Computer Networks

Computer networks are computers connected together to share data and communication through nodes. The linkage in nodes is called the communication channel. Tasks assigned to several computers in a process called distributed processing in the network.They are several categories of computer networks. We discuss a few in this article.

1. Local Area Networks (LANs)

LANs are computer machines with their peripherals put in a small area like a room in a building. They are interconnected together by dedicated circuits and media-type transmission. The technology for the network is limited and is associated with intranets.

2. Metropolitan Area Networks (MANs)

MAN networks are interconnection of computers and devices, set up in a geographical region. Example, a town, a country, a continent, or worldwide. The network connects two or more LANs of the same organization spread over a region. MANs use dissimilar media transmission technologies than LAN systems.

3. Wide Area Networks (WANs)

A WAN is a network that covers a large geographical area. WANs Interconnects LANs and MANs from different companies together, known as network of networks. Examples are, .org, .com, .ac etc. They are connected by circuits which are non-dedicated and use a variety of media and transmission technologies. Examples are telephone network and satellites.Categories of Computer Networks

1. Peer-to-peer

Peer- to- peer network is a network where no one computer is superior in its capabilities than the other. It is used in communication and not in administration. The network can operate on different operating systems or same operating system. Each operating System per computer machine regards itself as more superior than the other.

• They are manageable and less expensive. Require less expert knowledge.
• They are less secure, not expandable, and cannot be centralized.

2. Client-Server

Client server networks have a high capability and computer serves others in form of a client/workstation set up. A server installation with NOS, i.e., Novell, Netware, UNIX, Windows NT etc. is mandatory. NOS manage data and client resources that include disk space, processing power, communication ports and network printers. Clent server puts restriction on when and where users can access network. Client server directs what communication to be used by the ruler’s computer and supplies users with applications.Advantages

• It is easier to control and manage other computers from the main server.
• Due to use of login credentials creation, it is more secure because one has to use passwords.
• Filtered information

Disadvantages

• It is slow in the use of shared resources
• If the main server fails, an operation of an organization falters. Backups and secondary domain controllers have to be in place.
• The network is complex because of the software configuration to the serve other networks.

Servers

A server is a computer system designed to process data requests and deliver data to another computer on a local network or internet.

Type of servers

1. Database Server. This server handles databases and other applications. This type of database works alongside with another server to store data in group formations such as in Structured Query Language (SQL). Creation of this servers can use scripting in a language of the specific database.
2. File and print servers. They manage file transfer mechanisms and printing.
3. Web Server. This server manages content from the web to clients.  Web servers acts on the GET and POST instructions from clients by responding accordingly.
4. eMail servers. It is a server that runs on a protocol known as SMTP or simple Mail Transfer Protocol and take a client's mail and onward forwards the data to another server. You can get email for your business that is safe and secure at Google.
5. Communication serves. This server is for fax etc.
6. Proxy server. They keep history of the most visited websites to be locally accessed.
7. DNS Server. A Domain Name Service server or DNS translates domain names to their actual IP addresses. It is the reference point for a browser when you key in a domain name. If you plan on keeping your online presence, try Namecheap.
8. FTP Server. File Transfer Protocol servers manages and hosts among different users the file exchange. They do not offer encryption on default. FTP Servers allow a number of secured protocol version used more often. They allow both uploading and downloading of files. Files are authenticated by an FTP client before they are downloaded or uploaded.

Advantages

1. Share resources. It is easier to share Software (e.g., DBMS) and Hardware (e.g., RAM)
2. Less running cost. All files are located on the servers and thin on client
3. More efficiency. It is a more efficient network that guards against system failures because nodes can be bypassed and additional backed up servers. Heavy tasks on other systems share workloads to idle nodes on the network. Many participants can share similar free space.
4. Faster. It can have up to 10,100mbps or even higher mbps when compared to ordinary modems which can be at 56k.
5. Facilitate communication. Handles smooth sending of documents, Fax and internet i.e ISDN line emails.
6. Flexible working. Supports use of portable computers and even tele- working.
7. Security. Has a centralized controlled system via servers
8. Data integrity. There is no duplication of documents that exists in different file systems.

Disadvantages. 

1. It is hard to eradicate propagated errors
2. Virus attack spreads quickly in the entire system.
3. Managing the network is costly.
4. Offers less security when compared to a standalone network.
5. It is a complex network software and not easy to install.