Fundamental of VoIP and Security

    CHAPTER NO.2

II.BACKGROUND This chapter presents background information pertaining to this thesis study. It includes High level overview of the VoiP Technology. Also define the importance of VoiP Finally, take a look on VoiP Advantages and Disadvantages.

A.  OVERVIEW :VoIP uses IP or a packet-switched network as the data transmission vehicle. A VoIP system digitizes voice using an audio codec, divides the digitized voice into packets, and sends the packets over an IP network to the destination. All packets are routed without a guarantee that they will pass through the same path or not. Distinct a PSTN calls no committed circuit is ever formed for a VoIP calls. The accurate process required to set up a VoIP call that is dependent on the VoIP protocol. Two types of protocols are essential to complete a VoIP calls are signaling and media transport. A signaling protocol has the duty of establishing a session between the call participants and a media transport protocol specifies the rules and formats of the genuine voice packets. At present the Real Time Protocol is normally used as the media transport protocol in VoIP. However there is a wider range of signaling protocols.

For traditional phone systems, a phone number consisting of digits is used to locate a phone. A phone number in VoIP can be a regular traditional phone number, an address, or an assumed name. The �phone number� ultimately is translated to a 32-bit or 128-bit IP address depending on version of IP that whether IPv4 or IPv6 is used. Each VoIP signaling protocol must provide address resolution capability. There are four general VoIP communication modes. 1-Phone to Phone    2.  Phone to computer 3.Computer to Phone   4.Computer to computer . Voice transmission is carried by both PSTN and IP networks under the first three modes. A VoIP service provider that interconnects the PSTN and VoIP networks is needed for the first three modes when a call made from a PSTN network and arrives at a VoIP network or vice versa. Voice travels exclusively across the IP network in the fourth mode.

 B.   SIGNIFICANCE OF VOIP: One of the most significant resources to describe that is Voice over internet Protocol is not limited to voice communication. Actuality a number of hard work have been made to change this admired marketing term to better return. By this the truly VoIP means voice, video, and data conferencing. VoIP is significant because for the first time in more than 100 years, there is a prospect to bring about a major change in the way that people communicate. We have the option of using pure IP-based phones including desktop and wireless phones. We also have the capacity to use videophones that are being seen in science fiction movies. One of the more inspiring aspects of VoIP is that we also have the ability to put together a stand-alone telephone or videophone with the personal computer by which one can use a computer completely for voice and video communications, use a telephone for voice and the computer for video, or can simply use the computer in combination with a separate voice/video phone to provide data conferencing functions, like application sharing, electronic white boarding, and text chat.VoIP facilitates to use a single high-speed Internet connection for all voices, videos and data communications. This idea is commonly referred to as convergence and is one of the primary rules for business interest in the technology. The benefit of convergence is fairly clear and transparent, by using a single data network for all communications, it is possible to decrease the overall protection and deployment costs. The advantage for both home and business customers is that they now have the opportunity to choose from a much superior selection of service providers to provide voice and video communication services. Since the VoIP service provider can be located virtually anywhere in the world. Men with Internet access is no longer geographically limited in their selection of service providers and is certainly not bounded to their Internet access.In Simple words, VOIP gives the Strength and enables people to communicate in more ways and with more choices. Talk anywhere in the world with less cost, and safe environment with latest VOIP Phone.

 C.   ADVANTAGES :VoIP or Voice over Internet Protocol is becoming the fastest Technology of the telecom. Everyone is jumping on the internet phone due to the promise of inexpensive phone service for all. However like all rising technologies the excitement sometimes go beyond the reality and while VoIP is certainly a gifted new technology that will certainly change the way we think of the telephone. There are still a few defects in this technology and due to this it is not right or even available for everyone so far, but for many VoIP provides an attractive option to traditional phone service. VoIP Technology has a lot of advantages over the traditional Phone systems. These include the efficient use of bandwidth, possible elimination of long distance and phone charges, convergence of the voice and data networks and advanced features. Some of them will be describe below.

