Understanding VoIP Technology

        VoIP (Voice over IP) is a shining noun in the IT industry and telecom industry at this stage, and we can literally know what it is to solve the problem of technology. To put it simply, the basic principle of VoIP is to compress and encode our voice with voice compression devices, then the voice data according to the relevant protocol packaging, through the IP network packets to the destination, and then the voice packets together, after decoding and decompression processing, restored to the original voice signal 　　 , so as to achieve the purpose of transmitting voice by IP network. Reducing costs to introduce competitive communications costs to companies is a problem that bothers many business operators, but it seems to be a cost that cannot be compressed. Intensified market competition, resulting in enterprises to try their best to communicate with their customers, to obtain the customer's information to obtain customer demand, so as to improve their products and improve the service of enterprises, in the competition to ensure unbeaten. This encourages enterprises to focus on communication with the outside world, and increase investment. 　　And with the development of business and the size of the increase in communications costs will increase the trend of increase in telecommunications costs in this middle occupies a large proportion. So how can companies reduce these costs and improve competitiveness? 　　In addition to the management of ways to save costs, the advent of VoIP technology for enterprises from the technical level to reduce communication costs to provide the feasibility. The application of VoIP technology can be divided into telecom level and enterprise level according to enterprise size and service object. The main areas of application of the telecommunications level are what we often call IP telephony (including IP fax, the same below) and associated value-added services and supplementary services. 　　As we know from the above, VoIP technology is originally to achieve the use of IP phone, later we will explain why the IP phone is cheaper than the traditional telephone, before this first look at the status of IP telephony. IP telephony is one of the most widely and most important areas in the current VoIP technology application. The IP phones we use in our lives are generally provided by telecom operators. China's IP telephony Operation Market has developed rapidly in recent years, in a short period of time, five telecom operators have built their own nationwide IP telephone network. According to statistics, the first half of this year, the total number of IP phone business in China more than 8 billion minutes. China Unicom is building a nationwide IP network capacity of 450,000 lines, which will become the world's largest IP telephony network. It can be seen that the development of IP telephony to the original business of the telecommunications industry with a great competitive stimulus. 　　Experts pointed out that IP telephony for the telecommunications industry's important significance lies in: the introduction of competition, promote the reform and adjustment of telecom tariff structure, promote the development of Chinese Internet and traditional network transformation, stimulate the growth of the consumer market. As for how to use IP telephony, different objects can have different methods.Small and medium-sized enterprises and individual consumers are generally to buy the services of telecommunications operators, using their IP network across the country to dial IP telephony, so as to reduce operating costs. For some large enterprises or industries, some already have their own wan, they can also use the original network resources to run their own IP phone. Active in the domestic market to develop IP telephony network equipment of foreign manufacturers mainly Cisco, Crown Far, 3Com, Huawei, the Dragon and other domestic telecommunications network equipment manufacturers have corresponding products. The advantage of foreign enterprises lies in the early start, Good Market Foundation, technical input, their equipment for the operation of international IP telephone traffic domestic telecommunications operators have considerable appeal, is currently in the market basically dominant position. As a result of the initial focus on China's specific signaling standards, the domestic network equipment manufacturers of products in the localization has a certain advantage. 　　After a long period of exploration, some of these domestic enterprises have reached the international level in technology, gradually in the market to achieve their status. Under the stimulation of the operation Market, the demand of the IP telephone network equipment is also increasing every year. 　　 According to forecasts, the international market size of products including voice/data switches, VoB (Voice over broadband) gateways, VoIP (Voice over IP) gateways, Class 5 packet gateways, and software switches will exceed 2 billion U.S. dollars by 2002. Digital audio Interactive Application rich in addition to IP telephony, enterprises themselves can also use VoIP technology to build their own telephone or voice service applications. In fact, VoIP technology has two major market applications: one is the Internet (WAN) data, voice integrated access and transmission; the other is the use of VoIP technology to achieve real data and voice and even multimedia information integration and integration, so that the enterprise's intelligent devices can truly seamless interaction and processing of external information. For enterprises, the former means to save operating costs, while the latter helps to improve work efficiency and improve service quality. Enterprise-Class VoIP applications, including VoIP technology based on the relevant value-added applications, mainly voice connection business, IP video conferencing business, LAN telephone, call center, IP video Conferencing business, a variety of. 　　It can be said that in addition to IP telephony applications, our enterprises can also use VoIP to achieve many dreams. Network telephony system, also known as IP PBX or LAN phone, is the combination of data and voice of the typical application. It supports voice and data services through the local area network, and can replace the traditional PBX group telephone completely. Internet telephony not only makes the enterprise get rid of the maintenance of the original telephone, more attractive is, on this basis can realize multi-site communication, Unified Messaging (Unified message, a technology that integrates the data of voice, email, fax and Web page etc.), Computer telephony integration and Web call center, and many other functions of rich applications, which simplifies voice communication, improves work efficiency and saves user expenditure. 　　Network telephony a future-oriented enterprise voice communication platform, there have been many enterprises in this market to achieve results, 3Com, Cisco and other manufacturers have the corresponding products. 　　 VoIP has so profoundly affected the business and even our lives, let's take a closer look at VoIP technology and its important applications. Technical collaboration construction before we go into the details of VoIP applications, we need to learn more about the technical features of VoIP. In fact, VoIP does not refer to a single technology, but rather a collection of related technologies that are grouped and digitized for voice transmission on IP protocols. 　　