The session layer of the OSI/RM controls the dialogues (connections) between computers. It establishes,
manages and terminates the connections between the local and remote application. It provides for full-duplex,
half-duplex, or simplex operation, and establishes checkpointing, adjournment, termination, and restart
procedures. The OSI model made this layer responsible for graceful close of sessions, which is a property of
the Transmission Control Protocol, and also for session checkpointing and recovery, which is not usually used
in the Internet Protocol Suite. The Session Layer is commonly implemented explicitly in application
environments that use remote procedure calls.
Answer option C 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.
Answer option A is incorrect. The Data Link Layer is Layer 2 of the seven-layer OSI model of computer
networking. It corresponds to or is part of the link layer of the TCP/IP reference model. The Data Link Layer is
the protocol layer which transfers data between adjacent network nodes in a wide area network or between
nodes on the same local area network segment. The Data Link Layer provides the functional and procedural
means to transfer data between network entities and might provide the means to detect and possibly correct
errors that may occur in the Physical Layer. Examples of data link protocols are Ethernet for local area
networks (multi-node), the Point-to-Point Protocol (PPP), HDLC, and ADCCP for point-to-point (dual-node)
connections.
Answer option B is incorrect. The network layer controls the operation of subnet, deciding which physical path
the data should take, based on network conditions, priority of service, and other factors. Routers work on the
Network layer of the OSI stack.

Contingency plan is prepared and documented for emergency response, backup operations, and recovery maintained by an activity as the element of its security program that will ensure the availability of critical resources and facilitates the continuity of operations in an emergency situation.
A contingency plan is a plan devised for a specific situation when things could go wrong. Contingency plans are often devised by governments or businesses who want to be prepared for anything that could happen.
Contingency plans include specific strategies and actions to deal with
specific variances to assumptions resulting in a particular problem, emergency, or state of affairs. They also include a monitoring process and "triggers" for initiating planned actions. They are required to help governments, businesses, or individuals to recover from serious incidents in the minimum time with minimum cost and disruption.
Answer option B is incorrect. A disaster recovery plan should contain data, hardware, and software that can be critical for a business. It should also include the plan for sudden loss such as hard disc crash. The business should use backup and data recovery utilities to limit the loss of data.
Answer option D is incorrect. The Continuity Of Operation Plan (COOP) refers to the preparations and institutions maintained by the United States government, providing survival of federal government operations in the case of catastrophic events. It provides procedures and capabilities to sustain an organization's essential.
COOP is the procedure documented to ensure persistent critical operations throughout any period where normal operations are unattainable.
Answer option C is incorrect. Business Continuity Planning (BCP) is the creation and validation of a practiced logistical plan for how an organization will recover and restore partially or completely interrupted critical (urgent) functions within a predetermined time after a disaster or extended disruption. The logistical plan is called a business continuity plan.