COMPUTER NETWORKS

A computer network consists of two or more computing devices connected by a medium allowing the exchange of electronic information. These computing devices can be mainframes, workstations, PCs, or specialized computers; they can also be connected to a variety of peripherals, including printers, modems, and CD-ROM towers. Most networks are supported by a host of specialized software and hardware that makes these connections possible, including routers, bridges, and gateways, which help accommodate traffic between unlike systems.

Many different types of computer networks exist. Some, such as local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs), are defined by their geographic layout and the differing technologies that support such layouts. LANs are by far the most common, and in most cases, the fastest. Networks may be public, such as the Internet; semi-public, such as subscription networks (including subscription-based Internet service providers and other content-based networks); or private, such as internal corporate LANs, WANs, intranets, and extranets. Most networks are private, but of course the relatively few public ones, like the Internet, support a very large user base. Networks may also be open, or linked to other networks, or closed, which means they are self-contained and do not allow connectivity with outside resources. Most modern corporate networks are somewhere in between; they often allow access to the outside, but tightly restrict access from the outside. "Open" can also describe whether network technology is based on widely accepted standards that multiple hardware/software vendors support, versus a closed or proprietary system that is dependent on a single developer (or very few).

Common Network Terminology

Ethernet —a series of widely used hardware/software protocols for local area networks
• Local area networks (LANs) —networks that are confined to a single building or part of a building and that employ technology to capitalize on the advantages of close proximity (usually speed)
• Metropolitan area networks (MANs) —networks that are accessed from multiple sites situated in a relatively concentrated area (within 50 km or so) and that function as a faster alternative to wide area networks
• Nodes —individual computers on a network
• OSt —Open Systems Interconnection model, a broadly defined international model for the hierarchy of data communications between networked computers
• Packets —also called datagrams, these are measured pieces of information (usually ranging 500 to 2,500 bytes in size) in a data transfer that are each separately addressed to their destination and reassembled into the full original message at the receiving end
• Protocols —a set of rules dictating how hardware and software communicate with other devices
• Storage area networks (SANs) —a high-performance network of storage/backup devices integrated with one or more primary computer networks
• Topology —the structure of how networked computers are actually connected to each other and to other network resources
• Wide area networks (WANs) —networks that are maintained over two or more separate buildings and use technologies that maximize the ease and cost-effectiveness of connections between distant locations (often at the expense of speed)

of rules for how competing devices can share finite network resources. Through this protocol a computer on the network can determine whether it can send data immediately or whether it must compete with another device for network services. Collision occurs when two devices attempt to use the same resource, and the CSMA/CD protocol provides a simple mechanism for resolving this contention: it halts the colliding operation (the one initiated last) and keeps trying to resend the data at specified intervals until either it succeeds or reaches a maximum number of attempts. If the maximum is reached, the operation may be aborted and data may be lost.

INTERNET PROTOCOL.

The other significant development was that of the Internet Protocol (IP) and its many derivatives, which have been the center of innovation from the late 1980s until the present. IP, which is very basic, actually dates to the early 1970s, when the Internet's predecessor, Arpanet, was in its formative years. At its core, IP is a simple packet transmission protocol and an addressing scheme. This means that IP has certain parameters for how packets, often called datagrams, are addressed and formatted for exchange between two computers. IP forms the basis for a number of popular WAN and client/server protocols, notably Transmission Control Protocol/Internet Protocol (TCP/IP), which was developed during the 1970s and adopted for Arpanet in 1982.
BENEFITS OF NETWORKS

Networks can allow businesses to reduce expenses and improve efficiency by sharing data and common equipment, such as printers, among many different computers. While printers can be shared in other ways, such as by carrying information on floppy disks from one PC to another, or using manual or electronic data switches, networks have the capacity to accommodate more users with less frustration. The power of mainframes or minicomputers can be used in harmony with personal computers. The larger machines can process larger and more complex jobs, such as maintaining the millions of records needed by a national company, while individual PCs manned by individual users handle smaller jobs such as word processing. And older equipment can be rotated to less demanding jobs as workstations are upgraded. Many software programs also offer license agreements for networks, which can be more cost effective than purchasing individual copies for each machine. The costs of implementing a network depend on issues of performance, compatibility, and whether value must be added to a turnkey system through additional programming or the addition of special components.

By coordinating all data and applications through a single network, backup copies of data for all systems can be made more consistently than could be expected if left to individual users. Additional, updated software for all machines on a network can be installed through a single PC. A centralized system simplifies other aspects of administration, too. With the proper software, computer security can also be implemented more effectively in a network than among many individual hard drives. Access to files can be restricted to password holders or it can be limited to inquiry-only access for public users. Generally, security measures are more vulnerable at machines with single user operating systems than those with network security precautions.

What is a 4th Generation Intranet?

4th Generation Intranets have learning capabilities

Most of the out-the-box 3^rd generation intranets (Share Point etc) have a content management system with an attached search engine. This leads to a �one size fits all organizations� approach which means that most organizations suffer from poor find ability of documents and many of the documents that are published are just not of a high enough quality to be useful.

