Networking, also known as computer networking, is the practice of transporting and exchanging data between nodes over a shared medium in an information system. Networking comprises not only the design, construction and use of a network, but also the management, maintenance and operation of the network infrastructure, software and policies.

Computer networking enables devices and endpoints to be connected to each other on a local area network (LAN) or to a larger network, such as the internet or a private wide area network (WAN). This is an essential function for service providers, businesses and consumers worldwide to share resources, use or offer services, and communicate. Networking facilitates everything from telephone calls to text messaging to streaming video to the internet of things (IoT).

The level of skill required to operate a network directly correlates to the complexity of a given network. For example, a large enterprise may have thousands of nodes and rigorous security requirements, such as end-to-end encryption, requiring specialized network administrators to oversee the network.

At the other end of the spectrum, a layperson may set up and perform basic troubleshooting for a home Wi-Fi network with a short instruction manual. Both examples constitute computer networking.

ARPANET − Advanced Research Projects Agency Network − the granddad of Internet was a network established by the US Department of Defense (DOD). The work for establishing the network started in the early 1960s and DOD sponsored major research work, which resulted in development on initial protocols, languages and frameworks for network communication.

It had four nodes at University of California at Los Angeles (UCLA), Stanford Research Institute (SRI), University of California at Santa Barbara (UCSB) and University of Utah. On October 29, 1969, the first message was exchanged between UCLA and SRI. E-mail was created by Roy Tomlinson in 1972 at Bolt Beranek and Newman, Inc. (BBN) after UCLA was connected to BBN.

Internet

ARPANET expanded to connect DOD with those universities of the US that were carrying out defense-related research. It covered most of the major universities across the country. The concept of networking got a boost when University College of London (UK) and Royal Radar Network (Norway) connected to the ARPANET and a network of networks was formed.

The term Internet was coined by Vinton Cerf, Yogen Dalal and Carl Sunshine of Stanford University to describe this network of networks. Together they also developed protocols to facilitate information exchange over the Internet. Transmission Control Protocol (TCP) still forms the backbone of networking.

Telenet

Telenet was the first commercial adaptation of ARPANET introduced in 1974. With this the concept of Internet Service Provider (ISP) was also introduced. The main function of an ISP is to provide uninterrupted Internet connection to its customers at affordable rates.

World Wide Web

With commercialization of internet, more and more networks were developed in different part of the world. Each network used different protocols for communicating over the network. This prevented different networks from connecting together seamlessly. In the 1980s, Tim Berners-Lee led a group of Computer scientists at CERN, Switzerland, to create a seamless network of varied networks, called the World Wide Web (WWW).

World Wide Web is a complex web of websites and web pages connected together through hypertexts. Hypertext is a word or group of words linking to another web page of the same or different website. When the hypertext is clicked, another web page opens.

The evolution from ARPANET to WWW was possible due to many new achievements by researchers and computer scientists all over the world. Here are some of those developments −

Year - Milestone

1957 - Advanced Research Project Agency formed by US

1969 - ARPANET became functional

1970 - ARPANET connected to BBNs

1972 - Roy Tomlinson develops network messaging or E-mail. Symbol @ comes to mean "at"

1973 - APRANET connected to Royal Radar Network of Norway

1974 - Term Internet coined, First commercial use of ARPANET, Telenet, is approved

1982 - TCP/IP introduced as standard protocol on ARPANET

1983 - Domain Name System introduced

1986 - National Science Foundation brings connectivity to more people with its NSFNET program

1990 - ARPANET decommissioned, First web browser Nexus developed, HTML developed

2002-2004 - Web 2.0 is born

1. Based on Moe of Transmission

• Wired networking - requires the use of a physical medium for transport between nodes. Copper-based Ethernet cabling, popular due to its low cost and durability, is commonly used for digital communications in businesses and homes. Alternatively, optical fiber is used to transport data over greater distances and at faster speeds, but it has several tradeoffs, including higher costs and more fragile components.

• Wireless networking - uses radio waves to transport data over the air, enabling devices to be connected to a network without any cabling. Wireless LANs are the most well-known and widely deployed form of wireless networking. Alternatives include microwave, satellite, cellular and Bluetooth, among others.

As a general rule, wired networking offers greater speed, reliability and security compared to wireless networks; wireless networking tends to provide more flexibility, mobility and scalability.

