Peter Winzer highlights one particular slide, part of the operator-findings presentation, to explain the purpose of the Optical Networks 2020 (ON2020) group.
Source: ON2020
The slide shows how router-blade client interfaces are scaling at 40% annually compared to the 20% growth rate of general single-wavelength interfaces (see chart).
Extrapolating the trend to 2024, router blades will support 20 terabits while client interfaces will only be at one terabit. Each blade will thus require 20 one-terabit Ethernet interfaces. “That is science fiction if you go off today’s technology,” says Winzer, director of optical transmission subsystems research at Nokia Bell Labs and a member of the ON2020 steering committee.
This is where ON2020 comes in, he says, to flag up such disparities and focus industry efforts so they are addressed.
ON2020
Established in 2016, the companies driving ON2020 are Fujitsu, Huawei, Nokia, Finisar, and Lumentum.
The reference to 2020 signifies how the group looks ahead four to five years, while the name is also a play on 20/20 vision, says Brandon Collings, CTO of Lumentum and also a member of the steering committee.
Brandon CollingsON2020 addresses a void in the industry, says Collings. The Optical Internetworking Forum (OIF) organisation may have a similar conceptual mission but it is more hands-on, focussing on components and near-term implementations. ON2020 looks further out.
“Maybe you could argue it is a two-step process,” says Collings. “First, ON2020 is longer term followed by the OIF’s definition in the near term.”
To build a longer-term view, ON2020 surveyed network operators worldwide including the largest internet content providers players and leading communications service providers.
ON2020 reported its findings at the recent ECOC show under three broad headings: traffic growth and the impact on fibre capacity and interfaces, interconnect requirements, and network management and operations.
Things will have to get cheaper; that is the way things are.
Network management
One key survey finding is the importance network operators attach to software-defined networking (SDN) although the operators are frustrated with the lack of SDN solutions available, forcing them to work with vendors to address their needs.
Peter WinzerThe network operators also see value in white boxes and disaggregation, to lower hardware costs and avoid vendor lock-in. But as with SDN, there are challenges with white boxes and disaggregation.
“Let’s not forget that SDN comes from the big webscales,” says Winzer, companies with abundant software and control experience. Telecom companies don’t have such sophisticated resources.
“This produces a big conundrum for the telecom operators: they want to get the benefits without spending what the webscales are spending,” says Winzer. The telcos also need higher network reliability such that their job is even harder.
Responding to ON2020’s anonymous survey, the telecom players stress how SDN, disaggregation and the adoption of white boxes will require a change in practices and internal organisation and even the employment of system integrators.
“They are really honest. They say, nice, but we are just overwhelmed,” says Winzer. “It highlights the very important organisational challenges operators are facing.”
Operators are frustrated with the lack of SDN solutions available.
Capacity and connectivity
The webscales and telecom operators were also surveyed about capacity and connectivity issues.
Both classes of operator use 10-terabit links or more and this will soon rise to 40 terabits. The consensus is that the C-band alone is insufficient given their capacity needs.
Those operators with limited fibre want to grow capacity by also using the L-band with the C-band, while operators with plenty of fibre want to combine fibre pairs - a form of spatial division multiplexing - and using the C and L bands. The implication here is that there is an opportunity for hardware integration, says ON2020.
Network operators use backbone wavelengths at 100, 200 and 400 gigabits. As for service feeds - what ON2020 refers to as granularity - webscale players favour 25 gigabit-per-second (Gbps) whereas telecom operators continue to deal with much slower feeds - 10Mbps, 100Mbps, and 1Gbps.
What can ON2020 do to address the demanding client-interface requirements of IP router blades, referred to in the chart?
Xiang Liu, distinguished scientist, transmission product line at Huawei and a key instigator in the creation of ON2020, says photonic integration and a tighter coupling between photonics and CMOS will be essential to reduce the cost-per-bit and power-per-bit of future client interfaces.
Xiang Liu
“As the investment for developing routers with such throughputs could be unprecedentedly high, it makes sense for our industry to collectively define the specifications and interfaces,” says Liu. “ON2020 can facilitate such an industry-wide effort.”
Another survey finding is that network operators favour super-channels once client interfaces reach 400 gigabits and higher rates. Super-channels are more efficient in their use of the fibre’s spectrum while also delivering operations, administration, and management (OAM) benefits.
The network operators were also asked about their node connectivity needs. While they welcome the features of advanced reconfigurable optical add-drop multiplexers (ROADMs), they don’t necessarily need them all. A typical response being they will adopt such features if they are practically for free.
This, says Winzer, is typical of carriers. “Things will have to get cheaper; that is the way things are.”
Photonic integration and a tighter coupling between photonics and CMOS will be essential to reduce the cost-per-bit and power-per-bit of future client interfaces
Future plans
ON2020 is still seeking feedback from additional network operators, the survey questionnaire being availability for download on its website. “The more anonymous input we get, the better the results will be,” says Winzer.
Huawei’s Liu says the published findings are just the start of the group’s activities.
ON2020 will conduct in-depth studies on such topics as next-generation ROADM and optical cross-connects; transport SDN for resource optimisation and multi-vendor interoperability; 5G-oriented optical networking that delivers low latency, accurate synchronisation and network slicing; new wavelength-division multiplexing line rates beyond 200 gigabit; and optical link technologies beyond just the C-band and new fibre types.
ON2020 will publish a series of white papers to stimulate and guide the industry, says Liu.
The group also plans to provide input to standardisation organisations to enhance existing standards and start new ones, create proof-of-concept technology demonstrators, and enable multi-vendor interoperable tests and field trials.
Discussions have started for ON2020 to become an IEEE Industry Connections programme. “We don’t want this to be an exclusive club of five [companies],” says Winzer. “We want broad participation.”