The application scenarios of SDN are closely related to the characteristics of SDN technology itself. The following are the main technical features of the SDN I brought. For your reference.
The main technical features of SDN are embodied in three aspects:
● Separation of forwarding and control. SDN has the characteristics of separation of forwarding and control, and uses SDN controller to realize the functions of network topology collection, route calculation, flow table generation and distribution, network management and control. Network layer devices are only responsible for traffic forwarding and policy implementation. In this way, the forwarding plane and control plane of the network system can develop independently, and the forwarding can be generalized and simplified, and the cost can be gradually reduced; The control plane can be centralized and unified, with stronger performance and capacity.
● Centralized control logic. After forwarding and control are separated, control is centralized. The centralization of the control plane makes the SDN controller have the global static topology of the network, the dynamic forwarding table information of the whole network, the resource utilization rate of the whole network, the fault state and so on. Therefore, SDN controller can realize unified management, control and optimization based on the network level, and can rely on the dynamic forwarding information of the global topology to help achieve rapid fault location and elimination, and improve operating efficiency.
● Openness of network capability. Another important feature of SDN is to support the openness of network capabilities. After the centralized SDN controller realizes the unified management, integration and virtualization of network resources, the standardized northbound interface is adopted to provide network resources and services allocated on demand for upper-level applications, thus realizing the opening of network capacity. This method breaks the problem that the existing network is closed to business, and it is a breakthrough innovation.
The separation of SDN control and forwarding makes the hardware of equipment universal and simplified, which can greatly reduce the hardware cost of equipment and promote the application of SDN. However, due to the changes of equipment hardware and forwarding flow table, there are also compatibility problems between SDN equipment and existing network equipment, which may limit the application of SDN in large-scale networks in a certain period of time.
The characteristics of SDN control logic concentration make SDN controller have the global topology and state of the network, which can implement global optimization and provide end-to-end deployment, guarantee and detection means of the network. At the same time, SDN controller can centrally control different levels of networks and realize multi-layer and multi-domain cooperative optimization of networks, such as joint scheduling of packet networks and optical networks.
The open network capability of SDN makes the network programmable and easy to provide application services. Network is no longer just an infrastructure, but also a service, and the application scope of SDN is further expanded.
Application of SDN and NFV Technology in the Architecture of 5G Mobile Communication Network
abstract
In the current mobile communication network, the key is to break through the technical problems related to Software Defined Network (SDN) and Network Function Virtualization (NFV). Before that, we learned that if SDN and NFV technologies are used in the 5G network architecture, it will bring great convenience. In addition, the latest research status of SDN and NFV technologies in the world is expounded, and the design concept based on SDN/NFV network architecture is discussed. Finally, based on various factors, the architecture of 5G network based on SDN/NFV technology is preliminarily discussed, and the technical difficulties are analyzed, and the corresponding solutions are put forward, hoping to make some contributions to the development of the industry.
key word
Software-defined networks; Network function virtualization; 5G network architecture
Some market research institutions have concluded that the fifth generation mobile communication (hereinafter referred to as 5G) network will establish relevant protocols around 20 17, and the commercial time is tentatively set at 2020. However, in recent years, the consumption of Internet traffic has been rising, and the market demand is urgent. In addition, the fifth generation mobile communication technology plays an important role in the future strategy. Therefore, the research on 5G network technology in the market has already begun, and the demand for 5G networks is becoming more and more urgent.
In the domestic market, some enterprises and organizations have followed the development of the times and started the technical research of 5G networks. This is especially true in the world. Telecom operators all over the world are scrambling to put forward their own 5G ideas, and they are all conducting technical argumentation on their own schemes. Obviously, both at home and abroad, operators and equipment suppliers have begun a long research on 5G technology. Competition between organizations is very important for obtaining technical knowledge in the industry. For the industry giants, it is a critical period to obtain patents, seize the technological highland and win the future. The current 5G technology has not realized the technical knowledge in key areas. Because of this, the mobile communication field will usher in great changes, which will also bring unprecedented opportunities and challenges.
Firstly, the advantages of introducing SDN and NFV into the 5G network architecture.
Strictly speaking, SDN is a network innovation architecture with some obvious features:
1) The control part is isolated from the forwarding part;
2) Centralized control;
3) The used software interfaces are widely defined.
The core point is that the control plane is separated from the data plane, the forwarding function is only realized by the lower hardware devices, and the upper layer is separated for centralized control, thus realizing the programmability of network applications and functions. In the centralized control system, we can master the network usage of all users, and then control the network traffic as a whole, allocate network resources reasonably and improve the utilization rate of resources.