The 4^th Generation of Intranets

Like many of the major websites such as Amazon, Wikipedia and Facebook, a 4th generation intranet anonymously collect information about how individuals search and find content and how they navigate through the intranet. They constantly provide simple to use, yet workflow controlled mechanisms to highlight and review poor quality documents and information. The intranet then uses this �intelligence� to streamline the search engine, automatically promoting relevant information to users as they browse or search, not just randomly, but based upon the real world usage of other people in the same organisation. The net result is an intranet that becomes easier to manage, contains higher quality information and allows an everyday member or your staff to locate key information faster and easier than ever before. Overall a 4^th Generation Intranet will make a noticeable and measurable difference to an organisation.

Interact 4 is the World�s First 4G Intranet
It overcomes the age-old problem of out-of-date and unmanageable content that exists on any intranet when you add more and more documents. Version 4.0 has an intelligence store that learns as people use it. It anonymously logs every mouse click, learns and adapts and drives employee collaboration.

More Documents + More Use = A More Powerful and Efficient Intranet

Outstanding Findabillity

Interact 4's ability to learn ensures that the more you use the Intranet the easier it is to find information that is relevant to you. It also helps to ensure all documents are easy to find when they are added to the intranet.

• Automatic Content Cataloguing
  Interact 4 recommends where to store documents when you add them so a document will never be stored in the wrong place.
  
  
• Keyword Suggestion Tool
  Interact 4 suggests the best keywords to catalogue documents ensuring they are easy to find.
  
  
• Best Bet Search
  The content author tags a document as a 'best bet' ensuring the information (such as health and safety policy) is very easy to find. Similar to BBC's 'Best Link'.
  
  
• Sophisticated Search Analytics
  Helps authors understand what users are searching for and improve taxonomy.
  
  
• Search ALL Content
  Interact 4, unlike some intranet searches, searches ALL content including; staff directory, categories, managed documents and plug-in software.
  
  
• Keyword Cloud
  Provides a visual representation of how a document has been found. As the size of the keyword grows the more it is searched for, you can see at a glance which are the most popular searches on the intranet.
  

Exceptional Document Quality

Interact 4 ensures that your intranet content is kept up-to-date and relevant.

• Auto Review Dates
  When a document is added to the intranet the author can set a review date and a workflow alert will be issued to the author at the relevant time.
  
  
• Content Feedback - out-of-date Content Notification
  If a user finds out-of-date content, they can report this to the content author with a simple mouse click.
  
  
• Content Rating
  Users can rate the quality of the content.
  
  
• Content Author Tools
  Smart templates - ready made templates for items such as newsletters and meeting minutes.
  
  
• Media Library
  Stores and manages pictures, staff photos, videos and other media.
  
  
• Advanced MS Word^TM Format Clearing
  With Interact 4 it's now event faster and simpler to copy content from Word documents onto the intranet.

Superior Content Visibility & Promotion

Interact 4 has a user controlled interface that allows content to be profiled more efficiently.

• Homepage Layouts and Management
  Interact 4 has advanced homepage elements that allow more content to be visible on one homepage as well as the ability to produce more valid layouts.
  
  
• Interact 4 Recommends
  Interact 4 uses its Intelligence Store to make suggestions of similar documents that may also be of interest to the user.
  
  
• Interact 4 Search Alerts
  Receive emails on the latest relevant content added to the Intranet based on your choice of keywords and phrases.
  
  
• Article Statistics
  Users can see how popular articles are, when they were last updated and how many viewers the article has had in a given timeframe.

Operating Systems and Computer Networks

What Is a Computer Operating System?

Computers use low-level software called an operating system (O/S) to help people build and run their own programs. Operating system software runs not just on laptop computers but also on cell phones, network routers and other so-called embedded devices.

Types of Operating Systems

The best-known operating systems are those used on personal computers:

• Microsoft Windows
• Mac OS X
• Linux

Some operating systems are designed for certain types of equipment, such as

Google Android (a variant of Linux), and Symbian - for cell phones

Solaris, HP-UX, DG-UX, and other variants of Unix - for server computers

DEC VMS (Virtual Memory System) - for mainframe computers

Other operating systems enjoyed a period of notoriety but are of only historical interest now:
Novell Netware was a popular O/S for PCs in the 1990s

IBM OS/2 was an early PC O/S that competed with Microsoft Windows for a time but had limited success

Multics was an especially innovative operating system created in the 1960s for mainframes, that influenced the later development of Unix

Network Operating Systems

A modern O/S contains much built-in software designed to simplify networking of a computer. Typical O/S software includes an implementation of TCP/IP protocol stack and related utility programs like ping and traceroute. This includes the necessary device drivers and other software to automatically enable a device's Ethernet interface. Mobile devices also normally provide the programs needed to enable Wi-Fi, Bluetooth, or other wireless connectivity.
The early versions of Microsoft Windows did not provide any computer networking support. Microsoft added basic networking capability into its operating system starting with Windows 95 and Windows for Workgroups. Microsoft also introduced its Internet Connection Sharing (ICS) feature in Windows 98 Second Edition (Win98 SE). Contrast that with Unix, which was designed from the beginning with networking in view. Nearly any consumer O/S today qualifies as a network operating system due to the popularity of the Internet.

