Mobile Computing: Personal perspective

People choose to buy and use mobile computing devices for numerous reasons. These reasons are often much simpler then the business reasons because they are mainly to do with each persons own personal preference. People’s reasons range from wanting to keep in touch with others constantly, to be able to surf the internet for information whilst out, keeping up to date with schedules and organize their lives and wanting to have WLAN in their home so they can easily sit their laptop at the dining table or the TV whilst using it, plus many more.People wish to make their lives easier and more convenient and these wishes have created devices such as the organizers, video camera phones, and car kits.

How VPN services work

A Virtual Private Network (VPN) is a new technology that creates a secure tunnel through the internet. Each node on the VPN network will have a VPN device which is a specially designed router or hub switch this creates an invisible tunnel through the internet. The VPN device at the senders end takes the split up data called packets or frames and encapsulates it with a VPN frame so it knows how to process the frame (put the split data back together) This encapsulation is quite complex since it travels through an unsecured network like the public internet.

VPN services start with a user connecting a VPN device to at an ISP via a modem. Next the user’s computer generates a piece of data such as a web request message which is in HTTP protocol. This data then goes through the OSI model layers of transport and network adding TCP and IP packets. A data link layer protocol is then added for example a dial up protocol used is Point-to-Point Protocol (PPP) At this point the web request is ready for transmission under normal non VPN environments. But the VPN device encrypts the frame and encapsulates it with a VPN protocol such as Layer Two tunnelling Protocol (L2TP) The VPN device then places another internet protocol around the packet so the packet can travel through the internet and find the required VPN device. The frame which now has its final IP encapsulated (inside a L2TP which has a PPP, TCP, IP and then a HTTP) is now ready for secure transmission through the internet. As the packets reach the destination the process is reversed stripping each protocol down as it goes through the different devices.

There are three types of VPN: Intranet, Extranet and access. An intranet VPN provides virtual circuits between organisation offices or departments in neighbouring buildings. For example the ECU computer labs use a physical intranet; a virtual intranet is one which uses the internet to connect, where ECU uses CAT 5 cable. An extranet VPN is the same as an intranet VPN only it connects computers through different organisations. An access VPN enables employees to access an organisation network from a remote location as though the were inside the building.


Carr, H. H. & Synder, C. A. (2007) Data Communications & network security. United States of America: McGraw-Hill/Irwin pg 124-129

Dennis, A. (2002). Networking In The Internet Age Application Architectures. United States of America: John Wiley and Sons, Inc

Dostálek, L., & Kabelová. A. (2006). Understanding TCP/IP. Retrieved August 6, 2006 from

A repeater, bridge router and gateway

The repeater, bridge, router and gateway are all pieces of network equipment that work at various levels of the OSI model performing different tasks. The repeater network device exists in the physical layer of the OSI model and is the cheapest of all the mentioned devices. A repeater can be thought of as a line extender as connections on mediums such as 10BaseT and 100BaseT become weak beyond distances of 100 meters. The repeater receives a signal in an analog environment and replicates it to form a signal that matches the old one. In a digital environment the repeater receives the signal and regenerates it. Using a repeater in a digital network can create strong connections between the two connecting joins since any distortion or attenuation is removed. Unlike routers repeaters are restricted to linking identical network topology segments ie a token-ring to a token ring segment. Repeaters amplify whatever comes in and extends the network length on one port and sends out to all other ports (there is no calculation to find the best path to forward packets). This means that only one network connection can be active at a time.

A bridge is an older way of connecting two local area networks or two segments (subnets) of the same data link layer. A bridge is more powerful than a repeater as it operates on the second layer (data link) of the OSI network model. Messages are sent out to every address on the network and accepted by all nodes. The bridge learns which addresses are on which network and develops a routing or forwarding table so that subsequent messages can be forwarded to the right network. There are two types of bridge devices; a transparent hub bridge and a translating bridge. A translating bridge will connect two local area networks (LAN) that use different data link protocols. By translating the data into the appropriate protocol ie from token ring to Ethernet network. A transparent hub bridge will perform the same functions as a translating but will only connect two LANs that use the same data link protocol.

Routers are used in the majority of home networks today and are placed at the gateways of networks. They are used to connect two LAN’s together (such as two departments) or to connect a LAN to an internet service provider (ISP). Routers use headers and forwarding tables like a bridge to determine the best path for forwarding the packets. Routers are more complex than bridges and use protocols such as internet control message protocol (ICMP) to communicate with each other and to calculate the best route between two nodes. A router differs as it ignores frames that are not addressed to the router and use algorithms and protocols that allow them to send packets to the best possible path. A router operates at the third OSI layer (network layer) and can be dynamic or static. Once a static routing table is constructed paths do not change. If a link or connection is lost the router will issue an alarm but will not be able to change the path of traffic automatically unlike dynamic routing. Routers are slower than bridges but routers are more powerful as they can split and reassemble frames receiving them out of order also they can choose the best possible route for transmission, these extra features make routers more expensive than bridges.

