Voip Technology

Phone VoIP Technology for Communication

Sonal Garg : sonal11.3@rediffmail.com
Bharti Vidyapeeth’s Institute Of Computer Application and Management
Paschim Vihar,New delhi-110064

ABSTRACT
VoIP is a technology that play its role in economic revitalization in various ways. It plays an important role in presidential elections. It play lead role under NBN(National Broadband Network). It also provide security means for the small businesses. But the another system in which VoIP plays its important role is the Telecommunication system. Use of telephones and mobiles for the sake of communication is at its peak during current period, and it needs highly efficient technologies to make it cheap, fast and frequent to ease the communication. The technology which bring modifications to the Telecommunication system is the VoIP. This paper discusses about the Mobile VoIP, various services provided by it, advantages, disadvantages and its working. VoIP is a transmission technology, which effect the Telecommunication system to the great extent and provide a lots of new services to the communication system. To get the benefit of the VoIP technology to the fullest, we should know how and which VoIP service we have to choose, based on our system’s requirements. This paper discuss the working of the VoIP diagramatically also.

KEYWORDS
VoIP Technology, VoIP Services, Internet, Telecommunication.

1. INTRODUCTION
The Indian telecommunication industry is one of the fastest growing industry in the world. Telecommunication activities saw rapid growth in India starting at the dawn of the 21st century and since then, efforts have been made from both governmental and non-governmental organizations to further improve the telecommunication infrastructure. The eventual goal is to faster the development and to transform it into a country of technologically aware people. We face some problems within the telecommunication system,whose ranking is given below :
Ranking of Telecommunication Problems

Mobile phone costs 48.6
Mobile phone coverage 42.1
Billing complexity 41.3
Email and internet 41.2
Service response 40.3
Cost 38.2
Capacity to change providers 34.5
Range of services 34.0
Reception / signal quality 30.5

Overall assessment of telecommunications system 38.8

One of the solution to all these problems is VoIP technology. It solve all these problems to the large extent with some limitations.
VoIP and related real-time communication applications, such as video conferencing and instant messaging, continue to attract considerable interest worldwide, with millions of active private and business VoIP users today. Carriers and enterprises are increasingly seeing the benefits of VoIP services that allow voice messaging and video conferencing to be conducted securely, like email, as communications are transferred freely over traditional phone networks and the Internet. VoIP promises many business benefits and efficiency gains, from integrated and streamlined voice and data communications to cost savings. In the rush to realise these benefits and the economic impact it is easy to forget that VoIP is an IP service and that VoIP networks and applications servers are exposed to all of the threats and risks that face other IP network services. We are all familiar with the security threats that face email and web servers and the consequences of ignoring those threats. If anything, the threats that face VoIP systems are even greater. VoIP is a complex real-time communication service less tolerant of disruption than more traditional network applications.
Now the question arises What is VoIP technology. How it works and effect the Telecommunication system, What type of ease it provide to the communication system and what services it provide to satisfy the user requirements. What are the main objectives and goals of VoIP.

