China Broadnet smart bearer network solution

I. Introduction

In recent years, the competition between IPTV and OTT services has led to a serious loss of cable TV users, and the "price scissors between business volume and revenue" of networks cannot be mitigated. All these factors impose great pressure on the continuous revenue growth of operators. Therefore, China Broadnet should turn to emerging services and create new growth points. The integration of "One National Network" and the integrated 5G development of the radio and television industry have created new development opportunities to China Broadnet, but also new challenges to its IP bearer networks.

The traditional network is rigid, inflexible, and composed of a large number of dedicated devices with single functions. Besides, it requires a long expansion period and high construction and O&M costs. It cannot adapt to the elastic needs of the Internet, cloud computing, and IoT. The network elements adopt the integrated closed architecture of tightly-coupled software and hardware. The devices feature poor scalability, high prices, and heavy dependence on manufacturers. The provision of new services and functions requires the development of new hardware and protocols, resulting in a sharp increase in the types and quantity of devices and forming a large number of chimneys. Therefore, it is difficult to converge services, develop new services, or meet the requirements of rapid and flexible deployment.

In the era of cloud services and 5G, service development, industrial trends, and comprehensive costs have become challenges for bearer networks of China Broadnet:

Network intelligence

As China continues promoting the "Internet and Digital China" development strategy, digital transformation is popular in all industries. Innovative digital service applications speed up the network intelligence process for the radio and television industry. The "One National Network" strategy integrates and promotes the interconnected and intelligent development of radio and television networks to realize unified management and operation. "Smart radio and television" services require a network that can be deployed on demand and respond quickly.

Network bandwidth

4K and 8K UHD videos require a higher bandwidth of the China Broadnet bearer networks. Besides, the commercial application of 5G also requires a larger bandwidth and capacity of bearer networks.

5G bearer

5G brings massive connections and diversified high-quality services, which requires the bearer networks to automatically deploy services, rapidly provide services, and offer the capabilities such as network slicing, high-precision clock and frequency synchronization.

Comprehensive costs

Since 5G cannot use the existing bearer networks of China Broadnet, a substantial investment is required to construct new end-to-end 5G networks. The challenges faced by China Broadnet include the operation and development of comprehensive services such as 5G mobile services, the coupling of networks and businesses in traditional private network construction mode, and the high cost of multi-network construction.

II. China Broadnet smart bearer network construction planning

The above challenges point out the development directions of China Broadnet bearer networks. Through evolution, China Broadnet bearer networks should be able to:

Reduce comprehensive costs

The construction and O&M of a private 5G network is too expensive. To reduce the costs, the following measures can be adopted: a) reuse of network resources through technological innovations; b) converged bearer of both fixed and mobile services; c) decoupling of software and hardware in network elements to realize universal hardware; d) cloud migration of network resources; e) separate network control and forwarding; f) centralized control planes.

Full-service bearer

China Broadnet needs to provide individual users and group customers with comprehensive bearers for fixed and mobile network services Its key services include broadband and 4K/8K/VR/AR video services for individual users based on the fixed network and 5G; private lines, private networks and cloud services for government and enterprise customers based on fixed network and 5G; and smart innovation application, IoV, UHD production and broadcasting, smart health and smart campus based on 5G cloud-network coordination.

Improve user experience

The NaaS cloud service model can provide external services to enhance the user experience of high-value customers in the following aspects:
- Network visualization that provides users with application-based network resource views;
- On-demand resources that provide users' services with automated and on-demand network resource deployment;
- Self-service that enables users to manage services by themselves.

Intelligent operation management

China Broadnet can control and schedule networks in a unified manner to realize intelligent and efficient service operation and network O&M in the following aspects:
- Automated service deployment that enables services to go online quickly;
- Network visualization that realizes all-around monitoring of the quality of networks and services;
- On-demand network resources that enable China Broadnet to schedule the network resources such as link bandwidth and forwarding path in real-time as required by services.

Technically, is it possible for China Broadnet realize the above objectives by using the existing network architecture? It is unlikely according to the common attempts and the latest understanding of Chinese operators, unless it reforms the existing network architecture. Currently, the approach widely accepted by domestic operators is to reconstruct the network architecture and build an intelligent IP bearer network based on the technical innovations represented by SDN, NFV and cloud computing.

