title: Overhead with PPP and Ethernet
body: <p>What is the overhead for PPP and Ethernet sending 5000 bytes?</p>
  
  <p>Frame size for <a href="http://en.wikipedia.org/wiki/Point-to-Point_Protocol" rel="nofollow noreferrer">Point-to-Point Protocol</a>: 8 bytes
  MTU: 500 bytes</p>
  
  <p>Frame size for Ethernet: 18 bytes
  MTU: 1500 bytes</p>
  
  <p>Both sending 5000 bytes..</p>
  
  <p>I know this is just a calculation, but I am not sure how to do it. I can't find it anywhere. I would think that since a PPP frame takes 8 bytes and maximum transmission unit is 500 then it can send (500 - 8)bytes of information in one go. It sends 10 frames, resulting in 4920 bytes sent. Then sends the final (80+8)bytes with the last frame.</p>
  
  <p>Similar for Ethernet. (1500 - 18)bytes with each frame. 3 frames sent means 4446 bytes sent. Sending (554+18)bytes in the last frame.</p>
  
  <p>This obviously doesn't answer the "overhead" question. Anyone have any ideas?</p>