Suitable Network Infrastructure For Cybertrans Ltd Computer Science Essay

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Wireless Local Area Network (WLAN) allows computers and workstations to communicate with each other using radio propagation as the transmission medium. The wireless LAN can be connected to an existing wired LAN as an extension, or can form the basis of a new network. While adaptable to both indoor and outdoor environments, wireless LANs are especially suited to indoor locations such as office buildings, manufacturing floors, hospitals and universities [1]. WLAN is the finest solution for this company. VoIP over WLAN technology will contribute in providing efficient customers services to Cybertrans' customers and enable the employees to work anywhere using hand-held devices. It will also enable the company to track their drivers effectively and improve delivery service. Wireless mobile devices will allow the company to change the way they work.

The purpose of this project is to identify a suitable network infrastructure for their new temporary offices. Cybertrans Ltd. will be re-locating into a new temporary office for a period of two years before moving on to another location. They have indicated that they do not want to invest a lot in permanent infrastructure for their new offices as it will only be temporary. The scope of this project includes what technology will be best suited for this new office. The new technology must support voice, data and their existing logistics systems.

These technologies will provide Cybertrans' staff mobility by connecting to the Internet or office network wires-free through a wireless access point. This will thus improve the whole functionality and the profile of the company. In this case calls made over the wireless network and mobile network are separate. There is another type of technology available to allow mobile phones to use both the wireless and mobile networks at the same time. This is called, "Fixed Mobile Convergence". 

Chapter 1: Introduction

1.1 Introduction

Cybertrans Ltd is a logistic company that provides delivery services throughout the UK. It has a decentralised system that is already in place, but not running effectively and efficiently. The office is located in a remote area, having fitted network cable and using an old telephone system. Therefore, it is becoming increasingly difficult to ignore the fact that their network infrastructure of the building is now a legacy system. This system is unable to function at its best in a competitive market because it is too slow and network connections are mostly not available. Staff are not allowed to move around in the office due to network cables have to be moved.

The existing network doesn't meet the current business needs. By moving to the new temporary office it will allow Cybertrans to overcome some of these difficulties by deploying more suitable network infrastructure and technologies.  The company has already decided to deploy a Wireless LAN (WLAN) and to have a Voice over Internet Protocol (VoIP) telephone system which will run smoothly and be able to communicate effectively. This will allow them to compete with their competitors and increase their profits with a greater return on investment on their new network infrastructure. This will enhance productivity and allow staff to work and move anywhere they want. Having this new system in place, Cybertrans Ltd will improve efficiency and save time. It is hoped that this new system will create significant changes in the process and thereby produce economic gains and overall cost saving for the company.

As the company has been given a grant, it will enable them to relocate in new premises with the facility of implementing a new network infrastructure, which allows them to have better internet communication in the future.

This paper will address the issues of the importance of VoIP and Wireless LAN. VoIP is very popular and mostly used by companies to improve the way they work, that is to say it will help Cybertrans to offer a better and more efficient customer service. Wireless LAN is the new solution and has the potential to increase the productivity and flexibility of Cybertrans Ltd.

1.2 Problem Statement

Cybertrans' existing network infrastructure is wired and very old. It has a low capacity using older wired ports and staff are not able to access the network efficiently. It actually slows the process of tracking of their deliveries. Staff are using the old telephone system which does not work over the data network. Cybertrans' wireline network model limits the accessibility and the flexibility of the company network. Then broadband speed is very slow which delays the work to be done. Mostly, staffs are not able to do their work while they are moving around because it is heavily cabled when they are connected to the network. If they had the ability to still stay connected to the network while they are moving around the productivity would increase.

The proposed solution is to design a new system to solve these problems listed above. The plan is to have a Wireless system and Voice over Internet Protocol that need to be implemented in Cybertrans Ltd. The new system will allow the staff to move around in a defined area while they are still connected to the network. Staff will be issued with soft phones to connect to their PCs which will allow them to operate more efficiently. The new network system will provide better speed and better internet accessibility. Based on Geier' findings (2001), WLAN technologies offer the benefits of mobility, reduced installation time and cost, he argues that many challenges must be met by companies deploying them.[2] Thus, it can be discussed that how to best plan, design and implement WLAN technologies at Cybertrans Ltd.

