Do network adapters read incoming bits in a single stream?

Question

When a Gigabit network adapter is receiving data, how is it receiving the bits? Is it seeing it all in one stream of 0's and 1's? Or is there somehow multiple streams of 0's and 1's coming in at the same time? For example... let's say there's two sending devices and one receiving device. Devices 1 and 2 start sending network data to Device 3 at the same time. My assumption is that from Device 3's Network adapter's point of view, all the 0's and 1's are coming across in a single stream of data. It can figure out what data is from Device 1 or 2, but the data is still just one stream of millions/billions of bits. Am i totally wrong? :)

Answer 1

I think I may be able to answer your question in a certain sense. The 1s and 0s you describe are represented by, in the case of your gigabit ethernet port, electrical signals. However, those 1s and 0s, at a higher level of abstraction are organized into ethernet frames. When you are connected to an ethernet switch, the switch does not send 1s and 0s randomly from various sources to your machine out of order. It sends a collection of 1s and 0s from a single sender to a single receiver at a time in a single ethernet frame which can contain 1000s of Bytes of 1s and 0s. Frames are sent one at a time, not pell mell.

Hope that makes sense.