The evolution strategy of the current carrier bearer network is as follows:

The network architecture is horizontally layered and the spine-leaf architecture with flexible scalability is adopted, forming a new networking pattern with data centers as the core.

In terms of facilities, hardware and software of devices are decoupled, NFV and SDN are adopted in network elements, resources are deployed on clouds, and the cloud data center serves as the basic carrier for the network reconstruction.

NaaS is used as the service delivery mode. Various types of services are delivered to operators in the cloud mode through cloud-network collaboration and orchestration, providing users with unified services such as network, computing and storage.

Operators should solve issues in different scenarios to implement the intelligent IP bearer network.

III. H3C and China Broadnet smart bearer network solution

Target architecture of the intelligent bearer network

Taking 5G+ cloud-network collaboration as the technical core, the China Broadnet bearer network is built into a new smart network that features both cultural publicity and information services to fully support the smart radio and television development strategy.

Based on the evolution objective of the China Broadnet bearer network and the current reconstruction practices of operators in cloud-network bearer platforms, H3C proposed the target architecture of intelligent bearer networks for China Broadnet.

The intelligent bearer network for China Broadnet integrates cloud computing, big data, SDN, NFV, SR, telemetry and other technologies to achieve network-wide service management, control, adjustment and optimization.

H3C introduced the multi-level cloud architecture and deployed the cloud-based 5G core network, the network elements such as vBRAS or vCPE, and the edge computing service resources such as CDN or VR in cloud resource pools of different levels on demand, bearing multiple services through cloud-network convergence in a unified manner. The SDN controller is deployed throughout the network for centralized control and path scheduling. The SDN controller and cloud management platform in each network domain adopt open northbound interfaces that can be connected to the upper-layer super controller, the service orchestrator and the third-party multi-cloud management platform. The multi-cloud management platform uniformly manages the cloud resources of the cloud platforms at all levels. The super controller implements cross-domain coordination of services as well as deployment and O&M monitoring of E2E services. The service orchestrator orchestrates and deliver 5G services, private network services and fixed network services.

MAN has two construction modes. The first is the converged bearer of fixed and mobile networks. A network is used to converge and bear the services including individual user broadband, government and enterprise private lines, and 5G. The second is dual-plane bearer. A new private network is built to bear 5G services without changing the network architecture of the original fixed network.

The construction of the China Broadnet smart IP bearer network is divided into the following levels:

Backbone network construction

MAN construction

Access network construction

Multi-level cloud construction

Smart IP backbone network construction

Rapid development of the Internet and 5G stimulates changes in the demands of user services and increases in data traffic. The backbone network architecture should be reformed to expand network capacity, increase network flexibility and improve core competitiveness.

In the future, the backbone network should provide ultra-large processing performance and ultra-high service-bearing capacity, support cluster technology, and meet the capacity expansion requirements of the core layer of the IP backbone network. In addition, it should evolve with new technologies such as SR/SRv6 and EVPN. It should also emerge as an SDN with open network capabilities, so that it can be more flexible and can rapidly respond to user demands.

The intelligent backbone network can be divided into four logic layers. The top layer is the service orchestration layer where the network coordinator and service orchestrator orchestrate and deploy 5G services, private network services and fixed network services end to end. The network control layer is between the service orchestration layer and the interface layer. In this layer, the SDN controller receives northward service orchestration instructions, converts the service instructions into device configurations for delivery, and interfaces with the device layer southward through NETCONF, Telemetry, Netstream and SNMP protocols, collecting information, managing devices, monitoring services, and scheduling traffic. The interface layer is a bridge between the SDN controller and network devices. The device layer consists of core routers and deploys the SR or SRv6 protocol. The core routers form a smart, simple and efficient network.