Embedded Operating Systems

A so-called embedded system supports no or limited configuration of its software. Embedded systems like routers, for example, typically include a pre-configured Web server, DHCP server, and some utilities but do not allow the installation of new programs. Examples of embedded operating systems for routers include:

Cisco IOS (Internetwork Operating System)
DD-WRT
Juniper Junos
An embedded OS can also be found inside an increasing

An intranet to serve various departments

Human Resources: From employee training materials to the employee handbook, an intranet can offer quick easy access to fundamental publications to all employees. Benefits, 401 k tracking, job applications, and an employee directory are just a few examples. A company newsletter and employee newsgroups or chat boards are other opportunities an intranet affords.

Sales Department: One of the most productive uses of an intranet is interactive multimedia training. Sales reports, forecasts and goals, marketing strategies and geographic saturation are all tools the intranet can keep available at the click of a mouse. Profiles of potential new markets or clients, and information on potential competing markets can also be helpful to sales staff in designing better sales models.

Accounting Department: Requisition requests on an intranet will save time, resources and money. Pages within an intranet can be password protected to limit employee access, or administratively controlled. Payroll, receivables/payables, and budget reports are all processes that can reside on the intranet.

Information Systems: Data warehousing access, departmental software development applications, and network support can be invaluable uses of an intranet. Intranet support itself with FAQs and interactive tutorials for virtually any purpose or department, allow employees to teach themselves, minimizing training investment. Security information and technical resources are also common uses of an intranet.

Executive Branch: Bottom line information like quarterly profit/loss reports, stock market analysis, tax and legal information, and merger or partnership information can all be neatly provided on an intranet. Meeting minutes, appointment calendars and key profiles (employees, companies or clients) can also reside here.

An intranet provides access to information quickly and easily in a familiar environment, while keeping this information securely off the public Internet. It also facilitates interdepartmental cooperation and saves hard and soft resources.

What Is Intranet?

An intranet is a private computer network that uses Internet Protocol technologies to securely share any part of an organization's information or network operating system within that organization. The term is used in contrast to internet, a network between organizations, and instead refers to a network within an organization. Sometimes the term refers only to the organization's internal website, but may be a more extensive part of the organization's information technology infrastructure. It may host multiple private websites and constitute an important component and focal point of internal communication and collaboration.



An intranet is built from the same concepts and technologies used for the Internet, such as client–server computing and the Internet Protocol Suite (TCP/IP). Any of the well known Internet protocols may be found in an intranet, such as HTTP (web services), SMTP (e-mail), and FTP (file transfer). Internet technologies are often deployed to provide modern interfaces to legacy information systems hosting corporate data.

An intranet can be understood as a private analog of the Internet, or as a private extension of the Internet confined to an organization. The first intranet websites and home pages began to appear in organizations in 1990-1991. Although not officially noted, the term intranet first became common-place among early adopters, such as universities and technology corporations, in 1992.[dubious – discuss]

Intranets are also contrasted with extranets. While intranets are generally restricted to employees of the organization, extranets may also be accessed by customers, suppliers, or other approved parties.[1] Extranets extend a private network onto the Internet with special provisions for access, authorization, and authentication (AAA protocol).

Intranets may provide a gateway to the Internet by means of a network gateway with a firewall, shielding the intranet from unauthorized external access. The gateway often also implements user authentication, encryption of messages, and often virtual private network (VPN) connectivity for off-site employees to access company information, computing resources and internal communications.


Uses of Intranet:

Increasingly, intranets are being used to deliver tools and applications, e.g., collaboration (to facilitate working in groups and teleconferencing) or sophisticated corporate directories, sales and customer relationship management tools, project management etc., to advance productivity.

Intranets are also being used as corporate culture-change platforms. For example, large numbers of employees discussing key issues in an intranet forum application could lead to new ideas in management, productivity, quality, and other corporate issues.

In large intranets, website traffic is often similar to public website traffic and can be better understood by using web metrics software to track overall activity. User surveys also improve intranet website effectiveness. Larger businesses allow users within their intranet to access public internet through firewall servers. They have the ability to screen messages coming and going keeping security intact.

When part of an intranet is made accessible to customers and others outside the business, that part becomes part of an extranet. Businesses can send private messages through the public network, using special encryption/decryption and other security safeguards to connect one part of their intranet to another.

Intranet user-experience, editorial, and technology teams work together to produce in-house sites. Most commonly, intranets are managed by the communications.

Benefits of Intranet:

• Workforce productivity: Intranets can help users to locate and view information faster and use applications relevant to their roles and responsibilities. With the help of a web browser interface, users can access data held in any database the organization wants to make available, anytime and - subject to security provisions - from anywhere within the company workstations, increasing employees' ability to perform their jobs faster, more accurately, and with confidence that they have the right information. It also helps to improve the services provided to the users.
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• Time: Intranets allow organizations to distribute information to employees on an as-needed basis; Employees may link to relevant information at their convenience, rather than being distracted indiscriminately by electronic mail.
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• Communication: Intranets can serve as powerful tools for communication within an organization, vertically and horizontally. From a communications standpoint, intranets are useful to communicate strategic initiatives that have a global reach throughout the organization. The type of information that can easily be conveyed is the purpose of the initiative and what the initiative is aiming to achieve, who is driving the initiative, results achieved to date, and who to speak to for more information. By providing this information on the intranet, staff have the opportunity to keep up-to-date with the strategic focus of the organization. Some examples of communication would be chat, email, and or blogs. A great real world example of where an intranet helped a lot of company's.

