Networking

A computer network is simply two or more computers that are connected together via software and hardware so they can communicate.

Devices connected to a network are referred to as nodes. A node can be a computer, a peripheral (such as a printer), or a communications device (such as a modem). The main function for most networks is to facilitate information sharing, but networks provide other benefits as well.

they allow users to share peripherals
you can transfer files from one computer to another without using external storage media

If you install a device called a router to your network, you can share broadband Internet connections. There are two main ways a network can be administered; locally or centrally. A peer-to-peer network is the most common example of a locally administered network. The most common type of centrally administered network is a client/server network.

Peer to Peer Networks

In peer-to-peer (P2P) networks, each node connected to the network can communicate directly with every other node on the network, instead of having a separate device exercise central control over the entire network. When printing, for example, a computer on a P2P network doesn’t have to go through the computer that’s connected to the printer. Instead, it can communicate directly with the printer. Because they are simple to set up, P2P networks are the most common type of home network.

Client/Server Networks

Most networks that have 10 or more nodes are client/server networks. A client/server network contains two different types of computers: clients and servers.

The client is the computer on which users accomplish specific tasks and make specific requests. The server is the computer that provides information or resources to the client computers on the network. The server on a client/server network also provides central control for functions on the network (such as printing).

The Internet is a client/server network. When your computer is connected to the Internet, it is functioning as a client computer. When connecting to the Internet through an ISP, your computer connects to a server computer maintained by the Internet Service provider (ISP). The server “serves up” resources to your computer so that you can interact with the Internet.

Network Components

All networks include:

a means of connecting the nodes on the network (by cables or wireless technology),
special devices that allow the nodes to communicate with each other and to send data, and
software that allows the network to run.

Transmission Media

All network nodes are connected to each other and to the network by transmission media. A transmission medium establishes a communications channel between the nodes on a network and can take several forms:

Networks can use existing wiring (such as phone lines or power lines) to connect nodes.
Networks can use additional cable to connect nodes, such as twisted pair copper cable, coaxial cable, or fibre-optic cable.
Wireless networks use radio waves instead of wires or cable to connect nodes.

Network Adaptors

Network adapters are devices connected to or installed in network nodes that enable the nodes to communicate with each other and to access the network. Some network adapters take the form of external devices that plug into an available USB port. Other network adapters are installed inside computers and peripherals as expansion cards. These adapters are referred to as network interface cards (NICs).

Network Navigation Devices

Data is sent over transmission media in bundles called packets. For computers to communicate, these packets of data must be able to flow between computers. Network navigation devices help to make this data flow possible. In simple networks, navigation devices are built right into network adapters. More sophisticated networks need specialized navigation devices. The two most common specialized navigation devices are routers and switches.

Types of Peer-to-Peer Networks

There are two main types of P2P networks:

Wired Ethernet networks
Wireless Ethernet networks
Power-line networks

The major differences in these networks are the transmission media by which the nodes are connected.

Wired Ethernet Networks

Ethernet networks use an Ethernet protocol as the means by which the nodes on the network communicate. An Ethernet network requires that you install or attach network adapters to each computer or peripheral you want to connect to the network. Most computers come with Ethernet adapters preinstalled as network interface cards (NICs). If your computer doesn’t have a NIC, you can buy one and install it, or you can use a USB adapter, which you plug into any open USB port on the system unit. Although you can use USB versions in laptops, PC Card versions of Ethernet NICs are made especially for laptops.

Wireless Networks

A wireless network uses radio waves instead of wires or cables as its transmission media. Current wireless networks in Canada are also known as Wi-Fi (short for Wireless Fidelity). Just like other networks, each node on a wireless network requires a wireless network adapter. These adapters are available as NICs that are inserted into expansion slots on the computer or as USB devices that plug into an open USB port.

Wireless network adapters differ from other network adapters in that they contain transceivers. A transceiver is a device that translates the electronic data that needs to be sent along the network into radio waves and then broadcasts these radio waves to other network nodes. Transceivers also receive the signals from other network nodes.

Networking in Detail

Networking Advantages

A network is a group of two or more computers (or nodes) that are configured to share information and resources such as printers, files, and databases. Essentially, a network enables computers and other devices to communicate with each other.