Smart IP MAN construction

Resources of the existing devices should be fully considered and new technologies should be used in the construction of MAN to enable the reliable and efficient bearing of fixed network services and mobile services for various public customers and group customers. The diverse service scenarios of 5G and the different requirements of eMBB, mMTC and uRLLC for the network bring significant challenges to the evolution and development of MAN. At the same time, the network construction and O&M costs should also be considered. Under this background, H3C put forward two MAN construction modes: converged bearer of fixed and mobile networks and dual-plane bearer.

Dual-plane bearer:

In the dual-plane mode of fixed MAN and mobile MAN (mobile backhaul network), the original fixed network architecture is optimized and a new 5G bearer network plane is built. The fixed MAN still carries interactive television services, individual user broadband services, and government and enterprise services. Its difference from the original fixed network is the introduction of SDN and NFV for reconstruction. Most importantly, the forwarding plane and control plane of BRAS network elements are separated. The control plane network elements are deployed in the core cloud DC of MAN in the form of NFVs, while the forwarding plane network elements are deployed in the front end in the form of hardware or NFVs. The BRAS control and forwarding separation of the service control layer brings a series of advantages. For example, after the software and hardware of the BRAS are decoupled, the control plane and the forwarding plane can communicate with each other through standard interfaces, which breaks the limitation of the closed architecture and enables easy interchangeability between different manufacturers. The control plane network element adopts NFV-based vBRAS. It can access a larger scale of users depending on the strong computing power of x86, and realize elastic capacity expansion and reduction according to resource utilization, number of online users and other factors. The forwarding plane network element is only responsible for forwarding and processing and does not need to interact with external service systems such as AAA, simplifying the deployment and management of the overall service system. Besides, it is no longer restricted by the number of concurrent users, and the resources such as the IP address pool can be centrally allocated and used on demand, improving resource utilization.

To carry 5G services, a new mobile MAN should be built in each prefecture-level city. The 5G mobile MAN is based on the 5G IPRAN technology and adopts the 10 GE or 50 GE access loop for networking. Above device B at the convergence layer, the device ER is connected through 50 GE or 100 GE. Above the metropolitan area ER, the 100 GE link is used. For layered deployment of functional UPFs at the user plane of the core network, the provincial level, city level and county level can be selected. SDN controller is deployed in the DC of a metropolitan area for centralized control, unified management and unified operation of MAN.

The converged bearer of fixed and mobile networks:

Converged bearer of fixed and mobile networks is a new type of intelligent MAN based on the new network architecture. It uses an MAN to carry the individual customer services, group customer services and 5G services. The access network is still divided into two parts. 5G services access it through the 5G small cell and the IPRAN access loop passes back its data to the intelligent bearer network. The MAN adopts the flexible and scalable spine-leaf architecture. The 5G MEC edge cloud can select to access the leaf node to provide the nearest service capability for various new services including high-bandwidth 4K/VR/AR videos, campus-based services of group customers, and IoV low-latency services. The software and hardware of the BRAS are separated. The control plane network elements are deployed in the core cloud DC of MAN, while the network elements on the forwarding plane are deployed on the edge in a distributed manner. The SR/SRv6, EVPN, FlexE and high-precision clock synchronization technologies meet diverse function and performance requirements and provide personalized service bearers. The introduction of the SDN controller as the intelligent brain of the new intelligent MAN realizes the rapid deployment and scheduling of network services. SDN can cooperate with the SR technology to schedule TE traffic end to end. The SDN controller performs FlexE slicing and realizes the unified end-to-end control and management of the physical and sliced networks.

No matter which network construction mode is adopted, the separation of network control and forwarding and the collaboration of cloud and network are all the evolution trends of MAN. MAN adopts an open network platform and centrally manages the control planes through the SDN controller of MAN. Therefore, the batch delivery of configurations and flexible scheduling of paths can be realized. Besides, MAN can collaborate and orchestrate the resources with DC to realize unified scheduling of cloud and network resources.

5G access network construction

The traditional room distribution solution addresses the new challenges as the 5G era approaches. Higher-frequency 5G radio signals are less capable of penetrating obstructions from the outdoor environment to the indoor environment. In the next decade, mobile communication traffic will increase by 100-1000 times and indoor traffic will account for about 70%, imposing a high requirement for the indoor mobile network coverage. In the indoor scenario, 5G small cells are used for ultra-dense networking, resulting in a great increase in their quantity. Therefore, indoor coverage is one of the core competitiveness of operators in this 5G era.

