cordless phones and microwaves, etc.
Humidity and obstacles in the home can also interfere with radio signals.
The number of devices on the network itself does not matter if the router can support that many, but if each device requests and sends more data than your router can route, a bottleneck will occur. This is because the router has a limited amount of data it is capable of routing among all connected devices at once.
And, if your Internet connection is faster (can send and receive more data) than your router, you will not be able to enjoy the full speed of your Internet connection. The router will be the bottleneck.
Firmware Bugs. There are some known and some undocumented router firmware weaknesses where the router will drop devices connected to its 5GHz WiFi radio when (what it considers) “too many” devices connect:
“Sometimes there are undocumented bugs in router software. I was supporting a project that had about 300 volunteers on site daily. Our Access Points had an undocumented weakness: if too many devices connected on the 5GHz channel, the software would crash for that AP and no clients could connect, and the existing ones were dropped. Getting the vendor to believe it was happening, wasn’t easy.”
Sometimes routers have buggy firmware and are thus prone to malfunctioning when left to run for too long, or when otherwise pushed past the limits of the often very limited testing done by the manufacturers of those products. When connections drop, restart your router and see if that helps for another day or week.
WiFi Limitations: Congestion is fundamental to WiFi connections. Every device that talks to the same Access Point (often synonymous with your router box) is using the same shared resource: a slice of the radio frequency spectrum which in the case of a router WiFi signal is one of several WiFi channels.
How congestion happens to devices connected via a router:
- Only one device can be actively sending or receiving data on that slice of spectrum at a time; if two try to talk at the same time, then at least one — and probably both — will not successfully reach their target.
- There is no way for the devices to explicitly coordinate when they try to talk. So whenever one device has some data to give to another device, it first listens for a beat to see if anyone else is utilizing the line; if it doesn’t hear anyone, it fires up a connection and sends the data. But if it does hear that the line is in use, it waits for a bit, then tries again. This is called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance).
- The more devices there are speaking the same language (on the same slice of radio spectrum), the longer individual devices will be queued in line waiting their turn. If too many devices are sending and receive heavy amounts of data, the long waits by other connected or listening devices may result in timeouts and dropped connections.
- Check to see how many devices are connected to your router, and disconnect any unknown devices that you are sure are NOT devices in your house (be careful, sometimes you might disconnect security cameras or appliances that need internet connectivity):
Timeouts and the Hidden Node Problem: A related problem likely to occur in a crowded radio channel happens when two devices on a network simultaneously attempt to connect to a third device. Both devices can hear the third device, and the third device can hear both of them, but the two devices both wanting to send data, have not noticed each other. If this happens at just the right (or wrong) time and both try to send at the same time, both will wait a moment, determine that the network is clear, and then attempt again to send at the exact same time. The third device receives both signals from both devices at the same time: a data collision happens, killing either both or one of the signals sent to the third device. This is called the “hidden node problem” and frequently leads to lost frames that must be re-transmitted; and, this also contributes to timeouts and dropped connections.
Degraded Hardware: Another possibility is simply that the router is wearing out. The electronics in a lot of low-cost consumer-grade devices are not robust, and it is common for the radio deck (especially) to drift out of tolerance after only a year or so, especially if your router overheats.
Symptoms of a bad radio are reduced bandwidth due to being off-center, which causes reduced effective power (on transmit) and reduced sensitivity (on receive), both of which lead to lower signal-to-noise ratios. Eventually, the radio stops working entirely. This can also be compounded by congestion-related losses (as described above) to dramatically reduce the effective bandwidth.
- For congestion: Install additional Access Points throughout your home or office and set them to operate on different, non-interfering channels.
- If connections drop with many devices connected, another solution might be to replace the firmware on the router, either by upgrading the firmware (if available from the manufacturer) or an open source firmware like DD-WRT.
- If nothing else works, consider replacing your WiFi router or wiring your devices to your internet access point. But don’t throw away your old router.
Most often the culprit is buggy firmware, especially if the problem started after adding a new device to the network. Consider replacing the manufacturer’s default firmware with OpenWRT or DD-WRT. One user did just that, after his router began to drop connections when he added a ninth device to the network. He reports that since installing OpenWRT the router has run without a forced reboot for two years, and now routinely handles as many as twelve devices without a hiccup [after needing to be rebooted weekly with nine devices connected].
Number of Devices Connected to Router: WiFi vs Ethernet
As with WiFi connections, the number of wired connections will not affect the performance of the router significantly; rather, the more devices actively transferring data at the same time, the slower the network responsiveness.
But Ethernet ports can handle way more bandwidth than can a WiFi radio signal, on an average home router. Yet another reason to wire your Internet and home network, where possible.