There are many ways to deploy a 5G network, but most of them will cost you dearly ...
The 5G Core introduces huge opportunity for Mobile Operators to leverage the throughput and latency improvements that 5G New Radio provides in a flexible and standardized multi-vendor environment.
Isn't that all good news?
3GPP defines the UPF as a single element decoupled from the control plane that handles all aspects of data plane packet processing between the RAN and the DN through one or multiple instances. 3GPP concentrates on the access control, session management and packet processing aspects. In other words, 3GPP functionally prescribes the roles played by the serving/packet gateway in the EPC.
Operators, however, demand a pragmatic implementation for the UPF that offers enough flexibility to accommodate multiple use cases and regulatory obligations. These usually require niche user plane services and applications that, due to latency, performance and efficiency reasons, should ideally be part of the UPF ecosystem in the 5G Core.
Why is that a problem?
The problem with this approach is that the standards do not address how network services, which traditionally resided in the GiLAN, must be architected and deployed to leverage 5G throughput and latency improvements.
The 3GPP network architecture for the user plane group isolates functions into UPF entities. When introducing services in the core, operators might have to choose between:
- A single anchor UPF that integrates applications. A closed and proprietary UPF element imposes functional and business restrictions to Operators, introducing vendor lock-in. The Operator will become dependent on the UPF vendor for future services and use cases.
- Deploying a collection of UPF elements from different vendors. Although the 3GPP architecture for the user plane provides with both control and user plane interfaces to accommodate this model, this approach will inevitably add processing latency and complexity to the service rollout process and its scalability.
- Deploying services in the N6 interface, as a continuation of the traditional GiLAN model commonly adopted for the EPC. Again, this model will not allow the Operator to benefit from efficient packet processing, simplified orchestration and scalability, introducing multiple hops in the user plane.
“Traffic growth and encryption will intensify with 5G, so Openwave Mobility is focusing on providing operators with the right tools and capabilities to manage and monetise the new wave of mobile data.”
Solution to the Problem Posed by the 5G UPF
At Openwave, we treat the 5G UPF as an open framework that acts as the only user plane data processing element. However, as opposed to a monolithic element, as suggested by 3GPP, it leverages service decomposition to create an extensible framework through self-contained stateless functions. This architecture for the UPF, as an end-to-end data plane framework, is based upon the following key design principles:
Openwave’s design principles for the 5G Core User Plane Function
Service Flexibility and Extensibility
Open Framework Seamless Service Creation Best-In-Breed Applications
A UPF framework must enable and demonstrate the ability to decompose and on-board multiple services from different vendors. This enables operators to choose best-in-breed technology for each service function, eliminating vendor lock-in constraints without compromising operational management simplicity.
In addition to the traditional serving/packet gateway operations, the UPF ecosystem enables the necessary functions to deliver services relevant for a 5G environment as well as to preserve 4G and legacy services and guarantee a smooth transition.
Cloud Native. NFV Evolution: from Virtualized to Containerized Applications
Virtualization SDN/NFV Containerization
Our design introduces a highly-portable container-based packaging for the different decomposed UPF services and functional capabilities. It eliminates inter-service and framework dependencies, guarantees service assurance and maximizes performance.
Both the framework and the services are stateless by design and therefore meet 5G high scalability requirements. This helps minimize the time to onboard new services, facilitate seamless transitions between central and distributed edge sites and simplify failover scenarios by leveraging a shared data layer.
High-Performance Packet Processing
One-Hop Packet Processing Zero-Copy & Delay
The framework design eliminates the packet processing efficiency challenges that a modular user plane function traditionally leads to. It provides ultra-fast packet processing through a single packet processing function that performs inspection, classification and processing/orchestration enforcement only once per packet. It also uses direct access to shared memory to minimize ineffective abstraction layers, unnecessary system calls and packet copying. To optimally process traffic in the core, packets must have a single hop to and through the whole user plane.
Message Bus. Efficient Service Orchestration
Event-Driven Message Bus SBi
Our design leverages a subscribe-notify bus to exchange information between individual UPF functions.
Unified Data Layer. Seamless Transition to the Edge through Stateless Functions
CUPS Augmented Stateless Design
Subscriber session data (including session/PDU data) as well as any structured data is stored in a unified and federated data layer. This Unified Data Layer (UDL) is shared and accessible to any NF in the 5GC, including of course any UPF and UPF Service Function and/or microservice. It enables efficient management of analytics solutions, localization of edge data and unification of subscriber identity and session state while still allowing the fragmented identities to remain independent. When in combination with containerization, the UDL permits the deployment of different services at the edge with very little integration overhead.
Many of the 5G elements can be simplified by implementing their data transformation rules within the technology of the Unified Data Layer.
The Transition To 5G. One Network Function Serving Two Cores
Two Cores, One Function Performance & Cost-Effective Transition to 5G
Our design further creates a consolidated UPF in the 5GC that interworks with both the EPC and 5GC in the transition to 5G. In addition to efficient SBi-based communications, our UPF also provides 3GPP rel. 15 Sx interfaces, as well as Gx and Gy for interworking with the EPC and legacy components. The data layer – both for unstructured and structured data – is, in our architecture, separated and abstracted from the network function application and core network elements, facilitating this transition. Also, separation of the data from the EPC network function application becomes an interim step in the transition to a consolidated EPC and 5GC UPF.
Enea Openwave offers multiple deployment models for the UPF, whether as an Anchor UPF or Service Function UPF. For more information about Enea Openwave solutions for 5G, please contact a representative or fill up the details in the contact form