2.0 VoIP Technology
It is Voice over Internet Protocol, a way of routing voice conversations using the internet or any other IP-based system as we continue using a regular telephone instrument. Okay, but how does it work? Can we be working on our computer and talk at the same time? Is there special equipment we need?
VoIP means saving money on our monthly phone bill without sacrificing quality or convenience.
Use VoIP like any other phone: pick up, wait for the tone, and dial the number. That 's it. There are no extra numbers to dial and no special routines to follow. We don 't even need a new phone, just a VoIP adapter. If we have a headset and VoIP software, we don 't even need that: we can just call from our computer. Computer-to-computer calls may be free, too. If we call the public network or an external phone, we will probably have to pay by the minute.
One example is voicemail. We probably have some kind of answering machine with our old-school telephone. With VoIP voicemail, we get the improved functionality of voicemail (for instance, the ability to call someone back directly and easily), plus we can get each voicemail emailed to us as an audio file attachment. We can even use our email to track missed calls or call the person back & directly from our email. That nifty feature is called "Click to Call."
There are several companies that provide VoIP service. There is a cost savings because we have a single network to do everything-it carries both voice and data and on the same internet lines. If we have the right company that can carry both the voice and data lines together, there might be no additional cost to combine these two features.
The VoIP telephone system can help by automatically routing incoming telephone calls to our VoIP phone, regardless of whether or not we are connected to the network. We can take our phone with us on a trip and whenever we connect to the Internet we can accept incoming calls.
We can get free telephone numbers for use in some countries. People using this system can work anywhere as long as there is a sufficiently fast and stable Internet connection available to them. Like our other telephone system, we can usually get 3-way calling, call forwarding, automatic redial, and even caller ID.
So, is this system right for us? There are definitely advantages and as with all systems, some disadvantages. How do we choose? That depends and we should do some extensive research to make sure that the VoIP telephone system will work for us.
Today, advanced VoIP solutions enable all employees, whether they are down the hall or a thousand miles away, to respond rapidly to customers and business opportunities by allowing their phones and computers to integrate into one seamless system.

3. VoIP Services
If we intend to considerably cut down the cost of our mobile calls, here is a list of VoIP services that can allow us to cut down our mobile communication costs to the cheapest it can be so far. We only have to select the right service tailored to our needs, mobile phone type and model, connectivity, etc.
Yeigo
Yeigo is here to end paid-for mobile communication as you know it. It is a free software application that can be installed on mobile phones for calls and messages to any mobile or landline anywhere in the world. Calls are free to other mobiles using Yeigo, anywhere they can be in the world. Yeigo works on most recent mobile phones on the market. To use Yeigo, just like many of the applications of its like in this list, you need to have a data connection like Wi-Fi, 3G, GPRS, etc.
Fring
Fring is also a free application to be installed on a mobile phone for calls and messages. Calls to other Fring others are free, and are paid at cheap rates to landline and mobile networks. The cell phone models on which Fring works is more limited than for Yeigo. However, Fring users can communicate with users of other instant messaging service like Skype, MSN Messenger, ICQ, Google Talk, SIP, Twitter, AIM, Yahoo etc. Fring also requires a data service plan like WiFi, 3G, GPRS etc.
Truphone
By installing the Truphone software on your mobile phone, you can have your mobile phones routed through the Internet,and make free calls to other Truphone users. Calls to plain mobile and landline phones are cheap. Truphone allows you to make calls through Wi-Fi hotspots and your GSM network, which means you can use it really anywhere. It focuses mainly on high-end phone models like the iPhone, BlackBerry devices, Nokia E and N series etc.
Vopium
Vopium is a mobile VoIP service that offers cheap international calls through GSM and VoIP, without necessarily having a data plan (GPRS, 3G etc.) or Wi-Fi connection. If you do have any of the latter, you can make free calls to other users using the same networks. Vopium also offers new users 30 minutes free calls and 100 free SMS for trial.
Packet8 MobileTalk
Packet8 's MobileTalk is a pioneering service in the field of Mobile VoIP and is interesting for people who spend heavily on international calls. The rates are cheaper than for fixed VoIP. However, only US residents can benefit from it now. The service is different from other services on this list, in that it is hardware-based. It works through the GSM service, which means you don 't need a data service like WiFi or 3G or GPRS etc. However, local calls are not as cheap as you would expect with mobile VoIP, so the service is ideal only for heavy international callers.
Jaxtr
Jaxtr is a nice and completely free service that allows you to make phone calls to and from fixed or mobile phones. You first need to create an account and submit a phone number through which you can be contacted. Then you can call other people who have done the same. The first time, you need to call them through the web interface or jaxtr, then, once you have saved the virtual number of the person on your phone, you can call them from it the next time. International calls are also supported. Note that the phone number you submit will not be seen by other people, but a virtual number will be used instead, assigned by jaxtr.
Yackie Mobile
Yackie Mobile is a pioneering new type of service in the field of mobile VoIP - it offers VoIP on a SIM card. This eliminates the need for data plans or WiFi connections. You simply have to buy and insert the SIM card in your mobile phone, register for the VoIP service and start using it. The rates are standard cheap VoIP rates; and the international rates are quite advantageous.
Talkety
With Talkety, there is no software to download and install. You don 't need a computer for calls, but you do need one for registration, payment and recording numbers. Yes I said payment, because the service is not free. You can call anywhere on any kind of telephone anywhere in the whole world. They also have a Pro service. To use the service, you enter the numbers, the phone rings and the talkers are connected.
Jajah
We know Jajah works on a web page, but they also have a plug in that can freely be downloaded and installed on mobile phones. The plug in allows you to enter the phone number and call. Messaging is also possible. Jajah claims to offer rates that can cut down your phone costs by 95%, but no part of the service is free. Jajah works on a certain number of phones, and you can check the compatibility of your 's on their web site.
EQO
EQO is a free application that can be installed on mobile phones. That application gives you access to many services, as described on EQO 's web site. It is compatible with MSN, AIM, Yahoo, Google Talk, QQ, ICQ and Jabber. Nothing is cheap here apart from messaging, but with EQO to EQO communication, the rate is halved.
Skype
You might be asking why Skype does not come first of this list, with its hundreds of millions of users. While Skype shines in PC-to-PC communication (for how long more?), its presence in the mobile arena only fills a gap in its services. Skype has softphones for Nokia Internet Tablet, Windows Mobile devices and WiFi phones only. Recently, Skype has launched its own mobile phone, called the SkypePhone, which carries all Skype functionalities and services. It is however not yet available in all countries at the time I am writing this.
Rebtel
Rebtel gives international numbers for your local contacts, and therefore allows you to make international calls at low rates. What you pay is the local GSM fee plus a small fee for Rebtel. You have to type your contact 's international number and Rebtel will create a local number for the area you are in, for you to call them. VoIP also provide services separatly for various different machines. So it provide services for various companies such as APPLE, BLACKBARRY etc. In APPLE, it provide services for iPhone.

