Computer Network Infrastructure and Component

Computer Network Infrastructure and Component

In this article we describe Computer Network Infrastructure and Component that is Devices, Media and Services with some common examples.

The route that takes a message from the origin to its destination can be as simple as a single cable that connects one PC to another or, as complex as a network that literally covers the world. This network infrastructure provides the stable and reliable channel through which communications occur.

The network infrastructure contains three categories of network components:

1. Network Devices
2. Network Media
3. Services

The devices and the media are the physical or hardware elements of the network. Typically, the hardware is composed of visible components of the network platform, such as a laptop, a PC, a switch, a router, a wireless access point (Access Point) or the wiring used to connect those devices .

Network Devices

The network devices that people are most familiar with are called terminals . Some examples of network terminals are shown in the following figure:

A network device is the origin or destination of a message transmitted through the network. To distinguish one terminal from another, each terminal in the network is identified by an address . When a terminal initiates a communication, it uses the address of the destination terminal to specify where the message should be sent.

Some examples of terminals:

• Computers (workstations, laptops, file servers, web servers)
• Network printers
• VoIP phones.
• TelePresence Devices.
• Security cameras.
• Mobile portable devices (such as smartphones, tablet PCs, PDA and wireless debit and credit card readers, and barcode scanners)

INTERMEDIARY NETWORK DEVICES

These devices connect the individual terminals to the network and can connect several individual networks to form an internetwork . They provide connectivity and guarantee data flow throughout the network.

These devices use the address of the destination terminal, together with information on the network interconnections , to determine the route that messages must take through the network. In the figure, some examples of the most common intermediary devices are shown:

Functions of intermediary network devices:

• Regenerate and transmit the data signals.
• Keep information about the routes that exist through the network and 
• networking. (Routers)
• Direct the data in alternative paths when there is a link failure. (Routers)
• Report errors and communication failures.
• Sort and direct messages according to QoS priorities
• Allow or deny data flow according to security parameters. (Firewall)

NETWORK MEDIA

Communication through a network is transported by means. The medium provides the channel through which the message travels from the origin to the destination.


Modern networks mainly use three types of means to interconnect devices and provide the route by which data can be transmitted. As shown in the following figure, these means are as follows:

TYPES OF NETWORK MEDIA

• Metal wires inside cables : the data is encoded in electrical impulses.
• Glass or plastic fibers (fiber optic cable): the data is encoded as light pulses.
• Wireless transmission : data is encoded with wavelengths of the electromagnetic spectrum.

To know what network medium we should use, let's take into account the following criteria.

CRITERIA FOR CHOOSING A NETWORK MEDIUM

• The distance by which the media can carry a signal correctly
• The environment in which the media will be installed
• The amount of data and the speed at which it should be transmitted
• The cost of the medium and the installation

NETWORK SERVICES

Finally, the services include a large number of common network applications that people use daily, such as email hosting services and web hosting services. The processes provide the functionality that directs and moves messages across the network. The processes are less obvious to us, but they are critical to the operation of the networks.

THE NETWORK AS A PLATFORM

If we look at separate traditional networks, we could realize that each network has its own rules and standards. These separate networks could not communicate with each other and each network would use different technologies to transport the communication signal.

Advances in technology allow us to consolidate these different types of networks on a platform known as "convergent network", which is the ability to transmit data, voice and video over the same
network infrastructure . A single network channel capable of sending these forms of communication.

THE NETWORK ARCHITECTURE

Networks must support a wide variety of applications and services, as well as operate through the different types of cables and devices that make up the physical infrastructure. The architecture of the network refers to the technologies that support the infrastructure and the services and the rules, or protocols, programmed that transfer the data through the network.

As networks evolve, we discover that there are four basic features that the underlying architectures need to meet user expectations:

• Fault tolerance : These networks depend on several routes between the origin and destination of the message. If a route fails, messages can be sent immediately by another link. The fact that there are several routes that lead to a destination is called "redundancy."
• Quality of service (QoS) : QoS becomes a primary mechanism to manage congestion and ensure reliable content delivery to all users. Congestion occurs when the demand for bandwidth exceeds the amount available. The bandwidth of the network is the measure of the amount of bits that can be transmitted in one second (bps).
• Security : The security of the infrastructure of a network includes the physical assurance of the devices that provide connectivity and prevent unauthorized access to the administrative software that resides in them.