Verizon has sent a 400 Gigabit Ethernet signal over its network, carried using a 400-gigabit optical wavelength.
The trial’s goal was to demonstrate multi-vendor interoperability and in particular the interoperability of standardised 400 Gigabit Ethernet (GbE) client signals.
Glenn Wellbrock“[400GbE] Interoperability with the client side has been the long pole in the tent - and continues to be,” says Glenn Wellbrock, director, optical transport network - architecture, design and planning at Verizon. “This was trial equipment, not generally-available equipment.”
It is only the emergence of standardised modules - in this case, an IEEE 400GbE client-side interface specification - that allows multi-vendor interoperability, he says.
By trialing a 400-gigabit lightpath, Verizon also demonstrated the working of a dense wavelength-division multiplexing (DWDM) flexible grid, and a baud rate nearly double the 32-35Gbaud in wide use for 100-gigabit and 200-gigabit wavelengths.
“It shows we can take advantage of the entire system; we don’t have to stick to 50GHz channel spacing anymore,” says Wellbrock.
[400GbE] Interoperability with the client side has been the long pole in the tent - and continues to be
Trial set-up
The trial used Juniper Networks’ PTX5000 packet transport router and Ciena’s 6500 packet-optical platform, equipment already deployed in Verizon’s network.
The Verizon demonstration was not testing optical transmission reach. Indeed the equipment was located in two buildings in Richardson, within the Dallas area. Testing the reach of 400-gigabit wavelengths will come in future trials, says Wellbrock.
The PTX5000 core router has a traffic capacity of up to 24 terabits and supports 10-gigabit, 40-gigabit and 100-gigabit client-side interfaces as well as 100-gigabit coherent interfaces for IP-over-DWDM applications. The PTX5000 uses a mother card on which sits one or more daughter cards hosting the interfaces, what Juniper calls a flexible PIC concentrator (FPC) and physical interface cards (PICs), respectively.
Juniper created a PIC with a 400GbE CFP8 pluggable module implementing the IEEE’s 10km 400GBASE-LR8 standard.
“For us, it was simply creating a demo 400-gigabit pluggable line card to go into the line card Verizon has already deployed,” says Donyel Jones-Williams, director of product marketing management at Juniper Networks.
Donyel Jones-WilliamsThe CFP8 400GbE interface connected the router to Ciena’s 6500 packet-optical platform.
Ciena also used demonstration hardware developed for 400-gigabit trials. “We expect to develop other hardware for general deployment,” says Helen Xenos, senior director, portfolio marketing at Ciena. “We are looking at smaller form-factor pluggables to carry 400 Gigabit Ethernet.”
400-gigabit deployments and trials
Ciena started shipping its WaveLogic Ai coherent modem that implements 400-gigabit wavelengths in the third quarter of 2017. Since then, the company has announced several 400-gigabit deployments and trials.
Vodafone New Zealand deployed 400 gigabits in its national transport network last September, a world first, claims Ciena. German cable operator, Unitymedia, has also deployed Ciena’s WaveLogic Ai coherent modem to deliver a flexible grid and 400-gigabit wavelengths to support growing content delivered via its data centres. And JISC, which runs the UK’s national research and education network, has deployed the 6500 platform and is using 400-gigabit wavelengths.
Helen Xenos
Last September, AT&T conducted its own 400-gigabit trial with Ciena. With AT&T’s trial, the 400-gigabit signal was generated using a test bed. “An SDN controller was used to provision the circuit and the [400-gigabit] signal traversed an OpenROADM line system,” says Xenos.
Using the WaveLogic Ai coherent modem and its support for a 56Gbaud rate means that tunable capacity can now be doubled across applications, says Xenos. The wavelength capacity used for long-haul distances can now be 200 gigabits instead of 100 gigabits, while metro-regional networks spanning 1,000km can use 300-gigabit wavelengths. Meanwhile, 400-gigabit lightpaths suit distances of several hundred kilometres.
It is the large data centre operators that are driving the majority of 400 gigabit deployments, says Ciena. The reason the 400-gigabit announcements relate to telecom operators is because the data centre players have not gone public with their deployments, says Xenos.
Juniper Networks’ PTX5000 core router with 400GbE interfaces will primarily be used by the telecom operators. “We are in trials with other providers on 400 gigabits,” says Jones-Williams. “Nothing is public as yet.”