Computer network

Essay add: 13-11-2017, 19:44   /   Views: 6


As we all aware very well with telephony traditional voice communication, because these systems was running circuit switching techniques that's why system used to have limited functionalities. In traditional networks or data network architecture we used to send data (email, messages) across the network and every service used to have different network e.g. voice, video etc.

Traditional WAN communication and data communication was just transmission of data (just text and numbers) between networks using encoded information mechanism. For other technologies there used to be separate networks for example television required delivery of video information to specific distribution points (TV Stations), images were send by Fax transmission as images could not be encoded easily as data, and for wireless communication two way radio system (walkie-talkies) was in place that permitted intercom communication between two people regardless their physical location.

Telecommunications is the merging of voice, data (WAN), LAN, video, image, and also wireless communication technology as well as microelectronic technologies to enable communication between people and different networks more efficiently. Microelectronics is a mechanism or technology of contracting electronic circuits and devices in very small package. New telecommunication system represents a convergence of all these technologies, means voice, Image, video traffic can travel on one media using different protocols.

Evolution of Computer (Data) Network:

The history of internet is very interesting; when we talk about internet technology it's grown so fast even beyond the expert's predictions in old time. The internet history timeline is explained below briefly.

1957: The united state Department of defence formed small agency called DARPA (Defence Research Project Agency) for just military science and technology purposes.

1961-1965: an institute called Massachusetts Institute of Technology (MIT) started using small phone-linked network to share information. ARPA was one of their main sponsors.

1966:with the corporation of ARPA Larry Robert of MIT introduced the concept of packet switching, and managed to build a small university network. This is the first time when research started on ISDN.

1969:The Stanford Research Institute, UCSB, and the University of Utah develop first network nod called UCLA. The first node to node message was sent from UCLA to SRI.

1971- 1973: More nodes were joined in the network and number of nodes reached to 15 which includes Harvard and NASA, and this is also the time when ARPA net goes global and university college of London, Norway's Royal Radar Establishment join up.

1974-1976: TCP (transmission control protocol) introduced and network intercommunication became more fast and sophisticated, UNIX system was developed at AT and T; and Queen Elizabeth send out her first email message by using new technology.

1979-1982: USENET, the mother of all networked discussion groups, was developed.TCP/IP (Transmission Control Protocol and Internet Protocol) was developed, first time internet being a connected set of networks.

1984-1985: Number of hosts on internet reached up to 1000 and they were increasing day by day, also first registered domain called went online.

1987-1988: Number of hosts reached to 10,000 and first large scale Internet hosting

1991-1993: World Wide Web was developed by Tim Berners-Lee which gave internet more growth and annual growth reached to 341,634%.

1994-1997: ARPA net introduced their 25 birthday, and first time company called RealAudio introduced internet streaming, time internet usage started to boost up big names Microsoft and Netscape started fighting for world wide web browser supremacy.

1998-present: Internet continues to experience staggering growth. From 1998 many companies have realised the importance of internet in business. Internet became superhighway. As we know in old time just data used to travel on internet media but now internet became integrated data network(IDN) means not just data traffic travels through the internet media but also audio and video traffic travel and controlled by one network media. [Gregory,Gromov]

What Is Convergence and Why We Integrate Networks?

Telecommunication includes radio, telephone and TV networks. Providing information to clients is the main feature that makes these networks similar to computer network. In beginning computer network was intended to transmit just alphanumeric information (ASCII text) simply know as data this is the reason computer network was also as data network. Radio network were developed to transmit voice signals, TV network used to support voice and video technology. Then there was need to combine these technologies first attempt to combine these technologies was ISDN, where data and voice was integrated in one network.

Convergence is an end to end service architecture where the entire network the network application videos, voice, data and multimedia are delivered on one single IP based infrastructure.

When we talk about why do we integrate the network, there are many business and social reasons working behind it. Businesses are using IT to perform their activities and to achieve their goals but they are using legacy system (running different networks for different applications) business requirement is to upgrade the system to meet customers and market needs and also to achieve business goals more efficiently. So converged network infrastructure fulfil today's business requirements.

