5G backbone networks: flexibility opens up new business opportunities
Hello, Habr and dear habravchane! We decided to prepare a series of publications about 5G. Around the fifth generation cellular networks, which are scheduled to be launched in 2020, an incredible amount of controversy is unfolding. Despite the fact that they are of great interest in terms of new business opportunities, outsiders still have a lot of questions. For example, why do we need 5G if we have not yet developed 4G and even 3G networks? We will try to give answers to these questions and delve deeper into technologies, usage scenarios and methods for building new generation mobile networks.
First, let's look at 5G in terms of the business opportunities already mentioned. Many applications will work on the basis of 5G technologies: remote control of equipment, telemedicine, smart meters and broadcasting content to a wide range of mobile Internet users. The functionality of new generation networks will allow companies from various industries to develop products and services, and quickly adapt them to changing demand.
Flexibility is the main requirement that 5G networks must meet. Currently, technologies are already being used that provide a high degree of flexibility in network architecture, such as software-defined networks (SDN) and network function virtualization (NFV). Using these technologies, the network is divided into logical segments, each of which is configured in accordance with the parameters necessary for the operation of certain services.
Internet connection of a growing number of devices, as well as the launch of new applications and services will impose a number of additional requirements for cellular networks. Among them - a higher data transfer rate, minimum network response time, QoS, ensuring the protection of transmitted data, the constant availability of the network, as well as specific parameters that differ from service to service. It is logical that the income from each of the services will be different, and the operators are faced with the task of ensuring the economic efficiency of investments in each of them.
Under these conditions, service deployment time and flexibility of service settings are of great importance. Of course, the timing should be minimal, which means that it is necessary, first of all, to ensure the dynamic operation of the 5G core network. To this end, it will be necessary to test many possible scenarios of its work.
5G backbone concept
The 5G core network should become the basis for many new business applications, while still ensuring the functioning of existing services, such as, for example, mobile Internet. In addition, the fifth generation network core must support the collaboration of multiple access technologies and the transmission of incoming and outgoing traffic generated by a mass of devices of various types. This means that when designing the core network, it is necessary to provide for the sharing of resources by a variety of applications and take into account differences in the needs of different industries.
Flexible should be not only a core network, but the entire communication system. The core of the fifth generation network should have a modular highly elastic architecture and support virtualization of network functions (NFV), principles and protocols of software-configurable networks (SDN), technologies of dynamic orchestration of network resources, and also provide interaction with all possible types of access: LTE, Wi-Fi and others. At the same time, all new services and options should be brought to the market as soon as possible, and from the moment a request is submitted to the activation of the service, a minimum time should pass.
High level architecture
Network flexibility is provided by network slicing, which breaks one physical network into several layers, each of which has its own settings adapted for a specific service. Thus, costs are reduced, and the efficiency and flexibility of future services is ensured.
Segmentation is carried out through the use of NFV and SDN technologies. In order for a particular separate network segment to ensure the effective operation of a certain set of services, it must be tied to various infrastructure elements, including VPN, cloud services and access technologies, and also through VNF to the resources of the backbone network.
The figure below shows an option in which logically separated segments and isolated systems are used that have different architectures and are able to use common functional components. One segment is designed for the provision of mobile broadband access (MAN) services and provides network access to devices supporting LTE, Evolved LTE and NX technologies (a new type of radio access that will be developed for use in fifth-generation mobile networks. Currently under development requirements for the standard of a new type of radio access). Another segment is designed to work with industry applications and includes an optimized level of control of the core network and a simplified level of user data, and also supports various authentication schemes.
Network segmentation reduces the business risks associated with the launch of new services, since problems in one segment do not affect the functioning of services for which another segment is responsible. In addition, the use of segmentation provides seamless migration.
The network architecture should change with the advent of new communication standards, and the abandonment of the approach in which all services are provided on the basis of a single network in favor of network segmentation simplifies this task. Using mechanisms such as the Dedicated Core Network (DCN) is one of the steps in the right direction.