1.3 Wireless LAN Technologies

IEE802.11 is a family of wireless LAN (WLAN) specifications developed by a working group at the Institute of Electrical Engineers (IEEE) and based on Ethernet technology that employ spread-spectrum solutions. Existing WLAN technologies include infrared, ultra high frequency (UHF) narrow band and spread -spectrum (Garg, 2001). He also explains that most WLAN  systems use spread- spectrum, which is wideband radio frequency(RF) technique that uses the entire allotted spectrum in a shared manner as opposed to dividing it into discrete pieces as with UHF narrowband.(Garg, 2001). [3] Recently, Researchers have shown an increased interest in IEEE802.11and it is increasingly used in public and private sectors. However, Zahariadis (2004) states that Zyren et al. (1999) suggest that IEEE 802.11 is the most mature wireless protocol in the unlicensed band of 2.4 GHz for Wireless LAN communications, tested and deployed for years in corporate, enterprise private and public environments.[4] 


These IEEE802.11 standards also known as Wi-Fi (for Wireless Fidelity) are presented in a Wireless Technology Table showing the comparison between them as follows:

IEEE802.11 Standards Wireless Technology Comparison Chart



Layer 3 Data Rate

Maximum Physical rate


Compatible with




12 Mbps

1-2 Mbps




Signalling methods and services

Higher range

Limited throughout

Limited bit rate






Wired 10Mbps

Higher range

Widely deployed

Long coverage

Excellent Signal

Lowest cost

Bit rate too low for many emerging







Higher bit rate in less crowded spectrum

50 m in 5 GHz spectrum range

Less interference than 802.11b

Support more users per room

Can co-exist with 802.11b and 802.11g

Smallest range of all 802.11 standards

Limited to one room

Does not comply with various EU requirements

5 GHz frequency not available worldwide

Short Coverage

Does not provide any QoS mechanism





802.11 and 802.11b due to narrow spectrum

Higher bit rate in 2.4GHz spectrum

High speed

Provides higher capacity requirements for


Available worldwide

Excellent signal

Long coverage

Fast maximum speed

Compatible with 802.11b

Higher cost than 802.11b

May have interference on unregulated frequency






Fastest maximum speed

Best signal range

More resistant to signal interference from outside sources

New and latest one

Higher cost than 802.11g

Use of multiple signals may greatly interfere with nearby 802.11b/g based networks.

Not yet finalized

Table 1 shows the IEEE 802.11 WLAN Standards [5]

1.4 Product Specification

1.4.1 Wireless Local Area Network (WLAN)

WLAN is a wireless local area network that has devices like servers, clients, printers, etc. are all interconnected via a microwave radio signals instead of cables or wires. It operates practically the same as wired LAN, but it transmits through the radio frequency. According to Kezemitabar et al. (2010), Wireless LAN is one of the most useful technologies all over the world. [6] This technology allows staff to communicate easily by being everywhere at any given time. The research to date has tended to focus on Wireless LAN more than Wired LAN, because it has some characteristics such as it is mobile, simple, and furthermore, it is very efficient and cost effective. It has the opportunity to merge and enables to incorporate VoIP over Wireless LAN.

The Basic WLAN components that are needed are as follows


Wireless LAN Card

Wireless Access Point

Wireless Bridge

Wireless Broadband Router

Wireless Print Server

Wireless Signal Booster

Power Over Ethernet Adapter- it allows desktop Pc users access to the LAN.

Antenna - it transmits in a 360 degrees arc and receives signals from any direction.