Gateways connect networks with different architectures by performing protocol conversion at the application level. Gateway is the most complex device operating at all seven layers of the OSI model. Gateways are used to connect LAN’s to mainframes or connect a LAN to a wide area network (WAN) Gateways can provide the following things:

Connect networks with different protocols

Terminal emulation so workstation can emulate dumb terminals (have all computer logic on a server machine)

Provide error detection on transmitted data monitoring traffic flow.

File sharing and peer to peer communications between LAN and host.


Carr, H. H. & Synder, C. A. (2007) Data Communications & network security. United States of America: McGraw-Hill/Irwin pg 124-129

Dennis, A. (2002). Networking In The Internet Age Application Architectures. United States of America: John Wiley and Sons, Inc

Dostálek, L., & Kabelová. A. (2006). Understanding TCP/IP. Retrieved August 6, 2006 from

Client Server Architectures, technical differences

Client server architectures are one of the three fundamental application architectures and are the most common architecture for the internet. Work done by any program can be categorised into four general functions: Presentation logic is the way the computer presents the information to the user and the acceptance of user’s inputs.

Application logic is the actual work performed by the application

Data access logic is the processing required to access data ie queries and search functions

Data storage logic is the information that applications need to store and retrieve.

Client server architectures split this application logic up so work is separated between servers and clients. (Dennis, 2002)

The simplest of client server architectures is the two-tiered architectures. Two-tiered architectures have only clients and servers and split the application logic in half. With presentation logic and application logic kept on the Client computer whilst the Server manages the data access logic and data storage. Both a disadvantage and a advantage of client server architectures is the fact they enable software and hardware form different vendors to be used together. This creates a disadvantage as it is sometimes difficult to get different software to work together. This can be resolved using middleware software that sits between application server and client. This creates a standard way of communicating so software from different vendors can be used. It also enables easier installation if the network layout change occurs or is updated (a new server is added) as the middleware software tells the client computer where the data is kept on the server computer.

Three-tiered architectures make use of three computers and typically separates presentation logic, application logic and combines data access logic and storage together.  Whilst a n-tier architecture uses more than three sets of computers and usually spreads the logic on to separate computers sometimes spreading application logic across two or more different servers. The primary advantage of a n-tier client server architecture is it separates out the processing that occurs so that the load on the different server is more scalable. On a n-tiered architecture there is more power than if we have a two-tier architecture (as there are more servers) if an update is required we simply add a server, instead of replacing a whole machine. N-tier and three-tiered architectures do have certain disadvantages. Greater load is placed on the network this is because there are more communication lines and nodes in the network. Because of this a lot of network traffic is generated therefore a higher capacity network is required. Also n-tier networks are much more complex and it is more difficult to program and test software due to once again the number of communication lines.


Carr, H. H. & Synder, C. A. (2007) Data Communications & network security. United States of America: McGraw-Hill/Irwin pg 124-129

Dennis, A. (2002). Networking In The Internet Age Application Architectures. United States of America: John Wiley and Sons, Inc

Dostálek, L., & Kabelová. A. (2006). Understanding TCP/IP. Retrieved August 6, 2006 from

What is Mobile Computing?

Mobile computing is becoming an increasingly important in daily life whether personal or business, but what is it? Furthermore why do people want it and what are its benefits? It shapes millions of lives everyday, opening the door to Communication, Information and Productivity which is no longer restricted to the home or office. In today’s society it is already a prominent factor but what does the future hold? Major businesses are gearing towards better efficiency and performance, longer power life and true-mobility. What is mobile computing? Mobile computing is an industry that touches millions of people everyday, whether its business solutions such as access to a company’s database wherever their employees are, or for personal use like browsing the internet whilst dining out. It has a wide range of applications that help people organise their lives, work whilst on the move and communicate wherever they are. Typical mobile computing devices range from Laptop computers with wireless local area networks (WLAN), mobile phones and personal digital assistants (PDA’s) which incorporate Bluetooth technology. Mobile computing is the ability to access information resources whilst away from the home or office desk.

What does mobile computing encompass? As stated previously mobile computing incorporates many devices including laptop computers, PDA’s, mobile phones and pagers. Essentially a mobile computing device is any device which is able to be transported with relative ease and uses a computer to carry out its tasks. However this is not the only thing which makes them a ‘mobile’ computing device. In order for a device to be a truly useful mobile tool it was found by Caldwell and Koch (p. 6) that they needed to be supplemented with other technology which allows them to be used in a mobile context: It became evident that high speed networks and information storage systems are important complementary technologies. In fact, it is the ability of organizations to connect portable PC’s to reliable high speed networks and access to corporate databases from remote locations that has made mobile computing the valuable tool that it is. Without these technologies supporting mobile devices, the devices themselves would be little better then their more fixed counterparts such as PC’s. In fact they would be less useful due to their lesser power capability.