In the future network, we can make scientific and reasonable use of these advantages of SDN, so that it can make great achievements in the network communication industry. It is precisely because of the rational use of SDN technology that the basic functions of the mobile network can be more effectively played, which also makes its vertical integration a reality, simplifies the network and adapts to the increasing access rate. Tracing back to the source, SDN originated from Stanford University, while the concept of NFV came from the operator alliance. Their purpose is to deal with the problem that the hardware facilities are cumbersome, traditional and difficult to expand, and at the same time, they can make better use of the existing network and maximize the investment benefit.
In the NFV white paper released not long ago, we can know that the relationship between SDN and NFV is defined as follows: First, they are complementary and can be integrated, but they are not dependent on each other. In other words, NFV can realize independent layout without considering the influence of SDN. However, the two are complementary, mainly because SDN can make NFV more compatible and easy to operate. Conversely, technologies such as virtualization of NFV can improve the flexibility of SDN.
Second, the target network architecture
As far as the current market situation is concerned, Alang, China's Huawei, ZTE and other information and communication enterprises, major research institutions and forums are scrambling to put forward their own 5G white papers, which respectively bear the expectations of major companies for the 5G network era and their understanding of the relationship between market supply and demand. Nowadays, the architecture of the world's 5G network is not mature, and almost all the ideas have just been put forward and are undergoing technical certification.
Under the guidance of basic ideas such as SDN and NFV, the architecture of the designed 5G mobile communication network mainly has the following three design ideas:
(1) network element function division.
The current network is closed and disorderly, and even some functions conflict with each other, which requires redefining network functions and sorting and dividing them more clearly. The first step is to separate the control terminal from the forwarding terminal and decouple the software from the hardware. Through separation, the control function can be completely placed on the SDN controller. Using appropriate forwarding devices, usually standard components, on the forwarding surface has the advantage of low cost, and they are connected to the same interface. Both the control plane and the forwarding plane can be expanded or upgraded, which makes the equipment more convenient and efficient.
(2) network function abstraction
After processing the functions of each part of the network element separately, it is necessary to do the work of * * * extraction. After some regular packaging, modules with different functions are separated, and the interfaces used between modules are standard. Compared with the network function before division, there will be more and more network function modules after decomposition, which makes the interface and protocol extremely complicated.
Modularization of network functions is realized through abstract processing, and API interfaces are used between functional modules to make them more open. Reorganization is based on relevant standards, so that the function of the reorganized network element has a whole network vision, and at the same time, it tries its best to meet the needs of users and bring the best service data stream transmission and integration mode to customers, thus realizing the rational utilization of network resources and strengthening the service capacity of the Internet.
Nowadays, the development of Internet technology is changing with each passing day, and a large number of innovative practices based on the Internet industry have emerged. All this has a very important connection with the use of public hardware platform, allowing customers to use open API interfaces, simplifying people's innovation links and reducing innovation requirements. Therefore, if API is released to developers for free use, the design and development of the Internet will break through the traditional focus on operators and become more user-oriented, allowing operators to have more flexible network capabilities, thus solving the shortcomings of upgrading difficulties and poor scalability caused by existing hardware problems.
(3) Network function reconstruction
Sort out the functional sub-modules with open interfaces and use them in combination according to certain requirements. This can not only have the basic functions of the existing network, but also make the components independent of each other and even achieve dynamic scaling. At the same time, it can be quickly developed, debugged and rationally laid out in combination with the future development trend, reflecting brand-new functions. Therefore, on this basis, network resources can be shared, and on-demand scheduling and fault isolation can be carried out under the requirements of actual services. This is actually the purpose of re-division and abstraction.
As we all know, IT technology has the advantages of flexibility and quickness, which is also learned by telecommunication networks. In the coming 5G era, its network architecture will no longer be the fixed and closed architecture in the past, but will be replaced by a brand-new architecture relying on virtualization technology. After dividing and reorganizing the existing modules, not only the most basic existing network functions can be realized, but more importantly, redundancy can be reduced. For example, the functions or services of some modules have exceeded their service life and reached the condition of withdrawing from the market. But is this really the case? According to estimates, the utilization rate of more than 2,000 functions of its existing circuit switches does not even exceed 1%. On the basis of modularization, operators can make choices according to their actual needs, and maximize the use of investment resources while saving useless expenses.
Three. Concluding remarks
On the basis of SDN and NFV technologies, the decoupling, abstraction and reconstruction of the existing network are realized, and creative use ideas such as separation of control plane and forwarding plane, centralized control and programmable future mobile communication network architecture are put forward, and the future mobile communication network architecture is tentatively explored. Through summary and analysis, we can know that the new network architecture based on SDN and NFV can not only solve some inherent shortcomings of the traditional architecture, but also meet the requirements of more and more new services for network programmability and quick response in the future.
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