If the connection is demand-based, then "access-independent" IMS becomes the key to the success or failure of digital transformation.
From circuit switching to packet switching, IMS came into being.
With the rapid development of computer and network technology, countries all over the world have generally accepted this concept and invested a lot of resources in construction, and achieved certain results.
China's informatization started late, and it was not until 1990s that the first wave of informatization construction reached its peak.
In the initial stage of informatization of domestic enterprises, the key construction targets are internal administrative office networks, including internal fixed-line networks and computer local area networks. With the rise of multimedia technology, video conferencing and videophone systems have gradually become popular and entered many enterprises.
From the technical point of view, there are three obvious development trends of enterprise internal information network: one is to expand from wired to wireless; Second, from low speed to high speed; Thirdly, it has developed from a multi-architecture network to a unified and comprehensive IP network.
The public communication network has the same development trend. On the one hand, the traditional PSTN network and 2G CS mobile phone network, which are mainly circuit-switched, need further evolution; On the other hand, the demand for mobile Internet broke out, data services rose, and packet-switched networks represented by 3G PS and 4G LTE appeared and developed rapidly, which finally brought unprecedented prosperity to the mobile Internet.
Whether it is private network communication or public network communication, we need to consider the evolution and integration of circuit switching to IP packet switching, and find ways to meet the requirements of cross-platform multimedia services.
As a result, a brand-new communication platform standard appeared, that is IMS.
IMS, what's the use?
IMS, the full name is IP multimedia subsystem, IP multimedia subsystem. It was first put forward in R5 version of 3GPP, aiming at providing multimedia services for 3G users. Later, in the 4G era, its technical standards gradually matured, widely recognized by major operators, and widely used around the world.
In particular, the large-scale commercialization and promotion of VoLTE services have made many people know about IMS. Last year, the 5G message (RCS) service released by domestic operator * * * pushed IMS to the center of the stage again.
What exactly is IMS? Why can we solve the demand of unified communication mentioned above? Besides VoLTE and 5G messaging service, what else can it bring us?
In fact, the naming of IMS(IP Multimedia Subsystem) itself has revealed some answers to us.
First of all, IP, that is, IMS is based on IP bearer and completely adopts IP technology.
The core protocol of IMS is SIP (Session Initiation Protocol). This is an application layer control protocol tailored by IETF for the Internet. It is independent of the underlying protocol, very open and flexible, with strong scalability, especially suitable for multimedia communication.
Secondly, multimedia means that IMS can realize multimedia services.
Traditionally, multimedia services are voice, image, audio and video. IMS standard, which divides multimedia services in more detail, as shown in the following table:
Finally, the subsystem shows that IMS is an important part of the whole communication system and can cooperate with other networks to realize its functions. For example, if IMS cooperates with LTE, VoLTE can be realized. With the cooperation of IMS and 5G, VoNR service can be realized. IMS and instant messaging can realize RCS. ……
Simply put, IMS is a "call server" deployed on the IP network. Through its control and coordination, users on the IP network can conduct multimedia services such as video calls with each other.
The goal of IMS is to build a converged platform that has nothing to do with access, support a wide range of multimedia services, enhance the capabilities of IP networks, and meet the needs of customers.
Some people also say, doesn't softswitch also have communication ability similar to IMS?
In fact, softswitch is far less than IMS. As a product of the transition from program-controlled switching to IP, there is no unified standard for soft switching. IMS is the international established standard of the next generation communication core network, and everyone is actively exploring its application. However, due to high professional requirements, large R&D investment, long time period, unclear business model and other factors, IMS has not yet had a good application solution.
Internal architecture of IMS
IMS has complex internal architecture, many network elements and interfaces, and complex business processes.
From a macro point of view, IMS architecture adopts the idea of hierarchical design, which is divided into four layers, namely, service layer, control layer, transport layer and access layer.
This layered architecture completely separates business application, call control and transmission bearer, and adopts standard business open interface between functions, which is convenient for gradual deployment. At the same time, it also realizes the integration of fixed network and mobile network regardless of access Centralized storage of database is also beneficial to operation and management. In addition, it can effectively support QoS control mechanism and network security mechanism.
According to different functions, CSCF can be divided into three types: CSCF, CSCF and CSCF. Networking can be physically integrated or deployed separately, which mainly depends on the service access mode, access point location, service capacity and processing capacity of IMS, as well as the specific service needs of users.
IMS vertical industry application case
Based on its own platform capabilities, IMS can meet the customized needs of users from all walks of life, including energy, electricity, education, logistics, finance, etc., and play a greater commercial value.
Let's take State Grid Corporation of China as an example to see how IMS transforms enterprises into digital intelligence.
