2019 is the first year of 5G commercial use. Major operators worldwide are gearing up to deploy 5G networks. Because of the difference of market strategy and spectrum, 5G commercial networks at the early stage are fragmented in the following three aspects:
—Fragmentation of network deployment mode: The 3GPP standard defines five deployment modes for 5G networks such as 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 their deployment modes for 5G commercialization at the early 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 network architecture to 5G. However, during the virtualization of traditional core networks, some operators have completed the virtualization of traditional EPC and some have not yet begun commercial deployment because of the differences in decoupling mode, user-plane software and hardware acceleration mode, and virtualization products. Operators therefore have a quite different 5G commercial network architecture due to the difference in the virtualization process.
—Fragmentation of network objective: The objective of 5G network is to connect all things and meet the ever-changing needs of internet of everything (IoE). In the initial stage of 5G network construction, domestic and foreign operators can choose different network objectives to gradually transition to the ultimate IoE objective according to existing network needs, brand strategy and industrial chain maturity. Different network objectives have different requirements for 5G network deployment and functions.
The core network in the 5G era plays an increasingly important role. In particular, 5G introduces network slicing to fully help operators transform their business models, providing a fertile soil for extending the telecom industry chain and creating new profit models. As the fragmented 5G commercial network faces many challenges such as diverse requirements, complex architecture, and difficult evolution, it is necessary to build a "worry-free" core for the network control center, which is the key for operators to face many challenges and ensure competitive advantages. How is the "worry-free" core built up?
In the initial stage of 5G construction, the core network adopts an ultra-agile architecture to meet the needs of fragmented 5G network. The core network based on SBA+ independent service, independent configuration, independent upgrade, and independent elasticity provides more flexible plug-and-play of network services than traditional NFV and forms the basis for building a custom-made network. The ultra-agile architecture has the following attractions:
—Convergence enhancement: 5G Core (5GC) supports 2G/3G/4G converged access and totally re-architects its software. In this way, access convergence, data convergence, policy convergence, and forwarding convergence can be implemented. Also, 5GC is compatible with the existing network O&M system and billing system, and provides a supreme simplified network to meet the need of rapid 5G commercial use at the initial stage.
—Carrier-class microservice architecture: 5GC adopts the microservice architecture to build software and enhances key component features such as communication reliability and efficiency to meet carrier-class requirements. A variety of public microservices are abstracted, such as signaling, route control and LB. The key features of microservices such as ISSU and grayscale upgrade can be used to significantly shorten the time to market for new services and greatly reduce Opex for operators.
—Smooth backward evolution: Based on the services defined by 3GPP, self-defined services with finer granularity are provided to meet the requirement of long-term network evolution. The infrastructure is independent and can be quickly deployed in virtual machines (VMs), containers or bare metal resource pools.
In the initial stage of 5G network construction, ultra-wide forwarding capability is required in different deployment modes or network architectures. The virtualized forwarding plane is designed in distributed mode and can be linearly expanded to meet the needs of 5G explosive traffic growth. Hardware or software acceleration solutions can be used flexibly to meet large bandwidth needs of user planes for different mainstream operators.
Hardware Acceleration Solution
Based on the standard network interface card (NIC) or universal intelligent NIC, a single computing node supports single or multiple 10GE/25GE standard NICs or 40GE/100GE intelligent acceleration NICs. Large-size VMs are configured to fully utilize the NIC forwarding capabilities and maximize the use of CPUs and network resources. In the subsequent evolution, NIC can be swapped without changing the server. The maximum bandwidth can be increased by four times, and the latency can be reduced from 100 to 10 microseconds, meeting the needs of OpenFlow idea to subdivide the flow. The action is executed high-speed and low-latency services.
Software Acceleration Solution
Based on the standard NIC, the DPDK or SR-IOV acceleration technology is adopted to reduce the cost gap with traditional hardware. The software flow offloading technology, that is, the VPP design concept is used in combination with the according to the flow characteristics to achieve high-speed packet forwarding. In this way, 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, and the subsequent evolution needs to provide uRLLC and mMTC services. It is therefore necessary to provide a large-capacity network, a highly reliable network, and zero-interruption user experience. The following aspects are involved:
—Highly reliable service processing: The stateless cloud architecture adopts unified data storage to separate service processing from data. The service processing uses N+M load sharing mode to replace the original 1+1 active/standby mode, thus reducing the cost and improving resource utilization. Second-level elasticity is also implemented to improve user experience and operational reliability.
—Highly reliable data storage: Unified storage and management is used for online data sharing. The flexible synchronization mechanism ensures data consistency. When the network QoS is good, synchronous replication is used. Asynchronous replication is used when the network QoS is poor. Level-4 backup and recovery ensures data security and reliability. The memory, disk array, local hard disk, and external storage devices are all secured. Users’ dynamic and static data are saved in real time.
—Various disaster recovery networks: Data storage supports N+K geographic disaster recovery to meet different application scenarios. Access network elements (NEs) take over services flexibly in the Set according to the weight. In a hybrid network with multiple user planes and multiple control planes, users can still access the network even if any NE is faulty.
To meet the needs of fragmented 5G network construction, the core network must be designed, deployed, and secured to completely improve automatic full lifecycle operations capability. Design tools, end-to-end deployment, automatic service configuration and test, gray upgrade, cross-layer alarm correlation RCA are used to improve engineering and front-line operations efficiency, reduce Opex, and speed up service launch.
Fast Service Launch
Design tools are used to automatically generate the deployment script, including HLD/LLD design and generation of DC resources, networks, VNFs, and slices, providing end-to-end automatic deployment of hardware, cloud platform, MANO, VNF, and slices. The service configuration and test are completed automatically, and the service launch time is reduced from several weeks to one day.
Old and new versions are smoothly upgraded and rolled back to ensure service continuity. Through flexible gray policies, users and services are gradually swapped over by user group, APN, and link. The A/B test is made to discover or reduce the impact of failures on the commercial environment in advance.
Cross-Layer Alarm Correlation RCA
Both fuzzy match and precise match are supported, and alarms at the resource layer are abstracted. VNF only needs to concern about the resource attribute causes that trigger the alarms, such as network, memory, CPU, host, and cloud disk. The correlation rules between the VNF and the resource layer are established through abstract resource attributes, facilitating the decoupling between VNF and NFVI.
5G core network is the key to 5G network construction and service transport. Facing the needs of mainstream operators around the world for 5G core network construction in a fragmented manner, ZTE has put its core network products into practice. Through the "worry-free" core, ZTE can provide operators with a fast deployment channel for 5G construction, helping them build "worry-free" networks and head up into the era of 5G IoE.