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The above figure showed a Converged Network Infrastructure where different types (Voice, video) of traffic is running on single network.

Integrated Network Technologies and Their Use:

“Telephones, video and e-mail are no longer enough. Today, people need the ability to work with one another and their extended business network in real time and in the context of their business processes and preferred applications.”[IBM 2008][8] to fulfil all these requirement converged network infrastructure replace old technologies with new more advanced technologies such as VoIP, IP Video (VoD, IPTV), Data (HTTP, FTP, P2P) which uses different protocols e.g. SIP, H.323, MPLS, and H.248. Some of these technologies and their uses are defined bellow

Voice over IP (VoIP) Technology:

VoIP is a term which we use in IP telephony for a set of facilities that we use in IP (Internet Protocol) to deliver voice information. In other words sending voice information in discrete packets rather than traditional way where we used to have circuit committed protocols of the public switched network (PSTN). The term VoIP derived from VoIP Forum a major equipment provider to promote the use of ITU-TH.323 standard for sending voice and video using IP over public internet or intranet.

In addition to IP VoIP has been implemented in various ways using both proprietary and open protocols and standards. Examples of technologies used to implement Voice over Internet Protocol include: H.323, IP Multimedia Subsystem (IMS),Session Initiation Protocol (SIP), Real-time Transport Protocol (RTP).

How VoIP Works?

Many years ago we discovered that sending signals (analog) to a remote destination could also be possible using digital technology, before sending it we have to digitalize it with an ADC (a analog to digital converter), transmit it and then again convert it back in to analog format using DAC(digital to analog converter). VoIP works in the same fashion, it digitalize voice in to data packets send them over the network and on receiving end it reconvert them, digital format can work in batter and controlled way, we can compress data, rout it and convert it to new and batter format, also we know that digital signal is more noise tolerant than analog. TCP/IP packets contain headers to control the communication and payload to transport the data on network, VoIP use it to go across the network and come to destination.[2] There are different ways to implement VoIP in network which are described bellow

Computer to computer:

Using computer as a phone is very commonly used technology, some service providers (e.g. Skype) offer free software which you can install on your computer to communicate with some using other computer using VoIP technology.

Service providers to individual:

VoIP service providers offer planes for customers similar like traditional phone service planes, where you signup and pay a monthly bill. This system allows you to make long distance calls using your computer or VoIP phone device.

Service Providers to small Business:

Similar to individual's service provider offer planes to make long distance calls to small businesses and charge them some amount of money on monthly basis.

Custom VoIP:

This solution is created expressly for you either a very conversant, in house IT resource or a system integrator serving as a VoIP vender or expert. They work the same way that other VoIP solutions do for that they required a high broadband connection which allow you to integrate your phone services. But with a custom solution you can incorporate traditional PBX features that may not be available otherwise.

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The above figure showed the different phase of VoIP and it's availability on a different communication channels however used only one communication media.

Devices We Use In VoIP Communication

Any use of VoIP technology will require that you have reliable equipment and broadband connection. Here's a brief view of various types of VoIP devices which can be used for VoIP communication.

ATA: An Analog telephone Adaptor is a device which converts analog signals to digital data. This device allows you to connect a standard phone to you internet connection for use with VoIP, ATA's some time referred to as VoIP gateway.

Soft Phone: is a software application which you install on your computer to create VoIP interface, in order to use soft phone you will headset and Microphone installed on your computer.

P Phone: this device is similar to your normal cellular phone that can communicate directly to your internet connection in other words phone does not have to be routed through your computer or ATA and does not require any software.