• Web publishing allows cumbersome corporate knowledge to be maintained and easily accessed throughout the company using hypermedia and Web technologies. Examples include: employee manuals, benefits documents, company policies, business standards, newsfeeds, and even training, can be accessed using common Internet standards (Acrobat files, Flash files, CGI applications). Because each business unit can update the online copy of a document, the most recent version is usually available to employees using the intranet.
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• Business operations and management: Intranets are also being used as a platform for developing and deploying applications to support business operations and decisions across the internetworked enterprise.
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• Cost-effective: Users can view information and data via web-browser rather than maintaining physical documents such as procedure manuals, internal phone list and requisition forms. This can potentially save the business money on printing, duplicating documents, and the environment as well as document maintenance overhead. For example, Peoplesoft "derived significant cost savings by shifting HR processes to the intranet".
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• Enhance collaboration: Information is easily accessible by all authorised users, which enables teamwork.
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• Cross-platform capability: Standards-compliant web browsers are available for Windows, Mac, and UNIX.
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• Built for one audience: Many companies dictate computer specifications which, in turn, may allow Intranet developers to write applications that only have to work on one browser (no cross-browser compatibility issues). Being able to specifically address your "viewer" is a great advantage. Since Intranets are user-specific (requiring database/network authentication prior to access), you know exactly who you are interfacing with and can personalize your Intranet based on role (job title, department) or individual ("Congratulations Jane, on your 3rd year with our company!").
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• Promote common corporate culture: Every user has the ability to view the same information within the Intranet.
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• Immediate updates: When dealing with the public in any capacity, laws, specifications, and parameters can change. Intranets make it possible to provide your audience with "live" changes so they are kept up-to-date, which can limit a company's liability.
• Supports a distributed computing architecture: The intranet can also be linked to a company’s management information system, for example a time keeping system.

Planning and creation

Most organizations devote considerable resources into the planning and implementation of their intranet as it is of strategic importance to the organization's success. Some of the planning would include topics such as:

• The purpose and goals of the intranet
• Persons or departments responsible for implementation and management
• Functional plans, information architecture, page layouts, design
• Implementation schedules and phase-out of existing systems
• Defining and implementing security of the intranet
• How to ensure it is within legal boundaries and other constraints
• Level of interactivity desired
• Is the input of new data and updating of existing data to be centrally controlled or devolved

These are in addition to the hardware and software decisions , participation issues (like good taste, harassment, confidentiality), and features to be supported.

Intranets are often static sites. Essentially they are a shared drive, serving up centrally stored documents alongside internal articles or communications (often one-way communication). However organisations are now starting to think of how their intranets can become a 'communication hub' for their team by using companies specialising in 'socialising' intranets.

The actual implementation would include steps such as:

• Securing senior management support and funding.
• Business requirements analysis.
• User involvement to identify users' information needs.
• Installation of web server and user access network.
• Installing required user applications on computers.
• Creation of document framework for the content to be hosted.
• User involvement in testing and promoting use of intranet.
• Ongoing measurement and evaluation, including through benchmarking against other intranets.

Another useful component in an intranet structure might be key personnel committed to maintaining the Intranet and keeping content current. For feedback on the intranet, social networking can be done through a forum for users to indicate what they want and what they do not like.

Computer Hardware And Networking

Nowadays, we live in a world of computers in which the idea of networking has become more and more popular among users. This is an important reason why more users want to find out more about computer hardware and networking. The concept of networking refers to the idea of linking two or even more than two computers which the specific purpose of different users sharing data.

A very important aspect that has to be mentioned when talking about computer hardware and networking is the fact that any network is built by using a combination of hardware and software. An important way in which networks can be classified is by analyzing the area in which the network coverage sans. From this point of view there are two main types known by the most users: the local area network (LAN) and the wide area type of network (WAN). The first type is known to reach across one home, while the second type, the wide area type of network reaches even across several cities or across the world, in the case of the more improved ones.

Another important category in which networks can be divided is the one related to their design. In this respect, there are also two basic types: client-server and peel to peel. The first type is more often encountered in business, while the second one is more often encountered in personal homes. When categorizing networks by taking in account the way in which data flows and the structure of the networks, we can talk about bus networks and star networks. The first type includes the computers that usually communicate and share data by following the same conduit. In the case of star networks, the data usually flows through a certain type of centralized device.

Another important aspect related to computer hardware and networking is the protocol and that is the language used by computers to communicate between them. Very familiar types of protocol among users are TCP and IP, which are usually found on the internet and on the home established networks. These two types of protocols can be used with both wired and wireless networks. The wireless technology has become more familiar among users, and the newer networks are usually established in this way.

Wireless networking is very important in relation with computer hardware and networking nowadays, this is because almost everyone wants to have access to the latest technology in computers these days, and the wireless networking is part of the latest technology. This type of network can be established by using fiber optic types of cables between different network devices. When comparing a wireless network with a wired one there are both advantages and disadvantages that have to be taken in account for both types. One of the main advantages offered wireless technology in computer hardware and networking is the fact that assures the elimination of all the unnecessary cables used within wired networks. One of the main disadvantages related to this type of network is the possibility to encounter radio interference due to other types of devices or even due to weather. The wireless technology keeps on improving every day and it has become more and more familiar among users nowadays.

