Questions 1-16

Network Fundamentals

• Router, Switch, and Hub are intermediary devices in a network, but a Smart phone is not.
• A local area network (LAN) connects other LANs and backbone networks (BNs) located in different areas to each other and to wide area networks within a span of 10 to 30 miles.
• An intranet is a private LAN that uses Internet technologies and is not publicly available to people outside of the organization.

OSI Model

• The network layer performs routing functions in both the OSI and Internet models and is responsible for routing messages from the source computer to the destination computer.
• The correct order of the seven layers of the OSI model from layer 1 to layer 7 is: Physical, Data Link, Network, Transport, Session, Presentation, Application.
• The fourth layer of the OSI model is called the Transport layer.

Internet Model

• In the Internet model, the HTTP protocol is used in the Application layer.
• The Data Link layer performs error detection and correction.

Transmission

• In full-duplex transmission, two stations can send and receive simultaneously.
• Half-duplex transmission allows transmission in both directions, but only in one direction at a time.
• Simplex transmission allows transmission in only one direction.

Media

• Guided media refers to the type of media in which the message is sent through a physical medium (e.g., cables).
• Fiber optic cable carries signals in light form, not traditional electrical form.
• Microwave is a type of wireless media.
• Attenuation refers to the weakening of a signal over distance.
• Fiber optic cable is the most secure wired media and can best withstand harsh environmental conditions.

Media Access Control and Error Detection

• Media access controls refer to the need to control when computers transmit.
• Controlled access MAC approaches do not work well in a large network with high usage.
• Cyclical redundancy check is a popular polynomial error-checking scheme.
• The data link layer performs error detection and correction, but not routing, encryption, or application data formatting.
• The two sublayers of the data link layer consist of the Media Access Control sublayer and the Logical Link Control sublayer.
• Parity check, Cyclical redundancy check, and Checksum are error detection methods used in the data link layer.