[cloud native and 5g] micro services support 5g core network

author ： No.7 Huazai
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Personal creed ： Starlight does not ask passers-by , Time and tide live up to those who want to .
Personal direction ： Focus on 5G field , At the same time, take into account other network protocols , Codec protocol ,C/C++,linux etc. , Interested friends can pay attention to me , Communicate together .

1. Microservice architecture concept

1.1 Single architecture and distributed architecture

   Talking about microservice architecture , Inevitably, we will think of monomer architecture and distributed architecture first .
   Monomer architecture refers to the integration of all functions 、 modular 、 Database coupling in an application , It's called single architecture application , Of course, single architecture applications are deployed on a server . Due to the single architecture, all functional modules are coupled , If there is a problem, the whole system application will not work , Maintenance costs are high .
   Distributed structure is to split a large system , Deploy applications and data to different servers separately , Different servers communicate through the network , It embodies more physical distributed deployment . In fact, distributed architecture has the characteristics of microservices , But its coupling is strong , Each module is indispensable , In addition, the construction cost is high .

1.2 Microservice architecture

   Microservices are embodied in two words , The first is the " tiny ", The second is " service ". Micro explains small , Simple , Here I think of “ pure ” The word" , Single and pure . Service is different from system , Service a relatively small and independent functional unit or group of functions , It's the smallest feature set that users can perceive .
   Microservice architecture is an architecture pattern , It promotes the division of a single application into a small set of services , Services coordinate with each other 、 Cooperate with each other , Provide the ultimate value for users . Each service runs in its own process , Services and services use lightweight communication mechanism to communicate with each other . Each service is built around a specific business , And can be independently deployed to the production environment 、 Class production environment, etc .

Traditional monomer architecture and micro service architecture

   Microservices , The key is not just the micro service itself , But the system should provide a set of basic architecture , This architecture enables microservices to be deployed independently 、 function 、 upgrade , More Than This , This system architecture also enables microservices to communicate structurally with microservices “ loose coupling ”, And in terms of function “ High cohesion ”.

2. Micro service and 5G Core network

2.1 Microservice introduction 5G Core network

   With the development and popularity of microservice architecture , add 5G The evolution and development needs of Technology ,5GC Introduce cloud native microservice architecture , Build a business oriented SBA framework , Low coupling is realized + High cohesion technology upgrade .
   In business oriented 5G In network architecture , Integrate and unify the functions of the original control surface , At the same time, the function of the control surface is also decomposed into multiple independent network services , These independent network services can be flexibly combined according to business needs . Each network service and other services are decoupled in business functions , And provide the same type of service interface to the outside world , Provide services to other callers , Transform multiple coupled interfaces into service interfaces of the same type , It can effectively reduce the number of interfaces , And unify the service invocation mode , Then it improves the flexibility of the network .

2.2 5GC Core network SBA framework

5GC SBA framework

• NSSF:Network Slice Selection Function 　　　　　 Network slice selection function
• NEF:Network Exposure Function　　　　　　　　 Network capability and open function
• NRF:Network Repository Function　　　　　　　　 Network storage function
• PCF:Policy Control Function　　　　　　　　　　 Policy control function
• UDM:Unified Data Management　　　　　　　　 General data management
• AF:Application Function　　　　　　　　　　　　 Application functions
• AUSF:Authentication Server Function　　　　　　 Authentication service function
• AMF:Access and Mobility Management Function　 Access and mobility management functions
• SMF:Session Management Function　　　　　　　 Session management function
• SCP:Service Communication Proxy　　　　　　　 Service communication agent
• UE:User Equipment　　　　　　　　　　　　　　 user terminal
• RAN:RadioAccess Network　　　　　　　　　　 Wireless access network
• UPF:User Plane Function　　　　　　　　　　　 User interface functions
• DN:Data Network　　　　　　　　　　　　　　　 data network

   stay SBA Architecture , The interface of each core network element is uniformly named “N + Lowercase English function name abbreviation ”. for example , Network slice selection function NSSF The interface for Nnssf;5G The service operation name of the core network element starts with the interface name , for example ,Nnssf_NSSelection Express NSSF Network slice selection operation . In addition to the unified service interface ,5G The network still retains a small number of reference point interfaces , as follows ：

• N1:NAS Interface , Used for sending NAS news
• N2:AN And AMF Between NG Interface
• N3:AN And UPF Interface between , use GTP-U agreement
• N4: Control surface SMF And the user side UPF Separate device interfaces
• N6: Protocol interface between internal network side and external network side , use GTP-U agreement
• N9: Two UPF Interface between , use GTP-U agreement

2.3 Advantages brought by service-oriented architecture

   be relative to 3G/4G Reference point design , Service-oriented architecture makes 5G The function of each network element of the core network is modularized , Interface unification , Structural simplification and decentralization .

• Function modularization refers to the refinement of network functions , It is no longer a network element that integrates multiple functions , Instead, it is decomposed into independent functional modules . Each module can be sublet for independent development and rapid iteration , Make the test 、 Distributing software can be faster 、 Frequent and reliable .
• Interface unification means that the communication between network elements is no longer the processing mechanism of traditional communication , That is, different interfaces are adopted between the same equipment and other different equipment , The service-oriented architecture shields the differences of interfaces between the same device and different devices , Provide a unified service interface for all devices , Call a unified service interface from different network elements to communicate with the network element .
• Simplification of structure means that the business modules providing services can register themselves 、 Publish and discover , Cancel the coupling between traditional equipment , It simplifies the complex connection between different network elements , Thus shortening the business process . Decompose the functions of the whole control surface into multiple independent network services , Customers can flexibly select different network elements for slice combination according to actual needs , It is convenient to expand and shrink the capacity , Effectively reduce the system complexity , Save deployment costs .
• Decentralizing refers to getting rid of the past 4G“ Centralization ” The limitation of , It can be deployed in the core network （ Data center ）, It can also be deployed in the access network （ Edge data center ）, Implement distributed deployment . Distributed deployment can shorten the data transmission distance of the user plane , Reduce transmission delay , Bring a better user experience .

3. summary

   Microservice architecture is an architecture , It's an idea , Any advanced concept will be integrated and upgraded by different industries and fields , Mutual promotion , Like 4G Brought the era of mobile Internet , With the rapid development of mobile Internet, the demand for interconnection of everything has promoted 5G The development of . today ,5G Cloud has been discussed more and more , The design of traditional single equipment 、 Development 、 Release 、 Deploy 、 O & M moves to the cloud , Calculate at the edge , Network element cloud deployment , Massive data storage and processing , Cloud primary and 5G The relationship will be closer and closer .