Electronic – How is signal ‘discarded’


It has always been a puzzle for me how a certain type of information can be discarded from a system when it is unused. Say, for example, the Internet Protocol (IP) specification states that packets whose version is neither 4 nor 6 are 'discarded'. Since the packets' representation is a signal of some sort, how is this information 'discarded'? Where does it go? Is it dissipated as heat or something else?

(I don't know how to tag this, or whether it's in the right section so excuse me if I'm wrong here)

Best Answer

In this case, the packet is received into a memory buffer of some sort, so that its protocol version field can be examined. If it has a correct value, it is then forwarded to the next stage of processing, typically by copying the data to a different area of memory.

If not, then the memory buffer is simply over-written by the next packet received, and the data from the first packet is lost.