Wi-Fi/WLAN Phone: this pone is like IP phone but does not require the ATA or computer to use VoIP. These devices are wireless enable and connect to the Internet via a wireless base station. [3]

VoIP Vs TraditionalPublicSwitchedTelephone Network (PSTN) Approach

When we compare VoIP with traditional PSTN system we easily say that VoIP has many advantages over PSTN system but they all depend on the quality of internet connection and technology you are using. VoIP has all of the features of PSTN plus additional provided by internet as its backbone e.g. enhanced call handling, linking of voice and email etc. when it comes to security it's easy to tape PSTN line than breaching VoIP network security. Setup cost of VoIP entirely depend on its Implementation Computer-to-Computer its free there is some initial investment when switching to custom VoIP system but as compare to PSTN line it less costly. Mobility is the main benefit of VoIP service because its run on internet connection it travels with you just as you would access your email remotely, and PSTN service is not mobile. Where VoIP has many advantages over traditional telephony services its has some draw backs as well like VoIP totally depend on your network connection it can go down but PSTN is line bought from service provider and it guarantees reliability of service. To overcome this problem a group of protocols know as Quality of Services (QoS) was introduced to ensure that the packets arrive without delay and in sequence at their destination. [Intel, 2008] [3]

Today there are number of VoIP services are available over the public Internet. Skype is the most well-known example; Skype became the world largest VoIP provider with more than 30 million users in less than 2 years. Not just businesses but general users use these services every day, even there are Skype enabled cellular phone are available in market now which allow two people have Skype enabled phone to communicate free of cost using service provider network. [4]

IP Video Services

over a packet-switched network infrastructure, using architecture and network methods internet protocol television or IPTV is a system through which digital television services is delivered e.g. internet and broadband access networks, instead of being delivered through satellite signals, broadcast, and cable television formats.

We can classified IPTV into three main groups live television, time shifted programming, and video on demand. It is distinguished from general Internet-based or web-based multimedia services by its on-going standardization process (e.g., ETSI ) and preferential deployment scenarios in subscriber-based telecommunications networks with high-speed access channels into end-user premises via set-top boxes or other customer-premises equipment. The video service on network usually requires tens of Mbps bandwidth more than 20 times that of simple voice services. [4]

In standard IPTV system uses following protocols

  • IGMP version 2 or IGMP version 3 are used in live TV for IPv4 for connecting to a multicast stream (TV channel) and for changing from one multicast stream to another (TV channel change).
  • We use Real Time Streaming Protocol (RTSP) in VOD (video on demand services)
  • N-PVR (Network-based Personal Video Recorder) is also uses the Real Time Streaming Protocol (RTSP).

The main advantage of an IP-based network is it allows integration and convergence. This prospect is amplified when using IMS based solutions. A converged service implies interaction of current services in a flawless manner to create new value added services. Example of this is getting caller ID on your TV screen and ability to handle it e.g. send a voice main. Integrated IP based services (IPTV) allow users to anytime any where access to content over their televisions, PCs and even Cell phones. In the business IPTV eliminates the needs to run parallel information to provide live and stored video services.

There is an increasing trend toward IPTV use for purpose such as corporate communications, employee training, and even retail applications. For example, broadband solutions provider Broadcast International Inc. just announced plans to implement a private IPTV network in 335 McDonald's locations in Italy to provide customers with unique video content, including live news, sports, weather and pre-recorded commercials. [David Cotriss, 2008] [5]

Need of Converged Network Infrastructure in Business

The power of integrated network is a single IP network which simultaneously handles data, voice, video, and perhaps even optical traffic is indisputable. Convergence of network allows businesses respond to opportunities in the marketplace in real time and with greater flexibility. Because integrated network combines whole system in a single infrastructure such as telephony layered on the IP network it reduce a variety of costs.

As mentioned network convergence cancers with breaking down barriers between network resources that facilitate voice and videos communication, collaborative applications and data sharing. Integrated LAN, VoIP, WAN networks, e.g. deliver voice mail, data email, faxes, and calendar events to one inbox.

“The importance of unified communication is not only that it integrates communication channels, within the enterprise and with the key constituents, but also it offers the way integrate communication functions directly into business applications”[William Stallings 2008][6]

Integrated network has many advantages over traditional network infrastructure, imagine that there is only one network or communication interface from your office to outside world i would mean that you would have fewer systems to manage and fewer cables to connect and if you have any difficulty you would have only one organization to call for support. The application you are sunning on your computer's desktop could be integrated voice and data applications and these might be include voice mail or fax that could be redirect to your email account when you are away on business trip or a website that was integrated with live customer response centre making online purchase easier for customers. And mainly cost of single high speed network will be much less than the cost of multiple lower speed circuits.

