Page 213 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 3

Appendix I

IMT-2020 Networks, Services and Resources
Orchestration Functional Requirements

NOTE – The following requirements are the discussion/agreement from the sixth meeting of FG on IMT-2020.
It requires the further review in order to be inserted into main text.

I Functionality Applicable to all Networks, Services and Resources Orchestration

I.1 System Primitives

• Function Name: Slice Orchestration: - Slice life cycle management (i.e. including concatenation of
slices in each segment of the infrastructure and vertical slicing of the Data pane + Control plane +
Service plane); slice elasticity, placement of VMs in slices. It takes over the control of all the
virtualized network functions and network programmability functions assigned to the slice, and
(re-)configure them as appropriate to provide the end-to-end service. [Slice is the collection of
virtual network functions connected by links to create an end-to-end networked system. Slices are
composed of multiple virtual resources which is isolated from other slices. Slicing allows logically
isolated network partitions with a slice being considered as a unit of programmable resources such
as network, computation and storage. Considering the wide variety of application domains to be
supported by IMT-2020 network, it is necessary to extend the concept of slicing targeted by the
current SDN/NFV technologies.
• Function Name: Coordination: It coordinates the infrastructure components with the view of
protecting it from instabilities and side effects due to the presence of many service components
running in parallel. It ensures the proper triggering sequence of SC and their stable operation. It
defines conditions/constraints under which SC will be activated, taking into account operator service
and network operation requirements (inclusive of optimize the use of the available network &
compute resources and avoid situations that can lead to sub-par performance and even unstable
and oscillatory behaviors).
• Function Name: Service Platform Hosting – IMT-2020 Node hosting functions for Service Platform
full or partial functionality.

• Function Name: Recursiveness Enablers: Virtualization, slicing and orchestration are recursive and
involve far more than simply subdividing, aggregating or combining resources. A domain
orchestrator sees a set of resources for its exclusive use in satisfying the service request. Recursively
within each subordinate/sub domain, the local orchestrator likewise sees and coordinates resources
for its own use. Recognizing the generic and recursive nature of virtual resources, the Service
Platform may instantiate a VNF of its choice on some available lower-layer container that it knows
about in satisfying the service request.

I.2 Service Information Enablers
• Function Name: Service Platform Information Coordination - information / knowledge collection,
aggregation, storage/registry, knowledge production, distribution and use across all service
platform & SDK & infrastructure functions. The importance of the use of uniform information model
cannot be overstated as the risk of semantic mismatch is exacerbated if different functions have
incompatible information models. This allows purpose-specific APIs to be produced, while enforcing
common semantics for the resources of concern.

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