Comparing TCP and UDP

Transport Layer Protocols

Both TCP and UDP are transport layer protocols (Layer 4)

Both transport data between applications using port numbers

Connection Type

TCP is connection oriented (must have connection then can send data) and uses a three-way handshake

UDP is connectionless meaning it sends data immediately without setting up a connection first

Reliability

TCP is reliable, it checks whether data was received. If missing TCP can retransmit it.

UDP is unreliable, it does not acknowledge if data is received and does not retransmit data

Sequencing

TCP uses sequence numbers to make sure data is sequenced in the right order

UDP does not sequence data, if packets arrive out of order, UDP itself does not fix it

Flow Control

TCP uses flow control to prevent the sender from overwhelming, it uses the window size field

UDP does not use flow control, it sends data without checking if the user can handle it

Speed and overhead(extra non-payload data such as headers)

TCP has more features so it has higher overhead and slower than UDP

UDP has less features, so it has lower overhead and its faster

Error Handling

TCP provides error handling. If data is lost or corrupted, TCP can request transmission\

UDP has a checksum for error detection, but it does not recover from errors

Uses of TCP and UDP

Summary