Edit: Wireless Access Points, not Modems
I read some time ago that overlapping interference is a lot worse so all modems should use either 1, 6, or 11. But I see a lot of modems in my neighbourhood using all the channels from 1-11, causing an overlapping nightmare. Why do modem manufacturers allow overlapping to happen in the first place?
Edit: To clarify my question, some countries allow use of all channels and some don’t. This means some countries’ optimal channels are 1, 5, 9, 13, while other countries’ optimal channels are 1, 6, 11. Whichever the case, in those specific countries, all modems manufactured should be hard limited to use those optimal channels only. But modems can use any channel and cause overlapping interference. I just don’t understand why modems manufacturers allow overlapping to happen in the first place. The manufacturers, of all people, should know that overlapping is worse than same channel interference…
To add a scenario, in a street of houses closely placed, it would be ideal for modems to use 1, 6, 11. So the first house on the street use channel 1, second house over use channel 6, next house over use channel 11, next house use channel 1, and so on. But somewhere in between house channel 1 and 6, someone uses channel 3. This introduces overlapping interference for all the 3 houses that use channels 1, 3, 6. In this case, the modem manufacturer should hard limit the modems to only use 1, 6, 11 to prevent this overlapping to happen in the first place. But they are manufactured to be able to use any channel and cause the overlap to happen. Why? This is what I am most confused about.
In: Technology
I’ll add here that modems (as they’re used in the Internet access sense) are not WiFi devices (however, WiFi must necessarily have modulation and demodulation as part of the signal path).
The box your ISP provided that you’re referring to as a modem is actually several devices inside a single box:
the modem that connects to your ISP’s circuit allows interfacing between the ISP’s circuit and the router, as they have different physical layer connections.
The router operates at the network layer and its job is to move Internet traffic between your network and your ISP’s network.
The router then connects to an Ethernet switch, which is the foundation of your local area network, or LAN. In addition to a couple of internal ports for the router and the access point (more on that in a second), it also usually has a handful of external ports to connect various network devices.
Then you have your Wi-Fi Access Point – this acts as a bridge that translates the data link layer between Wi-Fi and Ethernet. In a wireless network, the “physical” layer consists of radio waves (I know, they don’t seem very physical, but physics play a huge part here).
Networking is generally referred to in “layers” like a burrito. A theoretical model is the ISO model, which is 7 layers. The TCP/IP model is more practical and consists of 4 layers. Each layer fits inside the data payload of the layer below it.
The Physical Layer (1) consists of bits – 1s and 0s. This can be electrical signals on a wire, electromagnetic radio waves (wireless), or electromagnetic pulses of light (optical). This could even be smoke signals or acoustic waves if you got crazy enough. This is the tortilla – it holds the burrito together.
The Data Link Layer (2) adds structure to those 1s and 0s by defining how a link carries data. This can be Ethernet, Bluetooth, Wi-Fi, or a variety of other ways of transporting data.
layers 1/2 in the ISO model correspond to the single Network Access layer in the TCP/IP model.
The Network layer (3) is where interesting stuff starts to happen – this defines specific ways devices on the network talk to each other. This is where IP lives. TCP/IP calls this the Internet Layer.
layers 4-7 deal with the actual user data being sent over the network. This is stuff like HTTP and all the other stuff you do on the internet. TCP/IP model calls this the Application Layer.
So your internet traffic operates at layer 3, and between you and the server, it goes over a whole variety of layer 1 and layer 2 connections to get there.
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