Separation of management level and user data level
To ensure the flexibility of the 5G network, it is necessary to implement various hardware, on the basis of which different functionality is deployed in different physical segments of the network. Particular attention should be paid to designing the user data layer, which should provide high throughput. For example, a scenario is possible in which most of the traffic requires only simple processing, and simplified hardware is sufficient for this. However, the rest of the traffic may require more complex processing. Cost-effective scaling of the user data level per single band or multiple aggregated frequency bands is a key component of the 5G backbone network.
The ability to separate the functions of the control level and the user data level plays one of the key roles in the architecture of the fifth generation core network. This separation allows you to scale the resources of the control levels and user data independently of each other. Also, this separation allows you to place resources of user data and control levels on different parts of the network. For example, the level of control can be placed on a central site, and thus simplify the management and operation processes. The user data level can be distributed across several local sites, in order to ensure that it is as close as possible to users. Thus, the signal travel time is reduced, and a smaller bandwidth is required to transmit data per unit time. This approach is well suited, in particular, for caching content,
Since the separation of the control level and the user data level is the basis of the SDN concept, the flexibility of the 5G backbone network is significantly increased when using software-configured networks. The figure below shows that the level of user data may not depend on the location of physical resources and transport features of L2 and L3. Typical control level functionality includes location data management, policy negotiation, and session authentication. Thus, separation at this level is natural.
The functionality of the user data layer can be deployed according to specific usage scenarios. Since connection needs vary from scenario to scenario, creating unique settings for each of them will be most cost-effective. For example, M2M connections have a small payload and mobility, while MVV services they are large. MVV services can be divided into several simpler services, such as streaming video and web surfing, which will allow them to be deployed as separate segments within a single layer. This approach ultimately helps to increase the flexibility of the core network.
Obviously, for the development of the business you need to build a network with great flexibility, and network segmentation allows you to achieve it. However, increasing flexibility can complicate all levels of the system, and as a result, increase the cost of operations and stretch them over time. Automation solves this problem.
Network management should take into account three main stages of the service life cycle: creation, activation and lead time:
• Creation of new services or customization of existing ones with a minimum time to market - allows, if necessary, to break down the solution into components and quickly create, execute and verify services and segments.
• Activation of the service with a minimum TTC - allows you to automatically activate the service in the shortest possible time.
• Lead time - providing the user with the capabilities requested by him, monitoring the operation of the service and SLA, adapting to changing conditions, ensuring the scaling of new services, each of which should be fully automated.
The advantages of network segmentation, in which each segment has its own capabilities, are supported by two levels of management functionality. One level is responsible for services and products, including B2B. Another layer is responsible for network segmentation as such. This is clearly shown in the following figure. Innovative offers can be created by combining the functionality of different layers, where one segment will have low performance and high latency, and the other - high performance and low latency. Each innovative proposal will include a set of characteristics such as SLAs, business policies, and control functions within the segment.
Management of the service life of a service includes the development and creation of different types of network segments and services, as well as their activation, taking into account the specific needs of users, monitoring work and upgrading (if necessary). This requires a plan. It indicates which components need to be installed, which functions to activate, which configurations to create, which resources to manage.
To launch a new service, a new network segment is created or, in some cases, the configuration of the existing one is changed. The segment can be independently managed or cover other resources, including both traditional (for example, EPC) and new types of architecture (for example, separation of control levels and user data). Network segments can have management functions, some of which can be controlled by the operator, and some by the user. The control layer uses several systems and interfaces that allow you to create and configure resources. At the same time, flexibility plays a key role in the automation and orchestration of the system, and is achieved, for example, through the use of plug-ins.
Virtualization, network programmability and 5G use cases will completely change the approach to designing and deploying networks. Network resources will never be grouped vertically again, instead, they will be located in different parts of the network, in close proximity to the location of users.
The 5G core network will have a high degree of flexibility, which will allow serving a wide range of needs of new business models, providing support for a variety of access technologies, as well as the work of a wide variety of services and devices.
Minimizing the costs of operators and industries depending on network connectivity is the most important task that needs to be addressed when designing a flexible and dynamic network core. The main role will be played by SDN and NFV technologies, cloud technologies and analytical systems. A flexible backbone network and integrated network segmentation will add value to networks built on the basis of a common infrastructure.
This concludes the first chapter of the story about 5G. Next time we will talk about 5G transport networks and how to ensure their flexibility through the use of SDN technologies.