Advantages And Disadvantages Of Networked Medium Information Technology Essay

Bus networks use a common backbone to connect all devices. A single cable, the backbone functions as a shared communication medium that devices attach or tap into with an interface connector. A device wanting to communicate with another device on the network sends a broadcast message onto the wire that all other devices see, but only the intended recipient actually accepts and processes the message.

Ring topology:

In a ring network, every device has exactly two neighbors for communication purposes. All messages travel through a ring in the same direction. A failure in any cable or device breaks the loop and can take down the entire network.

Star topology:

Many home networks use the star topology. A star network features a central connection point called a “hub” that may be a hub, switch or router. Devices typically connect to the hub with Unshielded Twisted Pair (UTP) Ethernet.

Compared to the bus topology, a star network generally requires more cable, but a failure in any star network cable will only take down one computer’s network access and not the entire LAN.

b) Advantages and disadvantages of each medium.

Network medium is the physical channel that used for transmission in the network. The types of the medium are:

Wire

Fiber

air

Wire:

UTP cable is a medium that is composed of pairs of wires. UTP cable is used in a variety of networks. Each of the eight individual copper wires in UTP cable is covered by an insulating material. In addition, the wires in each pair are twisted around each other.

Fiber:

Long distance signal transmission.

Large Bandwidth, Light Weight, and Small Diameter

Long Lengths

Easy Installation and Upgrades

Non-Conductivity

Security

Designed for Future Applications Needs

Air:

Mobility.

Elimination of unsightly cables.

c) Recommendation for topology and medium to use:

Topology:

Figure 1.1 : Star topology

We select the star topology for this in-house network. Because the star topology is most popular topology for in-house network (LAN). Also we can be benefit by using the star topology in a LAN.

Benefits:

Information can be easily shared allowing for quick and informed decisions to be made, saving time and money.

A more productive and competitive environment is achieved through greater teamwork within the organization.

Network-based communication such as email is considerably cheaper than using the phone or fax and sharing resources such as printers gives more efficient use of equipment at lower costs.

Standard versions of procedures and directories can be made accessible to everyone.

IT administration can be centralised.

Data can be backed-up from a single point on a scheduled basis ensuring consistency.

Medium:

Figure1.2: WI-FI network

We select the WI-FI for this in-house network. Because

Mobility.

Elimination of unsightly cables.

Problem Identification:

Task 2 – 10 Marks

Investigate the Internet connection requirements for the Fire Department.

a) Describe the Internet services that may be required.

b) Explain the connection speeds that are suitable for these requirements.

c) Find examples of Internet Service Providers (ISPs) that can meet these requirements in your country.

d) Make a recommendation to use one ISP based upon the services offered and price charged.

Solution of Task 2

a) Hardware and Software Requirements:

Computer with either: Windows 95, Windows 98, Windows ME, Windows XP Professional, Windows NT 4.0, Windows 2000, or Windows Server 2003 installed.

A CD-ROM drive for the installation compact disc.

Adequate disk space for the database, business objects, and Web pages – 10 MB free space minimum.

Transmission Control Protocol/Internet Protocol installed.

A network adapter card and local area network connection.

An Internet connection and Internet Protocol address from your Internet Service Provider.

Network Adapter board.

Figure 2.1: Intranet network system

b) Connection speeds requirements:

512 for upload is standard connection for sound only, the much required is 138 kbps, means that 512 – 138 = 374 kbps free for chat or image. Usually, download > upload is possible for internet provider to have busy server and in this situation you will be connected from phone standard line, with smaller speed.

So in this system it demands 512 kbps connection speed.

c) Examples of Internet Service Providers in our country:

Brack net.

Zip.

Qubee.

Grameen phone Internet.

Bangla lion.

Recommendation to use the ISP :

In this system we select Qubee as out ISP because,

Qubee has the solution which is fast and reliable.

Very much cost effective.

More then it is driven by WI-MAX technology.

 And obviously it is portable.

