Know Fundamentals of Networking

Networking Fundamentals

Information stored in computers can be shared with or communicated to other computers by using communication technology. Communication technology has altogether changed our lifestyles and way of working. Gone are the days when messages were delivered in weeks and we needed a power socket and modem to connect to the Internet. With continuous developments and convergence of computer technology with communication technology, we can conquer geographical distances. Mobile or Wireless computing and mobile Internet connection are the results of this convergence.

Introduction

In this session, you will have an overview of the fundamental concepts of networking and communication, the networking terminologies, and the working of data communications systems.

What is a Computer Network?

By definition, a Computer Network is simply communicating with each other. The basic concept of networking is quite simple. Two or more computers/computing devices are usually connected via cables to a central hub. There are different kinds of networks and the way they work. Some networks are rather simple and easy to set up while others are much more complex. We need to determine which network suits our needs the best. Large networks even use satellites, Cables Hub, and radio waves to cover great distances.

A question that must be coming to your mind is that 'Why computer networks are made? or what is the need to establish communication between computers?" So, let us understand the purpose of computer networks.

Need for Computer Networks

Computers have become an integral part of any type of organization, corporate, business, government agency, or educational institution. These computers are located at different locations within the premises/campus/organization. If these computers can be connected and managed properly, many of the overlapping of doing the same tasks on different computers separately can be avoided. Hence, networks are normally established at places where a large number of people have to work using a computer and they need to share information and costly resources like computer hardware and software. Networks can be generally found in offices of any kind of small or big organizations, public services, educational institutions, etc. 

Goals of forming computer networks are

1. Resource sharing: If the computers in a workplace are networked, many hardware and software resources like data, programs, hard disks, high-quality expensive laser printers, modems, peripheral devices, licensed software, etc. can be shared among users regardless of their physical locations. The physical locations may be a few feet, miles, hundreds of miles, or even thousands of miles away, but the users and computers exchange their data, and programs in the same way as they do locally.
2.  Reliability: In a computer network, backups of crucial information may be kept on several machines, so that if one computer is out of order, information can be retrieved from another computer as well. Reduction in the installation cost: In a networked setup of computers costly peripherals like printers, scanners, hard disks, etc. can be shared amongst the users. Thus, resulting in a reduction in the installation cost.
3. Communication: Networked computers facilitate communication. Users can send emails, documents, and other important data to other computers through the communication channels, thus saving time and money. on stored data by enforcing authenticity and Security of data: Networks ensure better security authorization rules for the users.

Networking technology did not evolve in days. It took pioneers several years to develop each technology which is a part of networking types and techniques of today. So, let us now have an overview of the major turning points in the development of networking technology.

Types of Computer Networks

There are different types of network classifications based on the size of the network, technology used in the network, data transfer speed in the network, and various other attributes. Theoretically, communication networks can be categorized into two different types. The two types are Broadband networks and Baseband networks. Broadband networks are usually high-speed or provide a lot of bandwidth to the user to transfer large volumes of data at once. Baseband networks are generally low-speed and suitable for non-critical, less-quantity data passing. However, these two types can have different behaviors in the practical world.

Networks can be classified in several different ways - By their scope, i.e. based on their geographical span, by their connection method (wired or wireless network), by their function, by the network topology (by their design or layout), by the protocol used, etc.

Do you Know? Different types of computer networks work at different speeds. In general, networks covering a smaller geographical area run at a faster speed. The transfer rate of WANS is slower than 1 Mbps, that of LANS is about 10 Mbps, and high-speed LANS have a speed of up to 100 Mbps. New technologies like ATM promise speeds up to 2 Gbps for all kinds of networks.

Unlike LANS, most WANS (like the Internet) are not owned by any one organization but rather exist under a collective or distributed ownership and management. WANS tend to use satellite communication, SONET (Synchronous Optical networking), radio waves, or fiber optics as their connection medium. The data transmission speed in WAN is 1 Mbps.

Global Area Network (GAN) - A network spanning geographically distinct cities.

Small Area Network (SAN) - A SAN is used to connect servers to data storage devices through a technology like the Fiber Channel technology. SAN is also known as System Area Network,  Server Area Network, or sometimes Storage Area Network.  

