Data, Information, and Network Communication Essentials

Data

Data is the collection of facts considered in isolation. It describes an organization and carries meaning, but generally is not useful by itself.

Information

Information is data that has been manipulated and is useful to someone. Information must have value; otherwise, it would be considered just data. Information tells people something that confirms what they knew or suspected. (What, who, and when?)

Why? Because telecommunication networks transmit data, the networks do not identify meanings (information). The objective of networking is to take data from one place to another.

Data Types

• Analog: Continuous
• Digital: Discrete

Symbols limited by their use and origin:

• Alphanumeric
• Graphic
• Image
• Audio
• Video
• Multimedia

Model of a Basic Communication System

Components:

• Source
• Transmitter
• Drive System
• Receiver
• Destination

Data Networks

Data networks were born out of a need for companies to resolve the following issues:

• How to avoid duplication of computer equipment and other resources.
• How to communicate effectively.
• How to configure and manage a network.

In the 1980s, networks grew rapidly. The first-generation networks were set up as Local Area Networks (LAN) and met the need to connect departments or small businesses.

Network Devices

Network equipment is directly connected to a network segment. There are two main types:

• End User: Computers, printers, scanners, and other devices that provide services directly to the user.
• Network: Devices that connect to end-user devices, enabling intercommunication.

End-User Devices (Hosts)

Also called hosts, these devices allow users to share, create, and learn. They can exist without a network, but their capabilities are greatly limited without network access.

Hosts are physically connected to the network media by a Network Interface Card (NIC). They use this connection for tasks such as emailing, printing, scanning images, or accessing databases.

A NIC is a printed circuit board that fits into the expansion slot of a bus on the motherboard of a computer, or it may be a peripheral device. Also called a network adapter, NICs for laptops or handheld computers typically have the size of a PCMCIA card. Each individual NIC has a unique code called the Media Access Control (MAC) address. The MAC address is used to control data communication to the network host.

Network Devices

These devices transport data between end-user devices. They provide cable connections, connection concentration, data format conversion, and data transfer management.

Examples:

• Repeaters: Used to regenerate a signal. Repeaters regenerate analog or digital signals that are distorted due to transmission losses caused by attenuation. A repeater does not make intelligent decisions about sending packages, unlike a router or bridge.
• Hubs: Concentrate connections, allowing the network to treat a group of hosts as a single unit. Passive hubs do this without interfering with data transmission. Active hubs not only concentrate hosts but also regenerate signals.
• Bridges: Convert data transmission network formats in addition to basic data transmission management. They provide connections between LANs. Bridges not only connect LANs but also verify data to determine whether it should cross the bridge, increasing the efficiency of each part of the network.

Network Topology

Network topology defines the structure of a network. One part of the topological definition is the physical topology, which is the actual arrangement of cables or media. The other part is the logical topology, which defines how hosts access the media to send data.

Bus Topology

A bus topology uses a single backbone cable that is terminated at both ends. All hosts are directly connected to this backbone.