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I'm wondering if this suspicion should apply to TP-Link wifi range extenders as well as they should be just layer 2 devices. I tried installing OpenWRT on my TP

I'm wondering if this suspicion should apply to TP-Link wifi range extenders as well as they should be just layer 2 devices. I tried installing OpenWRT on my TP-Link extender, everything was supposed to be compatible, but it did not work.

wtallis 2y ago
> TP-Link wifi range extenders as well as they should be just layer 2 devices Nope. Any device that has a wired Ethernet port and an antenna cannot be just a layer 2 device; WiFi is not just a wireless Ethernet. Also, any device that you can ping by IP address and configure over the network rather than over a serial cable is operating above layer 2 for at least the control plane.
- eqvinox 2y ago
  This is not correct, a wifi range extender is a layer 2 forwarder (aka bridge). It does not function as layer 3 forwarder (aka router), only as host, and that host function is theoretically optional. WiFi in fact goes to great lengths to behave as wireless Ethernet, putting all its complexity on layers below carrying Ethernet frames.
  - wtallis 2y ago
    > It does not function as layer 3 forwarder (aka router), only as host, and that host function is theoretically optional. Set aside the theory and look at how any of the real devices are implemented. These devices are all running Linux, and that Linux OS is managing a minimum of two separate NICs with the full software networking stack. They incorporate all of the software complexity of a full-blown router, and none of the simplicity and security/privacy advantages of an unmanaged Ethernet switch which is a purely L2 device. There's no separation of control plane and data plane; no hardware-accelerated forwarding between Ethernet and WiFi to allow packets to skip a trip through the CPU cores. In fact, it is often the case that the only meaningful difference between a consumer WiFi router and a WiFi extender is that the latter omits the Ethernet switch chip and consequently only has one or two Ethernet ports rather than 5+ ports. Presuming that a WiFi extender is less likely to be nefarious than a WiFi router by analogy to a layer 2 unmanaged Ethernet switch (with at most kilobytes of RAM and likely only an 8-bit or 16-bit microcontroller for a processor core) is entirely wrong.

wtallis 2y ago

> TP-Link wifi range extenders as well as they should be just layer 2 devices Nope. Any device that has a wired Ethernet port and an antenna cannot be just a layer 2 device; WiFi is not just a wireless Ethernet. Also, any device that you can ping by IP address and configure over the network rather than over a serial cable is operating above layer 2 for at least the control plane.

eqvinox 2y ago
This is not correct, a wifi range extender is a layer 2 forwarder (aka bridge). It does not function as layer 3 forwarder (aka router), only as host, and that host function is theoretically optional. WiFi in fact goes to great lengths to behave as wireless Ethernet, putting all its complexity on layers below carrying Ethernet frames.
- wtallis 2y ago
  > It does not function as layer 3 forwarder (aka router), only as host, and that host function is theoretically optional. Set aside the theory and look at how any of the real devices are implemented. These devices are all running Linux, and that Linux OS is managing a minimum of two separate NICs with the full software networking stack. They incorporate all of the software complexity of a full-blown router, and none of the simplicity and security/privacy advantages of an unmanaged Ethernet switch which is a purely L2 device. There's no separation of control plane and data plane; no hardware-accelerated forwarding between Ethernet and WiFi to allow packets to skip a trip through the CPU cores. In fact, it is often the case that the only meaningful difference between a consumer WiFi router and a WiFi extender is that the latter omits the Ethernet switch chip and consequently only has one or two Ethernet ports rather than 5+ ports. Presuming that a WiFi extender is less likely to be nefarious than a WiFi router by analogy to a layer 2 unmanaged Ethernet switch (with at most kilobytes of RAM and likely only an 8-bit or 16-bit microcontroller for a processor core) is entirely wrong.