International telecommunication union
Latency optimized network
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- Extensible network
- High-level IMT-2020 network architecture
- IMT-2020 network architecture
- Functional elements in IMT-2020 network architecture
- Data plane functions
- Control plane functions
Latency optimized networkThe IMT-2020 network should be based on a proper network architecture to support low-latency network services. The end-to-end latency may come along with the support of distributed network architecture where application servers placed on network edges and flexible signaling architecture in which light weight signaling can be supported for latency critical applications.
The IMT-2020 network should be flexible and extensible to cope with various and sometimes conflicting service requirements adaptably instead of having a dedicated network for each emerging new service. The IMT-2020 network should be future-proof as much as possible to accommodate even unforeseeable use cases. The clear separation of control and data planes and the enabling technologies are the basis to make the IMT-2020 network flexible and extensible.
The IMT-2020 network architecture should be defined in the end as a reference architecture which defines the functional entities and the interaction flows among the entities as well. In this document, however, we only define a high-level view of IMT-2020 network architecture as a guide for the reference architecture in the future standardization phase. Network softwarization definitely will be one of the key technologies for IMT-2020 network to cope with the various service requirements. The detailed softwarized IMT-2020 network is handled in separate chapter. In this chapter, therefore, we focus on more fundamental elements which will address the other requirements of the IMT-2020 network.
Figure . High-level IMT-2020 network architecture. Error: Reference source not found shows the high-level IMT-2020 network architecture. An IMT-2020 network differentiates itself from legacy IMT networks by further evolution and revolution as well in radio network, front/back-haul networks, and core networks. Multiple various access points, including a new IMT-2020 RATs, Wi-Fi AP, and even fixed networks, are connected to a converged data plane functions via an integrated access network so that mobile devices can be serviced through an access technology-agnostic network core. The converged data plane functions are distributed to the edges of an IMT-2020 common core network resulting in creating a distributed flat network. The control plane functions, which are responsible for mobility management, QoS control, etc., controls the user traffic to be served agnostically to the access networks to which it is attached. IMT-2020 network architecture also can support massive native flexibility with the support of network softwarization (network virtualization, functions virtualization, programmability, etc.) depending on different service scenarios and requirements, which is a major differentiation from existing IMT networks.
The key parts among all the required functional elements are described here. The detailed functional architecture and definition of reference points will be discussed in standardization phase.
The key data plane functions, which is expressed as converged data functions in the Error: Reference source not found, include the following.
This function provides a method to classify user traffic into individual service flows which can be added, modified, and deleted separately. Quality of service is managed and guaranteed per service flow.
This function is a traffic identification function to help control application flows according to their service characteristics in data plane.
This function monitors the condition of multiple wireless networks and control the traffic flows among selected wireless networks. The most suitable RAT may be selected as a sole access network or multiple RATs can be selected to increase user experienced data rate.
This function provides the computing and storage resources at the edges of IMT-2020 core network to support low latency services such as tactile internet more efficiently.
The control plane functions may be centralized while parts of them may be locally distributed depending on the requirements and also for the purpose of efficiency, each of which is expressed as core control functions and access control functions, respectively. The key control plane functions include the following.
This function provides a method to control sessions in a unified signaling across multiple different mobile access networks. This function should also address connectionless services by providing light-weight signaling mechanism.
This function provides a unified mobility control across multiple different mobile access networks – same types of mobile access networks and heterogeneous mobile access networks.
This function manages the resources from multiple wireless networks as an integrated virtual resource cooperating with multi-RAT coordination function in CGF.
This function controls the service policies and QoS control policies of user and each service flow based on the user and application identification.
This function manages all the identifiers of mobile devices including device identifier of 3GPP-types, MAC identifier of Wi-Fi, or other types of identifiers for user or device. All the identifiers need to be managed in such a way that the identifiers can be cross checked with each other.
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