TCP Analysis

What is TCP

TCP (Transport Control Protocol) allows 2 end points to exchange data reliably and efficiently over a network even with “packet loss”.

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TCP happens at “Transport” Layer.

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Ownership, within an enterprise, of TCP is debatable, because it straddles Network Ops and Server Ops/Dev Team. Issues could exist at network level, and/or server and app levels bringing ownership into contestation. It us usually determined by the structure of the enterprise.

Connection

TCP Connection: Channel between 2 endpoints. This channel is sometimes called a four-tuple.

• Fourtuple: IP address with a TCP Port value.
• Fourtuple is so name because there are 2 ports open on send and 2 on receive.

States

• Closed - No transmission
• Established - 3 way hand shake processed and connection made
• Time Wait - Open a connection, shut it down but then wait idle for a time before reopening.