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5
trAnsPort ProtocoLs
5.1 Introduction
e transport layer acts as a liaison between the upper layer protocols
and the lower layer protocols. To make this separation possible, the
transport layer is independent of the physical network. e objectives
of transport layer protocols include end-to end delivery of entire mes-
sage, addressing, reliable delivery, flow control, and multiplexing.
Two distinct transport-layer protocols are UDP and TCP. e user
datagram protocol (UDP) provides an unreliable, connectionless ser-
vice to the invoking application. e second of these protocols, TCP
(transport control protocol), on the other hand, offers several addi-
tional services to applications. First and foremost, it provides reliable
data transfer. Using ...