JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III DATA COMMUNICATION AND COMPUTER NETWORKS Previous Question Paper (August - 2022 - R16)

A connection refers to the physical or logical link established between two or more devices in a network to facilitate the exchange of data. It defines the communication path and the rules governing how information is transmitted between the sender and the receiver.

Connections are primarily categorized into two types:

• Point-to-Point Connection: This provides a dedicated link between two specific devices. The entire capacity of the link is reserved for transmission between these two nodes. An example is the connection between a remote control and a television via infrared.
• Multipoint (or Multidrop) Connection: This type of connection links three or more devices through a single shared medium. The capacity of the channel is shared among all devices connected to it, either spatially (simultaneous use) or temporally (time-division). An example is a wireless network where multiple devices connect to a single access point.

The OSI (Open Systems Interconnection) reference model is a conceptual framework developed by the ISO to standardize the functions of a telecommunication or computing system into seven distinct layers. Its primary principle is to divide the complex task of network communication into smaller, manageable sub-tasks, ensuring interoperability between different systems.

The seven layers are:

• Physical Layer: Handles the transmission of raw bit streams over a physical medium.
• Data Link Layer: Responsible for node-to-node delivery, framing, and error control.
• Network Layer: Manages logical addressing and routing of packets across multiple networks.
• Transport Layer: Ensures end-to-end communication, flow control, and error recovery.
• Session Layer: Manages sessions, dialog control, and synchronization between applications.
• Presentation Layer: Handles data translation, encryption, and compression.
• Application Layer: Provides network services directly to end-user applications.

Key features include layer independence, where each layer provides services to the layer above it and receives services from the layer below, and modular design, which allows for easier troubleshooting and updates to specific protocols without affecting the entire stack.