TCP Headers

• TCP headers are 20 bytes without options

• Options are padded to 4-byte boundaries

• • Unlike IP options, TCP options are very common
  • • Rare for a connection setup not to have at least one
  • Typical header total lengths
  • • 20, 24, 28, 32 bytes

• It is also common for TCP packets to have no TCP data

• • Control or “pure ACK” packets
  • Connection setup and teardown
  • “Mice”