Network Slicing

Part 1/3

Network Slicing is a pertinent topic in 5G . Vendors should develop a strategy on Network Slicing based upon below

1. Is there any target operating model defined or a balance scorecard for 5G network slicing Design and deploy the network slices
2. Automation in the ecosystem about the deployment of network slice, Doing a load balancing in an automated way so that efficiently entire resources are used and they are sweating the entire resources.
3. Assuring the network slices quality for selected services. Linking of operation domain and orchestration domain

 Network slice vision

Network slice is a virtual private service which is extending from the devices to the application servers on the shared physical infrastructure. Physical infrastructure comprises of Virtual Network function or shared network functions running on compute, Network and storage.

It can also be viewed as various multiple logical network paths on a shared network infrastructure. Multiple logical network paths are initiated from the clients to the Application servers. It is the efficient way to use the underlying network infrastructure. Multiple logical connections are happening over the single physical network infrastructure

 Network Slicing Requirements and characteristics

Let see how this Virtual private service is defined by the requirements and the characteristics.

 Requirement : High data speeds, high uplink speed, high reliable, high secure.

 Characteristics: Geographical Coverage , Mobility, TCO/ARPU, Management Control.

 Network slicing use cases

mMTC

This is more commonly known today as the Internet of Things, but at a much larger scale, with billions of devices being connected to the network. These devices will generate far less traffic than eMBB applications, but there will be many magnitudes more of them.

 eMBB

These applications are very video-centric and consume a lot of bandwidth and will generate the most traffic on the mobile network.

 uRLLC

These will allow for things like remote surgery or vehicle-to-X (v2x) communications and require MNOs to have mobile edge computing capacity in place.

 Let's see How Network Slice is actually realised by deploying on different type of network function. Network functions which are spanning on different domains and network functions

Domains refer to RAN , Transport and core. These domains are network functions which are consuming resources such as Compute, Network and Transport. Within Network slice we have Slice subnet such that the Transport slice subnet is connecting the RAN and the core slice subnet. Here Radio network slice is deployed on small data centres which are on the last mile of the network and then it is connected with Core Network Slice such as User plane functions and the control plane functions which then connects to the Application servers.

3GPP release 15 has defined the specs for the core part. AMF part can be shared among the slices. UPF and SMF cannot be shared among the slices. A device can have up to 8 slices also a guidence was given for 5G radio node. Capability of Network selection is defined in the Device and will be assisted through NSSAI which is passed on by gNB. gNB has the capability of differentiated network slices and policy enforcement. gNB should also ensure the resource isolation in a network slice. Also LTE interworking has been defined in 3GPP Rel 15. 

The concept of slicing was there in LTE as well where a LTE device was designed to only support one slice. A proper handover of slices is also defined in 3GPP Rel 15 mapping of parameters has been done in LTE to 5G.

However, for many of the relevant use cases, the biggest impact on end user experience in relation to throughput, latency and reliability happens to be in the Radio network. It is therefore clear that actual Network Slicing needs to be extended into the Radio domain.

The parameters passed from LTE core to 5G core are

LTE/EPC        5G Core

PLMN ID        PLMNID

DCN               S-NSSAI

APN                DNN

QCI                  5QI

 Slice management Function defined in 3GPP

• Communication Service Management Function (CSMF) translates communication requirements to network slices.
• NSMF translates the Network Slice request into a network slices across the entire network of the CSP.
• NSSMF realizes the slice within its own domain and is fully accountable for the lifecycle of the subnetwork-slice within its domain.
• NFMF provides the management services for managing one or more Network functions

3GPP is also defining relevant interface standards (APIs) for network slice and subnetwork-slice provisioning, configuration management and assurance (FM/PM), although some of these are not fully mature in our view.