Wireless LAN Card is the Radio Network Interface Card (NIC) that attached to computer. It is a network card that enables laptop users to connect wirelessly to a radio- based computer. It is an essential component for wireless desktop computer. TP-LINK TL-WN721N is designed to provide a high-speed and unrivalled wireless performance. It allows high packet transfer rate of up to 150 Mbps for maximum throughout. It also interoperates with IEEE 802.11g and IEEE 802.11b standards.[7]

Wireless Access Point is Radio equipment that connects the Wireless LAN Cards to the wireless network. It increases the effective range of a wireless network and provides additional network management and security features. Access points are useful for larger networks, and they are particularly well-suited for adding wireless capability to an existing wired network. [8]. An Access Point provides an easy way to connect staff, whether they are on site or remote to the business operations. It has different shape and size, but all share similar options, which are as follows:

• Fixed or detachable antennas

• Advanced filtering capabilities

• Removable radio cards

• Variable output power

• Variable types of wired connectivity- 10BaseTx, 10/100BaseTx, 100BaseTx,

100BaseFx and more

Cisco WAP4410N Access Point is secured, offers the fastest speeds with expanded range and coverage. Zoom 4402 Wireless Access Point works on all the IEEE 802.11 standards. Linksys -WAP54G Wireless-G Access Point. [9]

Wireless Bridge is used to link different Wireless Access Points. It converts a wired device for use on a wireless computer network. A device used to add desktop computers and printers in remote locations to the network without having to string

cables. Cisco WET200 Wireless-G Business Ethernet Bridge separates Ethernet networks together wirelessly and is ideal for small businesses.

Wireless Broadband Router is a device that processes traffic entering and exiting a network. This allows multiple computers and devices online at the same time with only one Internet connection. Linksys -WRT54G Wireless-G Broadband Route and WRT300N Wireless -N Broadband Route [10]

Wireless Print Server is a device that connects a USB printer directly to the network. It allows staff to send print jobs over the wireless network, reduces the printing bottleneck and set the pc free.

Wireless Signal Booster increases the range and signal of the wireless hotspots created by the Wireless Access Points. 

Power Over Ethernet Adapter allows desktop Pc users access to the LAN. It uses to place radio near antenna to avoid cost and loss of a long antenna cable. Linksys- WAP4400N Wireless-N Access Point with Power Over Ethernet

Antenna transmits in a 360 degrees arc and receives signals from any direction. It also provides extra distance and special applications. Planet ANT-OM8 8dBi Omni Directional Antenna provides the long distance connectivity.

1.4.2 WLAN Transmission Technology

There are three main ways by which WLANs transmit information; these are microwave, spread spectrum and infrared. With Spread Spectrum Transmission, there are two methods used by WLAN products, frequency hopping and direct sequence modulation. Infrared one, this method uses infrared light to carry information and have three types; these are diffused, directed and directed point to point. [12]

1.4.3 WLAN Infrastructure

All mobile, wireless devices, computers and terminals communicate with each other through an Access Point (AP). This means that when any terminal sends packets to other terminal, packets are first sent to the AP and then forward it to their destination. Wireless access points are usually physically connected to each other, the bridge and the router but connectivity to the end-points is wireless.

1.4.4 Voice over Internet Protocol (VoIP)

VoIP is an alternative to the traditional Public Switched Telephone Network (PSTN). Historically a company would have a number of PSTN lines for their staff. Even if the call was internal and going between two staff members it would cost the company money. By moving to VoIP in simple terms this means moving the voice calls onto the data network. This means that calls between two staff members in any of their offices using VoIP would be free and the company would only pay for calls that leave the company as a whole to the PSTN. This provides a large cost saving for customers and it provides a better return on investment on their network and voice infrastructure. 

When it is used, voice information is converted into digital packets and sent over the network and then converted back into signals before reaching the phone receiver at

the other end. Researchers like Kazemitabar et al. (2010), they suggest that VoIP is one of the most important technologies in the world of communication. It consists of

three essential components: CODEC (Coder/Decoder), packetizer and playout buffer [11]. Basically, VoIP system can be configured in these connection modes respectively; PC to PC, Telephony to Telephony and PC to Telephony. Karapantazis et Pavlidou(2009), they justify that VoIP is the cheaper call than a circuit-switched calls since most VoIP providers offer affordable long distance and international calling. [13] It can thus be argued that this will save Cybertrans Ltd a significant amount of money in making phone calls.