2. Based on Scope of Networks.

• PAN (Private Area Network) - PAN is for one person. A typical example of PAN is wireless communication network. A key capability of PAN is to enable devices to autonomously detect and acquire one another. Other PAN applications include mobile commerce in which user of a mobile device communicates with another machine for commerce such as ticket purchase.

• LAN (Local Area Network) - LANs are small size networks which only cover a few buildings or a campus of up to a few kilometers. LANs are widely used to connect personal computers and workstations in company offices, factories and universities to share resources and exchange information. Typical example of LAN is to share printers in a Lab or a department.

• MAN (Metropolitan Area Network) - The size of a MAN can cover a city whose scope is less than 100km. The best-known example of MAN is cable television networks, such as Rogers cable TV systems. High speed wireless Internet access is another MAN.

• WAN (Wide Area Network) - WANs span large geographical areas, often countries or continents. They contain millions of machines which are connected by communication subnets. Internet is the largest WAN ever established.

Computer networking requires the use of physical network infrastructure -- including switches, routers and wireless access points - and the underlying firmware that operates such equipment. Other components include the software necessary to monitor, manage and secure the network.

Additionally, networks rely on the use of standard protocols to uniformly perform discrete functions or communicate different types of data, regardless of the underlying hardware.

For example, voice over IP (VoIP) can transport IP telephony traffic to any endpoint that supports the protocol. HTTP provides a common way for browsers to display webpages. The internet protocol suite, also known as TCP/IP, is a family of protocols responsible for transporting data and services over an IP-based network.

Security systems, with sensors and a keypad, perform functions that are quite different than those of a surveillance system. And each of these systems, taken alone, can be adapted to a variety of uses. Before planning one or the other, or both, for your home, take a moment to consider what you want to achieve.

We think of security systems as being intrusion alarms to protect us from burglars, but they do much more than that. A well designed complete security system provides comprehensive protection for both the property and its residents. The optimum system protects from gas leaks, smoke and fire, floods, electrical outages, sudden temperature drops and more. It tracks comings and goings of specific individuals, allows for one part of the home to be partitioned from the rest, to be operated separately. It allows for other devices to be controlled by the system through output relays. It can link to lighting systems for integrated home control, including heat setback and lights out commands. It can include an emergency button for personal safety.

A surveillance system is about camera images. It may or may not be combined with a security system and it may or may not include image recording and playback.

THE MONITORED SECURITY SYSTEM

People often assume that security system monitoring is an unnecessary added expense, but it is really the core of the protection provided by the system. Sensors throughout the home report back to the panel, to indicate a change in the status of the sensor. A water sensor reports when it is wet, a door contact reports when it is open, a glassbreak detector reports the sound of breaking glass, etc. The system takes these signals and assigns definitions to them, so that they are understood at the monitoring station. Certain sensors, such as a smoke or gas detector, or personal medical alarm, are defined as urgent, so that the monitoring station, after checking to see if it’s a false alarm, immediately dispatches emergency responders. One of the greatest advantages of this monitoring is that it works whether you are home or not, so if a fire started while the house was empty, the system calls the fire department. A monitored system which will send the police is also much more effective in the case of a break-in than just sirens, which may or may not scare away an intruder. A monitored system also has a silent alarm, so that if someone forces you to disarm it, a secret signal can still alert the station so that the police will be sent. If the cable is cut the monitoring station knows it and dispatches emergency response. The monitoring station checks the system in the middle of the night to make sure that communication is working. People call you to let you know when something other than an emergency is a problem with your system. For all that you pay a monthly fee.

THE UNMONITORED SECURITY SYSTEM

If you install a system that is designed to connect to a monitoring station and don’t set up a monitoring contract you are wasting most of the system’s potential. Now when sensors detect a change of state, a siren will sound or a keypad will chime, depending on your programming. A message will show up on the keypad, either a few letters of text or a code. If it has detected a basement flood the keypad will chime intermittently until you acknowledge it by turning it off. You won’t get a phone call. If it detected a fire when you weren’t there, or an intruder, it would set off the siren, but would the neighbours respond? Would the burglar be scared away? How long would the siren sound before someone realized the house was on fire?

THE SELF-MONITORED SECURITY SYSTEM

You can install a system that puts you in charge of monitoring by calling your cell phone or sending you a text. You are usually doing something else, rather than waiting as a monitoring service does for the system to call, but at least you know what’s happening. Some self-monitored systems are very inexpensive and use wireless sensors. They let you avoid not only the monitoring but the wiring costs. Others combine with a home automation system so that you can use the security system to control lighting or heating, either by a preset schedule or with your phone. They can even include cameras that can be viewed from your phone. This is a system that puts it all on you, and if you’re comfortable with that, it can save money and provide fairly good security. You can get the best of both worlds if you connect a self-monitored system with automation to a system that’s designed to be monitored. That way the professionals keep an eye on things while you have the ability to control all kinds of things from a distance.

