wireless networks.docx

7/27/2019 wireless networks.docx

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Information Technology for Managers

Project Report

Topic: Wireless facility and the communication protocols used among the

devices in the hostels


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Abstract

The project focuses on a comprehensive study of the Wi-Fi facilities provided in the hostels,

the protocols followed, the operational problems that are faced and also to come-up with

some basic solutions to tackle them.

During the course of the project, we divided our work into two clear stages. During the

initial stage, we collected the information regarding the facilities that the college has, the

service provider, the mode of transmission, security layers, hardware deployed, etc.

followed by a research on the basic networking techniques, process and working

information, jargons, etc., to get a better view on the subject. We also studied the

advantages and limitations of the existing facilities in the campus, along with gathering

knowledge regarding the basic framework within which the communication facilities

function.

During the second stage we worked upon the shortcomings and the troubles that

were facing in providing the wi-fi facilities. We studied the reasons behind the frequent

drops that we face and also the speed constraints. Then we tried to bring up some feasible

solution regarding as to what steps should be taken to improve the overall facilities, reduce

the problems to least possible level, taking in both the long term and short term

prospective. The solutions suggested are possible within the existing functional framework.


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Wireless Technology & Communication Protocols

Wireless Communication is one of the fastest growing technologies. It is the exchange of

information between two or more devices that are not connected by electrical conductor.

Basically, wireless communication used in PCs, Laptops etc. are through the wirelessnetwork.

Wireless Networks refers to any type of computer network that utilizes some form of

wireless network connection. There are various types of wireless networks:-

1. Wireless PAN (Wireless Personal Area Network).2. Wireless LAN (Wireless Local Area Network).3. Wireless Mesh Network.4. Wireless MAN (Wireless Metropolitan Area Network).5. Wireless WAN (Wireless Wide Area Network).6. Cellular Network.

Most commonly used wireless technologies are Bluetooth, WI-Fi, Infrared, Wi-max (latest

technology). Some of the wireless technologies are described below:

Infrared Technology:A wireless technology allows computing devices to communicate or exchange data via

infrared radiation. Infrared is electromagnetic energy at a wavelength or wavelengths

somewhat longer than those of red light.

Infrared wireless technology is used in intrusion detectors; home-entertainment control

units; robot control systems; medium-range, line-of-sight laser communications; cordless

microphones, headsets, modems, and printers and other peripherals.

Unlike radio-frequency (RF) wireless links, IR wireless cannot pass through walls. Therefore,

Infrared communications or control is generally not possible between different rooms in a

house, or between different houses in a neighborhood (unless they have facing windows).

This might seem like a disadvantage, but infrared wireless is more private than radio-

frequency wireless. Some IR wireless schemes offer a level of security comparable to that ofhard-wired systems. It is difficult, for example, to eavesdrop on a well-engineered, line-of-

sight, IR laser communications link.

Bluetooth:A wireless LAN technology used for exchanging data over a greater range compared to

Infrared using short wavelength radio transmissions. It uses radio waves (in 2.4 GHz range )

& is designed to be a secure, low power, & inexpensive way of connecting & exchanging

information between devices without the need of wires or cables .
http://searchnetworking.techtarget.com/definition/wavelengthhttp://searchnetworking.techtarget.com/definition/wavelength


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Bluetooth technology was designed primarily to support simple wireless networking of

personal consumer devices and peripherals, including cell phones, PDAs, and wireless

headsets. Wireless signals transmitted with Bluetooth cover short distances, typically up to

30 feet (10 meters).

Bluetooth devices generally communicate at less than 1 Mbps.

Wi-Fi:A communication technology related to IEEE 802.11 family, used to exchange data using

radio waves. This technology enables exchange of data over large distances as compared to

Bluetooth.

Wi-Fi Alliance defines Wi-Fi as any wireless local area network (WLAN) products that are

based on the IEEE (Institute of Electrical & Electronics Engineer) 802.11 standards.

The major advantage of Wi-Fi is that it is compatible with almost every operating system,

game device and advanced printer.

How Wi-Fi works?

Like mobile phones, a Wi-Fi network makes use of radio waves to transmit information

across a network. The computer should include a wireless adapter that will translate data

sent into a radio signal. This same signal will be transmitted, via an antenna, to a decoder

known as the router. Once decoded, the data will be sent to the Internet through a wired

Ethernet connection. As the wireless network will work as a two-way traffic, the data

received from the Internet will also pass through the router to be coded into a radio signal

that will be receipted by the computer's wireless adapter.

