I have a
Raspberry Pi 3 B+ board and I am trying to connect it both to a local wireless hotspot and another machine via cable. I am not connected to the Internet on any of the devices and all data transfer is local. My question is that do wireless and wired connections affect each other? is their bandwidths seperated or using one, will slow down the other?
I have a
As noted by other answers, the physical mediums are of course separate and do not affect each other.
However, it is a valid question whether they share a common bus in the Raspberry Pi 3 hardware. Infamously, the wired network chip is on the same USB controller as the USB ports, causing bandwidth to be shared with any USB drives connected.
(Image source: shabaz on Element14 forums)
As visible in the block diagram, the 802.11n wireless network chip in the upper left has its own dedicated SDIO bus to the processor. The bandwidth available is thus fully independent of the wired network controller on the right side.
Wired and wireless data transmission are completely different. Wired connections for usual ethernet use electrical signals on the wire, wireless connections use radio waves with modulation on different frequencies, resp. channels. You do not have radio waves on the wire so they are completely independent from each other each with its own bandwidth.
Wired connections normally have 100 MBit or 1 GBit raw data with protocol overhead, wireless connections usually have about 100 MBit but with special technology up to 400 MBit.
The wireless and the cable connections are different media and do not interfere with each other. Therefore, basically saying, each have their own bandwidth and characteristics.
From there on, the operating system you use on the device will have a network stack, likely to respect the OSI model (physical, data, network...). At the network/transport layer, the OS will have a routing protocol to decide which link to use (cable or wireless) based on preference. All this to say that, if you run a simple test, you are likely to notice the bandwidth of only one connection