TCP Checksum

• Checksum is the 16-bit one's complement of the one's complement sum of a pseudo header, the TCP header, and the data, (padded with zero octets at the end if necessary to make a multiple of two octets.)

  • Checksum field filled with zeros initially

• Pseudo header (similar to UDP) used in calculations, but not transmitted. RFC 1071.

Source Adr

Dest. Adr

Zeros

Protocol

TCP Length

TCP Header

TCP data

32

32

8

8

16

Previous slide

Next slide

Back to first slide

View graphic version