This includes the following technologies: signaling technologies including ITU-T H.323 and IETF session Initialization protocol SIP (Sessions initation Protocol), and the real-time streaming protocol TRSP for real-time synchronous continuous media stream Transmission control; The media coding technology includes the popular g.723.1, g.729, g.729a speech compression coding algorithm and MPEG-II multimedia compression technology, the real-time transmission protocol is mainly used in the media real time transmission technology, the service quality assurance technology Using Resource Reservation Protocol RSVP and real-time Transmission Control Protocol RTCP for service quality monitoring to avoid network congestion and ensure call quality; The network transmission technology is mainly TCP and UDP. 　　With the cooperation of these technologies, the voice transmission on the Internet is realized. The basic flow of ordinary long distance calls is: The user in phone A to make long-distance calls to phone B, voice from A to PBX a, through the PSTN network, via PBX B to phone B. And the basic process of IP telephony is: the user in the phone a long-distance call to phone B, voice via PBX A to gateway a. 　　In the gateway A to the speech processing, the voice packet which can transmit in the IP network, by the IP network transmits the voice packet to the Gateway B, the Gateway B carries on the processing to the speech packet, restores to the voice, passes through the PBX B to the phone B. We can take a look at the technical comparisons between IP telephony and traditional telephony. The traditional telephone is characterized by the use of circuit switching, the IP telephony is a packet exchange with IP packet (packet), the traditional telephone uses synchronous time division multiplexing transmission, the channel utilization rate is low, but there is no lost information phenomenon, while the IP telephone uses asynchronous time multiplexing transmission, the channel utilization rate is high, but the transmission process appears may be packet loss of the phenomenon of traditional telephony end-to-end transmission delay is generally within dozens of milliseconds, and in a call process is fixed, the quality of the call is generally guaranteed, and IP telephony end-to-end IP packet transmission delay is generally longer and not fixed. Through the above comparison, we can understand why the IP phone compared with the traditional program-controlled telephone has low-cost advantages, but IP powerThe call quality of the conversation is currently lesser. Many users may recall that the original IP phone was of poor quality and was accompanied by significant noise, which may be intermittent. In fact, there are many factors that affect the quality of IP telephony, such as the construction of data backbone network. Because of the improvement of these kinds of technologies and the construction of infrastructure, the quality of VoIP calls has been greatly improved. 　　 We note that, with the joint efforts of the scientific and technological communities, the variety of applications is constantly appearing and the effect of application is getting better. Improved communication fluency The main application of VoIP technology IP telephony, it is easy to associate with cheap charges. 　　In fact, we should also note that the establishment of VoIP based on a variety of value-added services to enterprises in the efficiency of a wonderful improvement. Also in the communication with the customer, the enterprise also faces another problem, is how to make information transmission more smoothly. This problem also exists within the enterprise. Some core employees of an enterprise often fail to get the necessary information in time and accurately. We often have this experience, the customer calls to complain about their needs no one to pay attention to, employees complain because they did not get customer feedback in time to lose the order. We know, if not face-to-face communication (such a way for the enterprise cost too high), telephone is now the most commonly used voice transmission mode. You can see that there are already some applications running on the phone of the traditional PBX enterprise group. However, because the traditional telephone itself is based on voice transmission, it is doomed to the data information (relative to the voice information) of the interaction between the defects, and computer interaction problems. When the CIO of the enterprise is innovating in a technical way to cope with the management adjustment or business adjustment of the enterprise, they will feel that the telephone system in the past has all kinds of difficulties in the application with the computer, some even insurmountable. In addition, when we call the group, we have to build a parallel telephone line with the data network wiring, the two lines maintenance is really troublesome. VoIP technology is breaking into our eyes when it comes to sorting through the head of the problem above. 　　Yes, the IP combined with voice has the magical ability to solve these problems. LAN telephone with the open LAN packet switching technology to achieve a dedicated PBX voice service functions, and the existing LAN seamless integration. It can not only make the internal data network and voice network integration, but also to keep the enterprise continuous operation and vigorous development of all-round needs. From complex call control and call center capabilities to integrated voicemail and computer/telephony integration, from caller identity to multiple, multilevel automata, easy additions, moves, and changes to the terminal phone, connectivity from the LAN and Wide Area network (Lan/wan) to the Internet, And at the same time reduce the overall cost, so that enterprises can be economical, easy to manage the way to obtain all the features. Solve all the problems just mentioned, business information flow more smoothly, the staffWork efficiency can be improved. In addition, the introduction of VoIP technology to the original application of some enterprises to bring new vitality, such as call center. Call Center is an important tool for public service. With the development of Internet, the traditional method based on telephone exchange technology can not meet the actual needs of call center. The call center which introduces VoIP technology realizes the automatic traffic assignment through the Fusion software, realizes the IP network and the customer management with the IP telephony technology, can integrate the IVR automatic reply, the ASR speech recognition and the more complex CRM application system. Moreover, it can coexist with the traditional TDM network, support the traditional switching system, and of course, it can be used as a part of the IP network telephone to realize its function. In this way, enterprise users can easily configure remote branch offices or company local seating. At the same time, through the application of IP, we can realize the distributed call Center system of many pairs and many pairs.

Enterprises face the above application often will be exciting. However, to remind users that the introduction of technology should take into account the actual needs of the unit. At present, the above application in the domestic market has some advanced products, but these products and the corresponding traditional products compared to the initial investment will undoubtedly be higher. Most of the applications brought by VoIP technology are designed for the users with higher information level. This kind of system because the application time is not long, there are still the problem of the standard is not unified, not only is the compatibility between the existing equipment to consider, new technology and equipment are also emerging. You want to take these issues into account when you select a product.