Why mobile computing? The reasons for society’s desire for mobile computing are diverse. All the reasons end up boiling down to making life easier and more efficient; the main difference is what aspect of life is being made easier.

Mobile Computing Accompanying Technology

Accompanying technology? Mobile computing encompasses not only the devices but also the accompanying technology which allows them to function efficiently. A few examples of such technology are WLAN’s and Bluetooth technology. WLAN (wireless local area network) A WLAN is the same as a LAN (local area network) as such that it allows users access to the internet and communicate with others in the Network. WLAN is a replacement for office cabling which introduces numerous benefits over traditional LAN’s. Schiller (2003, p. 201) points out these benefits as being: • Flexibility whilst within the WLAN coverage. Traditional wired LAN’s still restrict where you can connect to the network and also firewalls (real firewalls such as brick walls not routers) can cause problems. With a WLAN you can connect to the network anywhere within their coverage, be that building or campus or single rooms. • No required planning, wired LAN’s need wiring plans, additional cabling with the correct plugs and switches whilst WLAN’s are able to by pass these and allow for communication without previous planning. They can be set up easily after the building is finished and do not need to be installed in the very beginning, or be installed later at major costs. • WLAN’s can survive disasters such as cabling being broken or an earthquake. If the wireless devices survive then people can still communicate. In a wired system, if part of the cabling fails for any reason it can cripple all communication. • The cost is much lower then wiring in a network as additional users to the network can be added easily without major costs involved. Adding to an existing wired network can have huge costs due to having to run new wires through existing walls and installing the plugs and switches associated.

WLAN is one of the most efficient and flexible mobile computing solutions around. However it does have disadvantages from LAN’s. These points have been identified by Schiller (2003, p. 202) as: • Lower quality, due to the lower bandwidth available with radio transmissions compared to wired transmissions. The bandwidth is 1-10Mbit/s user data rate compared to 100-1000Mbit/s in wired networks. As well as higher error rates due to interference which then incorporates higher delay because of the error detection mechanisms. • Standards are still being worked out and differ in different areas around the world causing problems. It is hard to establish global solutions due to these inconsistencies. • Security is a big disadvantage as radio waves for data transmission are able to get interfered with easily by other high-tech equipment. It is also much easier to eavesdrop in on a WLAN system, and all standards must offer encryption, privacy and anonymity mechanisms.

Bluetooth Bluetooth technology was introduced into the mainstream market a few years ago to deal with the interconnection between smaller mobile computing devices such as mobile phones. An article published by Phillips Business Information's Communications Standards News (1999) stated The Bluetooth technology is a specification covering small form factor, low-cost, wireless communication for networking between PCs, mobile phones and other portable devices. It is claimed that the Bluetooth technology will at re-define the personal communications market by expanding the capabilities of mobile devices and making these devices work better together. According to market research firm Cahners In-Stat Group, there will be over 670 million Bluetooth enabled devices worldwide by 2005. Bluetooth enabled devices are able to connect together and work in union. An example of Bluetooth technology is in Car kits. Bringing a Bluetooth enabled phone within the car will make it automatically connect with the Car kit and when a call is received it will allow hands free communication. The network or area under Bluetooth is relatively small and designed for smaller Mobile computing devices.

Mobile Computing: Business Perspective

From a business perspective the main goals of incorporating mobile computing into the company are

  1. Improving customer service
  2. Reducing cycle time and speeding decision making
  3. Attracting and maintaining a high quality workforce
  4. Knowledge management and exchanging best practices.

In business a major factor is giving employees flexibility in how and when they work. Improving customer service relates to communicating faster and more clearly with clients, being able to go to clients and complete the work with direct contact and also being able to build a team who are in different locations but are still able to work effectively together.

Mobile computing reduces cycle time and speeds decision making by allowing employees to access information and business services more frequently and away from the desk. There is no longer any delay by having to wait until your employees are back in the office before they can get required information or start on a project. Mobile computing allows them to access online resources, company databases and communication lines with ease away from the office PC.

It has been found that some businesses used mobile computing as a tool for attracting high level and professional employees stated that from their study: A number of companies reported that they used mobile computing as a tool for attracting workers. The three companies designed around mobile computing were most explicit in this. In these firms individuals were hired with the assumption that part or all of their work would be done either in their homes or in clients' facilities. This highlights how people value being able to work with more flexibility and how potential employees prefer to have the option mobile computing provides. Companies are keying into this and are offering mobile computing as an incentive to get highly skilled workers.