As we all know, State Grid is one of the largest enterprises in China. Due to business needs, the company established the company's administrative exchange network very early. The early administrative switching network experienced from analog switching to digital switching. Later, in order to adapt to the goal of building a world-class energy Internet enterprise, the State Grid administrative exchange network directly skipped NGN from program-controlled exchange and evolved to IMS.
In 20 18, the state grid built an IMS administrative exchange core network covering the headquarters and 27 provincial power companies, and gradually realized interconnection.
Nowadays, this administrative exchange network based on IMS technology meets all kinds of unified communication needs of enterprises in instant messaging, audio-video conferencing, intelligent dialing and so on, and realizes inter-regional and inter-departmental interconnection. IMS not only improves the efficiency of enterprise office business, but also greatly reduces the difficulty and cost of operation and maintenance.
For State Grid Corporation of China, the value of IMS goes far beyond administrative office. The company's power grid core business communication capability and safety production support capability are gradually being upgraded through IMS.
With the popularization of 5G and all-optical networks, the communication mode of industrial and energy enterprises such as State Grid is changing. The bandwidth of the network is getting bigger and bigger, and the delay of the network is getting smaller and smaller, which makes the digital intelligent production scene that can only be seen in science fiction movies become within reach. More and more real-time information such as power grid production data and operation data need to be collected, transmitted, analyzed and processed by multimedia means.
For example, with the help of AR helmet, Bluetooth watch and AR glasses, we can detect and warn the health of front-line production personnel, track the implementation of electronic work orders, and further carry out safety specifications and scene identification on the construction/emergency repair site based on "four straights" and "four pipes" to realize on-demand communication.
Not only can we seek technical support from the rear through real-time video and inter-departmental video conference, but we can also collect on-site image information and send it to the rear for analysis. These technical means are helpful to improve the efficiency of safety production control, operation and inspection, as well as timely handling of fault problems, and ensure the safety of power grid operation.
AR helmet (hongtian technology)
For another example, with the help of IMS-based dispatching command communication products, it supports intelligent dispatching in emergency scenarios, self-encrypted secure authentication access of terminals, and secure communication. Under the graphical management, it is convenient to quickly build the front and rear command channels and realize smooth communication.
Many people may ask, why should the State Grid build a private network instead of the operator's public network?
The main reason is that the public network adopts the design and construction management experience of the operator network, which is difficult to apply to the business and management characteristics of the State Grid private network. In addition, the security, reliability, self-controllability and on-demand customization of public network are not as good as those of private network, which can not meet the needs of State Grid Corporation.
Practice has proved that IMS technology, as an internationally recognized communication technology standard, provides strong support for the realization of the strategic goal of "Energy Internet" of State Grid Corporation of China, and also provides high-quality soil for the research and exploration of digital intelligent application in power industry.
Carbon dioxide emissions will peak in 2030 and be carbon neutral in 2060. Highly integrated information and communication network (ICT) will be the key for the State Grid to achieve this goal. Without the standard leading multi-system integration solution, it is difficult to solve the problems of information island, data fragmentation, network chimney and information communication network security.
For other industries, the application of IMS in State Grid has high reference value. Based on IMS and 5G, all industries can create a safe and reliable application scenario of Internet of Everything on the private network, and solve the problems of terminal security and trusted access authentication control, difficulty in multi-system integration, network security and so on.
The future of IMS
IMS network based on flat structure is the foundation of fixed-mobile integration and the support of unified coordination.
The global unified technical standards and specifications and the unanimous support of domestic and foreign operators have cleared the obstacles for the sustainable development of IMS. IMS is the mainstream technical standard of core network recognized internationally at present, and it is an indispensable part of modern communication network.
Especially for the government-enterprise private network market, IMS is facing a blue ocean. Almost all enterprises have an inherent demand for IMS. The multimedia capability endowed by IMS is the basic starting point of enterprise informatization, digitalization and intelligence. Without IMS, the digital transformation of enterprises will be impossible.
At present, in addition to multimedia conversation service, IMS has been widely used in telecom value-added service platform, emergency command and dispatch, enterprise-level unified communication system and other fields with excellent performance.
As for IMS vendors, as a first-line equipment supplier, Huawei ZTE has a large market share. They mainly focus on communication operators' 5G networks and application services. Abroad, Nokia Bell, Ericsson, AT & amp； Companies such as T are exploring the application landing scheme of IMS.
It is worth mentioning that domestic emerging scientific and technological innovation enterprises have also begun to exert their strength in the IMS field. For example, Hongtian Technology (www.hente.cn) mainly provides enterprise-level lightweight and customized IMS solutions with an independent digital team. Enterprises have been focusing on IMS application research and development for more than ten years, and have solved many key technologies that restrict the application landing. More than 50 Chinese and American patents have been applied, and in 2020, the first domestic project case of 700M power 5G application landing broadcasting and television will be realized.
In the future, with the deepening of national digital transformation and the continuous opening of enterprise private network communication market, I believe IMS will usher in a broader future!