We can drive several conclusions from above data, first note that the basic voice is the most important application followed by conferencing and long distance/toll bypass. Since all theses three applications are been considered to be very important for most business operations many network managers are looking to converge their network as a replacement technology as existing PBX, or centre or KTS systems are retired. But beyond these basic functionalities business also looking toward positioning their network to support improved technologies such as mobility and multimedia application in coming years. So IP based convergence system support both present needs and future applications. Integrated system provides many benefits to a business in this example i will explain how an automobile insurance company can perform its business activities more efficiently by using converged network. [7]

An automobile insurance company provided its adjusters a solution that enables them to complete the entire processes of accident claim, including connecting customers and colleagues through one interface. Using very easy to use system call centre representatives retrieve the customer data add some note and then send that data to adjuster working in the field using his/her preferred communication method. Once adjuster receive all the information about claim he/she can continue the claim processes including obtaining the map of accident location, submitting photos or other detail using provided wireless device. As integrated system installed in company which also support video communication, so the adjuster can use his/her wireless video share enable device to contact company or auto repair shop for help with assessment or other purposes. After assessment is done and call centre representative have all the details they can contact the customers using VoIP phone by using their computer. The integrated network solution enable employees to work more effectively and more efficiently together to provide faster and more accurate services to customers, this system help them to improve customer satisfaction while increasing productivity and reducing costs. [8]

Social Use of Integrated Network

Social needs and development of integrated network is same like businesses. Where businesses getting maximum benefit from these technologies individuals are also appreciating this too. For example internet telephony using VoIP enable users to make calls from computer to computer free of cost or some time very little cost as compare to PSTN system. People used to use cellular phone for just voice communication and texting purposes but now integrated network concept has been introduced in Mobile (Cellular) phone technology. This device is not longer a mobile phone which performs specific functionalities it has converted in to mini personal computer, Using converged network technologies such as Data (HTTP), Voice (VoIP), Video (IPTV). Integrated network allow users to access internet through wireless connectivity. Using converged network technologies users can watch live videos also network allow them to do live video conferencing. Similar using cellular phone integrated network technology (VoIP) allow users to call someone for free using some software applications (Skype), user can also use this technology to make long distance calls for very little cost.[ William Stallings., 2008] [6]

Future of Integrated Network Infrastructure
  1. All Electronic Will Have IP Address And Will Be Controlled Remotely:Networks of the future will be worlds apart from today's comparatively ordinary ones that simply carry packets from one end to the other. With the explosion of high definition of video streaming , Peer to Peer, and ever present computing projects like Internet are looking at the scenario where light bulbs and toaster will have their unique IP addresses means all the house hold appliance will be given a IP address and controlled remotely over the Internet. So now the question is how it would be possible to implement this idea it will cause allot of traffic on network.
  2. The whole scenario looks very Utopian, but already Pro Curve Networking a celebrative partners of HP offered a solution that will allow the network of the future ‘think' the way they are supposed to. According to their solution each port on the switch or router will have individual silicon chips the will be monitoring the traffic flow of network, so one chip will be managing your toaster and anther TV. To optimize the running of each and every device these mini-processors will have software installed, as software are programmable these can be easily switched from one application to other according to demand.

  3. Smart (Intelligent) Building:The concept of is not very common in present many companies cannot afford this technology, but I future this infrastructure will be implemented in every house. This technology will be very cost effective that everyone would afford to implement it in not just businesses but also in houses for security or energy saving purposes.
  4. Live Voice Communication between Buyer and Seller:When you do internet shopping you get the information written about your desired product on webpage but what about if you want specific information about product which is not mentioned on web page? You contact the seller through email or using other channels which can be time consuming, but in future this is possible that sellers use VoIP technique to answers customer queries about their product, live with voice communication. [David Goodwin]
  5. VoIP Technology growing Day By Day:In future it is possible that VoIP technology completely take over traditional PSTN or even cellular network. VoIP have capabilities and The way VoIP evolving day by day getting more famous in people it will be the only technology of telephony communication.[5]
  6. Cellular Phone Will Perfume More Functionalities:Technologies are integrating more and more in Cellular phone even it became a small pock size PC. But still many people are reluctant to use Cellular phone as PC because it has little screen and people feel uncomfortable working on small screen, but in the future this is expected that normal cellular phone will be having a projector functionalities that people could use this device as a PC and enjoy working on bigger screen. [David Goodwin]
Challenges To Converged Network

As businesses strive to converge data, voice and video over the LAN and WLAN, they are likely to face multiple challenges some of challenges are technical and a significant number of them are Business related.