Knowledge management has been cited as a reason company’s are moving towards mobile computing. The argument is that it makes it easier for workers to have access to previously done assignments and jobs, these knowledge repositories according to often contain ‘reusable’ pieces of work and the expertise of the company. Another reason was the sharing of information between colleagues, though in practice mobile computing only seems to help with the organization of face to face meetings in which ideas are shared.

Mobile Computing in the Future

Mobile computing is already making a huge impact in society, why? Because as points out “one great thing about mobile devices is how they appeal to both personal and professional users” Microsoft's Bill Mitchell, vice president, mobile platforms division stated “Market research indicates that mobile computing is growing 15 percent more than computing in general.” Big businesses are gearing up to bring mobile computing to a new level. Major computing businesses such as Microsoft, Intel, IBM and telephone companies Nokia, Ericsson and Motorola Inc are not only researching and developing their own devices and improvements in mobile computing but are also joining together to promote it. (Phillips Business Information's Communications Standards News, 1999) stated thatThe five founding companies of the Bluetooth Special Interest Group - Ericsson, IBM Corporation, Intel Corporation, Nokia and Toshiba Corporation - announced on December 1 at their Santa Clara meeting that 3Com Corporation, Lucent Technologies, Microsoft Corporation and Motorola Inc. will join them to form the Promoter group of the Bluetooth SIG. The Bluetooth Special Interest Group (SIG) was formed in 1998 and wishes to revolutionise connectivity for personal and business mobile devices. Goals for the future Intel and Microsoft have firmly expressed their views on where they believe the future of mobile computing is. Microsoft is pushing for ultra mobile computing and according to “Microsoft's newest mission is pushing for a Mobile PC for every person. These are not run-of-the-mill laptops or desktop replacements. Microsoft is aiming for broad, general acceptance of a whole new category of carry-everywhere, always-connected computing devices with batteries that last all day long.” Battery power is a major point for the future of mobile computing. For truly useful mobile devices you need them to last all day and Microsoft and Intel are both putting a lot of effort into achieving this outcome. Intel’s plans for the future include improving four key requirements in their mobile devices. These being: “integrated wireless LAN capability, breakthrough mobile performance, extended battery life and thinner, lighter designs.” (M2 Presswire, 2003) Intel have an agreement with “Matsushita Battery Industrial (MBI) to jointly develop more powerful battery technology to support the vision for "all-day computing" for future Intel Centrino(TM) mobile technology-based platforms.” (M2 Presswire 2005) Intel believe that adoption of wireless broadband services coupled and new energy-efficient and higher- performing developments in mobile devices are signalling the beginning of "mobility ubiquity" according to Intel's top executive responsible for mobile computing. This mobile ubiquity offers the industry substantial new growth opportunities. (M2 Presswire 2005) Microsoft has identified for itself the next 3 factors that it wishes to overcome so they can progress forward into the future, the factors they wish to over come are “form factors, battery life and time to access.” (Techweb, 2005)

From this we can conclude that the mobile computing industry will have an even greater impact on our daily lives. Already presented with so many possibilities, and with more coming every year the industry is booming. Big company’s are putting a lot of time and money into the production and research of mobile computing and for the moment it looks set to carry on sweeping the way with new innovative connect ability and performance. The future of mobile computing looks set upon longer battery life, power efficiency, performance and power innovation. References

  • Bayne, K.M. (2002). Marketing Without Wires. New York: John Wiley & Sons, Inc.
  • Schiller, J. (2003). Mobile Communications (2nd Ed.) London: Pearson Education Limited
  • Caldwell, D. & Koch, J.L. (n.d.) Mobile computing and its impact on the changing nature of work and organizations Retrieved May 15, 2005, from
  • Microsoft Corp. (2005, April 26). Microsoft pushes ultra mobile computing. TechWeb, 1, Retrieved May 15, 2005, from ProQuest Database
  • Maloney, S. (2005). INTEL: Innovation in mobility, ubiquitous wireless broadband to drive opportunity. M2 Presswire, 1, Retrieved May 20, 2006, from ProQuest Database
  • Chandrasekher, A, (2003, September 17). INTEL: Innovation in mobility, ubiquitous wireless broadband to drive opportunity. M2 Presswire, 1, Retrieved May 20, 2006, from ProQuest Database
  • (1999, December 20) Bluetooth technology set to re-define the personal communications market. Phillips Business Information's Communications Standards News, 1, Retrieved May 20 2006, from ProQuest Database
  • No author. (2002). Wireless and mobile computing. Department of Information Resources. Retrieved May 15, 2005 from