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9 March 2021

KDDI takes open cell site gateways a step forward with Mongolia trial

While the RAN gets the highest profile in the open cellular networking sector, the end goal of the Telecom Infra Project (TIP) is a platform that is open and disaggregated from end to end, driving cloud economics into all elements of 4G or 5G. It has several major projects focused on the transport network, under the auspices of its OOPT (Open Optical and Packet Transport) group.

One of the projects within that area of activity is to develop an open platform for a disaggregated cell site gateway (DCSG), and KDDI of Japan has emerged as an early triallist. It will run an interoperability test for a TIP DCSG together with multivendor aggregation, RAN and core equipment.

The initial interoperability tests will be between DCSG equipment housed in KDDI’s TIP Community Lab in Japan, and transport and core equipment outside that Lab, run by Mongolian operator MobiCom. The partners will assess the feasibility of a 5G end-to-end network that can support several combinations of hardware and software from different vendors.

The TIP DCSG provides a reference design for a white box cell site gateway, which can support 3G, 4G and 5G networks. It was trialled first by Telefónica O2 Germany in 2019, working with equipment from Infinera and Edgecore to enable IP/MPLS functionality for gateways, and to connect multiple gateways within a unified routing framework. That enabled the operator to double node capacity.

Other operators, such as Vodafone, MTN, Bharti Airtel and Telefónica Ecuador, have subsequently trialled systems based on DCSG, and Vodafone, Orange and TIM Brasil have prepared a joint RFI for this technology, to assess what the vendors, new and old, can offer in compliance with the new specs. Telefónica has 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.

But KDDI takes the work a step further by conducting interoperability tests with a second operator.

“TIP sees the trials of the DCSG and aggregation transport equipment … as a significant step toward the introduction of open and disaggregated network solutions,” noted TIP’s chief enginee, David Hutton, in a statement. “The DCSG and TIP’s OOPT solutions will help to provide the capacity within the transport network required to make 5G a success in satisfying the requirements of consumers, operators, and enterprises.”

There has been considerable vendor activity around DCSG in the past year or so. In October, ADVA announced general availability of its Ensemble Activator, a network operating system (NOS) specifically designed for these gateways and developed under the auspices of TIP.

Two vendors, Aviat and Microsoft-owned Metaswitch, have cooperated to develop a product based on TIP DCSG requirements. The gateway uses 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.

Two other partners, Volta Networks and Edgecore Networks, are also working on an open, virtualized cell site gateway. Volta’s cloud-native virtual routing software, the Elastic Virtual Routing Engine (VEVRE), has now been implemented on Edgecore’s AS7316-26XB open cell site gateway switch.

ADVA has also been working with Edgecore on a product called Odyssey-DCSG (used in the Telefónica Ecuador deployment). As well as the NOS, this supports 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 now part of ADVA’s integrated solution.

A year ago, OOPT added a new project, focused on Disaggregated Open Routers (DOR). That bid to enable open IP/MPLS routers is led by KDDI and Vodafone, with vendor support from ADVA, Delta, Edgecore Networks, Exaware, Infinera, Ufispace and Volta Networks, many of which are also participating in other OOPT initiatives.

Some of the DCSG work appears to overlap with efforts led by AT&T, which were placed into the open community via Facebook’s other cloud platform initiative, the Open Compute Project (OCP), rather than TIP. AT&T has developed its own white box cell site gateway/router and accompanying network operating system, which it aims to deploy in about 60,000 sites.

Although its own roll-out is based on its internal design, it has submitted the white box design to the OCP, and the NOS to the Linux Foundation, where it sits in the DANOS project.

TIP says its own DCSG will be aligned with the work of other groups such as OCP. Former chair Axel Clauberg said in 2019 that TIP had decided to develop its own specs, 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.”