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Network disaggregation – The new normal

As 5G brings the need for a more diverse set of services from the core to the edge, momentum around open and disaggregated networks is accelerating.

Network disaggregation has been in the making for the better part of the past decade. The advent of 5G is leading to significant strides in this area, resulting in important innovations and optimizations.

It allows network components to be virtualized, offering operators scalability and flexibility – this ultimately enhances the user experience when the capacity is increased. Additionally, such virtualization provides a level playing field of sorts that creates new and fair scalable opportunities for businesses.

The separation of hardware and software, based on standard networking white boxes, offer the economic benefits of hyperscale clouds, promoting higher scale at much lower CapEx and OpEx.

Disaggregation has already been applied in many network domains. Multi-layer optical transport systems were disaggregated into open optical terminals and lines systems. They feature standardized control interfaces for ease of integration and end-to-end service activation and assurance. Likewise, IT appliances, such as firewalls, intrusion detection systems, or SD-WAN devices are implemented as white box servers loaded with open operating systems and software appliances. It is a key enabling technology for digital transformation of IT. It also applies to OT networks, which control physical assets with critical operations, such as energy networks or transportation.

Unleashing the innovative power of open architectures requires moving away from proprietary, closed, single-vendor solutions. Disaggregating complex and monolithic network solution into manageable pieces is a key enabler. The old way was to have a single company managing the Herculean task of developing silicon, operating systems, applications and performing systems, and network integration. Now, specialized companies can leverage their key competences for fast, efficient, and economic realization of best-in-breed sub-systems, software components, and network devices. Open interfaces are a prerequisite for ease of integration, resulting in an open architecture that enables a global software community to quickly and efficiently create new, high-value services.

System integration is an easy task, as the single-vendor device and the disaggregated solution meet common requirements. The difference is with the suppliers that offer the solution. Established suppliers are now facing competition from original device manufacturers (ODMs) and independent software vendors.

As highly complex systems are disaggregated, new building blocks are defined, and additional open interfaces are required to assure ease of integration. There are not many companies with the expertise to integrate such complex networks, and so this task might be managed by major network operators, market-leading solution providers, or very-large system integrators.

Disaggregated networks lead to a disaggregated value chain. End-to-end suppliers gain less value from system components, and most likely will focus on system integration, with the intention of compensating for lower revenues by extending into end-customer IT domains. Alternatively, they may focus on competing with sub-systems and extending those systems into neighboring market segments. System suppliers will need to make such decisions and either grow their SI competencies or compete as specialized component suppliers with disaggregated solutions. Either way, the model of single-supplier end-to-end solutions is no longer an option.

As solution providers grow their system integration business and extend into enterprise IT solutions, they might move into a competing role with their established customers. This can be observed today with private mobile networks, which frequently are offered as managed service by mobile network operators as well as mobile infrastructure suppliers.

Technology experts with a disaggregated product offering can help their customers with the demanding task of system integration. Some of the components of an enablement strategy for disaggregated networking might include software tools, such as product simulators pre-integrated network elements, combining disaggregated software with white boxes, simplifying network integration on a component level, technology domain pre-integration, allowing ecosystem partners to verify the interworking of a larger part of an end-to-end solution and lab-as-a-service, enabling end customers and system integrators to cost-efficiently validate interworking through access to lab resources from a disaggregated solution provider

RAN disaggregation has been the final frontier to achieve a desirable end-to-end architecture, which can lead to further deployment innovation and promote many different deployments use cases. O-RAN Alliance has emerged as a standards body with wide industry acceptance both with the CSP and the vendors.

While open interfaces and virtualization are not new technology principles by themselves, the application of these principles, with disaggregation of the RAN infrastructure into interoperable elements and hardware and software, is creating alternative ways to build mobile networks.

Momentum is growing as the vendor ecosystem ramps up the product portfolio and operators commit to more trials and deployments. Highlighting the growing demand for more flexibility, four European operators, Deutsche Telekom, Orange, Telefónica and Vodafone pledged to work together. This helped drive the development of the disaggregated RAN ecosystem and commenced operation as soon as solutions become mature enough.

Diversification of the mobile RAN supply chain is also driving governments to take notice. The UK government, had decided to remove high risk vendors from UK networks, set its supply chain diversification objectives as supporting existing suppliers, attracting new suppliers and accelerating open interface solutions. Funding for testbeds, trials, and interoperability testing of open interface solutions was announced.

Open and virtuealized RANs are expected to deliver both technical and economic benefits, increasing the flexibility and diversity of the network equipment and software ecosystem and spurring innovation. By reducing the cost, open and virtualized RAN will also help to optimize the almost trillion-dollar global operator investment needed to achieve connectivity targets.