There package,

Monthly Usage Allowance

Speed

5GB

10GB

Sky

256 Kbps

BDT 850

BDT 950

BDT 1,250

512 Kbps

BDT 1,250

BDT 1,450

BDT 2,250

1Mbps

BDT 2,250

BDT 2,750

BDT 5,250

and

Qubee Modem

Tk. 3,000

Modem Installation

Free  

First month’s fee payable at the time of signup

Problem Identification:

Task 3 – 30 Marks

Investigate the methods the Fire Department could implement for two-way voice communications. As a minimum include the following information:

a) How each method works (frequencies, full/half duplex, etc).

b) Details of the legal requirements for operating the system in your country.

c) Costs of setting up and operating the system, including licensing costs, equipment costs, etc.

d) Limitations of each method.

Provide a recommendation for how voice communications should be set up and run including reasons for this recommendation.

Solution of Task 3

Method of full/half duplex system:

Half-Duplex:

A half-duplex system provides for communication in both directions, but only one direction at a time. Typically, once a party begins receiving a signal, it must wait for the transmitter to stop transmitting, before replying.

An example of a half-duplex system is a two-party system such as a “walkie-talkie” style two-way radio, wherein one must use “Over” or another previously designated command to indicate the end of transmission, and ensure that only one party transmits at a time, because both parties transmit on the same frequency.

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A good analogy for a half-duplex system would be a one lane road with traffic controllers at each end. Traffic can flow in both directions, but only one direction at a time with this being regulated by the traffic controllers.

Full-Duplex:

A full-duplex system allows communication in both directions, and unlike half-duplex, allows this to happen simultaneously. Land-line telephone networks are full-duplex since they allow both callers to speak and be heard at the same time. A good analogy for a full-duplex system would be a two-lane road with one lane for each direction.

Examples: Telephone, Mobile Phone, etc.

Two way radios can be, for instance, designed as full-duplex systems, which transmit on one frequency and receive on a different frequency. This is also called frequency-division duplex. Frequency-division-duplex systems can be extended to farther distances using pairs of simple repeater stations, owing to the fact that the communications transmitted on any one frequency always travel in the same direction.

Full-duplex Ethernet connections work by making simultaneous use of all four physical pairs of twisted cable, where two pairs are used for receiving packets and two pairs are used for sending packets, to a directly connected device. This effectively makes the cable itself a collision-free environment and theoretically doubles the maximum bandwidth that can be supported by the connection.

There are several benefits to using full duplex over half duplex. First, time is not wasted since no frames need to be retransmitted as there are no collisions. Secondly, full bandwidth is available in both directions because send and receive functions are separated. Third, stations/node do not have to wait until other operations complete their transmission as there is only one transmitter for each twisted pair.

Legal requirements for operating the system in our country:

1.1 As per the national frequency allocation plan 2005 (nfap 2005), spectrum from the ism band in 2.4000-2.4835 ghz and 5.725-5.875 ghz is allocated for wi-fi use.

1.2.    Access to the spectrum will be on shared basis. There will be no exclusive assignment to any individual or organizations, whether for private, public or commercial use.

1.3.    Any government or private organization/educational institution/corporate body can establish and use wi-fi network on non commercial/non-profit basis.

1.4.    Household/private users are not required to take any permission from the commission or pay any levy/charge for using wi-fi in the given ism band.

1.5.    Both indoor and outdoor wi-fi is permitted in the given spectrum of ism band. However, the maximum power output for the wi-fi equipment is limited to 1 watt.

1.6.    All commercial wi-fi hotspot operators/service providers shall possess an isp or equivalent license (e.g., bwa license). Existing operators having such license from the commission will be eligible to establish wi-fi network for providing last mile solution.

1.7.    Operators/service providers will submit a detailed list of wi-fi outdoor hotspots to the commission. There will be levy/charges applicable annually for all hotspots. the levy/charge shall be charged as per the rate list published by the commission.

1.8.    All service providers will obtain permission in the form of no objection certificate (noc) from the commission for importation, deployment, use and providing any service with wi-fi equipment. Guideline for application and application form is available at http://www.btrc.gov.bd. Existing ism band operators who wish to adapt their present wi-fi equipment for the same purpose may also be provided permission from the commission on case by case basis.

1.9.    All vendors in possession of “dealer possession and radio communication equipment vendor license” issued by the commission are eligible to apply for noc for importation and marketing of wi-fi equipment in Bangladesh.

1.10. The commission reserves the right to cancel the permission if any complication arises anytime.

c) Costs of setting up and operating the system, including licensing costs, equipment costs:

The cost of operating the system:

The cost of operating the system

Purpose

Cost

01.

