Which of the following layers of the TCP/IP model maintains data integrity by ensuring that
messages are delivered in the order in which they are sent and that there is no loss or duplication?

A.
Transport layer

B.
Link layer

C.
Internet layer

D.
Application layer

Explanation:

The transport layer ensures that messages are delivered in the order in which they are sent and
that there is no loss or duplication. Transport layer maintains data integrity.
Answer option C is incorrect. The Internet Layer of the TCP/IP model solves the problem of
sending packets across one or more networks. Internetworking requires sending data from the
source network to the destination network. This process is called routing. IP can carry data for a
number of different upper layer protocols.
Answer option B is incorrect. The Link Layer of TCP/IP model is the networking scope of the local
network connection to which a host is attached. This is the lowest component layer of the Internet
protocols, as TCP/IP is designed to be hardware independent. As a result TCP/IP has been
implemented on top of virtually any hardware networking technology in existence. The Link Layer
is used to move packets between the Internet Layer interfaces of two different hosts on the same
link. The processes of transmitting and receiving packets on a given link can be controlled both in
the software device driver for the network card, as well as on firmware or specialized chipsets.
Answer option D is incorrect. The Application Layer of TCP/IP model refers to the higher-level
protocols used by most applications for network communication. Examples of application layer
protocols include the File Transfer Protocol (FTP) and the Simple Mail Transfer Protocol (SMTP).
Data coded according to application layer protocols are then encapsulated into one or more
transport layer protocols, which in turn use lower layer protocols to affect actual data transfer.