Page 313 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 5

– user data downloading

– user data update
– information query
– restoration

6 Key technologies

6.1 Control and User Plane Separation
Control and User Plane Separation is to decouple the control plane function and the user plane function in
the network entity, and each function is implemented in separate equipment. The control plane function can
then be deployed in a more centralized way while the user plane function can be deployed more distributed
according to the service requirement. The upgrading, scaling can be applied separately on control plane and
user plane functions. Control and User Plane Separation can bring the advantages such as more flexibility of
network upgrading, faster new service deployment, etc.
Control and User Plane Separation makes it possible to integrate different access technologies under a single
network architecture due to the following reasons:
– the composed network entities are too complicated to be converged
– the different user plane functions needs to be deployed centralized or distributed depends on the
access technology it serves.
With Control and User Plane Separation, different user plane functions can be deployed on demand while
under control of the unified control plane function.

6.2 Reconstruction of control plane

Network slicing is a concept introduced in 5G, by which operators can deploy different network slices to serve
different service requirements. A network slice is an end-to-end network, including RAN and CN. The
functions in network slice can be virtualized or dedicated. Network slicing, together with NFV/SDN, can
enable a flexible, programmable, and extendable network architecture.
Function modularization, customization and composition are the basis of network slicing with NFV/SDN.
When redesigning the functions of control plane functions, the following issues should be taken into account:
1. Control plane functions of fixed network should be included
2. Mobile network control plane function should be included
3. WLAN control plane function should be included

4. Which functions can be common?
5. Which functions should be specific?
6. Which functions should support unified control to these different networks?
Besides, orchestration of control plane is also important for network slicing. That can enable creating a
network slice which includes corresponding control functions required by service requirement.

6.3 Service Chain

In order to adapt to the rapid development of data communications services, fixed broadband and mobile
operators will develop a variety of value-added services such as video optimization, Web cache, HTTP header
enhancement and network acceleration based on different user groups and market demand. With the
development of value-added services, the value-added service network is gradually evolving into the status
of serial connection or hairpin connection, which will lead to data traffic roundabout, management and
maintenance difficulties, low business deployment flexibility and time consuming problems.
Service chain can be introduced in the mobile or fixed broadband communication network to break the
traditional serial or hairpin mode of value-added services. It can provide customized value-added services for

307