4. Working of VoIP
VoIP phone service (Voice over IP; also known as digital phone service, digital telephony, or broadband phone) replaces your phone line with a high-speed Internet connection. It 's that simple.
While traditional telephone service compresses your voice into a frequency on a wire, VoIP compresses the sound of your voice into packets of data. In milliseconds, these data packets are sent over the Internet. When the data reaches the final destination, it is converted back to sound. If use VoIP to call someone on the traditional phone network (the "PSTN" or Public Switched Telephone Network), the VoIP call is converted to sound once it reaches the network and the call is routed normally. The difference is that you 've paid a lot less for that call.
If you 're a visual learner, the diagrams below will show you how VoIP calls are routed in specific situations. The last diagram shows the most typical call path: phone-to-phone. This is what your call path will look like when it 's routed by a VoIP company, such as Phone Power or ITP, to the PSTN.
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5.0 VoIP Benefits
There are many good reasons to switch from a landline telephone service to VoIP, both for businesses and individuals.The reason for the prevalence of VOIP is that it gives significant benefits compared to legacy phone systems. The key benefits are as follows:
Cost savings—The most attractive feature of VoIP is its cost-saving potential. When we move away from public switched telephone networks, long-distance phone calls become inexpensive. Instead of being processed across conventional commercial telecommunications line configurations, voice traffic travels on the Internet or over private data network lines. For the enterprise, VoIP reduces cost for equipment, lines, manpower, and maintenance.For consumers, VoIP reduces the charge of subscription or usage, especially for long distance and international calls.
Rich media service—The legacy phone system mainly provides voice and fax service even though limited video service is possible. However, the demand of users is much higher than that, as shown in today 's rich media communications through the Internet. People check out friends ' presence (such as online, offline, busy), send instant messages, make voice or video calls, transfer images, and so on. VoIP technology makes rich media service possible, integrating with other protocols and applications