An important hardware technology that is used to network computers inside homes, and buildings such as schools and offices, by using cables and adapters is the Ethernet. Among the many standard cables that can be used with this technology very common are CAT 5 and CAT 6cables. CAT 5 is a standard type of cable used with computer networks and is much appreciated because it supports high-speed type of networking. There are two categories of CAT 5 cables, one with solid type of wires and one with stranded types of wires.

Another important term related to computer hardware and networking is the term route. Routers are known as physical types of devices used to connect networks together. This device can be used with both wired and wireless types of networks. Routing table is another important term which is used to represent a piece of storage in which it is maintained configuration type of information. Some types of routers allow the networker to use a Web browser type of interface so as to update the routing table.

A broadband router refers to the type of routers that are able to combine features form the traditional type of networks with a DHCP type of server. These types of routers are appropriate for home networks, but especially for those who have DSL type of internet service. A broadband router is known to support all sorts of sharing including files sharing, internet sharing and even LAN type of home gaming. As the wireless technology is improving every day, nowadays we can find wireless types of routers which are able to support broadband types of internet access as the wired ones.

When discussing about computer hardware and networking it is also important for the users to know that there are many ways in which they can protect their computers from being damaged by receiving files from unauthorized devices that might connect to their computer network. One possibility that the users have to overcome this risk is by using a network firewall. A network firewall is either a hardware device, or a software program or maybe both. These types of devices are very important to be used by those users who want to protect their computers from unauthorized access from outside their network, access that might cause several damages to the user's computer.

Nowadays, everyone is interested in finding out as much information as possible related to the latest technology in almost every domain. In what concerns the computers the latest technology has become more familiar among users. This is because everyone uses a computer these days and needs to be aware of every new accessory that can help him or her to work easily with the computer or to do something that they were not able to do in the past. Among the many aspects concerning the latest technology a very important one is that relates to computer hardware and networking, as even in this field wireless technology has become available.

Successful Networking: 8 Expert Tips

Networking is a crucial tool in the development of business and social relationships. Knowing how to network effectively can lead to success in both areas. Experts have provided eight helpful tips on how to network productively.

The first hint on successful networking involves getting out there. Whether its attending a party, going to a business event, or joining an organization, the first step in networking is getting involved. You cannot expect to make and develop relationships without making yourself accessible to others. People need to meet you and feel comfortable in order for networking to be a success. For this reason you should try to involve yourself in as many activities as your schedule allows.

Meeting new people and attending social functions is not enough. You need to arrive prepared. This means you need to do research on what events will be beneficial to you. Once you decide which gatherings to be a part of you should do some fact finding on the organization or people that will be there. By knowing what to expect, and by being knowledgeable about potential contacts you will stand out from the rest.

Thirdly, never leave home without your business cards. Make sure your cards include your name, address, important phone numbers and an email address. They should also include a business logo and slogan or tagline. You should give out your business cards generously, even two at a time. The more cards you have circulating at any given time the more helpful they will be. Handing out your business cards is vital but it is equally important to collect them from others. The proper business card etiquette is that whenever you give out a card, you should always ask for one in return. When you are given the business card do not stick in your pocket or in your handbag. You should take a few seconds to look it over to show your interest. You should keep a pen available to jot notes on the back of business cards that are given to you. These notes should include something that will make you remember the person, or anything you committed to do for them.

Next, you should have an effective 15 to 30 second pitch ready. You should be prepared to introduce yourself and make your contact aware of what you can do for them in 30 seconds or less, because that may be all the time you have. You should be passionate, energetic and personable. Have a few introductions prepared that way you can use the appropriate one for any given situation.

The next expert tip emphasizes that you should not try to sell during your networking attempt. Networking is about meeting new people, making contacts, and building relationships, not sales pitches.
Also, while you are at a networking event and meet new people, it is important to ask your new connections about themselves or their businesses. By asking questions you’ll be better able to determine what you can offer them. In addition, people generally enjoy talking about themselves, so being inquisitive will often make you look friendly and interested.

The sixth expert tip is to be a problem solver. When you approach a new person tell them how you can be of help to them now o in the future. Cutting to the chase is usually more appealing.
Also, when networking, you should be assertive. This means go up to people and introduce yourself; don’t wait for them to approach you. Try not to spend too much time talking to people you already know. While this might be more comfortable it is not an effective way to make new connections.

Computer networking device

A full list of Computer networking devices are units that mediate data in a computer network. Computer networking devices are also called network equipment, Intermediate Systems (IS) or InterWorking Unit (IWU). Units which are the last receiver or generate data are called hosts or data terminal equipment.

List of computer networking devices

Common basic networking devices:

Gateway: device sitting at a network node for interfacing with another network that uses different protocols. Works on OSI layers 4 to 7.

Router: a specialized network device that determines the next network point to which to forward a data packet toward its destination. Unlike a gateway, it cannot interface different protocols. Works on OSI layer 3.

Bridge: a device that connects multiple network segments along the data link layer. Works on OSI layer 2.

Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2.

Hub: connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time. Depending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc). It provides bandwidth which is shared among all the objects, compared to switches, which provide a dedicated connection between individual nodes. Works on OSI layer 1.