However, as is often the case with the early phase of innovative solutions, a number of challenges will need to be overcome to enable mass deployment of these technology principles. These include the security of networks, industry readiness, and cost effectiveness. Whilst the mobile industry is undertaking a number of initiatives to address, there is a recognition that accelerated measures are needed to ensure equipment interoperability, security, and reliability, as well as sufficient systems integration capabilities and skills.

While 3GPP and O-RAN both share several key common technological features, allowing for the freedom of choice for vendor-specific implementations, O-RAN takes a step further in disaggregating the RAN. It goes further by opening up the 5G base station in more functional elements (like the RU) and standardizes new interfaces like for the fronthaul, management and control functions and interfaces for O-RAN functions, and virtualization for the covered functions. Hence, O-RAN is an extension of the 3GPP standard, both in terms of network functions aspects, as well as network implementation aspects (virtualization).

The disaggregation of RAN also comes with the challenge of securely integrating the disaggregated O-RAN solution. Cost and capability aside, the O-RAN Alliance has formed a Security Task Group (STG), within O-RAN WG1 (Architecture) to address the new associated security risks with O-RAN. Ericsson is an active participant in the STG and has been collaborating with the O-RAN community to address these security risks.

Disaggregation for 5G. AT&T, China Mobile, Deutsche Telecom, NTT DoCoMo, Rakuten Mobile, Telefónica, and Vodafone are just some of the big-name operators, championing an open RAN and working with organizations like 3GPP, O-RAN Alliance, TIP, and others to accomplish this goal. In doing so, these operators expect faster innovation, lower costs, and a break from vendor lock-in.

Functional decomposition of the radio unit (RU), distributed unit (DU), and central unit (CU) RAN components is a prerequisite for RAN interoperability. Such decomposition presents operators with multiple architectural options, each of which affects transport network technologies and choices. On one end is the fully distributed RAN (like traditional macro cells), on the other end is a fully centralized RAN. And, in between, there are several other split-RAN variations.

In networks, in which RAN functions are physically separated from one another, the transport network is the glue that holds the RAN together. It includes fronthaul (connecting the RU to the DU), midhaul (connecting the DU to the CU), and backhaul (connecting the CU to the mobile core) segments where RAN interoperability is needed, so is standardized transport.

In another trend, the concepts of open RAN are coming to the mobile transport network elements themselves – including disaggregation of the network operating system (NOS) and the underlying switching hardware. In the white box model, the disaggregated switching hardware and software are built to open requirements defined in groups, such as OCP and TIP. The disaggregated cell site gateway (DCSG) segment for mobile networks, promoted by TIP, is one prominent example of the hardware and software disaggregation model. But the NOS/hardware separation model extends to other routing segments as well, including edge and core routing.

Once disaggregation reaches scale in commercial networks, networks will not be built from end-to-end by a given supplier. Instead, they would be built on open standard interfaces, using equipment from any number of potential companies within the communications ecosystem. This creates a lot of opportunities for the end users of networks, who will have many more options to tailor networks to their needs, particularly in private networks, whether they are built by the company using them or hosted by a carrier. For instance, in an application like shipping port management, the network needs to cover a large open area while also overcoming interference from containers or other large, moving objects. An application like mining will have a different set of needs since the networked environment is always changing and will often require signals to navigate a confined space with limited lines of sight. Meanwhile, in automated factory applications, latency and security may be paramount.

The interoperability and flexibility enabled by open networks will create more opportunities for companies to develop novel services that are geared specifically toward these divergent application areas and hence are engaged closely with a range of ecosystem partners to understand and offer solutions to meet their unique needs. The opportunities for companies in the communications ecosystem and the users of this technology are very exciting.

Open optical networks. Momentum around open and disaggregated networks is accelerating, particularly for the partially or horizontally disaggregated flavor, in which the transponder vendor is chosen separately from the line system vendor. While components are supplied by separate vendors, the optical network is controlled and managed as a unified system (through open APIs).

Disaggregation is not just a new way to implement networks. It creates disruption to the supplier landscape in networking. New entrants will compete with established suppliers, which will focus on new roles, in some cases competing with their previous customers.

Any player will need to carefully evaluate opportunities in a disaggregated network market and develop a strong profile in a tight segment. Some suppliers will re-focus on key technologies complemented by domain-specific services offerings.

While others strengthen their end-to-end system integration business, applying disaggregated solution components from leading technology suppliers, what is certain is that specialization will be crucial. Either you’ll be among the best or you’ll be out.

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