5G Slicing: What, Why, How
What is 5G Network Slicing and Why is it a 5G Game Changer?
Network slicing allows network operators to create multiple virtual networks on a shared physical infrastructure, tailoring each slice to meet specific requirements and use cases. By creating a logical separation of virtual networks for different services, different teams can manage and implement changes where they see fit, independent of one another. For example, an individual team wanting to launch a new service that is vastly different from current core services, could do so without reengineering the whole network every time – boosting go-to-market time and potentially reducing cost of deployments. This enables operators to deploy new services in a much quicker fashion to meet customer demands.
With network slicing, operators can rapidly deploy and configure virtual networks to support new services or applications. Network slices can be dynamically provisioned, modified, or scaled based on real-time requirements, providing flexibility and scalability to meet varying needs. This capability opens up new revenue streams for operators by catering to diverse industries and service providers. Network slicing enables operators to offer premium services with differentiated performance and quality, allowing for potential monetization of enhanced network capabilities.
The value network slicing brings to both operators and enterprise customers is significant in terms of service agility, flexibility, and customization which inevitably trickles down to enterprise customers (B2B) as well.
Figure 1: Summarization of the key benefits of 5G Network Slicing
Highlighting some key benefits of network slicing include:
Service agility: Network slicing provides operators with the ability to deploy and configure virtual network functions based on the demand to support new services or applications. This agility allows for quick adaptation to changing market demands and the introduction of innovative services.
Flexibility: The ability to tailor network characteristics according to use cases means diverging from the “one size fits all” approach past generations of cellular networks have taken. Ultimately, this means offering solutions that can better meet the specific needs of a broader set of customers – whether in different industries, geographies, or both.
Customized solutions: Network slicing will be a key part of telcos’ private networking services menu. Rather than having a dedicated private mobile network (4G LTE or 5G), enterprise customers can use one or more network slices suited to their specific connectivity requirements.
New Business Models: Network slicing can be seen as a disruptor to the traditional form of network operators. The slicing enterprise and business possibilities are limitless. An example would be to offer a flexible, scalable and tailored slices to MVNOs. Another example would be a car manufacturer can potentially have several slices each tailored to a specific need such as telemetry, entertainment and autonomous driving.
Efficient Network Management: Network slicing allows an operator to manage each slice individually. Slices can be monitored, and optimized individually and if issues arise, they will not impact the other slices or overall network.
Resource Efficiency: Network slicing optimizes resource allocation by assigning dedicated resoures to different services or applications. This ensures that each slice receives the necessary network resources, such as bandwidth and processing power, to deliver optimal performance. This is where capacity management is crucial in order to maintain network performance, reduce congestion and provide unfaltering quality of experience to the end user.
5G network slicing brings significant benefits by enabling customized services, resource efficiency, service agility, efficient network management, and monetization opportunities. This flexibility and versatility make network slicing a fundamental feature of 5G networks, supporting a wide range of applications and industries.
Challenges Faced with Network Slicing
While 5G network slicing offers significant opportunities, it also presents certain challenges that need to be addressed. Here are some of the key challenges associated with 5G network slicing:
Complexity: Operators need to define and configure multiple slices with specific performance characteristics, manage slice lifecycle, and ensure seamless coordination between slices. This complexity requires advanced orchestration and management systems to handle the dynamic provisioning, monitoring, and optimization of slices.
Figure 2: Summary of Network Slicing Challenges
Service Orchestration: Coordinating and orchestrating services across different slices and infrastructure components is a complex task. Ensuring end-to-end service continuity, dynamic scaling, and efficient handover between slices require sophisticated orchestration mechanisms. Integrating network slicing with existing service orchestration systems is essential for seamless operation and service delivery.
Service Assurance and SLA Management: Service orchestration enables real-time monitoring, analytics, and performance management across network slices. It allows operators to monitor key performance indicators (KPIs), detect anomalies, and take proactive actions to ensure SLA compliance. By providing visibility into the performance and health of each slice, service orchestration facilitates efficient troubleshooting, capacity planning, and quality assurance.
Interoperability: Network slicing involves the interaction and coordination of different network components, including radio access networks, core networks, and edge computing infrastructure and often tiems all from different vendors. Ensuring interoperability and compatibility across different vendors' equipment, protocols, and systems can be a challenge.
Automation and Scaling: Service orchestration automates slice lifecycle which includes provisioning, configuration updates, and scaling. It enables dynamic scaling of resources based on demand, ensuring that slices can adapt to changing traffic patterns and service requirements.