Wi-Fi Frequencies

A wireless network will transmit at a frequency level of 2.4 GHz or 5GHz to adapt to the

amount of data that is being sent by the user. The 802.11 networking standards will

somewhat vary depending mostly on the user's needs, as explained below:

1. The 802.11a will transmit data at a frequency level of 5GHz. The Orthogonal Frequency-

Division Multiplexing (OFDM) used enhances reception by dividing the radio signals into

smaller signals before reaching the router. You can transmit a maximum of 54 megabits of

data per second.

2. The 802.11b will transmit data at a frequency level of 2.4GHz, which is a relatively slow

speed. You can transmit a maximum of 11 megabits of data per second.

3. The 802.11g will transmit data at 2.4GHz but can transmit a maximum of 54 megabits ofdata per second as it also uses an OFDM coding.
http://compnetworking.about.com/library/glossary/bldef-kbps.htmhttp://compnetworking.about.com/library/glossary/bldef-kbps.htmhttp://compnetworking.about.com/library/glossary/bldef-kbps.htm


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4. The more advanced 802.11n can transmit a maximum of 140 megabits of data per second

and uses a frequency level of 5GHz.

Many products conform to the 802.11a, 802.11b, 802.11g, or 802.11n wireless standards

collectively known as Wi-Fi technologies.

Comparison of Wi-Fi & related technologies:

802.11

Created bythe Instituteof Electricaland

ElectronicsEngineers(IEEE) in 1997

Supported amaximumnetworkbandwidth of2 Mbps

Radiosignalingfrequency of2.4 GHz

Slow andhence nolongermanufactured

802.11b

IEEE'sexpansion onorignal 802.11in July 1999

Targetedtowards homemarket

Bandwidth of11 mbps

Pros - lowestcost; signalrange is goodand not easilyobstructed

Cons - slowestmaximum

speed; homeappliancesmay interfereon theunregulatedfrequencyband

802.11a

IEEE's Secondextension to802.11

Usually found

on businessnetworks

Supportsbandwidth upto 54 Mbps

Regulatedfrequencyspectrumaround 5 GHz

Pros of802.11a - fastmaximum

speed;regulatedfrequenciesprevent signalinterferencefrom otherdevices

Cons of802.11a -highest cost;shorter rangesignal that is

more easilyobstructed

802.11g

New standardintroduced in2003-04

Backward

compatiblewith 802.11b

Supportsbandwidth upto 54 Mbps

Pros of802.11g - fastmaximumspeed; signalrange is goodand not easilyobstructed

Cons of802.11g -costs morethan 802.11b;appliancesmay interfereon theunregulatedsignalfrequency

802.11n

Multiplewireless signalantennas toimprove

bandwidth(MIMO)

Supportsbandwidthupto 600mbps

Pros of802.11n -fastestmaximumspeed andbest signal

range; moreresistant tosignalinterferencefrom outsidesources

Cons of802.11n -standard isnot yetfinalized;costs morethan 802.11g;the use ofmultiplesignals maygreatlyinterfere withnearby802.11b/gbasednetworks.


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Wireless Protocols:

Communication between devices requires certain communication protocols. They are a set of digital

rules for exchange of information between computers. Various types of communication protocolsused are TCP/IP, HTTP, FTP, IMAP, etc.

Wireless security:

It is one of the important aspects of wireless network. It is used for the prevention of unauthorized

access or damage to computers using wireless networks. The most common types of wireless

security are Wired Equivalent Privacy (WEP) and Wi-Fi Protected Access (WPA). WEP is a notoriously

weak security standard. WEP is an old IEEE 802.11 standard from 1999 which was outdated in 2003

by WPA or Wi-Fi Protected Access. WPA was a quick alternative to improve security over WEP. The

current standard is WPA2; some hardware cannot support WPA2 without firmware upgrade or

replacement.

Topology:

The Physical topology refers to the way in which a network is laid out physically. Two or more

devices connect to a link which further forms a topology. The topology of a network is the geometric

representation of the relationship of all the links & linking devices (nodes) to one another. There are

four basic topologies:-

1. Mesh Topology2.

Star Topology

3. Bus Topology4. Ring Topology

Connecting LANs & Backbone Networks

LANs do not normally operate in isolation. They are connected to one another or to the

Internet. To connect LANs, or segments of LANs, we use connecting devices. Connecting

devices can operate in different layers of the Internet model. There are five different

connecting devices:

1. Passive Hub ( operate below physical layer)A passive hub is just a connector. It connects the wires coming from different

branches. In a star-topology Ethernet LAN, a passive hub is just a point where the

signals coming from different stations collide; the hub is the collision point. This type

of a hub is part of the media; its location in the Internet model is below the physical

layer.

