Computer Network Communications

Processor Front

The processor front involves three components: source, destination, and message. The source (e.g., a terminal or computer) sends a message. The destination (e.g., another terminal or computer) receives the message. The front-end processor acts as the connection between the source and destination, managing the message transfer. It frees the host processor from communication tasks, handling message routing, transmission monitoring, code translation, and encryption. All data transmitted to or from the host processor are managed through this specialized front-end processor, allowing the host processor to operate more efficiently and focus on application processing.

Types of Communications

A network enables computer connections to share resources, enable remote access, and optimize equipment use. Any network consists of nodes (or terminals) and a transmission medium. A node can initiate or terminate communication. Communication requires a transmission medium to carry information between nodes. A node can be a PC, supercomputer, printer, bridge, or router. The medium can be a cable or electromagnetic waves. Three communication types exist:

1. Simplex (Unidirectional): Communication flows in one direction only.
2. Half-Duplex (Bidirectional Alternating): Communication flows in both directions, but not simultaneously.
3. Full-Duplex (Bidirectional Simultaneous): Communication flows in both directions simultaneously.

Peer-to-Peer Networks

In a peer-to-peer network, two terminals are linked by a shared line or cable. Each terminal can act as both client and server. Supported topologies include ring, star, tree, and mesh.

Ring Topology

In a ring topology, each terminal connects to two adjacent terminals via a dedicated line, forming a closed loop. Communication is unidirectional, flowing from terminal to terminal until it reaches the destination and returns to the source. A disadvantage is that any line failure disrupts the entire network.

Star Topology

In a star topology, all terminals connect to a central hub. The hub manages the flow of information between terminals. This topology is more robust than a ring; one terminal's failure doesn't affect the others. However, hub failure disables the entire network.

Tree Topology

A tree topology extends the star topology by connecting multiple stars through concentrators. Some stars have higher priority, directing information flow.