The Basic VoIP components that are needed are as follows:€ 

Public Switched Telephone Network (PSTN)   

Private Branch Exchange (PBX)   

Routers  and Switches (The Network)   

IP Phones


Public Switched Telephone Network (PSTN) is a circuit- switched based network which requires a dedicated line for telecommunications activity. Some parts of the PSTN are also utilized for VoIP and other Internet-based network technologies.

Private Branch Exchange (PBX) switches calls between one or two traditional telephone users.

IP Phones also known as Soft phone is used to create a phone connection on a computer. D-Link's DPH-540 IP phone supports all SIP-based VoIP providers and works with 802.11b or g Wi-Fi networks. It supports WEP, WPA, and WPA2 encryption. Cisco's Unified Wireless IP phone 7920 works with the Cisco Unified Communications Manager and supports EAP-FAST authentication for increased security. [14]

Gateway acts as translator between networks with different signalling protocols. It provides specialised authentication and connectivity for wireless clients.

 Based on Chen et al. (2006) findings, they state that the technology requirements for VoIP environments fall into four categories namely signalling, coding, transport and gateway control. [15] The purpose of signalling protocol is to manage connections between destinations. The coding one is to transform the analog signal generated by human speech into digital data. Gateways are responsible for converting packet-based audio formats into protocols.

1.4.5 Other Technologies

Bluetooth is a short-range wireless standard which uses the same frequency of 2.4 GHz band as 802.11b wireless networking, but it is very different to the latter. Zahariadis (2004) suggests that Bluetooth specification communication is based on ad hoc networking, which means it does not have an access point to link communication. It is also referred as Wireless Personal Area Network (WPAN), because it only brings close proximity connectivity. [16] Brewin (2001), companies deploying these high rate WLAN technologies must be aware of possible inference between IEEE 802.11, Bluetooth, and other 2.4 devices sharing the same bandwidth. [17]

Chapter 2

2.1 Evaluation of WLAN Technologies

802.11b and 802.11g has some similarities between them such as they both provide an excellent signal and their coverage penetrates most walls. Both of them operate in the 2.4 GHz frequency and thus it has the advantages of using the products that are built in these standards. 802.11g is compatible with wireless-B networks and hotspots. However, 802.11a and 802.11b are incompatible because they utilize different frequencies, but 802.11n are compatible with 802.11g. Therefore it is crucial to have a better knowledge of the IEEE 802.11 standards before buying and implementing any WLAN products.

2.2 Benefit of WLAN and VoIP

WLAN offers companies the ability to enable wireless mobility throughout a facility and facilitates relocation of workstations. It is widely used in many places to provide mobile access to the internet. While providing Wi-Fi in most places such as retail stores, Café and restaurant, companies are increasing their benefits in customer care. WLAN is cost much cheaper than Wired LAN and it helps using held devices. Thus, it can be suggested that WLAN is simple, mobile, scalable, efficient and cost effective.

VoIP is simple to use, cost effective and portable. It has extra features than a traditional phone service such as better quality sound, call waiting, voice mail and call forwarding. It provides a better return on investment on the network and voice infrastructure. 

2.3 Challenges of WLAN and VoIP

WLAN security is the main issue of WLAN technology. These are the treats facing WLAN, Unauthorised access, Hackers, Viruses and eavesdropping, when someone sniffs the network without gaining physical access. Data can be lost and corrupted. Interference occurs when operating in the same spectrum. Companies have to consider whether the wireless networks will integrate with the wireline infrastructure, which add on the financial cost.

VoIP does have some quality problem because quality depends on many factors like the band width, Internet connection over the routed call and the Codec being used by the provider. Power loss can cause the internet connection to go down and it will be unable to make calls. With VoIP, there are some other factors, such as Delays, Jitter, Packet loss, Echo, and Throughput.

