DT chooses Nokia for a major optical network upgrade

Deutsche Telekom is redesigning its domestic optical network and has chosen Nokia as its equipment supplier.

“They are re-architecting and rolling out, in a short time, a huge portion of their optical network,” says Kyle Hollasch, (pictured) director of optical portfolio marketing, Nokia. “We are displacing in many parts of the network four different vendors.”

Network architecture

Deutsche Telekom’s legacy mesh-based wavelength-division multiplexing (WDM) network uses equipment from several vendors. In the last decade, Deutsche Telekom also added to the core an IP-optical solution from Cisco Systems.

Now, the CSP is replacing the mesh-WDM network and the Cisco IP-optical core with an OTN-WDM core from Nokia.

“They are unifying their traffic from all of their business services, government services, 5G anyhaul and the core IP network onto one core WDM network,” says Hollasch. 

The pandemic made obvious that government was not prepared in terms of their WAN connectivity while businesses are re-evaluating the connectivity requirements they have, he says.

Nokia is the key vendor supplying the OTN-WDM core and ‘close-to-sole-vendor’ for some 900 aggregation sites.

Sitting between the core and the 900 sites are regional horseshoes: open WDM rings that collect traffic from the aggregation sites and passed to the core.

“That is yet to be awarded and we hope to have a portion with another vendor at a later phase of the project,” says Hollasch.

The deployment provides an end-to-end OTN network that offers diverse path, 50-millisecond protection and guaranteed bandwidth. “That is something government and businesses require and that wasn’t easily possible on the existing legacy infrastructure,” he says.

Deployment will start in the second half of this year.

Equipment

Nokia is supplying various chassis from its 1830 Photonic Service Switch (PSS) portfolio that use its PSE-V coherent digital signal processor (DSP) technology and it is also providing its WaveSuite and WaveHub software.

“In the core, it is what you’d expect: it’s scalable WDM with the PSE-V transponders and muxponders, and CDC-F (colourless, directionless, contentionless with flexible grid) multi-degree ROADMs (reconfigurable optical add-drop multiplexers),” says Hollasch.

 “It is all about 400 Gigabit Ethernet (GbE) so they can use combinations of the high-end PSE-Vs [super coherent DSP] and we can do 600-gigabit wavelengths anywhere in the country,” he says, enabling combinations of 400GbE and 100-gigabit wavelengths.

For the metro regional, Nokia offers pluggable solutions using its PSE-Vc Compact DSP in a CFP2-DCO pluggable module.

OTN will be supported by Nokia’s 1830 PSS 24x, 12x and 8x platforms, depending on the location in the network. “That platform is largely used in the 900 aggregation sites,” says Hollasch. “For these 900 sites, one of our OTN boxes has 3 terabits of capacity.”

A further Nokia product is the 1830 PSD (photonic service demarcation), a 10-gigabit network interface device (NID) that is the size of a hardback book.

“It can be an OTN NID or an Ethernet NID,” says Hollasch. “That is part of our end-to-end business services solution; they can use that at customer locations.” Nokia also has a product for 100-gigabit demarcation.

WaveSuite and WaveHub software

Nokia is providing what it calls its “digital twin” service which allows real-time simulation of complex networks and preparation for the end-to-end management and control of the network. This software is part of Nokia’s WaveHub ecosystem programme.

“One example of what Deutsche Telekom can do with it is third-party integration with open APIs (application programming interfaces) into a digital twin of their exact network,” says Hollasch. “So even before any box has shipped, they can start integrating ther multi-vendor end-to-end transport controller onto our gear.”

One element of Nokia’s WaveSuite software tools offered is the Commission Expert that simplifies the deployment of customer premise devices. Another component is Network Insight which uses telemetry data from the DSPs as input to machine learning techniques to manage optical wavelengths, make best use of network capacity and predict network failures.

“This [Network Insight] is a product that has almost become a selling point in any large core network,” says Hollasch.

Nokia offers its software to CSPs and points to the value it believes it adds. “But the table stakes are the APIs and being able to integrate to those,” says Hollasch.

Transition year

Nokia says 2021 is a transition year for the industry regarding the emergence of pluggable coherent modules: 400ZR, ZR+ and CFP2-DCOs.

“We need to see hardware in networks sending bits and we haven’t yet, except for small trials,” says Hollasch.

There will also be industry announcements regarding next-generation pluggables that will use 5nm CMOS DSPs and operate at a symbol rate of up to 130 gigabaud.

Such pluggables will send 800-gigabit wavelengths over longer distances and be able to transmit two 400GbE streams.

“400GbE will be the predominant interface for a long time; the IEEE doesn’t even know what the next Ethernet rate will be,” says Hollasch.