 1.     POSSIBLY ELIMINATION OF LONG DISTANCE & PHONE CHARGES:Charges of the phone depend on distance and duration. Generally the longest you call the more you pay is being followed but in the VoIP the cost of long distance calls is same as local calls. VoIP service providers have monthly flat-rate plans that offer unlimited or fixed-number of minutes to make calls, including long distance calls. These strategies are much more cost effective than the conventional charge by minute service. Thus VoiP will much reduce or possibly eliminate the phone and long distance charges for individuals and organizations that make ordinary long distance phone calls.

 2.     ADVANCED FEATURES: Voice over internet protocol phone provides all the services of a usual telephone including busy signaling, speed-dialing, call waiting, caller-ID, etc. In addition, traditional phone systems lack such as video-conferencing, instant messaging, email, click-to-dial, and directory service but VoIP have all these.

3.     CONVERGENCE OF VOICE AND DATA NETWORK:Normally a data network only carries data and voice network that only transmits voice. But now this is not a spot because two different networks are converged to a quality and cost effective service. In various cases, maintenance and management of two dissimilar networks has proved to be uncomfortable and costly for organizations. Upgrading the voice network equipments such as the Public Branch Exchanges (PBX), telephones burden organization budgets. If VoIP is deployed, the voice network will no longer be desirable and leaves the organizations with only the data network.

4. EFFICIENT USE OF BANDWIDTH: Bandwidth is a key to measure performance of a network. It defines how many bits can be transmitted every second which means the more bandwidth available the more data can be sent in a given period of time. Traditional phone system requires a minimum of 64 kbps of dedicated circuit between the two calling devices. The circuit is reserved for the whole duration of the call regardless of whether or not any data is in transmission. There for this is being wasted but in VoIP there is the flexibility to assign bandwidth as needed and reserve the unallocated bandwidth for other data. Thus the use of network bandwidth in VoIP is more competent.

D.   DISADVANTAGES: Every advance technology in every century shown the pros and cons the same condition is applied for VoIP too. Instead that VoIP provides the more features like provides phone calls with lower cost as compare to traditional phone but still not every body use VoIP phone. There are also some disadvantages of VoIP phone therefore it is not being used by everybody. Let�s discuss the disadvantages of VoIP.

1.      AVAILIBILITY

Making a VoIP call requires an Internet connection through properly configured network devices that are dependent on a stable electrical power supply. Power outage and connection problems stops an individual for making or receiving a VoIP call.

2.   SECURITY: More a technology secure more it is liked. VoIP converge data and voice networks. Through convergence of both networks makes management easy and reduces cost. However convergence leads to security problems. Voice will not be clear to the same attacks as other data traveling across an IP network. Attacks include interception, modification, spoofing, Denial of Service (DoS).

3.  911 HELP LINE: Presently not any of the VoIP protocols offer information by which they can identify the physical place of the caller. Caller�s physical place to the emergency operator can not be known. Secondly when the caller dials 911 then there is no guarantee that the call will be routed to the nearest 911 police station. At the same time the 911 operator has no technique of identifying the location of the caller. �911� is helpline this is for American but in other countries there are many emergency numbers like in Pakistan 15 for police etc. if this technology is applied then the cost and effectives increased and crime level is also decreased.

4.  QUALITY OF VOIP: Voice data traveling across an IP network is highly at risk to delay and loss due to routing and network latency. Voice in analog form has to be converted and compressed into digital packets before transmitting over an IP network. A compression method that aggressively minimizes the size of voice packets will depreciate the quality of voice. As a result, the quality of voice using VoIP may be the worse than that obtained from PSTN due to delay, loss, and compression of the information.

  Back: CHAPTER#1            Next: CHAPTER#3

HOME |Wallpaper | Earn Money | e-Books | Contact Me