2.4 Counter Measures are as follows:[18]

Rename the wireless network that is not easily recognisable by unauthorised users.

Use Encryption techniques such as Equivalent security Protocol (WEP) and the Wi-Fi Protected Access (WPA) protocol.

Use Authentication methods. such as change password regularly.

Install Antivirus Software and Firewall to protect unauthorised access.

Use a Virtual Private Network (VPN) which will allow employees to connect securely to the network when they are working away from the office.

Disable file sharing when connecting to a public wireless access point.

Use UPS backups whenever there is power failure.

Chapter 3: Review New Technologies [19]

3.1 Impact on United Parcel Service (UPS)

UPS is to spend $127m (£81m) on global deployment over the next five years of a driver terminal that features built-in cellular, wireless LAN and Bluetooth short-range wireless systems. The Deliver Information Acquisition Device (DIAD) IV includes GPS receivers and a barcode scanner. 

This electronic data capture will ensure UPS customers have the most current package tracking information available to them anytime and anywhere.

3.2 Impact on FedEx

FedEx is trying to use a similar driver terminal based on the Pocket Pc operating system and has a project of $ 150m to design to equip 40,000 drivers. The PowerPad operates over the AT&T Wireless Services GPRS network, incorporates Bluetooth and a built-in 802.11b WLAN system.

Chapter 4: Recommendation

4.1 Overall Solution

I would recommend Cybertrans Ltd to choose the wireless products that support the finalized 802.11g wireless networking protocol. It is a standard that is widely deployed by many organisations and transmit data rates up to 54 Mbps in 2.4 GHz. This technology is chosen because it operates in the 2.4 GHz frequency, it allows other products that have been built in the 802.11b standard can be used in this standard. Hence, it offers a range of products that can be used to implement the system and has the opportunity to bargain on the prices. It is a high speed extension to 802.11b and uses ODFM for backward compatibility. It is available worldwide and likely to be less costly than 5GHz in 802.11a standard. It has a better coverage and excellent signal. There is a new and latest 802.11n standard which provides data rates of over 100 Mbps better than 802.11g, but it is not yet finalized and it does not has the popularity in the market. If Cybertrans Ltd would like to change in the future, 802.11n will be backward compatible with 802.11g gear.

Recent developments show that it will provide path to even higher speeds in the future. Thus, it can be argued that this 802.11g standard is more efficient and intends to have much greater security than others. This will increase employee productivity, reduced communication costs and access resources anywhere and anytime. The disadvantage of wireless LAN is the increase of security issues such as authentication and encryption need to be considered carefully. These issues can be addressed by using the WEP and WPA techniques to encrypt the wireless communication and use a firewall built -in router. But the most important one is to turn off the identifier broadcasting to prevent unauthorised access.

VoIP solution is very cost effective for Cybertrans Ltd because it will merge the voice and data infrastructure together. Codec used today is G.729 and G.711. G.729 is better as it is compressed and use approximately 38 kbps per connection where as the G711 is uncompressed and has 64kpbs per connection. [20] I would recommend G.729 because it provides quality calls and uses less bandwidth on the network. An IP Centrex with a SIP trunk is more appropriate rather than an IP PBX because it is flexible if the company has to move in two years.

Other products need to be bought for WLAN clients, because it is a company that delivers service, it will therefore require barcode scanners, update their PCs, Laptops, PDA and other hand-held devices.

The emergence of new services for Cybertrans Ltd will be E- Business, to provide delivery services globally. They will expand their business and implement new systems to compete with their rivals, for example UPS is trying to have the built-in 802.11b WLAN system at all its sorting facilities worldwide. The option is opened if Cybertrans Ltd would use the same 802.11g technologies in the future to

do business globally or use the other technologies. Finally, I would recommend

Cybertrans Ltd to go ahead with this solution because it is efficient and cost effective.