The H3C 5G small cell solution is composed of virtual BBUs, expansion switches and pRRUs. The O-RAN architecture and decoupled software and hardware of BBU are adopted by this solution. Besides, the small cells are deployed on universal x86 servers and can be flexibly expanded on demand. The open interfaces between BBUs and RRUs and the white-box implementation in RRUs not only reshuffle the rigid supply pattern and promote the openness of the industrial chain, but also help operators reduce the network construction and O&M costs. Through the combination with MEC, they can truly make full use of the edge clouds of operators, making industrial applications more open and flexible. The RRU can be expanded and elastically scaled as required for a single BBU through multiple expansion switches, increasing the utilization of resources.

Multi-level cloud platform construction

Driven by 5G and network reconstruction, the three major Chinese operators are planning and rolling out the construction of multi-level cloud platforms. On the one hand, the 5G core network will adopt the all-cloud technology; on the other hand, the architecture with decoupled software and hardware of network elements, highly centralized control planes and dispersed data planes have become the mainstream architecture. The evolution of the virtual network elements such as vBRAS, vCPE and vEPC needs the collaborated planning and construction of network clouds in provinces and prefecture-level cities. With the development of high-bandwidth and low-latency services, the unified planning and layout of multi-level cloud platforms should also incorporate the construction of MEC edge clouds.

The multi-level cloud platform is designed according to the reference architecture of the "region-core-edge" cloud platform. The edge DC is generally deployed in a city, county or integrated access room. The core DC is generally deployed at the center of a city or province. The regional DC is generally deployed at the center of a province or national region. The multi-cloud management platform is deployed at the top level for unified management of cloud resources.

Cloud DC: It adopts the fabric architecture and the hybrid overlay method. It carries IT and CT services in a centralized manner. For CT services, the network overlay is adopted to meet the performance requirements. Host overlay is mainly adopted for IT services.

Resource scheduling across cloud DCs: DC-leaf devices are deployed at DC egresses. The DCI devices adopt the SR and EVPN technologies to realize IP interconnection. The SDN controller of MAN manages the DC-leaf devices of the whole network, realizing flexible scheduling of service traffic, mapping of DCI services and intra-DC services, mapping of rate-limiting priority of DCI services, and routing deployment of DCI services. The northbound interfaces of the SDN controller are connected to the unified cloud management platform.

Edge DCs can carry a variety of innovative services for China Broadnet, bringing new growth points, including:

For ordinary broadband users: The edge cloud deploys CDN cache nodes to speed up the acquisition of UHD videos. It deploys video games such as VR and AR to improve user experience. It also deploys advertising services that enable the accurate marketing of customers.

For 4K/VR/AR media producers: The edge cloud deploys production applications, such as 4K/VR/AR live streaming for sports events. It also performs instant rendering, coding, compositing and AI analysis of audio and videos collected by the front end, and then rapidly releases such contents to different types of terminal users in real-time.

For vertical industries: The edge cloud deploys enterprise park services for localization. It deploys the IoT gateway to provide IoT services. It also deploys IoV and self-driving services to ensure low-delay data processing.

IV. Operator practices

H3C is committed to providing open and flexible 5G products and solutions for operators (including China Broadnet) to create an open, converged, intensive and elastic intelligent bearer network.

The H3C intelligent bearer network has operator-grade reliability and strong service-bearing capacity. It is a solid and stable bearer platform for operators' 5G services. In 2020, the 5G Smart Transport Network (STN) of H3C won the bid in China Telecom's centralized procurement to enter 12 provinces and serve over 50% of telecom services in large southern provinces of China. In the same year, H3C won the bid in China Unicom's centralized procurement for all packages of the smart MAN and will implement MAN in 19 provinces nationwide.

H3C has assisted China Broadnet in constructing the smart bearer platform that integrates 5G and cloud network collaboration, creating advanced networks with China Broadnet characteristics, promoting business transformation, and facilitating the implementation of smart radio and television strategy.