Rich media service not only provides multiple options of media to users, but also creates new markets in the communications industry, such as VoIP service in mobile phones.
Phone portability—The legacy phone system assigns a phone number with a dedicated line, so you generally cannot move your home phone to another place if you want to use the same phone number. It is a common hassle to call the phone company and ask for a phone number update when moving to a new house. However, VoIP provides number mobility: The phone device can use the same number virtually everywhere as long as it has proper IP connectivity. Many businesspeople today bring their IP phones or softphones when traveling, and use the same numbers everywhere.
Service mobility—The context of mobility here includes service mobility as well. Wherever the phone goes, the same services could be available, such as call features, voicemail access, call logs, security features, service policy, and so on.
Integration and collaboration with other applications—VoIP protocols (such as Session Initiation Protocol [SIP], H.323) run on the application layer and are able to integrate or collaborate with other applications such as email, web browser, instant messenger, social-networking applications, and so on. The integration and collaboration create synergy and provide valuable services to the users. Typical examples are voicemail delivery via email, click-to-call service on a website, voice call button on an email, presence information on a contact list, and so on.
User control interface—Most VoIP service providers provide a user control interface, typically a web GUI, to their customers so that they can change features, options, and services dynamically. For example, the users log in to the web GUI and change call forwarding number, speed dial, presence information (online, offline), black/white list, music-on-hold option, anonymous call block, and so on.
No geographical boundary—The VoIP service area becomes virtualized without geographical limit. That is, the area code or country code is no longer bound to a specific location. For example, you could live in South Korea but subscribe to a U.S. phone number, which makes it possible that all calls to the U.S. become domestic calls (cheaper) even though you live in South Korea.
Rich features—VoIP provides rich features like click-to-call on a web page, Find-Me-Follow-Me (FMFM), selective call forwarding, personalized ring tones (or ringback tone), simultaneous rings on multiple phones, selective area or country code, and so on.

6.0 VoIP Disadvantages
The benefits of VoIP do not come free of charge. There are significant disadvantages for using VoIP, as follows:
Complicated service and network architecture—Integrated rich media services (such as voice, video, IM, presence, and fax) make it difficult to design the service and network architecture because many different types of devices for each service are involved, as well as different protocols and characteristics of each media. Rich features (such as click-to-call and FMFM) also make the architecture more complicated because many different applications (such as web and email) and platforms are involved. This complication requires extra time and resources when designing, testing, and deploying. It also causes various errors and makes it harder to troubleshoot and isolate them.
Interoperability issues between different protocols, applications, or products—There are multiple VoIP protocols (such as SIP, H.323, Media Gateway Control Protocol [MGCP], and Skinny), and product companies who choose whatever they like when developing products, which means there are always interoperability issues between the products that use different protocols. Even between the products using the same protocol, interoperability issues still come up because of different ways of implementation, different versions (extensions), or different feature sets. Therefore, it is common for VoIP service providers to spend a significant amount of time and resources for testing interoperability and resolving the issues.
Quality of service (QoS) issues—Voice and video streams flow over an IP network as real-time packets, passing through multiple networks and devices (such as switches, routers, firewalls, and media gateways). Therefore, ensuring QoS is very difficult and costs lots of time and resources to meet the user 's expectations. The main factors in QoS are packet loss, delay (latency), and jitter (packet delay variation).
Power outages—Legacy home phones continue to work even during a power outage because the phone line supplies 48 volts constantly. However, VoIP phones use regular data network lines that do not provider power in most cases, which means you cannot use VoIP phones during power outages. Of course, there are inline power solutions (such as Power over Ethernet), but these are mainly for enterprise environments.
Emergency calls—Unlike legacy phone connections, which are tied to a physical location, VoIP allows phone portability as described in the previous section, which is convenient for users. However, the flexibility complicates the provision of emergency services like an E-911 call, which provides the caller 's location to the 911 dispatch office based on the caller ID (phone number). Especially for users using softphones on their mobile computers, E-911 service is almost impossible unless the users notify the service provider of their physical location every time they move. Although most VoIP vendors have workable solutions for E-911 service, government regulators and vendors are still working out standards and procedures for 911 services in VoIP environment.
Security issues—In a legacy phone system, the security issue is mainly intercepting conversations that require physical access to phone lines or compromise of the office PBX. In VoIP, based on open or public networks, security issues are much more than that. Between a caller and callee, many elements (such as IP phones, access devices, media gateways, proxy servers, and protocols) are involved in setting up the call and transferring the media. Each element has vulnerable factors that are targets for attackers. The next few sections provide examples.
Legal issues (lawful interception)—Legal wiretapping in VoIP, also called lawful interception (LI), is much more complicated than that in legacy phone systems, because of the complexity of VoIP service architecture. For the details, refer to Chapter 10, "Lawful Interception Fundamentals." Among these disadvantages, the security issues are becoming more serious because traditional security devices (such as firewalls and Intrusion-Detection Systems) and protocols (such as encryption) cannot protect VoIP services or networks from recent intelligent threats.

