Similar to the OSI model but more condensed. TCP has four (4) layers: 1) Application 2) Transport 3) Internet 4) Network Interface Similar to the OSI model, information is added at each layer of the TCP model as the data or packet traverses it (again this is encapsulation with the reverse being called decapsulation). **MAJOR:: TCP is connection based, so TCP has to establish a connection between a client and another acting as a server before data can be sent.** See the [[TCP Three Way Handshake]]. Doing so guarantees the integrity of data. The disadvantage is that a slow connection can bottleneck another device as it will have to wait as the connection will be reserved for another device. Slower then UDP because TCP requires more computing to be done along with the fact that if any bit of data is missed the data as a whole cannot be used and must be retransmitted. TCP uses headers that are applied to data throughout the encapsulation process.