On the other hand, with the maturity and practicality of WDM and DWDM technologies, ultra-large capacity optical fiber transmission has made broadband networks a reality, which has played a decisive role in improving the transmission capacity of IP networks and the practicability of network services. This paper attempts to make a brief analysis of some problems of IP network and optical fiber communication technology and their mutual influence.
1, IP technology
A few years ago, people were still discussing the possibility of multimedia transmission on the traditional circuit-switched integrated service transmission network (ISDN), worrying about the complexity of its implementation. With the emergence and development of IP technology, all this has changed from complexity to simplicity.
IP is a network layer protocol, which has nothing to do with the underlying physical network that supports it. The network based on IP protocol is collectively called IP network, and all kinds of application services supported by this network are collectively called IP services, and the technology to realize these services is IP technology. The most attractive feature of IP technology is that all systems can be connected together, and almost any combination of computer hardware and operating system has IP network protocol drivers. This extensive physical network adaptability of IP technology; As well as the characteristics of various computer and network equipment manufacturers supporting IP, the geographical scope and application business fields of IP business are very extensive.
The communication network addressed by IP is based on TCP/IP protocol. IP protocol and TCP protocol are a pair of important protocols in the network. At the same time, it is necessary to use real-time transport protocol (RTP) and real-time transport control protocol (RTCP) in order to ensure the good operation of real-time services in IP networks. In order to provide a wide enough channel for real-time services or other specific services, the Resource Reservation Protocol (RSVP) is also used. These five communication protocols are the main communication protocols and communication bases of IP network, and all services of IP network are basically based on these communication protocols.
Since the mid-1990s, the data network with IP technology as the core has developed unprecedentedly, and the future "three networks in one" will undoubtedly be based on IP technology. Therefore, IP network has become the focus of IT circles in various countries, and the IP network in China has begun to take shape. At present, our widely used IP protocol is IPV4. However, with the almost exponential growth of the Internet, the address space of IPV4 is in danger of running out. Especially in countries like China and Japan that need a lot of IP addresses but can't get enough. Therefore, people put forward a solution to transition from IPV4 to IPV6. IPV6 adopts 128 bit address space, which is a reliable, manageable, safe and efficient long-term solution for IP network. Although the practical application of IPV6 still needs patience, it is foreseeable that IP network will be more widely used after overcoming this major shortcoming.
IP technology has developed to a mature commercial stage, which requires network developers to constantly look for low cost and higher cost performance. Obviously, the rapid development of optical fiber communication has largely met the growing demand for bandwidth, making IP possible. It can be said that optical fiber communication technology is the foundation and development direction of modern IP communication.
2. Optical fiber communication technology
Optical fiber communication technology is a communication technology that transmits information through optical fiber. At the transmitter, the information is converted and processed into an electrical signal which is convenient for transmission. The electric signal controls the light source, so that the emitted optical signal has the characteristics of the signal to be transmitted, thus realizing the electro-optical conversion of the signal. The optical signal sent by the sender is transmitted to the remote receiver through optical fiber and converted into electrical signal through photodiode, thus realizing photoelectric conversion of the signal. After processing and conversion, the electrical signal is restored to the same information as the original sender.
At present, the second generation optical fiber communication technology marked by long wavelength light source and single mode optical fiber has also matured. The communication distance without relay is about 30 kilometers, and the communication capacity is about 5000, which is suitable for long-distance trunk communication. All-optical and optical integrated fiber communication technology is under study. All-optical means that the optical signal is directly amplified in the repeater, which saves the process of photoelectric conversion and electro-optical conversion. All-optical optical integration function greatly reduces the size of repeater and optical transceiver, reduces power consumption and cost, and improves reliability.
Although the loss of optical transmission is small, it is inevitable. Due to material absorption, waveguide scattering, material scattering, leakage mode and other reasons, the signal will be attenuated. We need optical amplifiers to amplify and integrate signals. Fiber amplifier is generally composed of gain medium, pump light and input-output coupling structure. At present, there are three commonly used fiber amplifiers: erbium-doped fiber amplifier, semiconductor optical amplifier and fiber Raman amplifier.
The future optical fiber communication will evolve to ultra-high speed system and ultra-large capacity WDM system, and realizing optical networking is the strategic direction of the whole optical fiber communication development. We look forward to the realization of these new technologies and further promote the development of the entire information industry.
3.IP technology and optical information technology are inseparable.
IP technology has changed our world, and the optical fiber communication technology it relies on makes all our bandwidth dreams come true. With the deepening of scientific research, they will be more closely combined, such as optical interconnection and all-optical network technology that will be realized in the future. IP technology and optical information technology are inseparable, promote each other and become the cornerstone of supporting communication.