RCN's website has a document that states: 'most routers will slow down to the speed of your slowest device' (link, FAQ #1). Assuming this is true, how does a home user figure out whether and which device is slowing down the router (or whether the router itself is to blame for slower-than-advertised speeds)?
Given a generic network setup:
- Connection from wall (e.g., Cable, Fiber, DSL) with some promised speed (e.g., 25Mbps down, 5Mbps up), connected via coax, fiber, or phone line to
- Modem (or ONT), connected via ethernet cable (Cat 5e) to
- Wi-Fi Router, connected via ethernet cable (Cat 5e) or Wi-Fi to
- Device(s) - e.g., phone, smart speaker, TV, printer, game system, security cam, etc.
There are three connections that matter:
- ISP to modem
- modem to router
- router to device(s)
ISP to Modem Test:
Test the modem's wired speed by connecting a laptop directly to the modem via ethernet cable (good luck finding a laptop that still has an ethernet port! If connecting via usb-ethernet dongle, may be dependent on USB port or dongle speeds.). Run internet speed tests on the wired modem connection. Call this speed 1.
Modem to Router (Wired) Test:
Test the router's wired speed by connecting a laptop directly to the router via ethernet, and router to modem via ethernet cable. Run internet speed tests on the wired router connection (max = speed 1). Call this speed 2. If speed 2 is a lot slower than speed 1, then the router is to blame?
Router to Device (Wi-Fi) Test:
Finally, test the connection speed of a device that is wirelessly connected to the router (max = lower of speeds 1 and 2). Call this speed 3. If speed 1 and 2 are basically the same, and speed 3 is a lot slower than speed 2, then either the router's wifi or the device is to blame? Some devices you can't check directly (e.g., how do you test a printer, tv, or smart speaker's connection speed?) The best I can think of is testing the speed of a laptop connected to the network while the other device (printer, tv, speaker) is connected?
Switch which device is wirelessly connected to the router and re-test.
Switch a wireless device (e.g., printer) to wired connection and re-test.
Turn off all the Wi-Fi devices and then only connect one at a time to the network and test speeds. e.g., laptop + phone 1, laptop + speaker, laptop + printer, etc. (is this even worth the effort?)
Is there a programmatic way to test the connection speed of each of the devices that are connected to the router?
Is there some way to figure out whether your wireless router is limited to slower speeds and that upgrading to a different router would result in faster speeds, without going out and buying a new router, installing it, activating it (typically a lengthy and time-consuming ISP phone call), and speed testing it?