In-Line architecture: bringing efficiency and performance to Cloud RAN
As we look forward to MWC 2023 in Barcelona, it’s timely to update you all how Nokia and its partners are continuing to build on our strong collaboration to deliver best-in-class Cloud RAN. This of course follows my previous blog.
Cloud RAN utilizes the vertical disaggregation of the Radio Access Networks (RAN) baseband software from baseband processing hardware. To do so, the virtual Distributed Unit (vDU) and Centralized Unit (vCU) baseband functions run as containers on a Container-as-a-Service (CaaS) software layer. The functions and software run on Commercial-Off-the-Shelf (COTS) server hardware. At the heart of the servers are General-Purpose Processors (GPP) and hardware accelerators.
Hardware acceleration technology is a critical element in Cloud RAN performance. The two primary options for implementing Cloud RAN acceleration are the so-called “Look-Aside” and “In-Line” architectures. As concluded in our newly released whitepaper, the overall benefits of In-Line acceleration outweigh those of Look-Aside for any commercial Cloud RAN deployment aiming for highest performance, lowest Total Cost of Ownership (TCO), and greatest flexibility.
Here is why:
Best performance with an In-Line accelerator
3GPP has functionally split the baseband unit into the real-time DU and the non-real time CU. In Cloud RAN, both are virtualized and called the virtualized Distributed Unit (vDU) and the virtualized Centralized Unit (vCU). In RAN, the vDU L1 processing is highly complex with sophisticated algorithms that require specialized computing beyond the capabilities of GPPs used in COTS hardware, in order to cope with the extreme computing capacity needs of L1 and very tight latency requirements in end-to-end mobile networks.
Therefore, specialized hardware accelerators are required for L1 processing in Cloud RAN vDUs. In the In-Line architecture option, this is done with the help of a RAN SmartNIC (Network Interface Card). SmartNICs are commonly used today as accelerators in server and cloud infrastructure environments, including those of global webscalers. The RAN SmartNIC enables offloading all or part of the L1 processing from the general-purpose Central Processing Unit (CPUs). Unlike in the Look-Aside architecture, this frees up valuable CPU resources enabling higher performance for L2 and L3 application processing. With the Nokia In-Line SmartNIC, less complex and less costly non-accelerated CPUs (GPPs) can be used for L2 and L3 processing where they are better suited.
In-Line acceleration provides significant system scalability benefits, as L1 capacity can be increased by adding in a cost-efficient manner RAN SmartNICs independently from the CPUs (GPPs) that are processing L2/L3. And vice-versa, CPU (GPP) capacity can be increased independently from In-Line SmartNIC capacity.
It is widely recognized that for highly demanding workloads such as L1 processing, purpose-built silicon technology provides higher performance and is also more energy efficient. Typically, In-Line solutions use energy efficient ARM-based silicon that is also commonly used in Classic RAN networks and increasingly across all networks, including webscalers’ cloud data centers.
Our benchmarking results show a significantly lower power consumption per cell with an In-Line solution compared to a Look-Aside solution. This translates into a lower cost per cell for the In-Line solution.
Feature and performance parity between Cloud and Classic
While RAN networks are expected to evolve gradually towards Cloud-based RAN solutions, most operators will choose to adopt a hybrid network approach, so Cloud RAN will have to co-exist with Classic RAN for many years. This hybrid mobile network will evolve over time with Cloud RAN being introduced for specific use cases and/or geographies. In-Line accelerated Cloud RAN architecture provides the unique opportunity to use common L1 System-on-a-Chip (SoC) technology for both Cloud RAN and Classic RAN. This brings feature and performance parity with the same software release management cadence, providing consistent end-user experience across the whole mobile network.
Cloud RAN solution flexibility
The Nokia Cloud RAN solution supports a choice of technology suppliers and operating environments. With a truly cloud native vDU and vCU software, Nokia’s Cloud RAN solution can operate with any mainstream CaaS layer, server maker and webscaler cloud environment. This gives our customers the flexibility to build their Cloud RAN solution using their own servers and private clouds, or public service clouds, with their preferred cloud infrastructure software and hardware stacks.
We are working closely with our semiconductor, server maker, webscaler and managed cloud service partners in order to ensure we make the best and proven technology choices for our customers’ Cloud RAN solution including our Nokia RAN Smart NIC for In-Line acceleration.
To conclude, there are significant benefits from the implementation and deployment of the Cloud RAN architecture, enabling our customers to continue to grow, develop and monetize their networks whilst enabling new segments such as Enterprise to thrive.
We are looking forward to sharing our industry leading technology and ideas during Mobile Word Congress in Barcelona at the end of this month. Please visit our booth and learn more about our Cloud RAN technical innovation and industry partnerships.
Share your thoughts on this topic by joining the Twitter discussion with @nokia or @nokianetworks using #CloudRAN #NokiaPartners