Repeater: device to amplify or regenerate digital signals received while setting them from one part of a network into another. Works on OSI layer 1.
Some hybrid network devices:

Multilayer Switch: a switch which, in addition to switching on OSI layer 2, provides functionality at higher protocol layers.

Protocol Converter: a hardware device that converts between two different types of transmissions, such as asynchronous and synchronous transmissions.
Bridge Router(Brouter): Combine router and bridge functionality and are therefore working on OSI layers 2 and 3.

Digital media receiver: Connects a computer network to a home theatre
Hardware or software components that typically sit on the connection point of different networks, e.g. between an internal network and an external network:

Proxy: computer network service which allows clients to make indirect network connections to other network services

Firewall: a piece of hardware or software put on the network to prevent some communications forbidden by the network policy

Network Address Translator: network service provide as hardware or software that converts internal to external network addresses and vice versa
Other hardware for establishing networks or dial-up connections:

Multiplexer: device that combines several electrical signals into a single signal

Network Card: a piece of computer hardware to allow the attached computer to communicate by network

Modem: device that modulates an analog "carrier" signal (such as sound), to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information, as a computer communicating with another computer over the telephone network

ISDN terminal adapter (TA): a specialized gateway for ISDN

Line Driver: a device to increase transmission distance by amplifying the signal. Base-band networks only.

Network Device Connectivity

How to Increase Internet Connection Speed

Find out from your Internet Service Provider (ISP) what Internet connection speed your paying for. Make sure the speed your paying for is the speed programmed in their network.

Test your Internet connection speed. You can do this by going to one of these speed test websites: Speakeasy.net/speedtest or Speedtest.net. Record your results.

Compare the speeds from step one and step two. If your getting the speed your paying for go no further. If your not, go to the next step.

Disable web-browser Add-ons that can slow down your Internet connection speed. Check to see if you have multiple web browser Add-ons operating with your browser. For example, if your web browser is Internet explorer, go to Tools, select Manage Add-ons, and look at what Add-ons are enabled. Disable the ones you do not want to use.

Run anti-virus, adware, spyware, and malware scans. All of these, if found on your computer, could negatively affect your Internet connection speed.

Run Disk Cleanup and Disk Defragmenter from your System Tools menu.

Download TCP Optimizer software to optimize your computers MTU (Maximum Transmission Unit) values, RWIN (Receive Window) values, and broadband related registry keys. The most popular and FREE TCP Optimizer that I found is called "SG TCP Optimizer". You can download it at CNET: http://www.download.com/SG-TCP-Optimizer/3000-2155_4-10488572.html?tag=lst-1 or at PCWORLD: http://www.pcworld.com/downloads/file/fid,68524-order,1-page,1/description.html.

Retest your Internet connection speed by going to one of these speed test websites: Speakeasy.net/speedtest or Speedtest.net. Record and compare these results with the results obtained from steps one and two.

Disadvantages of Computer Networks

Following are some of the major disadvantages of computer networks.

Security Issues: One of the major drawbacks of computer networks is the security issues involved. If a computer is a standalone, physical access becomes necessary for any kind of data theft. However, if a computer is on a network, a computer hacker can get unauthorized access by using different tools. In case of big organizations, various network security softwares are used to prevent the theft of any confidential and classified data.

Rapid Spread of Computer Viruses: If any computer system in a network gets affected by computer virus, there is a possible threat of other systems getting affected too. Viruses get spread on a network easily because of the interconnectivity of workstations. Such spread can be dangerous if the computers have important database which can get corrupted by the virus.

Expensive Set Up: The initial set up cost of a computer network can be high depending on the number of computers to be connected. Costly devices like routers, switches, hubs, etc., can add up to the bills of a person trying to install a computer network. He will also have to buy NICs (Network Interface Cards) for each of the workstations, in case they are not inbuilt.

Dependency on the Main File Server: In case the main File Server of a computer network breaks down, the system becomes useless. In case of big networks, the File Server should be a powerful computer, which often makes it expensive.

Computer Networking Advantages

Following are some of the advantages of computer networks.

File Sharing: The major advantage of a computer network is that is allows file sharing and remote file access. A person sitting at one workstation of a network can easily see the files present on the other workstation, provided he is authorized to do so. It saves the time which is wasted in copying a file from one system to another, by using a storage device. In addition to that, many people can access or update the information stored in a database, making it up-to-date and accurate.

Resource Sharing: Resource sharing is also an important benefit of a computer network. For example, if there are four people in a family, each having their own computer, they will require four modems (for the Internet connection) and four printers, if they want to use the resources at the same time. A computer network, on the other hand, provides a cheaper alternative by the provision of resource sharing. In this way, all the four computers can be interconnected, using a network, and just one modem and printer can efficiently provide the services to all four members. The facility of shared folders can also be availed by family members.

Increased Storage Capacity: As there is more than one computer on a network which can easily share files, the issue of storage capacity gets resolved to a great extent. A standalone computer might fall short of storage memory, but when many computers are on a network, memory of different computers can be used in such case. One can also design a storage server on the network in order to have a huge storage capacity.

Increased Cost Efficiency: There are many softwares available in the market which are costly and take time for installation. Computer networks resolve this issue as the software can be stored or installed on a system or a server and can be used by the different workstations.

