Intro to Transmission Control Protocol

• The OSI model is primarily a theory model.
• The TCP/IP Model is more practical oriented.
• Both are useful at different times. We are primarily concerned with OSI layers 2,3,4,7 in this class.

TCP is a connection oriented protocol that provides error checking and reliability of communication.

Most protocols commonly used on the internet use TCP including: HTTP, SMTP, and SSH.

TCP connections open with a handshake, data is transmitted, and then the connection is closed with a teardown.

TCP provides reliable transfer via:

• Correctly ordering packets received in arbitrary order.
• Validating received packets were not corrupt.
• Re-requesting packets that were corrupt or not received at all.
• Flow and congestion control.
• Requires positive acknowledgement before next data transmission.