2019 is the first year of 5G commercial use, and the world's major operators are gearing up to deploy 5G networks. Due to different market strategies and differences in spectrum, 5G commercial networks initially show fragmentation, mainly in the following three aspects:
Fragmentation of network deployment mode: The 3GPP standard defines five deployment modes for 5G network (Option 2, Option 3, Option 4, Option 5, and Option 7). Based on their own characteristics and needs and the maturity of the industry chain, operators mainly choose Option 2 and Option 3 as the deployment modes for 5G network commercial at the initial stage.
Fragmentation of network architecture: As the basic technology of 5G network, NFV helps operators better adapt to service deployment and innovation in the Internet era and meet the needs of evolving the network architecture to 5G. However, in the virtualization process of traditional core network, some operators have completed the traditional EPC virtualization transformation and some operators have not yet begun commercial deployment due to the choice of decoupling, user-plane software/hardware acceleration mode, and difference of virtualization products. Therefore, due to the difference in virtualization process, different operators have a large difference in the network architecture of 5G commercial.
Fragmentation of network goal: The goal of 5G network is to connect all things and meet the ever-changing needs of Internet of Everything. In the initial construction stage of 5G network, domestic and foreign operators can choose different network goals to gradually transition to the ultimate goal of connecting all things according to the requirements of existing networks, brand strategy and industrial chain maturity. Different network goals have corresponding differences in the deployment requirements and functional requirements for 5G network.
The core network in the 5G era is playing an increasingly important role. In particular, 5G introduces network slicing to fully support the transformation of operators' business models, providing a fertile soil for the extension of the telecom industry chain and new profit models. Facing the fragmented 5G commercial network, there are many challenges such as the diversity of requirements, the complexity of the architecture, and the difficulty of evolution. For the core network of the network control center, it is necessary to build a “worry-free” core, which is the key for the operators to face many challenges and ensure competitive advantages. How do you build a "worry-free" core network?
In the initial construction stage of 5G, the core network adopts an ultra-agile architecture to meet the needs of fragmented 5G network. The core network with the ultra-agile architecture, which is based on independent service, independent configuration, independent upgrade, and independent flexibility of SBA+, provides the more flexible plug-and-play function of network services than traditional NFVs, and realizes the foundation of constructing a user-customized network, mainly with respect to the following aspects:
Convergent enhancement: 5GC is integrated with 2G/3G/4G, and comprehensive software reconstruction is made for the core network. These features are provided to achieve access convergence, data convergence, policy convergence, and forwarding convergence. The core network is compatible with the existing network operation and maintenance system and billing system, and provides a minimalist network to meet the initial rapid commercial requirements of 5G;
Carrier-class micro-service architecture: The core network adopts the Microservice architecture to realize software construction, and enhances the architecture (characteristics of key components such as communication reliability and communication efficiency) to meet carrier-class requirements. A variety of public Microservices are abstracted, such as signaling, control routing, and LB. The key features of Microservices (such as ISSU and grayscale upgrade) can be used to significantly shorten the commissioning time of new services and significantly reduces operators OPEX.
Backward smooth evolution: Relying on the services defined by 3GPP, the operator has made a self-defined service division with finer granularity to meet the long-term evolution of the network. Due to its independence, the infrastructure can be quickly deployed in virtual machines, containers or bare metal resource pools.
In the initial construction stage of 5G network, different deployment modes or different network architectures require extremely wide forwarding capabilities. The virtualized forwarding plane is designed in distributed mode and can be expanded linearly to meet the 5G explosive traffic growth requirements as needed. For the large bandwidth requirements of the user planes from different mainstream operators, hardware acceleration solutions or software acceleration solutions can be adopted for flexible adaptation.
Hardware acceleration solution: Based on the standard network card or universal intelligent network card, a single computing node supports single or multiple 10GE/25GE standard network cards or 40GE/100GE intelligent acceleration network cards. Large-scale VMs are configured to fully utilize network card forwarding capabilities to maximize CPU and Network resources. For the subsequent evolution, the NIC instead of the server can be exchanged. The maximum bandwidth can be increased by 4 times and the latency can be reduced from 100 microseconds to 10 microseconds, to meet the needs of high-speed and low-latency services.
Software acceleration solution: Based on the standard network card, the DPDK or SR-IOV acceleration technology is adopted to reduce the cost difference between the software acceleration solution and the traditional hardware solution. Through the software flow unloading technology, the VPP design concept is adopted, together with the OpenFlow idea, to segment the flow. The action is executed for the flow characteristics, thereby realizing the high-speed forwarding of the message. The performance can be improved by 20%, and the cost can be saved by 10%.
Highly reliable network
5G network provides the eMBB service in its initial stage. The subsequent evolution needs to provide uRLLC and mMTC services. Therefore, it is necessary to provide a highly reliable network and zero-interrupt user experience when providing a large-capacity network. The features are mainly reflected in the following aspects:
Highly reliable service processing: The stateless cloudified architecture adopts unified data storage to realize service processing and data separation. The service processing is made in N+M load sharing mode instead of the original 1+1 active/standby mode, reducing cost, improving resource utilization, achieving second-level scaling-in/out, and improving user service experience and network operation and maintenance reliability.
Highly reliable data storage: Unified storage and management is made for online data sharing. The flexible synchronization mechanism ensures data consistency. The synchronous replication is made when the network QoS is good. The asynchronous replication is made when the network QoS is poor. The four-level backup and recovery mechanism guarantees the data security and reliability. The memory, disk array, local hard disk, and external storage device are composed of four layers of insurance. The user's dynamic data and static data are saved in real time.
Rich disaster recovery networking: Data storage supports N+K geographic disaster recovery to meet different application scenarios. Access network elements flexibly take over services within the Set according to the weight of NEs. Multiple user planes and multiple control planes are combined for networking to ensure that the user can still access the network normally when any one NE breaks down.
Because of the fragmented 5G network construction needs, the core network needs to improve the automatic operation and maintenance capability of the whole life cycle with respect to design, deployment and guarantee. Design tools, end-to-end deployment, automatic service configuration and testing, grayscale upgrade, and cross-layer alarm correlation RCA are used to improve the efficiency of the project and the first-line operation and maintenance, reduce the OPEX, and improve the speed of the business.
Fast commissioning of services: The design tools are used to automatically deploy scripts, including designing and generating DC resources, networks, VNFs, and sliced HLDs/LLDs, provide end-to-end automated deployment of hardware, cloud platform, MANO, VNF, and slice, and automatically complete services configuration and testing so that the service provisioning time is reduced from a few weeks of deploying traditional equipment to about one day of deploying new services.
Grayscale upgrade: New and old versions are smoothly upgraded and rolled back to ensure service continuity. Through flexible grayscale policies, users and services are gradually cut over according to the user group, APN, and link. The A/B test is adopted to discover or reduce the impact of failures on the commercial environment.
Cross-layer alarm correlation RCA: The network supports fuzzy matching and precise matching at the same time, and abstracts the alarms at the resource layer by models. VNF only needs to care about the resource attributes that cause the alarms, such as network, memory, CPU, host, and cloud disk. The correlation rules between VNF and the resource layer are realized by achieving the abstract resource attributes to facilitate the decoupling of VNF from NFVI.
5G core network is the key to support the construction of 5G network and carry 5G services. In the face of the needs of all major operators around the world for making fragmentation construction of 5G core networks, ZTE's core network products have been put into practice to, through the “worry-free” core, provide a rapid deployment channel of constructing 5G network for operators and build a “worry-free” network for heading into the era of 5G Internet of Everything.