1pr cross connect wire wh/red red/white 1m feet

3000/=

02.

Programming cable for air-phone

1500/=

03.

IP network station port

35000/=

04.

Controller card f/60 units non scrolling

25000/=

05.

Pc-console-software

50000/=

06.

Access control keypad f/jb-dv

12000/=

07.

Video monitor

15000/=

08.

Human (per/month)

5000/=

12.

Total

14,6,500/=

Table-3.1The cost of operating the system

The cost of equipments:

The cost of equipments

equipments

Price

01.

Handset spare part f/ie1gd

1500/=

02.

Complete handset f/men-na

3000/=

03.

Pc-380 select switch pc f/ap-m

1500/=

04.

Ja av modulator

12000/=

05.

Color mem vandal set

50000/=

06.

Access control keypad f/jb-dv

12000/=

07.

Door station adaptor f/ 1 door

5000/=

08.

C.o. audible ringer

5000/=

09.

Calling switch

5000/=

10.

Single line auto phone dialer

5000/=

11.

Power adapter

1000/=

12.

Total

10,1,000/=

Table-3.2 The cost of equipments

Limitations of each method:

During the time when one wave passes through another we say that the waves interfere. It is really not correct to say that the waves collide or hit, although this is often how such an interaction is termed.

When the crest of one wave passes through, or is super positioned upon, the crest of another wave, we say that the waves constructively interfere. Constructive interference also occurs when the trough of one wave is super positioned upon the trough of another wave.

During any wave interference the shape of the medium is determined by the sum of the separate amplitudes of each wave. We often say that when waves interfere, amplitudes add.

Using the arrow buttons step through the above animation to see how the amplitudes add during constructive interference. Notice that in this animation the crest of the red wave constructively interferes with the crest of the blue wave.

Recommendation for voice communications set up:

Wireless Fidelity, better known as Wi-Fi, is a term used to describe the underlying technology of wireless local area networks based on the Institute of Electrical and Electronics Engineers 802.11 standards. Initially intended to connect mobile computing devices in local area networks, Wi-Fi applications have grown to include various data, voice, and video services such as Internet access and Voice over Internet Protocol.

Wi-Fi technology platform is based on single-carrier direct-sequence spread spectrum and multi-carrier Orthogonal Frequency Division Multiplexing radio technologies to transmit and receive signals.

Wi-Fi is more commonly used in point-to-multipoint environments to allow extended network connectivity of multiple portable devices such as laptops, telephones, or PDAs. Wi-Fi also allows connectivity in point-to-point mode, which enables devices to directly connect and communicate to each other. A region covered by one or more APs is considered a “hotspot.” Home networks commonly deploy one AP that is typically connected directly to an Internet service provider , whereas larger networks may require at least several APs positioned in strategic locations to provide flexibility of service to a large number of users. Because of range constraints, Wi-Fi networks are used in localized regions.

Figure 3.1: Common Wi-Fi Network

Wi-Fi can be used in conjunction with other emerging wireless technologies, such as Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Mesh Networking, to extend the coverage area of terrestrial networks and to provide high-speed mobile data and telecommunications services. For example, WiMAX can be used as a backhaul technology to connect multiple Wi-Fi hotspots with each other and to other parts of the Internet. WiMAX describes the technology behind wireless networks based on the IEEE 802.16 standards.

Wi-Fi technology has been highly utilized for many applications such as voice communications, video communications, and various data services. This section describes how Wi-Fi technology supports these applications.

The expansion of telecommunications has spawned great need for new technologies to provide sought-after voice communication services. Internet telephony, better known as VoIP, is a technology that allows for transport of voice traffic using an Internet Protocol (IP) network infrastructure. VoIP and Internet telephony have come a long way since their inception, and with the impressive development of Wi-Fi technologies, the popularity of voice communications over wireless will continue to increase. Common VoIP networks consist of the hardware and software enabling the end users to leverage the Internet as the transmission medium for telephone calls. IEEE 802.11 Voice over Wi-Fi is the wireless version of this technology that is designed to work with wireless devices. VoWi-Fi solutions provide mobile users during critical missions with the ability to roam wirelessly.

