Deutsche Telekom finally reveals details of its fixed network upgrades

Deutsche Telekom (DT) is heavily involved in open source groups such as the Open Networking Foundation (ONF), the Telecom Infra Project and some Linux Foundation open source projects. Yet, when it comes to talking about its internal work to upgrade its own network, DT has been decidedly closed-lipped.

The service provider recently opened up about its network transformation, which it calls Access 4.0. The company said that it is focusing on its fixed-line network for fiber-to-the-home and fiber-to-the-basement. Apparently, the company still has a lot of copper connections in the last mile, and DT didn’t say anything about its plans to lay more fiber. But the 4.0 upgrades will impact access-relevant hardware and broadband network gateway (BNG) functions in central offices.

Considering that these networks currently use Juniper Networks’ BNG solutions, that vendor could be under some threat of lost business.

“It’s not that we want to walk away from Juniper, but the focus is on having a more open, more flexible solution,” said Robert Soukup, DT’s senior program manager for Access 4.0, in an interview with FierceTelecom.

Juniper Networks declined to comment for this story. But the company has reported reduced revenues in its service provider business on recent earnings calls.

Soukup said DT first began thinking about upgrading its fixed networks a few years ago with the initial motivation to save money. DT, like many service providers, is not thrilled with the traditional pricing model of telecom equipment where prices seem arbitrarily set on price lists. Vendors will often give steep discounts off the price list, “so you can feel good,” said Soukup. But DT wants to pay prices that are directly related to the bill of materials and development and labor costs.

Access 4.0

For Access 4.0, DT is leaning on its work with the central office re-architected as a data center (CORD) open source projects. The service provider plans to deploy mini data centers at about 1,000 existing locations in Germany where it currently hosts BNG equipment.

“We have those locations, said Soukup. “The room is there, but we need to bring in the technology. Today we use the BNGs. The idea is to put those data centers next to the BNGs. A rollout will happen gradually beginning in 2020.”

DT has called out two vendors that are helping it with its Access 4.0 project: RtBrick and Reply. It is working with these vendors in conjunction with open source software from the CORD projects. DT is customizing CORD software for Access 4.0, adapting it for its specific needs.

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The basic idea behind CORD is to replace legacy, proprietary equipment at telco central offices with more generic hardware that can run open source software. As the acronym said, the idea is to “re-architect the central office as a data center.” CORD is one attempt by telcos to emulate the data centers created by webscale companies such as Google and Amazon.

“The whole story is about disaggregation of hardware and software,” said Soukup. “We take bare metal boxes and put our own software on it with an abstraction layer.” DT is using bare metal switches that are Open Compute Project (OCP)– compliant. "RtBrick brings a piece of software that sits on the switches," he said. "They have built a software that can program Broadcom chips, so they do the full BNG function.”

DT is also working with Reply to develop the control and management software for the mini data centers. And for the software-defined networking (SDN) element, DT has its own SDN controller. The company is also using the open source VOLTHA software for the optical line terminals. VOLTHA is another project of the ONF.


DT is working closely with the ONF along with other operators that have expressed frustration with traditional vendors whom they consider are dragging their feet on network virtualization. Some of these operators include AT&T, China Unicom, Comcast, and Telefonica.

The operators are working with the ONF on a strategic plan that includes modular reference designs to solve specific network problems. The reference designs embrace merchant silicon and white boxes. And the ONF’s strategy is also designed to encourage vendors to get involved in key areas of the supply chain that relate to the reference designs.

RELATED: ONF operators push reference designs out for membership review

Juniper Networks is a partner involved with the ONF’s strategic planning group. And Soukup said, DT and Juniper “are exchanging on Access 4.0,” and he said, “we see a change in the business model.”

Beyond Fixed Networks

Although Deutsche Telekom is initially upgrading its fixed-line network via the Access 4.0 program, the platform will be technically ready to power other applications such as edge compute, 5G backhaul and content caching or IoT. Eventually, the mini data centers could play into DT’s mobile offerings as well.

Soukup said if the fixed-line network upgrade is successful, then DT’s top executives will probably be open to doing more with it. “Looking at the topology of DT in Germany, you could also bring the mobile traffic on it,” he said.