A network is a system that sends and receives data and messages enabling two or more computers communicated with each other. They allow computers to share files, share printers and send messages to each other.
There are 2 types of network
- Client/Server Networks
- Peer-to-peer Networks
The clients are usually computer workstations sitting on the desks of employees in an organization. The servers are usually more powerful computers and are held in a central location or locations within an organization.
There are several types of servers. File servers which store and distribute files and applications, and print servers which control printers. Client/Server networks need client software which is installed on the workstations
Peer-to-peer networks have workstations connected to each other but do not have servers. Files can be shared between workstations, and a printer connected to one workstation can be accessed by another workstation.
Peer-to-peer networks are often much simpler to set up than client/server networks. They lack centrally managed security and ease of backing up of files. Peer-to-peer networks only are set up within an office or single room.
Local Area and Wide Area Networks
A network contained within one building or site is called a Local Area Network (LAN). A network spans several sites across a city, country or even the world is called a Wide Area Network (WAN)
A Client/Server network may be a LAN or WAN. A peer-to-peer network can only be a LAN.
WAN is the Internet, which contains many thousands of servers and many millions of clients right across the world.
A server is a computer that performs a service for other computers on the network. LANs and WANs have file servers and print servers. The Internet has other types of servers such as web servers and mail servers.
Print servers control the printers on the network. The computer is thus a file server and print server together.
File servers store the files that are created by the network users. They also store word processing programs, spreadsheets etc. Users can access parts of a file server’s hard disk.
Networks – Security
Most companies and organisations have computer files that are critical to their business. The files may be technical specifications of products, customer accounts etc. Military organizations and industries will have files that are important to the defence of the country.
This makes it vitally important to ensure that the files are secure.
Security is maintained by login names and passwords and is restricted to files and directories.
The Growth of Networking Technology
Modern Benefits of Networking
Easy sharing of data and sharing the printers. Today network link every part of the globe.
1. Data sharing
E-mail has become one of the leading motivators for companies to invest in networks. The ability to effortlessly and quickly move data from one person to the next is an option too good to pass up for many organisations. Transmitting E-mail is one method of sharing data. Networks offer the capabilities of multi-user access. Inherent danger in two people accessing and altering the same file at the same time. What happens if two people update the same record at once? It would result in the “deadly embrace”, where both parties became locked up and had to reboot, resulting in lost or corrupted data. Record locking, a means by which a person updating a record has exclusive use of the record while others who attempt to access it can not do so.
2. Resource sharing
Few companies have the available resources to place a printer on every user’s desk. Networks offer a logical and cost-effective solution. The introduction of several users could cause conflict at the printer, spooling is utilised so that print jobs can be arranged in an orderly manner. Network provides such services in the form of print queues and print servers
The ability of sharing printers and disk space has been the driving force behind many companies installing PC based networks. Shared modems are typically called modem servers.
Life before Networking
The early computers were large in size due to the fact that vacuum tubes were used to facilitate their processing. It wasn’t until the transistor was developed and then the integrated circuit, that hardware began to assume a more compact size. The type of memory utilized was called “core memory” consisting of metal rings and rods that were bulky at best.
The ability to balance processing load and resources was the prime motivator for launching us into the modern ear of networking. This expansive network was called ARPANET (Advanced Research projects Agency Network). ARPANET was the creation of protocols for linking dissimilar computers together; the huge internetwork that sprang from ARPANET is now called the Internet. Ethernet is often referred to as a “media” protocol. Like Ethernet, ARCnet is a set of media protocols. ARCnet is probably the most standardized network in terms of interoperability because of the strong commitment to interoperability amongst the vendors.