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22 November 2019

Telefónica follows AT&T, bringing white boxes to cell site gateways

While Vodafone and OpenRAN dominated the big news at the Telecom Infra Project (TIP) Summit last week, Telefónica was once again in the spotlight too, this time driving forward TIP’s other commercially mature solution, DCSG (Distributed Cell Site Gateway).

The Spanish group will deploy DCSG commercially “at scale” in Germany and also in Ecuador, it said. This will be valuable in building vendor and operator confidence in the DCSG specs, as will new lab trials for the platform, with India’s Bharti Airtel, South Africa’s MTN, TIM Brasil and Vodafone. Vodafone, Orange and TIM Brasil also plan to announce a joint Request for Information (RFI) to assess what the vendors, new and old, can offer in compliance with the new specs.

The DCSG project is important because it highlights that TIP is not just about the RAN but that it is seeking to drive open disaggregation and commoditized hardware in all network domains.

Telefónica’s head of R&D, and TIP board member, David del Val Latorre, said: “The whole value chain, the whole technology stack of telcos needs innovation … in access, transport, operations and support … I think we need to continue working for a few years until we have this ambition of a fully disaggregated network from end to end where innovation really happens at the speed it is happening in other areas of computing or elsewhere in the Internet.”

The DCSG project was kicked off at the TIP Summit last year within the Open Optical & Packet Transport (OOPT) project group, and quickly produced specs for an open white box gateway which can be deployed in current networks while including the port speeds and density that 5G will require.

The DCSG gateways being used by Telefónica were  developed via a collaboration between TIP, Infinera and Edgecore Networks and this is the first large-scale live roll-out.

A cell site gateway is a router that is located near the cell site to support various functions for 4G and 5G base stations, including time synchronization, and routing Internet packets between the base stations and the packet core for backhaul.

More vendors line up behind DCSG and Odyssey:

The specific design that Telefónica is deploying is a 100G version of a DCSG design called Odyssey, supplied by Edgecore and running Infinera’s Converged Network Operating System (this is not open source, highlighting the hybrid nature of TIP’s licensing processes, which do not insist on full open sourcing). Telefónica has also specified a 10G version of Odyssey.

Odyssey-DCSG was the first result of the DCSG working group, and promises to support open operations and management (O&M) approaches in order to allow MNOs greater freedom to select different technologies for each layer of the stack. Edgecore contributed the hardware design of the cell site gateway to TIP and it is being adopted by various software partners such as Infinera, Volta and ADVA.

The platform is becoming more multivendor. For the software, ADVA and IP Infusion have been approved to provide network operating system code, while Volta Networks has been chosen for its cloud-native routing engine. As well as Edgecore, two other Taiwanese vendors are producing hardware – Alpha Networks and Delta Electronics – and of course, the Taiwanese electronics manufacturing ecosystem is always critical to scaling up products to mass market.

At the show, Altran announced its own DCSG offering, a combination of its Intelligent Switching Solution (ISS) software framework and network OS, with a DCSG white box based on Edgecore’s AS731x, which is powered by Broadcom StrataDNX Qumran-AX.

Earlier this year, two vendors – Aviat and Metaswitch – cooperated to develop a product based on DCSG specs, using Aviat’s network operating system, AOS, and a routing stack and network operating system toolkit from Metaswitch, an early pioneer in virtualized networks including the core. The combination of software runs on hardware which conforms with the TIP specs.

And Edgecore has also worked with Volta on an open virtualized cell site gateway, running Volta’s cloud-native virtual routing software, the Elastic Virtual Routing Engine (VEVRE), on Edgecore’s AS7316-26XB cell site gateway switch.

Telefónica’s initial roll-out will be just “a handful” of white box routers in each country and then, if all goes well, the deployment will be scaled up and could be extended to other markets.

AT&T has its own gateway project, but with OCP:

It will take some time before it gets to the scale envisaged by AT&T for its own open cell site gateway/router, which it aims to deploy in about 60,000 sites. This white box product has also been submitted to a Facebook-initiated group, but to the Open Compute Project (OCP) rather than TIP.

In line with other discussions about TIP’s relationship to other open groups, TIP chairman Axel Clauberg said that the DCSG was aligned with similar work on cell site equipment, being undertaken at the OCP. Like TIP, OCP was initially founded by Facebook to drive the development of an open, white box cloud platform, and last year, AT&T submitted its specs for a white-box cell site router to this group. The US carrier is now deploying products based on this design in its commercial transport network.

Clauberg told FierceWireless that TIP had decided to develop its own specs, while staying aligned with OCP, because TIP members had some specific requirements. “When you look at the Edgecore product, that is something that is accepted by OCP and used in TIP,” he said. “We did everything possible to align with the OCP working group and the OOPT group within TIP. Nevertheless, our members, for example Vodafone, had separate requirements that were not 100% aligned with the AT&T spec.”

AT&T’s reference design runs its own network operating system, dNOS, which has also been placed in open source via the Linux Foundation’s DANOS project. The US telco aims to replace all its current cell site routers (it has 60,000 towers and 5,000 central offices). Any supplier wanting to be part of that roll-out will have to conform to the specs, which will enable AT&T to source boxes from multiple suppliers, choosing the cheapest or most innovative, while ensuring interoperability.

If the design is taken up by other OCP members, the scale of the ecosystem, and the consequent price competition, could be very significant. AT&T’s reference design can be used as a guideline by any hardware vendor, though it currently has to be based on a specific chip (the Broadcom Qumran-AX switch-chip). Submitting it to OCP should encourage more suppliers to rise to that challenge (and other chips might follow in future). The gateway router design is supposed to support current and future cellular backhaul systems, being future-proof to some extent, by embracing a wide range of speeds on the client side, including 5G baseband units operating at 10G/25G and backhaul speeds up to 100Gbps.

Meanwhile, Telefónica said it went through a request for proposal (RFP) process before deciding on a white box approach, and studied submissions from traditional router vendors too, but went for the flexibility and low cost of a disaggregated, multivendor solution.

Others may follow – BT, Orange, TIM Brasil and Vodafone have been working to develop the DCSG blueprints, and MTN and Airtel have adopted the platform for trials.

The next TIP-based open hardware to come to commercial availability is likely to be the  OOPT group’s Cassini packet/optical transponder unit, which has been in field trials with Telefónica and NTT, and even deployed in a live network by Japanese specialist operator Mixi. Another important project in the OOPT transport network environment is the Apollo optical transponder.