Local Area Networks (LAN)

A single building or campus of few kilometers in size, LAN acts as privately-owned networks. LANs are limited to a single building or group of buildings. By using telephone lines and radio waves, one LAN can be attached to other LANs over any distance. A system of multiple connections of LANs is called a wide-area network (WAN).

Most LANs are used to connect workstations and personal computers. In a LAN, each host means individual computer has its own CPU with which it runs programs but it also able to access data and devices anywhere on the LAN. This means that many users can share data information and expensive devices like laser printers. By sending e-mail or engaging in chat session users can also make use of LAN to interact with each other.

In today's world, Local Area Networks become fundamental part of communication. LAN applications are used in hospitals, educational facilities businesses, stock exchanges and warehouses. Local area network provides reader-friendly, comprehensive coverage of LAN technologies to be used in real-world applications.

LANs are typically identified by the following properties
1)Multiple systems connected to shared medium
2)High total bandwidth
3)Low delay
4)Low error rate
5)Broadcast/Multicast capability
6)Limited geography 1-2 km
7)Limited number of stations
8)Peer relationship between stations
9)Confined to private property

LANs are distinguished from other network by three characteristics:
1)Their size
2)Their transmission technology and
3)Their topology.

LANs are limited in size which means that the worst case transmission time is restricted and known in advance. Knowing this limitation makes it possible to make use of certain kinds of designs that would not otherwise be possible. It also simplifies network management.

LANs often make use of a transmission technology including of a single cable to which all the machines are connected like the telephone company party lines used in rural areas. Traditionally LANs operates at speeds of 10 to 100 Mbps with low delay and make very few errors. Newer LANs are working at speed of up to 100 megabits/sec.

Various topologies of LANs are:
1) Bus Topology:
In a bus or linear cable network, at any instant one machine is allowed to transmit data or information. All other machines are needed to desist from sending. When two or more machines want to transmit simultaneously an arbitration mechanism is used to resolve conflicts. The arbitration mechanism used may be centralized or distributed. IEEE 802.3 known as Ethernet is a bus dependent broadcast network with decentralized control working at 10 or 100Mbps. Computers on an Ethernet can deliver data whenever they want to if two or more packets collide with each other then each computer just wait a random amount of time and tries again later.

2) Ring Topology:
A second type of topology used in broadcast system is the ring topology. In a ring topology, each bit circulates around on its own not waiting for the remaining packet to which it belongs. Each bit circulates the entire ring in the time. It uses to deliver a few bits usually before the complete packet has been delivered. Like all other broadcast system, some limitation is required for arbitrating simultaneously accesses to the ring. IEEE 802.5 known as token ring is a popular ring based LAN working at 4 and 16 Mbps.

3) Star topology:
In Star topology all devices are attached to a central hub. To install and manage Star networks are relatively easy but bottlenecks can occur because all data must pass through the hub.

4) Tree topology:
A tree topology is a combination of linear bus and star topologies. It includes groups of star-configured workstations attached to a linear bus backbone cable.

Design considerations :

1) Cabling medium :
The most costless cable is Category 5 twisted-pair cable. This cable operates with standard Ethernet at a speed of 10 Million bits per second or 10 Mbps and "fast" Ethernet works at a speed 100 Mbps and is able to speeds up to 150 Mbps with existing technology. This cable is used in most LAN designs. Fiber-optic cable delivers more data but its materials and installation are much more expensive. In building proper installation of fiber-optic cable is very difficult to achieve because the cable should not be bent during installation.

2) Wiring plan
In the building the location of wiring cabinets/closets is based on distances between computers. The maximum distance should be 10 meters between a computer and a network wiring cabinet/closet. In refrigerator-sized cabinet, cables come together. Network transmission equipments are collected can be enclosed with doors and stand in a large room or it can be located as an open rack in a small room or closet. Wiring cabinets/closets can be attached with twisted-pair cable but fiber-optic cable provides higher speed.

3) Number of network connections (plug-in points) :
Every computer requires a network connection and each connection is consists of
(1) A plug-in point in the wall of the room
(2) Wiring from this point to the wiring cabinet/closet.
While deciding for network connections short and long term technology aims need to be considered

LAN Hardware
Ethernet and Token Ring are common types of LAN hardware. Ethernet is easily designed and consists of data transfer devices which are less expensive than similar Token Ring devices. Ethernet and Token Ring’s performance are same in most situations. While it is possible to connect Ethernet and Token Ring networks in the same location, it adds to cost and complexity. It is best to maintain the data communication infrastructure’s configuration as simple as possible. Asynchronous Transfer Mode is another standard for data communication. It is more expensive than Ethernet or Token Ring but offers higher speeds and will eventually offer better integration of computer-data, digitized voice (telephone), and video.

PC to Phone Calls to India from Foreign Lands

Voice over Internet Protocol is perhaps one of the best changes that has taken place in the world and is now being able to give Indian citizens the chance to enjoy free calls due the highly relieving innovations which have been made in this particular genre of communication.



VoIP started off in the year 1973 as an experimental creation known as network voice protocol being created by talented scientists especially for improving the performance of ARPANET service providers. The time jingled on to the point of realisation of business capabilities by becoming a communication medium for the common public and for the enhancement in the features involved in making international calls and also national calls. One of the major features which is now one of the main reasons for the success of the VoIP technology is to be able to take to friends by making absolutely free calls.




