Principles for Open RAN

Future networks need to be built with a understanding of the sprit Open RAN as well as the technical adherence . To this end DCMS has issued a guide to implementation. Simon Rockman has taken a look.

THE GOVERNMENT HAS published a set of principles to help build a stronger telecoms supply chain. These are designed to inform the thinking behind organisations which are building and implementing Open RAN networks. Components in the networks of the future should be built to open, interchangeable standards and those components from a more diverse selection of suppliers.

The four key principles are open disaggregation, standards-based compliance, demonstratable interoperability, and implementation neutrality.

Underlying the principles is the ambition that the UK’s critical national infrastructure should not beholden to a small handful of suppliers. If the mobile network operators were to implement a network which was built to the full Open RAN standards, but were only to buy all the components from existing mainstream suppliers, then little would have been achieved. The policy goal is a thriving market of alternative suppliers.

Vendor Selection

While the idea of having lots of potential suppliers may seem attractive on the surface, particularly to operators, many of those implementing networks regard it as a complication. Two decades ago a good mix of companies provided network equipment, including such names as Nortel, Siemens, Motorola and Marconi. The mobile networks found it easier to deal with fewer companies, and in the end, just Ericsson, Nokia and Huawei were able to weather the vicious cost cutting and erosion of markets.

One of the problems of having multiple suppliers is that when two parts of a network don’t work with each other, it’s the mobile network operator which must then arbitrate between the two. Using something as standard as a router to connect to a base station means lot of configurations to ensure security: functions such as establishing a VPN or encryption. Standards for such functions are often implemented differently by different vendors. Choosing two suppliers therefore may create a lot more work. The two suppliers may claim that the other one is at fault. That is behind the push for more strict, standardsbased compliance, and vendors being able to demonstrate interoperability with other vendors products and services. Products built to a standard, using well defined protocols, ought to be easier to install successfully.

The government does not define those protocols – that’s the job of the standards bodies such as ETSI and 3GPP. Choosing which ones to use has been part of the work undertaken by the Telecom Infra Project. Swapping parts from different vendors will require some testing and engineering to ensure optimal operation, but the adoption of standardised interfaces should ensure that vendors start from a much closer position: lowering the friction involved in swapping components by decreasing the cost of integration and interoperability testing.

One example of friction today is the continuing use of proprietary protocols.

Standards Variation

This is where demonstrating interoperability is important. While telecoms has many open, standardised interfaces they often do not specify enough detail, leaving implementations open to interpretation and to vendors including proprietary extensions. The only way to ensure that products are genuinely interoperable is to demonstrate them actually working successfully with other vendor products in realistic environments. It’s traditional to resolve this via a “plugfest” where manufacturers meet up with their equipment to test compatibility. Such events were very important in the early days of Bluetooth, making sure that particular mobile phones worked with particular car systems before the days of smartphones. This interoperability testing is undertaken by the O-RAN alliance – which runs Plug Fests to carry out OpenRAN interoperability testing. It has so far tested 77 scenarios across seven events across the world. In the UK, DCMS has funded SONIC Labs, run by Ofcom and Digital Catapult. These interoperability labs invite Open RAN suppliers to come and test their kit in a sandbox environment and build functional commercial relationships.

A mobile operator will be much more

Principles In The Dcms Guidelines

Open disaggregation

This allows, and expects different elements of the RAN to be sourced from different equipment suppliers.

Standards-based compliance

Allowing all suppliers to test solutions against standards in an open, neutral environment.

Demonstrated interoperability

Ensuring that disaggregated elements work together as a fully functional system.

Implementation neutrality comfortable buying a piece of equipment from a new vendor if it has been shown to work reliably with the equipment that the vendor already owns. The DCMS Open RAN principles note that equipment which is deployed needs to be able to work with other vendors in reality, and is not just theoretically compliant with open standards. That level of assurance is needed between functional elements within each base station, between adjacent base stations, and between the base stations and the core and management networks that support the RAN. The guidelines note that “previous initiatives have succeeded in creating open interfaces, but failed to deliver multi-vendor interoperability because of proprietary management approaches.”

Allow suppliers to differentiate and innovate and on performance of their products.

Over-standardisation runs the risk of stifling innovation and creating a market which differentiates only on price. The Principles look to implementation neutrality to counter this. The move to Open RAN and a more diverse supplier market won’t happen overnight, but a greater choice of suppliers should benefit the industry by lowering costs, while removing the reliance on a small number of companies that has been identified as a national security issue.

OPEN STANDARDS : AN ANALOGY

Discussing Open RAN in context gets very confusing and mired in technical terms, so let’s go through an analogy.

Think of a systems integrator as a wedding planner. There are lots of interrelating aspects to worry about. The number of guests affects the size of the venue, which caterer you use will depend on which venues they work with. The venue having a dance floor or not may mean you do or don’t have a band. Does the venue have its own lighting and AV or do you need to contract that in.

