Page 173 - ITU-T Focus Group IMT-2020 Deliverables

ITU-T Focus Group IMT-2020 Deliverables 3

Action_activateSliceResources: This action causes a Slice to be activated according to the results of a
computation of which resources should be allocated. It will have to configure the fronthaul network, decide
where the DSP needs to go, allocate the resources both hardware and software for the RAT/DSP create any
necessary fabric interconnect in the C-RAN, configure any inter C-RAN connectivity, configure any datacenter
fabric, configure the servers to run the core, pick the software for the core and request it be started, configure
any IPVPNs and/or L2VPNs, chain together the core elements and of course provide QOS control end to end.
These would be done by making requests to the CRAN components, DC components and IDC components
controllers respectively. The error handling here is complex, for example, should the slice come up if all
resources are not available.
Action_computeSliceResourceDelta: This would take a running Slice and a new Slice definition based on a
changed profile and would compute what new resources are needed (or what needs to be released) to make
the running Slice equal to the new Slice. It does not take any action but simply tries to optimize what the
changes should be and augments the running Slice with the delta results.

Action_activateSliceResourceDelta: This uses the results of the delta computation action to actually
allocate/de-allocate resources in the running slice to bring the current slice into agreement with the delta. If
a RAT / CORE or MEC function is going to be aborted it should be given time to gracefully shut down and
therefore interfaces would be required to communicate this between the orchestration system and these
applications.

Action_shutdownSlice: This would force a slice to be shut down. There are a variety of ways to do this from
a graceful slow approach to a sudden and abrupt termination and freeing of all resources. The Profile could
specify shutdown behaviours for various components. The RATs/COREs/MECs functions should be informed
that they are going down and given time to gracefully shut down prior to being aborted.
Action_querySlice: This event would return the status of the slice. It would query the independent
components that make up the slice and would returned detailed status of each individual component.
Various wild carded forms of query should be supported to get subsets of the information.
Action_xyzSlice: A place holder for many more possible actions.

8.2.3 Action timelines
This section lists the rough sequence of events that have to occur for a given action at the orchestration layer
and what the sub controllers would need to do in response to that action.

Action_connectToCran: This action will attempt to establish a secure tunnel to the controller for the named
C-RAN. A key exchange is done to obtain a secure connection after which a request is sent for the
CranCapabilities. These capabilities should contain all the antennas, their locations, properties, name of their
attachment points (what would switchable fronthaul look like outside the C-RAN?), descriptions of the
general purpose compute resources and special purpose hardware resources and the fabric that
interconnects them together with different RATs available and for each its requirements in terms of compute
/ acceleration components and available spectrum options.
Action_connectToDran: This action will attempt to establish a secure tunnel to the controller for the named
D-RAN. A key exchange is done to obtain a secure connection after which a request is sent for the
DranCapabilities. These capabilities should contain all the antennas, their locations, properties , name of
their attachment points, descriptions of the general purpose compute resources and special purpose
hardware resources and the fabric that interconnects them together with different RATs available and for
each its requirements in terms of compute / acceleration components and available spectrum options. This
is very similar to a CRAN except much smaller and may have only a few antennas and very limited compute
resources.
Action_connectToIDC: This action will attempt to establish a secure tunnel to the controller for the named
Inter Data Center network (metro etc.). A key exchange is done to obtain a secure connection after which a
request is sent for the IDCCapabilities. Since the IDC controller may be flexible and able to allocate new
resources on demand, the Capabilities are not hard upper bounds and may have a flexible representation to
indicate this. The Capabilities should list the attachment point names such that correlations can be made to
the attachment point names in the C-RANs and other DC’s or other networks.

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