Campus Area Network (CAN) -A CAN is a network spanning multiple LANS but is smaller than a MAN, like in a university or local business campus. It is also called a Controller Area Network or sometimes Cluster Area Network.

Personal Area Network (PAN) -A PAN is a computer network used by a person to connect a laptop, a cell phone, and/or a handheld computing device such as a PDA placed within 10 meters (30 feet) range to transfer document files, E-mails, appointments, digital photos, and music. PAN can be constructed with cables or wirelessly. USB and FireWire technologies are normally used to connect devices in a wired PAN while wireless PANS typically use Bluetooth or sometimes infrared connections. Bluetooth PANS are also called piconets. A Personal Area Network & Intranet-An intranet is a network open only for internal employees of a company. The employees should use the network for inter-organization procedures-may be to communicate with a remote branch.

Extranet -Extranet is another type of internetwork owned by a single enterprise. Instead of inside usage, an extranet will offer services to the outside world - mainly to the customers and suppliers of the venture. (E.g. ATM network)

What is Internet?

The internet is a network of computers spanning the globe. A network simply means two or more computers connected. It is a network of interconnected computers, enabling users to share information along multiple channels.

The Internet or indeed a wonderful and amazing addition to our lives a Internet can be known as a kind of global meeting place where people come together. The major advantages of the internet are:

Advantages of the Internet the World Wide Web is

E-mail: E-mail is an online correspondence system. With e-mail, electronic messages work like writing letters. 

You can send and receive in Access Information: The Internet is a virtual treasure trove of information. The 'search engines on the Internet can help you to find data on any subject that you need.

Shopping: Along with getting information on the Internet, you can also shop online. Many online stores and sites can be used to look for products as well as buy them using a credit card.

Online Chat: There are many chat rooms on the web that can be accessed to meet new make new friends, as well as to stay in touch with old friends.

Downloading Software: You can download innumerable, games, music, videos, movies, and people host of other entertainment software from the Internet, most of which are free.

Classification by Functional Relationship based on their way of functioning, networks are classified into two categories - Peer-to-pe networks and Client-server networks.

1. Peer-to-peer networks: This type of network is more commonly used in set-ups involving less than ten computers, where strict security is not necessary. All computers have the same status, i.e. they can act both as clients and servers, hence the term 'peer' is given to them. Data Files and hardware devices connected to any one computer can be shared across the network. An example of a Peer-to-peer network is Microsoft Windows-based networks.

2. Client-server networks: These networks are more suitable for larger set-ups. A central computer, or 'server', acts as the storage location for files and applications shared on the network. Usually, the server is a high-performance computer. It also controls the network access of the other computers which are referred to as the 'client' computers. The server offers services to client computers upon their request. These may include storage services, internet services, printing services, and so on. For example, in a school network, teachers and students will use the client computers for their work and only the network administrator (usually a designated staff member) will have access rights to the server.

Wireless Local Area Networks (WLAN) - WLANS provide wireless network communication over short distances using radio waves, infrared signals, Bluetooth, or Wi-Fi technology instead of the traditional network cabling. WLANS are built by attaching an Access Point to the edge of the wired network. Clients (like computers, cell phones, or PDA) communicate with the AP using a wireless network adapter similar in function to a traditional Ethernet adapter. For WLANS that connect to the Internet, Wireless Application Protocol (WAP) technology allows Web content to be more easily downloaded and rendered on any device. WLANS provides wireless network communication over short distances using radio or infrared signals instead of traditional network cabling.

Components of Wireless Local Area Network 

A wireless local area network (WLAN) consists of two key components: an access point (also called a base station) and a wireless card. Information can be transmitted between these two components as long as they are fairly close together (up to 100 meters indoors or 350 meters outdoors).

Wireless LAN Card

A wireless LAN card contains an in-built antenna that receives signals from other computers and establishes a wireless connection between them. In some notebook PCs, this card comes in-built. Otherwise, it can be inserted into the relevant slot in the notebook PC or in Desktop computers to connect them to a wireless network.

