End-to-End Network Slicing Architecture: Logical Layers Explained
Grasping Logical Layers Regarding End-to-End Network Slicing
As 5G networks continue to evolve, network slicing is vital to support differentiated services for various industry clients. Network slicing is based on a logical architecture with distinct logical layers. The logical layers are designed to abstract technical complexity while supporting interoperability with the use of open APIs. The purpose of this blog post is to clarify the logical layers from an end-to-end network perspective as illustrated in the graphical representation.
🔍 Why Logical Layers in 5G are Important
The use of logical layers provide:
Segregation of service and control logic
Abstraction in technology management and complexity
Modular and scalable orchestration
Zero-touch automation for the service lifecycle.
Each layer has unique functions, and open API interfaces to provide testing, service, and knowledge relationships between the layers.
🧱 The Seven Logical Components Of Network Slicing
Layer Management Function Role/Function
- Customer Service Layer CSMF (Communication Service Management Function) Responsible for mapping customer requirements to network slice requirements.
- End-To-End Network Slice Layer NSMF (Network Slice Management Function) Responsible for the coordination of slice lifecycle across several Network and Service provider domains.
- Subnetwork Slice Layer NSSMF (Subnetwork Slice Management Function) Responsible for domain slices; example Radio Access Network (RAN), Core Network, Transport.
- Network Slice Network NFVO (Network Function Virtualization Orchestrator) Responsible for the orchestration of Virtualized Network Functions and Services.
- Network Function Layer VNFM (Virtual Network Function Manager) Responsible for management of VNFs, CNFs, PNFs.
- Infrastructure Layer VIM (Virtual Infrastructure Manager) Managing physical and virtual compute, storage, and network
- Information Hiding Through Abstraction — Abstraction hiding through the complexity that resides between layers with Open APIs
Each function communicates vertically through processing interactions and horizontally through cardinal symmetry, in turn enabling modularity and scalability.
🔗 Fundamental Concepts and Technologies in the Reference Architecture
🔄 Processing Involves Interactions.
Bidirectional flows of interaction occur between layers to navigate slice operation execution and lifecycle management.
🧩 Hiding Information through Abstraction.
Each layer is hiding its complexity; each layer exposes standardized interfaces for upper layers to request services without knowledge of how they will be accomplished.
🌐 Open APIs.
Standardized APIs (for example REST, NetConf/YANG) will ensure:
Interoperability between vendors
Automates, orchestrates
Decouples services from infrastructure
🧠 Break down functions & relationships
CSMF (Communication Service Management Function)
Maps user/customer service requests to technical needs.
Interacts with NSMF to trigger slice creation.
NSMF (Network Slice Management Function)
Responsible for slice instantiation, monitoring, scaling, and termination.
Interacts with a set of NSSMFs for domain-specific orchestration.
NSSMF (Network Slice Subnetwork Management Function)
Manages slices at specific domains like RAN, Core, or Transport.
Reports health and status back to NSMF.
NFVO (Network Function Virtualization Orchestrator)
Orchestrates multiple VNFs, and creates service chaining.
Interacts and coordinates with both VNFM and NSSMF for resource orchestration.
VNFM (Virtual Network Function Manager)
Manages lifecycle of VNFs; deploy, update, healing.
Operates under the NFVO to satisfy service function chaining.
VIM (Virtual Infrastructure Manager)
Controls access to compute, storage and network resources.
📈 Benefits of Layered Architecture
✅ Modularity and flexibility
✅ Service and infrastructure are decoupled
✅ Better automation using orchestration APIs
✅ Vendor agnostic interoperability
✅ Scalable to accommodate different 5G \ use cases
🔮 Conclusion: looking into the future of layered slicing
The logical layering of slices in network slicing helps establish the foundation of 5G which is Dynamic, Programmable 5G Infrastructure. By abstracting complexity and supporting open programmability and open interfaces between layers, the network operator may realize dedicate value added services from consumer type connectivity (mobile broadband) to mission critical IoT to be consumed by human, devices or machines.
Following standards as described in the ETSI NFV framework and 3GPP SA5 provides the classic ultimate vision that this architecture provides the foundations for an intelligent, self-adapting network, while developing capabilities for an even more autonomous network 6G is awaiting.
🔧 Examples of End to End Network Slice Layering Use Cases
This multi-layered network slice framework is not just a design vision but encapsulates several important 5G and beyond use cases:
🏥 Healthcare - Remote Surgery
the Customer Service Layer requires ultra low latency and is highly reliable =
NSMF uses NSM to create a dedicated slice persistent for URLLC (Ultra-Reliable Low-latency Communication).
VNFM & VIM manage compute resources on the edge in real-time capacity.
🚗 Automotive - Autonomous Driving
Subnetwork slices of the NSSMF would handle V2X for the RAN and Core Network.
The NFVO manages the Edge VNFs orchestrated for safety.
🧩 Visual Recap of Communication between Layers
To show you how the layers work together, figure 11 presents a simplified flow:
User Request Created: There is a service request (e.g, smart grid requires low-latency control).
The CSMF decodes this and calls on the NSMF.
The NSMF calls on the NSSMF to orchestrate slice creation in each domain.
NFV orchestrates the provision of VNFs and service chains.
VNFM orchestrates the VNFs.
VIM provisions and activates the physical/virtual resources.
Each layer has its purpose with the boundary being API defined which empowers operators to automate slice creation and service assurance in scale.
🌍 Industry Player Movement
A number of telecom’s largest organizations and alliances are pushing layered network slicing into the mainstream.
NTT Docomo: Actively piloting CSMF and NSMF, orchestration for enterprise slicing.
Deutsche Telekom: Launched E2E slice orchestration platforms within this layered model.
TM Forum & GSMA: API standardization (Open APIs, ODA components).
Open RAN, Kubernetes-native VNFs and AI-based orchestration reinforce the necessity of logical layers.
📌 Next Steps for Network & Telecom Engineers
If you are designing, deploying, or enhancing 5G networks, here’s advice you should look to incorporate on your next slice at any stage.
📘 Know-API ways: Learn REST, NetConf/YANG for cross layer collaborations.
✅ Conclusion:
Creating the Future with Modular Network Slices
The logical layers of network functions moving from customer intent to infrastructure realization allows operators to deliver on the promise of 5G - agility, automation, and ultra-customization. The layered and logical approach to the network enables faster time-to-market, service assurance and efficient consumption of network resources.
Combined with open APIs, cloud-native orchestration, and AI-driven automation, this architecture provides the foundation for zero-touch networks and the eventual leap to 6G.