Computer Science

The Session Layer is responsible for establishing, managing, and terminating communication sessions between applications. It ensures that sessions are properly maintained and synchronized, which aligns with option A.

A router operates at the Network Layer (Layer 3) of the OSI model and forwards packets between different networks using IP addresses. Switches and bridges operate at the Data Link Layer, and hubs operate at the Physical Layer, so they do not perform routing based on IP addresses.

A Network Interface Card (NIC) provides the physical connection between a computer and a network, enabling the computer to communicate over the network. It does not route data or amplify signals, but rather facilitates data transmission at the physical and data link layers.

A gateway acts as a translator between different network protocols, enabling communication between networks that use different protocols. This is its primary function, distinguishing it from devices like routers or repeaters.

A Network Interface Card (NIC) operates at the Data Link layer (Layer 2) of the OSI model, handling physical addressing and framing for data transmission over the network.

The Network Layer (Layer 3) of the OSI model is responsible for logical addressing, routing packets across networks, and controlling traffic to ensure data reaches its destination efficiently. This distinguishes it from other layers like the Data Link Layer, which handles physical addressing and local delivery.

The Presentation Layer (Layer 6) of the OSI Model is responsible for data translation, encryption, and decryption, ensuring that data is presented in a readable format for the application layer.

A hub is a network device that broadcasts incoming data packets to all connected devices and operates at the Physical Layer (Layer 1) of the OSI model. Switches, routers, and gateways operate at higher layers and do not broadcast to all devices indiscriminately.

A standalone computer requires RAM, a hard drive, and an operating system to function properly. A LAN card is not necessary for basic operation as it is used for network connectivity, which is optional for standalone use.

The Internet is best defined as an interconnection of wide area networks (WANs), which allows computers and networks across the globe to communicate. This distinguishes it from a single network or just local area networks (LANs).