Client/Server Networks

To review, a server is a computer that both stores and shares resources on a network, whereas a client is a computer that requests those resources. A client/server network contains servers as well as client computers. The inclusion of servers is what differentiates a client/server network from a typical peer-to-peer network.

The main advantage of a client/server relationship is that it makes data flow more efficiently than in peer-to-peer networks. Servers can respond to requests from a large number of clients at the same time. Also, servers are configured to perform specific tasks (such as handling database requests) efficiently. Client/server networks are also scalable networks, meaning additional users can be added easily without affecting the performance of the other network nodes. In addition, client/server networks are centralized, meaning all clients connect to a server that performs tasks for them.

INTRANET

An intranet is a private corporate network that is used exclusively by company employees to facilitate information sharing, database access, group scheduling, videoconferencing, or other employee collaboration. The intranet is not accessible to non-employees; a firewall protects it from unauthorized access through the Internet.

Networking Needs

Servers serve many different network users and assist them with accomplishing a variety of tasks. The number and types of servers on a client/server network depend on the network’s size and workload.

Dedicated servers are used to fulfill one specific function such as handling e-mail. When dedicated servers are deployed, the main server becomes merely an authentication server and/or a file server. Authentication servers keep track of who is logging on to the network and which services on the network are available to each user. Authentication servers also act as overseers for the network. They manage and coordinate the services provided by any other dedicated servers located on the network. File servers store and manage files for network users. On corporate networks, employees are provided with space on a file server to store files they create.

A network with a centralized printing service will have a print server that routes print jobs to appropriate devices and prioritizes printing according to order of request, unless overridden by special needs. Application servers store and distribute application software for each system on the network. In these configurations, upgrades and new software installs are done just once on this server rather than deploying the programs throughout the organization. Database servers are dedicated to an organization’s database storage, queries, and retrievals. In large organizations, e-mail servers handle the large volume of incoming, outgoing, and internal e-mail.

A communications server handles all communications between the network and other networks, including managing Internet connectivity. All requests for information from the Internet and all messages being sent through the Internet pass through the communications server. Often, the communications server is the only device on the network connected to the Internet. E-mail servers, Web servers, and other devices needing to communicate with the Internet usually route all their traffic through the communications server. Providing a single point of contact with the outside world makes it easier to secure the network from hackers. A Web server is used to host a website available through the Internet. Web servers run specialized software that enables them to host Web pages.

Network Topology

Network topology refers to the physical or logical arrangement of computers, transmission media (cable), and other network components. The most common client/server network topologies are bus, ring, and star. Combining multiple topologies into one network is known as constructing a hybrid topology

Bus Topology

A bus topology uses a single cable or “bus” to handle transmission of signals between computers. This is most often used in P2P networks. Each computer on the bus network can communicate with every other computer on the network directly. All computer and peripheral devices see all the packets on the network but only process the packets with their address.

A limitation of bus networks is that data collisions can occur easily if two computers transmit data at the same time because a bus network is essentially composed of one main communication medium (single cable). An access method is established to control which computer is allowed to use the transmission media at a certain time. Computers on the network “listen” to the network data traffic. When no other computer is transmitting data, the computer knows it can transmit data. This avoids data collisions. When data collides, it is often lost or irreparably damaged.

The data is broadcast throughout the network to all devices connected to the network. The data is broken into small segments called packets. Each packet contains the address of the computer or peripheral device to which it is being sent.

Ring Topology

The computers and peripherals in a ring (or loop) topology are laid out in a circle. Data flows around the circle from device to device in one direction only. Data is passed using a special data packet called a token. This type of topology is commonly referred to as a token-ring topology. Token-ring networks originally had data transfer rates of either 4 Mbps or 16 Mbps. More recent token technologies can deliver speeds up to 100 Mbps.

Star Topology

A star topology is the most widely deployed client/server network layout in businesses today because it offers the most flexibility. In a star topology, the nodes connect to a central communications device called a switch, thus forming a star. The switch can send to any node on the network but when the switch receives a signal from the sending node and retransmits it, it sends it to the correct node on the network. Because the switch retransmits data signals, a star topology is an active topology.

Review

Networking, it is important not only to business but also to ourselves. We must however look after these networks to make sure we do not allow them to be infiltrated by persons whose sole purpose is to either take your identity or some form of important information from you.

Next we will take a brief look into other types of digital devices, such as your phone or a tablet.