Service Assurance Questions in the Time of 5G Standalone
How does service assurance change with the movement to 5G standalone?
The movement to 5G standalone (SA) is much more than a new radio access technology such as that we saw in the migration from 3G to 4G. The overall complexity of the network increases as mobile operators transition network elements from dedicated, purpose-built appliances to virtual machines and onto cloud-native virtual functions.
This technology shift introduces a microservices-based architecture that causes the overall network plumbing to change—with complex network address translation (NATing) and transient IP addresses adding to the complexity of achieving the network visibility needed for service assurance. IP addresses are no longer unique across clusters, and they can change for many different reasons. Thus, unique IP addresses no longer identify each 5G virtual network function (VNF). Plus, the signaling control plane messages within the 5G service-based architecture can now be encrypted with Transport Layer Security (TLS) 1.2 or 1.3.
There is also the introduction of multi-access edge computing (MEC), constructed to move service intelligence closer to the user or device to reduce latency and increase throughput and reliability. With service intelligence at the edge, continuous latency measurement becomes essential to assuring each service and device.
Network Slicing Unlocks Differentiated Services
In addition, mobile operators are looking to offer network slicing that works by partitioning and provisioning a series of virtual networks within a single physical infrastructure to optimize traffic for specific use cases that may need high reliability, low latency, or specialized security. For mobile operators, network slicing unlocks differentiated services at scale to enterprises and consumers. However, to get there, mobile operators need tools that provide unprecedented and real-time network visibility. These network changes call out for enhanced visibility for latency service level agreements (SLAs), slicing visibility from RAN to core, and SLAs per slice.
Changes in Network Plumbing Impact Visibility
How does encryption of the 5G SA service-based infrastructure (SBI) impact visibility for service assurance?
These changes in the network plumbing and encryption of the 5G SBI interfaces have a serious impact on service assurance and require a new method for identifying traffic. Fortunately, a unique means has been developed to identify each 5G SA network function as it is instantiated. A new identifier, NF-Peer-Info, was added to the 3GPP release 17 specification that helps to identify what 5G function is talking to another 5G function (an AMF communicating with an SMF, for example).
Packet-level Data Provides the Best Intelligence
Why is packet-level data preferred over direct communication with the VNF?
Packet-level data is really the highest-fidelity communication you can utilize for network visibility and service assurance. Other examples of metadata (for example, summarized data created by the NVF) have been utilized but do not provide the same richness of information, insight, and intelligence without interpretation. Packet data reveals the richest level of communication information between the virtual functions for service assurance.
Another example is service assurance instruments communicating with the virtual functions directly for data. This concept began to fall apart with the Network Data Analytics Function (NWDAF) network element introduced in 3GPP release 16. Again, changes were made to redesign the NWDAF architecture in release 17 because direct communication places an unwanted and unneeded load on VNFs, whereas packet-level capture does not place any additional strain on the VNFs and provides a much richer view of the actual communications taking place between each VNF than asking for summarized data.
To better serve their customers and maximize the return on their 5G SA network investment, mobile operators need to adopt technologies that allow them to identify and anticipate service degradations and disruptions. That all starts with network visibility.
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