TCP
The three way handshake verifies that data arrived
TCP
Reliable delivery
Layer 3 deals with logical addresses and operates with IP addresses.
Typically TCP (the Transmission Control Protocol) is responsible for adding reliable delivery mechanisms to information flows. It operates at the Transport Layer. Some applications use the session layer in addition to or in place of transport layer mechanisms however.
A reliable protocol is one that ensures reliability properties with respect to the delivery of data to the intended recipients
1. TCP provides reliable, ordered and error-checked delivery of a stream of octets between programs running on computers connected to a local area network
UDP
UDP
It appears as though you have the two concepts reversed; if you are using flow control than you are using a reliable delivery method - these are at layer 4 of the OSI model, which is TCP for reliable delivery. TCP provides flow control. UDP would be used for speed, when you do not need reliable delivery. However, UDP does not use flow control, since there is no handshaking between transmission and reception, and it is a connectionless protocol.
Transport layer is responsible for reliable delivery of information, error correction and so on.
Guaranteed reliable delivery is provided by TCP transport.
transport layer
The Transport layer which handles segments is responsible for End-to-End connections and reliability. Problems at this layer can negatively impact reliable message delivery. Although the Transport layer is supposed to be where reliability is provided, problems at the Network layer where packets are handled can also significantly affect reliable message delivery if the path determination and/or IP (logical addressing) are messed up.
TCP protocol insures that your data was delivered in reliable and rapid way.
delivers data reliably across the network using TCP
Because of the overhead, TCP should not be used as a transport mechanism if the user or endpoints do not require reliable delivery, but are more interested in speed than quality.
Standard Oil provides heating oil at affordable prices and they have reliable delivery services. Chief Energy is another reliable and affordable heating oil company.
UDP as a transport protocol is used in situations where speed is more important than reliability in the delivery of the packets. Therefore, any application that requires speed as its primary delivery could use UDP. This type of delivery is not checked for consistency or reliability, so you wouldn't use it if the delivery has to be reliable.