title: what is overhead, payload, and header
body: <p>Can someone please explain me what is overhead, payload, header and packet. As far as I know a packet is the whole data that is to be transmitted. This packet consists of the actual data which I think is the payload and the source/destination information of the packet is in the header. So a packet consists of header and payload. So what is this overhead? Is overhead a part of the header? I got this from the internet &quot;Packet overheard includes all the extra bytes of information that are stored in the packet header&quot;.
  The header already contains source/destination info. What are the extra bytes of information that this packet overhead has? I'm confused.</p>