7. Conclusion
There are three clear messages to be learned and remembered as you start up any VoIP service at any level. First – it isn 't about saving money – it 's about added value, features and services. Second – you CAN find a VoIP provider that will meet and exceed your needs and expectations. Third – buyer beware – you need to look at the details. Compare plans over three to five years with expected growth scenarios. Look at the costs to drop a poorly performing plan as well as the startup costs. And expect more from your telephony system than ever before.

8.0 Future Scope
VoIP is a great and economic way to make telephone calls, both local and long distance. However, there is the problem with VoIP in that it is still not wireless. Now, it is possible to use a Wi-Fi connection to the internet via a computer but then that is not as wireless as a cellular phone. What is worse is that there seems to be no move towards integrating VoIP into the cellphone.
The integration of VoIP and the cellular phone is just the first step. After all, as the number of Wi-Fi hotspots increase and the area-range of internet connectivity broadens in its scope there will an ever increasing tendency to use VoIP instead of the regular cellular network because VoIP is much cheaper. In the end, this points to the demise of he cellular network and its replacement with a VoIP network. Such a network, called WiMax, is already being constructed. WiMax will be a citywide wireless network (in as many cities as possible of course) that will operate at speeds that will be much higher than the ones we have today). We are talking about a network where video and audio can be shared in real time.
Another exciting possibility is free Internet Telephony. When you send an email, you do not have to pay. When you share your photographs, you do not have to pay. What you pay for is your broadband connection to stay connected to the internet. What you do with that connection is not charged by the ISP. The same applies to VoIP because in the end it is nothing more than data exchange between two parties. Why should that be charged?
So if further investigation will be done in this area, we can overcome all these problems of VoIP.

9. References
[1] http://ezinearticles.com/?How-Does-The-VOIP-Telephone-System-Work?&id=548856
[2] http://www.voipreview.org/how_does_work.aspx
[3] http://www.prlog.org/10016683-the-economic-impact-of-voip-security-vulnerabilities-and-how-to-secure-voip-for-business.html
[4]http://www.acci.asn.au/text_files/surveys/SURVEY.PDF
[5]http://www.networkworld.com/subnets/cisco/011309-ch1-voip-security.html
[6]http://voip.about.com/od/mobilevoip/tp/VoIPForMobilePhones.htm

References: [1] http://ezinearticles.com/?How-Does-The-VOIP-Telephone-System-Work?&id=548856 [2] http://www.voipreview.org/how_does_work.aspx [3] http://www.prlog.org/10016683-the-economic-impact-of-voip-security-vulnerabilities-and-how-to-secure-voip-for-business.html [4]http://www.acci.asn.au/text_files/surveys/SURVEY.PDF [5]http://www.networkworld.com/subnets/cisco/011309-ch1-voip-security.html [6]http://voip.about.com/od/mobilevoip/tp/VoIPForMobilePhones.htm