Now imagine there are only two suppliers to the wedding market. Let’s call them Ericia and Nokasson. The planner has to choose between one or the other. There is still a lot of work to do in terms of what size of table to order, which items to select from their menu, but ultimately all the spend is going with them.

They are good. Top class caterers, they buy only the best ingredients, their florists do the most amazing displays and their covers band sounds like it has Aretha Fraklin on vocals, Eric Clapton on guitar and Ringo Star on the drums. But they are expensive. Not only are they premium products, the lack of price competition is reflected in their margins.

Nipping into the mobile phone world for a moment, Ericsson’s 2021 Gross margin was 43.4%. and Nokia’s 2021 Gross margin 39.8%, both figures from their respective annual reports. Without going into details one 4G deployment was quoted £8m for an upgrade to 5G from a high risk vendor, and £72m by one of the Scandinavians.

So back to the analogy. What the wedding planner wants is some openness. The ability to use a different florist perhaps. Ericia will say, “yes you could do that, but there is no guarantee the flowers will fit in the vases, you can bring your own vases but we’ll charge to put them on the tables”.

Nokasson will say, “yes you could do that but if the arrangements burn on our candles or the flowers get pollen on the bride’s dress, we won’t take responsibility”.

With each of the parameters it’s just too hard to make the main vendor cooperate. So what if there were standards for all the bits that had to work together? All the tables were from a set of standard sizes, all the candles a set height. There were set menus which allowed from Kosher gluten intolerant to keto lactose free.

All bands have parameters for their playlists, and set options for their number of musicians. All venues have standard procedures for delivery and tear down. In this scenario Ericia and Nokasson have no excuse not to work with whoever the planner chooses. It guaranteed to work with everything else. What is more, the choice means there is more variety and the costs come down. This is the promise of Open S tandards.

The wedding organiser can send out the same standard to all the florists, another to the caterers and another to the bands each asking for the same flowers, food and music.

What comes back are directly comparable quotes. But there are downsides. It has a cost overhead. Making sure that all the things each supplier does not only works but does so to a number of limited parameters that may or may not be required builds in cost. If the rules say a meal must have a proportion of roughage and fibre, a certain number of calories and limits on salt, that means not only must the caterer comply, it needs to be measured to ensure that it does. It’s very possible that no-one else involved in the wedding cares about the nutritional value but they all need to be assessed.

Even when the whole event was bought from one supplier there may be instances where the tablecloths don’t fit the tables, perhaps because a measurement in metres became confused with yards. In the single supplier scenario, the organiser only has one person to shout at. In the multiple supplier scenario, the linen supplier blames the table supplier and vice versa.

This can be addressed by being rigorous in the definition of the terms the wedding planner uses in the standard forms that are set out. Tablecloths all must be of a defined material, with set diameter, finish, elasticity, hem, and gather. This is applied to every aspect of the event.

The consequence of this is that it stifles innovation. It becomes impossible for anyone to invent the hexagonal table. To do so would be incompatible with the table planning software, with the linen and the transport. In an industry like weddings which has been around for millennia this is a problem, but a wedding today is still pretty much like the one your grandparents had. Mobile networks evolve with each release, in general there are seven releases to each “G”, so 5G will see seven major changes in the decade before it becomes 6G.

To hamper innovation in the evolving world of telecoms is a mistake. The guidelines say “that to achieve interoperability the open interfaces between parts must be standardised. Failure to do so will inevitably lead to the proliferation of proprietary extensions. This will in turn lead to the formation of end-to-end solutions by one vendor, or coalitions of partnered vendors, effectively re-aggregating the RAN into a single ‘black box’ once again.” www.IOTAS

In the world of standards what often happens is that an extension that is outside the specification later becomes adopted as part of the standard.

There are also security implications. Imagine that the wedding is for a famous couple. Given that a tabloid journalist has admitted to dressing up with a photographer in a horse costume to gatecrash a celebrity wedding it’s clearly important that you keep tabs on who is involved. With a sole supplier, especially one that is on the hook for the whole contract, it’s much easier to ensure that all the staff are trustworthy. Once you introduce more suppliers you have to do the security checking much more vigilantly.

There is a valid argument that by being more open it’s easier for security researchers to check, but it becomes more necessary because there is more opportunity for something untoward to happen.

A move to Open RAN isn’t without problems. It will take a lot of development That slows deployment and work on new features for 5G. It does add to the bill of materials for equipment, and have security implications, but if the alternative is a choice of two suppliers who control the future development and price that’s not a world we want to live in. It would be bad enough for weddings. As part of a critical national infrastructure, it’s not one we can afford to live in.

Open RAN and supporting a British supply chain is the best solution to a position we didn’t want to be in. Having the backing of government, operators and the new generation of vendors is essential to our getting to a position where there is choice, innovation and security.