Desktop PC Wireless LAN Card

Laptop PC Wireless LAN Card

Wireless Access Point

In a wireless network, an 'access point' has a similar function to the hub in wired networks. It broadcasts and receives signals to and from the surrounding computers via their adapter card. It is also the point where a wireless network can be connected to an existing wired

Advantages and Disadvantages of Wireless LANS 

Every technology has certain pros and cons associated with it. Though wireless technology becoming very popular, given all its merits, it has certain disadvantages as well.

Advantages of Wireless LANs:

1. Wireless network provides more flexibility in the connection.

2. It is easier to add or remove computers. Computers need not be fixed in a place. 

3. It is easier to provide connectivity in areas where it is difficult to lay cables.

4. Installation can be fast and easy and can eliminate the need to pull cables through walls and ceilings.

5. Access to the network can be from anywhere within the range of an access point.

6. The installation expenses for wireless LAN are significantly lower. 

7. It is possible to connect computers across the road buildings, with directional antennae, to avoid digging trenches under roads.

Disadvantages of WLANS:

1. In WLAN, there are greater chances of radio interference due to weather conditions, other wireless devices, or obstructions such as walls.

2. Data transfer rates drop as distance increases or if the number of computers using the network increases.

3. As standards change, it may be necessary to replace wireless cards and/or access points.

4. Lower wireless bandwidth means some applications such as video streaming will be more effective on a wired LAN.

5. In WLAN, security is difficult to guarantee and requires configuration. 

6. Devices will only operate at a limited distance from an access point, with the distance determined by the standard used and buildings and other obstacles between the access point and the user.

7. A wired LAN is generally required to provide a backbone to the wireless LAN; a wireless LAN can be a supplement to a wired LAN and not a complete solution.

Communication Mediums Used in WLAN The communication mediums used in wireless LANs are Wi-Fi, Bluetooth, and Infrared rays. 

Let us learn about these technologies:

Wi-Fi, which stands for Wireless Fidel private business popular wireless communication protocol used for home, private business LANs, and public hotspots. Wi-Fi is also often used for connecting computers to the Internet.

The Standard for Wireless Fidelity.

To set up a Wi-Fi system, two types of wireless components are required to transmit the necessary radio waves between computers: AWI-FI Radio device: There are several versions of Wi-Fi radio devices, including PCMCIA Radio or PC Card for laptops, a USB adapter that includes a built-in Wi-Fi radio that can be used in both laptops and desktops, and PCI or ISA Bus adapters that can be installed in your desktop. Many newer laptops and desktops have Wi-Fi radios already built in.

Gateways and Access Points: Although Wi-Fi Radio devices can be configured to talk with each other with no other equipment involved, the easiest way to handle Wi-Fi transmissions is with an Access Point or Gateway. Gateways are generally used for home networking applications, while Access Points are used mostly by larger businesses.

In a Wi-Fi network, computers with Wi-Fi network cards connect wirelessly to a wireless router. The router is connected to the Internet using a modem, typically a cable or a DSL modem. Any user within 200 feet or so (about 61 meters) of the access point can then connect to the Internet, though for good transfer rates, distances of 100 feet (30.5 meters) or less are more in order. Wireless signal boosters can be used to extend the range of a wireless network.

Advantages of Wi-Fi:

1. It is fast (11 Mbps).

2. It has a long-range (1,000 ft/ 305 m in open areas, 250 to 400 ft/76 to 122 m in closed areas) 4. It is easily integrated into the existing wired-Ethernet networks.

3. It is reliable.

Disadvantages of Wi-Fi: 

1. It is expensive.

2. It can be difficult to set up.

3. Speed can fluctuate significantly.

Bluetooth

Bluetooth is a wireless protocol used to wirelessly link phones, computers, and other network devices over short distances, typically up to 30 feet (10 meters). Bluetooth devices generally communicate at less than 1 Mbps speed. It is generally used to create a Personal Area Network (PAN), also termed as Piconet that can contain a minimum of two and a maximum of eight Bluetooth peer devices. Compared to Wi-Fi, Bluetooth networking is much slower, more limited in range, and supports fewer devices. Examples of uses of the Bluetooth technology in devices are Bluetooth Printers, Bluetooth keyboards, Bluetooth cameras, Bluetooth Mouse, Bluetooth headsets, Bluetooth mobiles, and home devices such as furnaces and refrigerators to a PC, etc.