What happens if an error is detected at the lowest possible layer of the stack ISO/OSI for Ethernet?
For example, considering 100BASE-TX, it is implemented with a 4B5B coding this means that there are 16 combinations of bits are invalid. What happens if a receiver "reads" from the physical medium an invalid combination of bit, e.g. "00001"?
- It discards that bit (invalidating the entire frame)
- It select the "most similar" combination
- or something else?
I know that upper layers can detect the error, e.g. the MAC layer via the FCS field, but I don't know how the transreceiver works with an error detected in the signal.