By: Mark Mortensen

3GPP standards provide specifications for communications service providers (CSPs) to “slice” their shared network to support near-guaranteed different QoS characteristics for various service types and service instances. To create and control these networks, vendors have created slicing managers that are managing the full lifecycle of slices for trials with commercial services soon to start in earnest. Still in question is whether these slicing managers represent a new category of OSSs or are just for the trials.

Slicing is just starting

Network slicing is in its technical adolescence but its commercial infancy. Although it was specified in 2017 by 3GPP standards, there are only a few examples deployed in networks today. Most CSPs are experimenting with slicing in POCs, working with leading-edge vendors. These vendors have added slicing to their domain control and cross-domain orchestration systems and to selected network functions. Commercial deployment is expected to start in earnest in 2022 to 2023. Major commercial growth is expected in 2024, focusing on several use cases that are now becoming clear, especially special events venues, private 5G networks, and MVNO slices. Slicing of the network into one or two dozen slices is reasonably easily achievable and will dominate in the next two years. Scaling up to hundreds or thousands (or even tens of thousands) of slices will require massive automation to handle the operational complexity throughout the service lifecycle.

Network slicing requires an overall lifecycle, end-to-end network view that includes design, provisioning, inventory, and assurance functions, all working together (the P-A-I-D functions). Most CSPs desire that these be provided as a “decomposable suite” that provides all the functionality but partitioned into microservices-based components that can be selectively replaced in the architecture by other vendors’ components (usually ones that are already in place).

Network slicing is being implemented in a way that requires no changes to the network equipment (whether virtual or physical) already in place. Instead, a combination of specialized network surveillance of sliced resources, slicing markers in an inventory system, and slice provisioning templates are implemented in external software systems—integrated into, or integrated with, domain control systems and cross-domain orchestration systems. All the vendors are implementing a combination of standard interfaces as defined by the GSMA 3GPP, TM forum, IETF, and ETSI standards bodies.

Many network function vendors are ensuring that their elements and their domain control systems can support network slicing and integrate with cross-domain orchestration systems. Vendors such as Infinera, among others, are following this path. Some NF vendors, such as Huawei, are providing a full solution, ensuring that their NFs are fully supported with external software for the DC and CDO functions that supports both their own NFs as well as those from other vendors requested by their CSP customers. Ericsson has this same basic strategy, with more of a professional services-oriented approach than others.

Some NF and independent software vendors (ISVs) are offering comprehensive multivendor slicing management systems, basically CDOs enhanced with added slicing functionality, with a goal of excellent multivendor support and usually incorporating the DCs of other NF vendors (where available) into their architecture. Leaders in this area are Amdocs, Ciena Blue Planet, NEC/Netcracker, Sedona, and Oracle.

Other ISVs are building more targeted software components, usually based on open source, for DC and CDO functionality.  ISV service assurance and inventory specialists are working with other vendors to integrate their products into overall slicing management architectures. TEOCO is a leader here.

Other specialized players are providing specialized slicing NFs and DCOs that provide enhanced slicing capabilities in the NFs themselves. Kaloom and Pluribus are standouts in this area.

Network slicing: the state of the art

Nearly all network slicing vendor offerings today involve people engineering the network slice to specified quality of service (QoS) values, then monitoring it via service assurance OSSs to ensure that the QoS values are met. If they are not, then manual methods are employed (usually via engineering changes).