Total Cost of Ownership: Network slicing involves investments in infrastructure, equipment, and management systems. The deployment and maintenance of multiple slices can incur additional costs for operators. Balancing the cost of implementing and managing network slicing with the potential revenue generated from differentiated services is a challenge that operators must address.
Network Slicing Lifecycle Assurance
Network slicing lifecycle assurance includes the management and automation of the end-to-end slice lifecycle. The 3GPP (3rd Generation Partnership Program) standard is the defacto standard used in Mobility. As per the 3GPP standard, the entire slice lifecycle needs to be closely monitored as to maintain the stringent customer SLAs. Each of the phases are briefly described below:
Preparation Phase: This phase is the Design and Assign of a network slice. Part of the design and assign includes on-boarding and evaluation of the network function which requires working closely with network inventory. It also involves all the network environment preparation required to implement the network slice.
Commissioning: This includes the instantiation of the network slice instance. During the commissioning phase, all required resources are configured and allocated to meet the network slice requirements. This is the phase where the Network Slice Instance (NSI) has been created and configured and is ready for operation.
Operation: This phase includes activation, supervision, performance monitoring, resource capacity, modification and de-activation of a. Network Slice Instance.
- Activation: This includes the activation of an NSI (for example, diverting traffic to the NSI etc) thus making it ready to support communication services.
- Resource Capacity Planning: Requires the calculation of the resource usage of an NSI, providsioning and performance monitoring. This phase also generates modification policies based on the resource usage calculation.
- Modification: This phase include the creation or modification of Network Slice Instance. It can also include capacity and topology changes. Modification can be triggered by either receiving new network slice requirements or the result of the closed loop supervision and reporting functionality.
- Deactivation: Stops the communication service and includes actions to disable or make the network slice inactive – taking the NSI out of active duty.
Decommissioning: Includes the reclamation of dedicated resources (e.g. termination or re-use of network functions) and re-configuration to remove NSI specific configuration from shared/dependent resources. After decommissioning the NSI no longer exists.
Below is a graphical depiction of a Network Slice Lifecycle management as per 3GPP.
Figure 3: 3GPP Slice Lifecycle Management (TS 28.530)
Slice definition is required to properly configure and instantiate a network slice. The GSMA Slice template (Version 9) provides a framework called the Generic Slice Template (GST) of Network Slice attributes (or characteristics) that are characterized by a network slice type (for example eMBB, uRLLC, mMTC). These characterizations are not tied to any specific network deployment and are available with ServiceNow out-of-the-box implementation.
After completion of the input parameter values in the slice template, the generic slice template (GST) then becomes a specific NEtwork Slice Type (NEST). These values for the specific attributes represent the requirements to support a specific customer network slice use case. Other parameters can be included based on customer requests but the OOB capability will be based on the GSMA generic slice template.
Visualizing the workflow based on the GSMA slice template can be seen below.
Figure 4: GSMA Generic Slice Template (Version 9)
When looking into network slicing, it is critical to start looking at Network Slice Lifecycle Assurance. Service assurance is crutial from when the slice order is placed through the self-service portal to then fulfilling the order as per specific requirements or SLAs. The next step is then executing slice workflow service management orchestration which then comes full circle with end-to-end slice monitoring and maintenance through closed loop automation. This Lifecycle assurance ensures that a customer’s slice never deviates from the stringent Slice SLAs which creates differentiated business services.
This is where slice service assurance is essential from slice performance monitoring, case, incident and problem reporting to creating workflows to manage the resolution in real time that properly enables slice SLAs to be continuously monitored and remediated.
Figure 5: Main Focal Points in Managing Slice Lifecycle
ServiceNow Implementation of Network Slicing
3GPP Implementation of Network Slicing
Based on 3GPP TS 28.531the network slicing management functions consist of the following components:
CSMF (Communication Service Management Function): Responsible for translating the communication service related requirement to network slice related requirements and communicates with the Network Slice Management Function (NSMF).
NSSF (Network Slice Management Function): The NSMF represents the slice manager and will be able to analyze and subdivide slice requirements into 1:N sub-slice requirements. It can select the proper sub slice instance or deploy one if one is not already available and the sends these requirements to the NSSMF southbound. The NSMF is responsible for managing and orchestrating the network slice instance (NSI).