Typically, a VoWi-Fi user device will connect to an AP to authenticate to a designated VoIP network. Once associated to an AP and authenticated to the appropriate network, a user will have the capability of mobile voice communications across enterprise networks, residential broadband networks, or even public/private hotspots. VoWi-Fi products are becoming more advanced and readily available to support various challenging short- and long-term voice service needs, such as in commercial, healthcare, private, and incident site environments.

Given the steadily increasing demand for voice services and mobility, wired and wireless VoIP deployments continue to grow and eventually will become more prevalent than traditional circuit switching voice systems. One advantage VoWi-Fi provides over traditional circuit-based voice communications is an ability to easily accommodate user growth in many different operating environments, through software configuration. Typically, physical attributes of circuit-switched voice systems can limit the flexibility of real-time configuration. Deploying a wireless VoIP system can provide significant savings in cost and deployment time when compared with other wireless voice communication solutions.

Problem Identification:

Task 4 – 30 Marks

Investigate telephone systems available in your country for single-site organisations like the Fire Department. Pay particular attention to:

a) The main equipment that would be installed.

b) The features available with each system.

c) The cost of equipment and installation.

d) The cost of operating the system.

e) Provide a recommendation for which system to purchase including reasons for this recommendation.

Solution of Task 4

a) The main equipment that would be installed:

The following equipments are generally installed through telephone systems:

2.4 GHz digital cordless voice transmission, the latest cordless technology

Up to 10 cordless handsets can share a single base station

Up to 20 voice mailboxes on a single system

Speech recognition enables you to control your system with your voice

Text to speech synthesis technology enables your system to read your e-mail to you over the phone

Smart call forwarding; have your calls forwarded to you when you’re on the road

Connects to your Windows computer to give you advanced unified messaging and computer telephony features

b) Features available with each system:

The following features are available with the installed telephone systems:

Call Transfer

Direct Inward Dialing and Direct Outward Dialing

Hunting

Line Restriction

Station Line Identification

Station-to-Station Dialing Centrex with Voice Mail

Automatic Callback

Call Forwarding-Busy Line

Call Forwarding-Don’t Answer

Call Screen

Call Trace

Call Waiting-Incoming

Directed Call Pickup

Direct Inward Dial to Direct Outward Dial Transfer

Call Transfer: Transfers calls, even cellular calls, to another line – either inside or outside your Centrex system.

Direct Inward Dialing and Direct Outward Dialing: Allows you to route calls directly or through an attendant.

Hunting: Automatically sends an incoming call from a busy line to the next designated line.

Line Restriction: Limits phone access on selected lines so that only authorized numbers or regions can be called.

Station Line Identification: Provides a detailed record of calls made by each Centrex station – including start time, duration, and toll call numbers.

Automatic Callback: Allows a station user to be called when a previously busy station

becomes idle.

Call Forwarding-Busy Line: Automatically reroutes calls to a designated station or your voice mail if your line is busy.

Call Forwarding-Don’t Answer: Automatically reroute calls to another phone if you haven’t responded within a preset number of rings.

Call Screen: Manages interruptions by having annoying or harassing calls diverted – this

feature allows up to ten customer-designated numbers to be routed directly to a prerecorded

announcement.

Call Trace: Allows you to alert the authorities with useful information when harassing or

threatening calls are made to your business.

Call Waiting-Incoming: Lets you take a second call if you are already on the line.

Directed Call Pickup: Lets you answer a fellow employee’s line (within the call pickup group) without moving from your desk.

Direct Inward Dial to Direct Outward Dial Transfer: Allows you to transfer an incoming direct dialed call to another location, either within the Centrex system or to an outside company, residence, car phone, etc.- instead of having the caller hang up and dial the new number.

c) The cost of equipment and installation:

Figure 4.1

The cost of equipments

equipments

Price

01.

Handset spare part f/ie1gd

1500/=

02.

Complete handset f/men-na

3000/=

03.

Pc-380 select switch pc f/ap-m

1500/=

04.

Ja av modulator

12000/=

05.

Color mem vandal set

50000/=

06.

Access control keypad f/jb-dv

12000/=

07.

Door station adaptor f/ 1 door

5000/=

08.

C.o. audible ringer

5000/=

09.

Calling switch

5000/=

10.

Single line auto phone dialer

5000/=

11.

