cable modem info

Hi I have another ? on cable modems or at least the network i was wondering if someone could tell me if cable companys on there network do alot of arping it seems when i do tcpdump om my eth interface i see them arping like the whole network they have is this normal if not is there some way to not have this happening it it is normal then i guess then that be it Sorry if this is an bit off topic but i didnt know where else to ask and the list has been great thanks in advance Bob