NSSMF (Network Slice Subnet Management Function): NSSMF is responsible for the management and orchestration of the Network Slice Selection Instance (NSSI) along with maintaining the lifecycle management of the NSSI. NSSMF converts the sub slice requirements received from NSMF into service requirements and requests the instantiation of the network function instance. NSSMF also requests the network service configurations and manages and reports on the progress of the deployment results northbound.
Figure 6: ServiceNow Network Slicing Implementation
With the Vancouver release, ServiceNow supports the implementation of the CSMF (Communication Service Management Function) as part of OMT (Order Management for Telecommunication). Some key benefits for supporting 3GPP and implementing the CSMF are listed below:
- Industry Leader in Order Management
- Simplicity: One Platform, One Database, One Data Model
- Workflows for automating business and network processes
- Data accuracy dashboards for actioning
- Integrated with OSS platforms e.g. discovery, provisioning etc.
- Deliver insight for assurance workflows and use cases
- Dynamic and intent based networks
- Extendable data model for new networks and services
Network Slice ServiceNow Workflow
ServiceNow has the unique capability of
- Creating a Generic Slice template(GST) – having the capability to created a GST with out-of-the box capability is critical in minimizing TTM and helping service providers monetize their investments by increasing their B2B product offering.
- The next step is creating a Network Slice Specification (NeST) based on the GST.
- Create the Slice Product Offering for a slice specification. Serveral types of Network slicing product catalogues can be created depending on the end customer requirements and those include:
- Pre-Configured Slice Offering
- On -Demand Slice Offering
- Hybrid Slice Offering
- Network -as-a-Serice Slice Offering
- Slicing orders are then ingested with TMF Open API 622.
- Decompose customer order into product and service orders
- For each Service Order, create a service profile with service order characteristics.
- Decompose the service orders to child services based on the NeST parameters. Return to step 6 for child service orders.
Trigger southbound request of NeST to the resource/slice orchestrator (NSMF) via TMF641
Figure 7: ServiceNow Network Slice Workflow Infographic
ServiceNow fulfillment process includes
- ServiceNow order management as CSMF layer
- Industry (TM Forum) aligned API’s to interoperate easily with the ecosystem
- Customer and Service Order Management for slice offering
- Key capabilities include:
- Order decomposition
- Order orchestration
- In flight order management
- Order fallout management
- Order lifecycle
Below is a visual representation of the fulfillment process for a slice order. The highlighted in green is ServiceNow Vancouver release supported functionality. OMT supports the sending of the entire NeST characteristics southbound via TMF641 to the Slice Orchestrator. It also supports the receiving of the confirmation response from the Slice Orchestrator that the slice has been successfully instantiated and configured thereby completing the order.
ServiceNow also supports the capability of making any modifications to both existing completed orders and in flight orders. For instance, if a mobile private network would like to change the t-shirt sizing for their Edge Core from Small to Medium, that can be executed and implemented in real time.
In the likelihood that additional hardware equipment will need to be added, OMT supports the integration with FSM to seamlessly request the deployment of additional required hardware for the slice order.
Figure 7: The fulfillment process for a slice order
High Level Architecture of OMT Network Slicing
ServiceNow supports out-of-the-box CSMF functionality along with as part of the Design & Assign functionality. Below is the high level architecture implementation supported in the current Vancouver release.
Figure 8: ServiceNow Network Slice High level architecture
ServiceNow OMT Implementation of Network Slicing
ServiceNow supports template creation as an out-of-the-box functionality. As part of the template creation, the following will be described in detail in the following sections:
- Create a slice template. Adding Characteristics to the template and then publish the template to the Product Catalogue
- Create Service Specification using a Slice Template
Creating a Network Slice Template
- Navigate to the Workspaces > CSM/FSM configurable workspace.
- To view all the available templates
- Select Template > ALL
3. The Name and the Description should be entered and the select SAVE
- Name: eMBB2 Slice Template (as an example)
- Description: This is an enhanced Mobile Broadband Slice Template
- Once Saved, the Template Characteristics tab will appear. Select the Template Characteristics tab to add characteristics to the template and select NEW
4. Characteristics can be selected and added to the Template. Once the characteristic is added, click on SAVE
- The State now changes to Published
- The State now changes to Published
- The State now changes to Published
4. Select NEW after you have clicked on the tab > Template Characteristics Option
6. Select Characteristic Options that are applicable for the Speed Characteristic. Once selected click on SAVE
7. Additional characteristics and characteristic options can be added. Once all the characterisitcs are added, you will need to navigate back to Template Details, and then select Publish UI action to Publish the template to the catalogue.