The major processes that are involved in the actual process that take place when a person makes a phone call with a tool which uses this technology is quite complex and is liable to be understood mostly by Telecom engineers and persons involved in some way or other in the technical back end process that takes place when a call is being made.



However the prospect of understanding the working of this technology is not bleak due to the overlying simplicity of the basic concept behind this technology. Hence when a person makes PC to Phone calls to India, the primary event that takes place is the modification of the sounds of his voice into digital packets of information which are then sent over a network to the phone of the person to whom he is making the call too. Both of these persons have the requirements for being able to make free phone calls, as being very few in number. Hence all that the person needs to make free calls to India is an free account with a VoIP service provider and a computer with the necessary software and a modem.



The benefits that are a feature of making free calls are evident by the word 'free' itself and hence, the user is able to make calls to his friends and talk for lengthy periods of time without having to pay a single symbol of monetary worth. Therefore, the need to pay a single penny, or a cent or even a paisa is completely nullified. Another major benefit is the fantastic quality of sound that the person hears when he makes a call with another one being the basic service being available in the form of numerous offers being available by the different service providers.



The feature of being able to make free PC to phone calls is hence now quite real and hence Indians regardless of the place where they are living, are able to make calls and those too free and hence, become capable of remaining in touch with their friends and relatives living in the wonderful abode known as India.Calls to India can now be made without the need to think about international call rates and how to talk with the minimum of sentences due to this feature being available quite easily. There are quite a lot of websites of various service providers who offer the feature of making free Phone calls to India and hence, the person who wants to talk to someone who is living in India can do so without having to worry about the bill that he has to pay (which in the old days, used to be quite a large one in the case of making long phone calls and also quite considerable even if the person making the call was watchful enough to keep the small time period of the call.).

The result of advances being made for the better in the Indian economy has led to an increase in the overall living standards of the Indian people and hence, the computer is now becoming quite a routine feature in most of the households of urban centres of this fantastic country. The result is the increase in free PC Phone calls being made, due to the increase in the number of people who are learning the process of making free calls.

Networking Jobs Interview questions

Here are the basic interview questions for the network administrators, system administrators and IT manager posts. These questions provide the basic information about the network communication technology, network topologies, network troubleshooting techniques, network devices and the basic overview of the LAN/WAN communication model.

What is DHCP?

DHCP stands for Dynamic Host Configuration Technology. The basic purpose of the DHCP is to assign the IP addresses and the other network configuration such as DNS, Gateway and other network settings to the client computers. DHCP reduces the administrative task of manually assigning the IP addresses to the large number of the computers in a network.

What is DNS and how it works?

DNS stands for Domain name system and it translates (converts) the host name into the IP address and IP address into to the host name. Every domain and the computer on the internet is assigned a unique IP address. The communication on the internet and in the network is based on the IP addresses. IP addresses are in this format 10.1.1.100, 220.12.1.22.3, 1.1.1.1 etc. IP addresses can't be remembered but the host names (e.g. www.networktutorials.info, xyz.com, abc.com) are easy to remember instead of their IP addresses.

What is a Firewall?

Firewall is a protective boundary for a network and it prevents the unauthorized access to a network. Most of the Windows operating system such as Windows XP Professional has built-in firewall utilities. There are the large number of the third party firewall software and the basic purpose of all the firewall software and hardware is same i.e. to block the unauthorized user access to a network.

What is WAN?

WAN stands for wide area network and it covers the broader geographical area. Basically there are three types of a computer network LAN (Local Area Network), MAN (Metropolitan Area Network) and WAN (Wide Area Network). The communication in a WAN is based on the Routers. A WAN network can cover a city, country or continents.

Define VOIP Communication Technology

VOIP stands for Voice over IP and this technology is used for transmitted the voice over the IP based long distance network to make phone calls. VOIP phone calls are very cheap and a large number of the corporate offices and home users are using VOIP technology to make long distance phone calls.

What is Wi Max Technology?

Wi Max is a wireless broadband technology and it is a advance shape of the Wi Fi (which was a base band technology). Wi Max supports data, video and audio communication at the same time at a very high speed up to 70 Mbps.Define Network GatewayNetwork Gateway can be software or a hardware. A gateway is usually a joining point in a network i.e. it connects two networks. A computer with two LAN cards can act as a gateway.

What is a Router?

A router routes the traffic to its destination based on the source and destination IP addresses, which are placed in the routing software known as routing table.How Fiber Optic Cable WorksFiber optics provides the fastest communication medium for data and voice. Data can travel at the speed of light through the fiber optic cables. ISPs and corporate offices are usually connected with each other with the fiber optic cables to provide high speed connectivity.

What is File Server?

A file server is a computer in a network that authenticates the user access in a network such as Windows 2000/2003 Servers.

Define Seven Layers of OSI Model

There are seven layers of the OSI model. The basic purpose of these layers is to understand the communication system and data transmission steps. The seven layers are Application, Presentation, Session, Transport, Network, Data Link and Physical. You can remember the name of these layers by this phrase. “All people seems to need data processing".

Define GSM Technology

GSM is a short range wireless technology and is usually used in the mobile phones, hand help devices, MP3 players, Laptops, computers and in cars.