Technical Challenges

The main technical challenges involved in building converged networks are as follows:

QoS- Introducing diverse services with different network characteristics into the same network requires the ability to prioritize more time-critical network users such as VoIP over less time-dependent services such as data. Introduction of QoS involves a significant technical challenge and may require a network equipment update and refresh.

Security- In traditional telephone system the only way to access other user's traffic is to physically get the access to their phone cables or break in to the PBXs or distributions frame which normally are locked up. But with the share network infrastructure you use only one network and if this network is not secured properly then unauthorized access to other users data may be ensure without accessing through physical media, with methods such as ARP poisoning.

Quality-of-Service- Introducing the different services with diverse network characteristics in to the same network requires capability to prioritize more time significant network users such as VoIP over less time dependent services such as data. Quality of Service involve a major technical challenge and will require equipment update and refresh.

Training- IT support staff used to work with the legacy system and equipments and required to be trained with new system and technology. With legacy system used to mange by different support staff e.g. support for data network, support for voice or video, but with the integrated system which run on one data network support should be also merge for better end to end service quality for this purpose you need highly skilled staff or need you spend allot of money to train existing staff.

Troubleshooting- As integrated network combines different technologies in to one network so putting more eggs in the same basket always makes it more difficult to find out root causes of problem. To mange converged network more efficiently right management and troubleshooting tools have to be created for support staff?

Costly Equipments For Redundancy- In converged network infrastructure now voice in depended on data network, so engineers should consider redundancy in mind while designing the network redundant equipments and multiple links are expensive for company to buy.

Technology Misuse: Integrated network encourage end users to use internet on cellular devices, people keep their personal details (bank details) on cellular phone which is not secure media as much as your laptop or PCs are.

Business Challenges

Beside some technical challenges there are multiple business oriented challenges that should address before integrating your network.

1. While some organisations might combine mainframe and open systems connectivity on platforms they already have deployed, for reason of business rules these organizations have chosen to keep these application separate on dedicated network infrastructure. Keep their network separate means that can maintain proven operational and organizational processes and ownership that would otherwise need to be reengineered in a new model.

2. Another disadvantage of converged network is its dependency on single infrastructure, if that one network goes down whole business can stop functioning.


IP has been accepted as the universal transport protocol for enterprise by communication industry. As a result in last decade all the transport protocols have converged to IP. Now the trend of this network convergence is rapidly growing and industries are moving to IP based network technology to take advantages of converged network. Businesses have realized that managing separate networks for different applications is not longer feasible. Technologies used in IP based network such VoIP, IP Video etc. do not just improve business processes and customer services but also these technologies give companies long term cost benefits. It's not just businesses but also general internet or mobile phone user's are getting benefits from this IP based technology. Using their small cellular phone device they can access the Internet, watch online videos, as well as make free calls using VoIP technology.

For better utilization of resources converged IP based networks also enable class of service differentiation and QoS routing. For different types of applications the infrastructure intelligently handles error rates and performance differences. Integrated network systems are future proof and leading directly to the next generation of integrated communication solution. Less vulnerability points, more simplifies backup and recovery process, and less admin overhead makes this technology easier to manage and maintain security.

There are some challenges to this technology have been mentioned above such as security and complexity but when we compare them, converged network offer more benefits than drawbacks. In future we can see this IP based technology will completely dominate over traditional network infrastructure, especially VoIP technology the way is evolving one day it will take over the traditional PSTN technology, and that time is not very far when all the house appliances (microwave Oven, Refrigerator etc.)Will have IP addresses and will be remotely accessed and controlled over the data network

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