8. On the pop up Window, select OK to publish the template in the product catalogue.
9. The State now changes to Published
Mapping the Slice Template to a Category
- Navigate to ALL > Decision Builder
Once in the Decision Builder, search for Template Selection Policy decision table.
3. The Template Selection Policy should be selected.- This is a decision table that is used to auto select a template for a specification.
- This is an out-of-the-box capability and the specification category field is used to as a condition for the template.
- For example, when creating a slice product specification of category “eMBB”, the template field would be auto selected with “Slice Template for eMBB”
- Additional inputs and columns can be used to define conditions per the business requirement by selecting the Add New Decision Row option.
- A new decision row should be added to be able to map the eMBB Slice Service Service specification category.
Creating a Product Specification using the Slice Template
- Navigate to Workspaces > CSM/FSM configurable workspaces
- Select Service Specifications
- Followed by selecting New
3. On the Service Specification Form > Category Field > Select eMBB Slice Service. The form can be completed as follows:
- Name: Private 5G Campus
- Display Name: Private 5G Campus
- Category:
- Type: Customer Facing
- Sub Type: Slice (you will notice the template field is autopopulated with eMBB2 Slice Template established as part of the decision table that was previously configured)
- Start Date: Today
- Description: Private 5G Campus
- Click on SAVE which creates the Service Specification
4. When the service specification is created, all the Specification Characteristics will be automatically populated with the template characteristics created.
- Non Maditory characteristics can be removed from the service specification before publishing.
- Select Publish to Publish the Service Specification and Click OK on the pop up
Creating Orders using a Slice Product Offering – Showcasing Catalogue Hierarchy
- As part of the Demo Data, orders have been created for Funco Intl. account using a slice product offering.
- Navigate to Offerings > Product Offerings
- Select Premium Connected Navigation – Single Tenant
2. Navigate to Catalogue Hierarchy tab to view the complete hierarchy of the product offering. Here you can see that it is composed of multiple sub slices.
Submitting an Order from Workspace
This section will be reviewing how to submit a new order with the order capture UI followed by approving the order. The following call to action will be to fulfill decomposed orders and order tasks. The proceeding sections will review both these requirements.
Creating a New Order with Order Capture UI
In order to create a new order with the order capture UI, the following steps should be completed.
- Navigate to Wordkspaces > CSM/FSM Configurable Workspace
- Under Lists, navigate to Customer > Accounts and open the account information for Funco Intl. You can search for the name by clicking on the 3 dots next to the name and a pop up as below will appear – simply enter the name you are looking for and select apply. Once you get the Funco Intl. account, select and click on it.
3. Once in the account information overview page, select Create Order in the UI Action
4. A pop-up window will appear to select the order type. Select the option Order New Product and clock on Create. This will lead to a guided ordering flow.
5. As part of the guided ordering flow, sample data can be found below:
- Account: Funco Intl.
- Contact: Sarah Johnson
- Once this is complete – Click Continue
6. A pop up will appreas to select a location (you might need to refresh the browser if it doesn’t appear.
- Click on the Locations Box and select one location that appears on the list
- Click on Add once the location has been selected
- The location will be added to the order in the left pane.
- Under Product Offerings, select the Offering: Premium Connected Navigation – Single Tenant. The quantity remains as 1
- Click on Configure Item
- All the Order Line Items have Missing Information which means that there are characteristics that are missing values that are required for order submission.
- Select the order line item one by one and add the characteristic value
- For the Connected Vehicle order line item, click on the Characteristics tab
- Hover over the name Slice Type characteristic and click on the “i” when it appears – this is the preview icon
- Click in the Characteristic option box, select the value and then click on Update
- Update the characteristic values for each of the line items. Once completed the missing info warning message will disappear.
8. When Completed Click on Review action button at the top right hand corner after updating all the characteristic values.
- This page displays the Order Line Items and pricing information
- Click on Submit button to submit the order
- A pop-up Returns the order number
- Click on View Orders to continue
View and Approve the Order
Navigate to the order that was just created: Workplace > Customer Order > All and select the order that was previously created.
- Click on the number to open the order
- On the Details tab, the following should be noted and reviewed:
- Account information
- State of the order (Is is New?)
- Version (Is it 1?)
- PONR flag (Point of no return – is it unchecked?)
- Revision operation – is it None?
