How Rakuten Mobile corralled vendors for its open RAN vision

Assembling a greenfield mobile network with commoditized hardware surrounded by a moat of software from at least 10 vendors was an uphill climb for Rakuten Mobile. Complexities were abundant and corralling vendors for a virtualized, cloud-native, open radio access (RAN) network required intensive work that other mobile operators haven’t pursued yet. Especially at this level.

“We at Rakuten had to play a significant role in software development,” Tareq Amin, group EVP and chief architecture officer, told SDxCentral in a phone interview. “We had to build the entire apparatus of automation to pull this piece together. Had we not done this, I’ll be very honest with you, there was nothing off the shelf you could buy and say ‘go make this happen,’ it will not work.”

Early on, Amin realized that he and his colleagues would “have to become the glue and the system integrator for everybody. If you leave this only to the existing vendors and incumbents, I don’t think this will ever work,” he said.

“Despite how much discussion and how much excitement had happened around VNF (virtual network function) architecture, the truth and reality at least from our experience was it feels to me that this is the first time all these vendors are doing this at scale,” Amin said.”I’m seeing some rudimentary mistakes, some rudimentary architectural gaps that made it difficult had we not intervened and built the right software platform to orchestrate these 188 unique VNFs over now 6,000 virtual machines (VM), and make the elasticity auto-healing work together.”

Rakuten Mobile Pushes RAN Leaders to Open Up

Heading into this project, Amin was confident that industry forums and standards bodies were progressing sufficiently, but “the gaps were much bigger than I anticipated,” he said. With no end-to-end deployment at scale like this to date, Rakuten Mobile couldn’t simply turn to one of its vendors and thus had to “spend a considerable amount of energy” building its software and orchestrating its operations support systems (OSS).

In addition to that effort, Amin and his colleagues successfully convinced Nokia to open up its optical networking and radio equipment for an open RAN. He described it as “an extremely complex ask” it made to Nokia, but he framed it as a path for the vendor to make more revenue than it could by selling closed, proprietary systems.

“This was not a simple decision for them to take this play, but I have given them an unbelievable revenue opportunity. I said ‘look, if you open your interface for your remote radio heads, I am willing to outsource to you all our build-out construction for phase one and project management,’ which was by the way a substantial amount of revenue potential,” Amin said.

Nokia could and Amin is rooting for it to replicate that approach across the world. “They will be 10-times more profitable if they replicate just the business model [and] the engagement strategy,” he said.

Earning that goodwill with Amin also enabled Nokia to win some business beyond its initial scope, including backbone infrastructure and IoT. “The more that they show me that they’re open, I have no problem to work with them,” he said. “I think these traditional vendors need to examine and need to get, in my opinion, over this idea that they will lose a lot of money.”

Heavy Lifting Required for Containers

The experience gained building a completely cloud-native network also enriched Amin’s aspirations for containers and the opportunities that operators can achieve in that environment. “It is amazingly super exciting that every workload today is really resembling what IT companies have enjoyed and webscale companies have enjoyed for more than a decade now,” he said

The benefits of containers go beyond reduced capex, he explained, adding that Rakuten Mobile can instantiate workloads in less than nine minutes. By designing a network where macro base stations act, behave, and operate like WiFi — mostly a plug-and-play operation — Rakuten Mobile has achieved its goals with no field technicians.

“I only have site reliability engineers [and] their only job is building the automation apparatus that is required to instantiate these VMs, enrich them with configuration, but that’s all done autonomously through our OSS and orchestration,” Amin said.

“In the radio domain, unfortunately this has been a very complex thing. It requires field technicians, it requires engineers. You send them to the field and the process of turning up a site could be anywhere from a day to three days,” he said. Nonetheless, he describes end-to-end orchestration as a “daunting challenge” and notes that the biggest weakness in virtualization today is the “harmonization and the orchestration of unique VNFs to achieve common objectives for healing and elasticity.”

But because Docker containers cannot address the gaps Rakuten Mobile confronted, it had to orchestrate its unique VNFs across the network itself and that work is “not trivial,” Amin explained. Virtualization does not achieve the same merits as cloud-native architecture, he said.

Telco-Grade Requirements Still Lacking in Open Source

While Docker containers provide some “elegance” for microservices, software architecture, and active configuration across multiple data centers, an operator cannot simply take an open source Docker container and move the workloads of virtualization to containers. “This requires a fundamental re-architecture on the software code,” he said. “The containers architecture platform itself needs to be enriched with telco-grade requirements,” such as support for IPv6 and service meshing.

“All these features were lagging behind,” Amin said. “They’re all available in the open source community but nobody wanted to push them and package them as part of the main branch of containers, so we’ve done that” in partnership with multiple vendors.

The technologies underpinning Rakuten Mobile’s network have also fostered a security apparatus and framework that provides a level of visibility from the IP layer to the core and support systems, according to Amin. That provides “a little bit of comfort” about the clarity of the entire packet as it transfers from radios to the network core, he said.

Rakuten Mobile has also adhered to a zero-trust philosophy around security in every aspect of the construction of its network, including supply chain management, and security protocols run by software in the cloud, Amin explained. “There’s a lot of also very good hardening that we have done on the security part,” and Rakuten Mobile is ultimately the owner of that security apparatus.

―SDX Central