2. Repeater/Active Hub (operate at physical layer).A repeater is a device that operates only in the physical layer & work with signals oncables that carry information within a network can travel a fixed distance before


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attenuation endangers the integrity of the data. A repeater receives a signal and,

before it becomes too weak or corrupted, regenerates the original bit pattern.

Fig: Repeaters

A repeater does not actually connect two LANs; it connects two segments of the

same LAN. The segments connected are still part of one single LAN. A repeater is not

a device that can connect two LANs of different protocols.

3. Bridge/2-layered switch (operate at physical & data-link layer).A bridge operates in both the physical and the data link layer. As a physical layer

device, it regenerates the signal it receives.

A bridge connects two or more LANs.

4. Router/3-layered switch (operate at physical, data-link & network layer).A router is a three-layer device that routes packets based on their logical addresses

(host-to-host addressing). A router normally connects LANs and WANs in the

Internet and has a routing table that is used for making decisions about the route.

The routing tables are normally dynamic and are updated using routing protocols.


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WAN

Router Router

To the

rest of the

internet

5.

Gateway (operate at all layers).It understands the format & contents of data & can translate messages from one

format to another. It operates in all the five layers of the Internet or seven layers of

OSI model.A gateway takes an application message, reads it, and interprets it. This

means that it can be used as a connecting device between two internetworks that

use different models.

Note: - All the connections described above i.e. between routers, bridges, switches etc. are

wired & connect through devices through a wireless connection such as Wi-Fi.

LAN

LAN

LAN

LAN


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Structure at IIM Rohtak

Data Collected:

o Wireless Technology: WI-FI.o Wireless Topology: Hybrid Topology.o Service provider: RailTel Corporation of India Ltd.o Access Point provider: Ruckus Wireless

Selected via a tenders. Suited the environment of IIM Rohtak. One time investment with an extendable 3-year warranty. Quoted the lowest price.

o Controllers installed to control all the access points & contain information of the connectedaccess points at a particular time.

o A GUI interface in place that helps in accessing the information about department wiseallocated access points.

o Centralized server populating all the networks of academic block & both the hostels.o 15-16 switches in academic block & 1 in boys hostel.o 7 routers in the girlshostel & 12 in the boys hostel.o Range of a particular router varies between 30-35m, which decreases during high traffic.o While moving from the range of one router to the other, switching takes place without any

hiccups as the network access is continuous.

o TCP/IP protocols used.o WPA (Wi-Fi Protected Access) encryption used for wireless security.o MDUs optical fibres used for wired network.


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Structure of Wireless Network in IIM-Rohtak:

As it can be seen from below diagram, network in IIM-Rohtak is of wireless topology wherein

multiple computers, laptops, mobiles etc. are connected to each other through routers & switches.

Wi-Fi is the wireless technology used in hostels & academic block to connect to the network.

Railtel (ISP) provides services via its router. The router is wired to a L3 switch which is further

connected to multiple L2 switches. L2 switches are further connected to multiple access points

placed in hostels. Using these access points, different laptops or mobiles can be connected through

Wi-Fi.

Access Points

Router

UsersUsersUsersUsersUsers UsersUsers Users

L3 Switch

L2 Switch L2 SwitchL2 SwitchL2 Switch

Firewall

ISP (Railtel)


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Network configuration used in IIM Rohtak:

Name IIM- Rohtak

SSID IIM- RohtakNetwork type Access point

Security type WPA-Personal

Encryption Type AES

Connection-specific DNS Suffix iimrohtak.ac.in

DHCP Enabled Yes

NetBIOS over TCP/IP Enabled Yes

DHCP Enabled Yes

NetBIOS over TCP/IP Enabled Yes

Future Enhancements:

Fluctuations in connectivity occur often due to power cuts. Need to manually restart the UPSevery time there is a power cut.

Better security system with stronger wireless encryption can be adopted. As the number of students is increasing per year, need to install more Wi-Fi routers in the

hostels in order to ensure high speed internet access despite of heavy traffic.

Source:

http://en.wikipedia.org/wiki/Wireless_securityhttp://compnetworking.about.com/cs/wireless80211

/a/aa80211standard.htm

Books: Computer Networks by Andrew S. Tanenbaum
http://en.wikipedia.org/wiki/Wireless_securityhttp://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htmhttp://compnetworking.about.com/cs/wireless80211/a/aa80211standard.htmhttp://en.wikipedia.org/wiki/Wireless_securityhttp://en.wikipedia.org/wiki/Wireless_security

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