- Priority Value (Evaluated and Assigned)
- Select the Order Line Items tab to check the line items
- Once everything is checked – Select Approve (Note that the order state changes from New to Acknowledge to In Progress
Fulfill decomposed orders and order tasks
Once the order is approved, the decomposition process kicks off, the domain orders are created and the sub-flows are required for the fulfillment process to be able to trigger the creation of order tasks. The below steps are meant to provide guidance in implementing this process.
- Navigate to the order record that was previously created
- Open the Connected Vehicle Order Line Item and select the Product Orders tab.
- Select the Product Order for the Connected Vehicle Line Item
- Then select the Service Order Number to view the decomposition of the service order into the mMTC Service Order.
- Once on the service order – select the Order Task Tab
6. Select the Order Task to design an mMTC slice task
7. To Design mMTC Task, select the Change Request tab to see the change request created in the Telecom Inventory application for the Design mMTC Slice Task. Once you click on the Change Request tab, Select the Actual Change Request number and in the Details Tab, complete the following information and then select CLOSE.
- Assignemnt Group, Assigned to, Close Code, and Close Note.
Note: The OMT to TNI integration is supported to have change requests created in TNI for OMT order tasks for different use cases. This configuration is managed in the TNI Request Type to Record Producer Policy decision table.
8. Once the Change Request is closed, the corresponding Design mMTC Slice Order task is auto-closed
9. In this step -The triggering of the Outbound request to the NSMF to provision and activate the slice for mMTC will be sent.
- OMT supports the triggering of Outbound service order via API.
- To Trigger the outbound fullfillment request, select Create Outbound Fullfillment Request on the service order for mMTC form and confirm to proceed.
- Notice that the State of the fulfillment request got updated to fulfilled State. This is based on the mock response OMT received for the outbound request sent. In a network configuration, OMT waits to receive the response.
11. Notice that all the 64 NeST Parameters – Service Order Characteristics are available and those required are populated. These Service Order Characteristics are sent outbound via TMG641to the slice orchestrator to begin the slice resource instantiation and configuration.
12. Navigate back to the details tab of the Service Order for mMTC in the details tab and notice that the service order is auto-closed.
13. Navigate back to the Details tab of the Product Order for Connected Live Apps and notice that the product order is also auto-closed. This concludes the fulfillment of the Connected Live apps product and the mMTC Slice required to support that particular order.
14. Similarly, to fulfill the Product Order for Autonomous Driving, On the Connected vehicle product order form, select Product Orders to view the child product orders created. Select Product order for Autonomous driving.
Select the Service Orders tab on the Product Order for Autonomous Driving form to view the decomposed service orders. The Autonomous driving product order is decomposed into the uRLLC service order. To view that, select the Service order number.
15. On the Design uRLLC slice task, select the Change Request tab to view the change request created in the Telecom Network Inventory application for the Design uRLLC slice task.
- Enter details for the following fields and select Close to close the Change request: Assigned group, Assigned to, Close code and close note.
- Once complete select CLOSE
- Once the change request is closed, the corresponding task is auto-closed.
16. This following step, the outbound request to the NSMF will be sent to instantiate and configure the slice for mMTC.
- To trigger an outbound fulfillment request, Select Create Outbound Fulfillment Request on the Service order for uRLLC form and confirm to proceed.
- Click on OK in the pop up
- Select SAVE
17. Notice a new tab is added for outbound requests. Select ths tab to see the newly created outbound request. The state of the fulfillment request got updated to fulfilled State. This is based on a Mock response. OMT will be waiting to receive the response from the southbound slice orchestrator via TMF641.
18. Navigate back to the Details tab of the Service order for uRLLC, and notice that the service order is auto-closed.
19. Navigate back to the Details tab of the Product order for Autonomous Driving and notice that the product order is auto-closed. This concludes the fulfillment of the Autonomous Driving product and the uRLLC slice required to support that. Select CLOSE to close the order.
20. Similarly repeat Steps 4-13 for the remaining product order for Infotainment
21. Please note that the order line items will change state to Completed
ServiceNow provides an End-to-End Network Slice Business Orchestration
ServiceNow provides network slicing automation on a single platform for implementing 5G services. ServiceNow in turn enables new business models, helping service providers monetize their investments.
ServiceNow is critical in breaking silos by supporting the complete slice lifecycle automation that decreases complexity and reduces TTM. From establishing the ease of Slice Design & Assign via the service portal, to order fulfillment, to enabling workflows to fascilitate orchestration and closing the loop with providing slice assurance. ServiceNow delivers an unparalleled end customer quality of experience.
