Sequence and Acknowledgment Numbers

• TCP provides reliability and flow control with a dynamic sliding window transmission protocol

• 32-bit sequence and acknowledgement numbers are used to track TCP packets

• The sequence number indicates the number of the first byte of data in the packet

• • Initial sequence numbers are “somewhat random”. don’t expect to start counting from 0
  • Length of TCP data segment = IP total length - IP header length - TCP header length

• The acknowledgement number indicates the next byte of data the sender expects to receive