Power adapter

1000/=

12.

Total

101000/=

Table-4.1 the cost of equipments

d) The cost of operating the system:

The cost of operating the system

Purpose

Cost

01.

1pr cross connect wire wh/red red/white 1m feet

3000/=

02.

Programming cable for air-phone

1500/=

03.

IP network station port

35000/=

04.

Controller card f/60 units non scrolling

25000/=

05.

Pc-console-software

50000/=

06.

Access control keypad f/jb-dv

12000/=

07.

Video monitor

15000/=

08.

Human (per/month)

5000/=

12.

Total

146500/=

Table-4.2The cost of operating the system

Problem Identification:

Task 5 – 10 Marks

The Fire Department needs to remain operational in the event of a serious incident such as a major terrorist attack or war. Explain the measures you would put in place that would allow the Fire Department to operate in the event of Newtown having no electrical power and fixed telephone lines being broken.

Solution of Task 5

Disaster recovery plans are complex, and can ultimately take two years or more to complete. While this can be taken in one way as from a disaster recovery consultant, it also comes from experience.

To make a plan for the fire department network to deal with major disasters

and also to deal with the short term failure of the system fallowing topics are included

1. Reason for Planning

protect human life;

recover critical operations;

protect competitive position;

preserve customer confidence and good will; and

protect against litigation.

2. Recognition

initial reaction procedures to a disaster report;

notification procedures for police, fire, medical; and

notification procedures for management.

3. Reaction

mobilizing the EMT (executive management team);

filing of initial damage assessment reports to the EMT;

assisting EMT in preparation of statements; and

opening a critical events log for audit purposes.

4. Recovery

modified signing authority for equipment purchases;

procedures for getting cash;

procedures for maintaining physical security;

procedures for arranging security at the damaged site;

procedures for finding and getting to the recovery center (maps!); and

procedures for arranging security at the recovery center.

5. Restoration

coordination of restoration of the original site;

restoration of electronic equipment;

reloading of software;

restoration of power, UPS, common building systems;

replacement of fire suppression systems;

rewiring of the building;

restoring the LAN; and

restoring the WAN connections.

6. Return to Normal

testing procedures for new hardware and software;

what constitutes a successful test (before recommitting production);

training operations personnel;

training employees;

scheduling migration back to original site; and

coordinating return to original site.

7. Rest and Relax

schedule compensatory time off; and

make visits to employees in rehab from stress.

8. Re-evaluate and Re-Document

review your critical events log;

evaluate vendor performance;

recognize extraordinary achievements;

preparing final review and activity report; and

Aid in liability assessments.

Problem Identification:

Task 6 – 10 Marks

Create a comprehensive, professional report describing your network recommendations. This should include the details of Tasks 1 – 5, have estimates of cost throughout and have an executive summary at the start giving the key points.

Solution of Task 6

In this task I have Investigate the company telephone system requires a central switchboard for the whole building plus direct dialing into each individual member of the company. Typical modern telephone functions such as call waiting, conference calls, etc will be required.

Investigate the in-house network (LAN) topology .In this network system we must select a topology and a medium thus we connect our network stations. Also we must provide a recommendation about the topology and media. Possible network topologies for each branch are:

BUS

RING

STAR

To setup a company intranet we need to consider the requirements for the media and connector in each implementation. This topic outlines the cable and connector specifications used to support network implementations.

Network Media: A star may be wired with twisted-pair ,coax or WI-FI.

Recommended: Unshielded Twisted Pair (UTP)

Type: Category 5 commonly know as CAT-5

A plan for Advertising Agency network to deal with major disasters and also to deal with the short term failure of the system. It is important that the system can be updated after temporary failure and that data is accessible in the event of a major disaster. Problems are going to occur. Hardware is going to fail. Networks are going to crash. The best thing Advertising Agency can do is plan for the inevitable, implement as many disasters avoidance mechanisms possible and be ready to react quickly when necessary. Some key points include:

Implementation physical data security

Protect critical systems

Conclusion:

Completing this work I have a good idea and experience about researching, creating reports, solving problems, on setup Local Area Network that I was required to complete for my assignment. During the completion of the work, I have to face many problems and I learn how to overcome these problems. I hope in future this assignment will help anyone to improve their study on LAN and to apply it on real life.

Bibliography