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Ip Telecom Network Architecture Discussion

Because the reality and the evolution of

Summary reasons, IP-based telecommunications network is an unstoppable trend. IP technology is the most successful application of Internet, but the Internet has grown from 30 years of education research into the commercial applications, coupled with technological and social progress, and other reasons related to policy adjustments, the core design concept "end to end transparency" facing tough challenges, has become a lot of problems (especially business model and security issues) roots. Therefore, the IP telecom network construction should not be simply to increase over the existing IP service control, QoS and security mechanisms, but to update the Internet's design, from architecture to begin to reconsider.

1, IP technology is an unstoppable trend

People for an integrated technique of data, voice, and video services, "catch" the pursuit of the dream has never stopped.

80 years from the 20th century's Integrated Services Digital Network (ISDN) technology, to 90 years based on Asynchronous Transfer Mode (ATM) for broadband ISDN, until now the IP + MPLS (Multi Protocol Label Switching) technology. In this process, although the technology choice defeated, but they keep on fighting and the pursuit of the integration goals have never wavered. The question now is not whether to integrate, but what kind of technology used and the way of integration issues.

In the 21st century, IP technology completely beat ATM technology, the industry generally optimistic about the next generation network (NGN) bearing technology. But the IP was originally designed to do what (besteffort) work the way, for education and research purposes, therefore facing the quality of service (QoS), security and business applications and so on.

While IP technology will be "Telecommunications" of the work has been for several years, but not ideal. For example, in QoS, the economy has not been able to find a reasonable solution: the cost of high light-load mode, flow planning difficult; InterServ / RSVP model needs to retain state information in the network, scalability bad; DiffServ model can not strictly guarantee QoS; traffic engineering technology is too complicated.

Recent years, although the field of IP technology in the application of data communications continues to expand, but some people in the industry began to IP technology for next-generation network to meet the expectations of the "carrier class" services, in a shaking. I thought: why choose IP, IP technology is not advanced technology than the other much, but the result of many reasons of:

Market realities. Needless to say, data communication services business is the development direction. Almost all the market data services (including sensor networks, home networks, mobile data networks, etc.) have been or may be based on IP's. Reality has proven: the development and deployment of IP-based data service is not only feasible, but also reasonable.

Have input. Now there is a support IP services to the global Internet; with a large number of users who use and support of IP, business development personnel, operation and maintenance personnel; and is putting in a lot of human, financial and material resources improved IP technology, developing new business and IP application.

Separation of business and bearing. NGN advocated the separation of business and bearing, while the IP would have done so. IP is a comprehensive, open, proven user programming interface (SOCKET), new business and application development and deployment of independent IP network, innovative applications for the business and provide a wider space. Browser, portal, Search engine , P2P applications, and both are caused by IP open innovation.

Practice has proved that IP bearer voice (VoIP) and other real-time business is feasible. Successful operation of VoIP networks shows that, properly handled, IP Technology sufficient to ensure the security and voice quality of service. Although other techniques for carrying data from the principle of the business is feasible, but has never been a real validation. Imagine, if re-enter the huge human, material and financial resources to try such as WWW / E-mail / FTP / Telnetover ATM (or over PSTN, or over SDH / WDM) what will be the case.

A virtuous circle. Industry has virtually ceased in the time division multiplexing (TDM) and ATM technology research and development, increased R & D investment in IP technology, the same time as ITU, ETSI and other international organizations in the field of telecommunications technology intervention in IP, IP telecom of inputs, R & D talent pool there, and a virtuous circle scenario, TDM and ATM faces the opposite situation.

Can be expected, with the IP technology, the popularity of broadband access, IP-based emerging new business, business operation mode of the mature IP-based data services will not only become the operator as it has done business flow the subject of future revenue will be become the subject of change now facing the main body of such IP services and voice services accounted for the absolute income accounts for the absolute subject of "embarrassing" situation.

2, Internet architecture core: end to end transparency

IP technology is the most successful application of Internet. Described in RFC3439 and other "end to end transparency" is the rare Internet, has always insisted on the core architecture design. The so-called end of the transparency is in the TCP / IP in the design, the Internet system, and communication-related part (IP network) and high-level application (endpoint) separation, maximum simplifying network design. In some literature also referred to as "hourglass" model, shown in Figure 1.

Figure 1 Internet's "hourglass" model

Internet "end to end transparency" principle of the design basis (assuming) is:

Internet was originally developed by technical experts with a common interest in the design and development, and mutual trust between them.

Internet by research organizations or governmental research institutions under the management of non-commercial network.

This idea was received with the Internet extension of the development, included in its meaning openness and reliability, is extended to: TCP / IP protocol design should be possible to maintain state information on the endpoint , within the network does not maintain any specific application-related state information, because the only way to be a part of the network failure will not interrupt traffic, unless the communication endpoint itself fails. According to this expanded concept of the emergence of the following well-known corollary:

(No connection) packet switching technology is superior to the traditional circuit-switched networks, packet switching networks because not maintain state information, so only the communication end