WIRELESS VS. HARDWIRED

Theoretically the hard-wired security system should be more reliable because the information travels over dedicated paths. It’s true that interference can get in the way of wireless sensors. But every system, whether hard-wired or wireless, monitors its sensors constantly and if you lost the signal from the sensor you would know right away. It’s not a common occurrence in the real world, where wireless sensor devices are pretty reliable. Many systems designed to be monitored allow for hybrid connections, sharing both hard wired and wireless sensors in the same panel. It’s a way to get around difficult retrofit wiring and also to expand the panel’s capabilities without requiring more terminals to wire in.

SURVEILLANCE

A surveillance system is all about watching, maybe also listening, and usually recording. It can be combined with a security system but can’t take over all of the capabilities of a comprehensive security installation. There are only four elements to a surveillance system: cable, cameras, recorder and monitor. The cable transmits power for the camera in one direction and the images (and sound) captured by the camera in the other. Cameras come in many shapes and sizes to suit their application, from pinhole cameras at the ATM to large heated camera enclosures hanging from the eaves. The recorder stores the images, sorts them in a way that they can be retrieved, and sends them to a monitor or the Internet. The monitor is just a TV screen, and most surveillance systems can be displayed on an old CRT screen or a new flat screen. Now a laptop, tablet or phone can also be used as a monitor.

ANALOG AND DIGITAL

Like everything else to do with audio and video, the time-tested analog devices are being supplanted by digital replacements. In a surveillance system it makes good sense to go digital if you’re starting from scratch and even convert to digital if your existing system is getting old. Nothing is the same, except the monitor, between an analog and a digital system. An analog camera requires two cables, one coax for the image, and one pair for power to the camera. A digital camera takes care of everything with one Cat 5 cable. An analog camera sends images to the recorder, optimized with focal length and focus control. A digital camera processes the images before sending them, to allow you to target specific parts of the image and make the camera respond to specific parameters. An analog recorder converts the images from the cameras to digital data and stores them according to the parameters you’ve set. It can also upload the converted images to the Internet. A digital recorder is basically a network switch with a hard drive attached. Many digital surveillance systems offer the option of software to use your regular computer to process and access the video rather than a separate device with the software and hard drive built in to it.

REMOTE VIEWING AND CONTROL

Most surveillance systems, whether analog or digital, now allow the images to be uploaded to the web, so that you can see them from any location using a computer, laptop, tablet or smart phone. With digital Internet network cameras, a storage component is not even required if you just want to look at live images. Because the camera can connect directly to your home network, you can connect to it through the software. Some cameras can be operated from a remote location, with pan, tilt and zoom options. In a commercial installation this type of control can be handled with a joystick at the desk of the the security guard, but it you are using it to cover your home, you can set it up to be controlled through your smart phone.

STAND ALONE SYSTEMS

A door intercom with a built-in camera is an example of a system that works on its own, but it can also be integrated into other home systems. For example, when someone is at the front door, the system may allow you to turn your TV to a specific channel to see who it is, or it may mute the loud music you’re playing so that you know someone is at the door, or it may allow you to push a button on your phone to unlock the front door, and use your phone to tell the person to come in.

INTEGRATION

Having systems which can communicate and interrelate to each other is the ultimate in home electronics. If you plan it properly, you can have a home system in which the security and intrusion functions, the surveillance images, and the home automation commands can be interconnected. For example movement at a specific window within a camera view can be programmed to alarm the security system. The corollary is that a door contact or motion from the security system can trigger the camera to record. Both security and surveillance systems can trigger outside events, so they can be tied into a home automation system. A motion sensor or door contact can turn on lights, or an automation system controller can simultaneously control the security system. Temperature sensors, door contacts or motion sensors can also control the heating and air conditioning, to achieve cost savings.

TAILOR THE SYSTEM TO YOUR SPECIFIC NEEDS

There is no cookie-cutter approach for security and surveillance. It depends on what is most important to you and how you want to use the system on a day-to-day basis. The first step is always to discuss it with someone who knows the options available and has the expertise to guide you on how to integrate different systems to achieve the most effective result.