COBO brings operational benefits to the data centre

Brad Booth admits the hyperscalers have a problem.

“Our operational inefficiencies are massive and it is only going to get worse,” says Booth, principal network architect for Microsoft’s Azure Infrastructure and chair of the Consortium for On-Board Optics (COBO).

The COBO-enabled 12.8-terabit demonstrator switch. Source: COBO

The issue, he says, is that when a switch arrives at the data centre, it comes without the optics installed. The operations staff must unpack the optical modules, plug them into the switch and verify that each is working; an exercise that is repeated thousands of times when they commission a new data centre.

“The time it takes for us to get the network up and running impacts how quickly we can monetise the data centre,” says Booth.

Click to read more ...

Lumentum completes sale of certain datacom lines to CIG

Brandon Collings, CTO of Lumentum, talks CIG, 400ZR and 400ZR+, COBO, co-packaged optics and why silicon photonics is not going to change the world.

Lumentum has completed the sale of part of its datacom product lines to design and manufacturing company, Cambridge Industries Group. 

The sale will lower the company's quarterly revenues by between $20 million to $25 million. Lumentum also said that it will stop selling datacom transceivers in the next year to 18 months.

Brandon CollingsThe move highlights how fierce competition and diminishing margins from the sale of client-side modules is causing optical component companies to rethink their strategies.

Lumentum’s focus is now to supply its photonic chips to the module makers, including CIG. “From a value-add point of view, there is a lot more value in selling those chips than the modules,” says Brandon Collings, CTO of Lumentum.

Click to read more ...

Switch chips not optics set the pace in the data centre

Broadcom is doubling the capacity of its switch silicon every 18-24 months, a considerable achievement given that Moore’s law has slowed down. 

Last December, Broadcom announced it was sampling its Tomahawk 3 - the industry’s first 12.8-terabit switch chip - just 14 months after it announced its 6.4-terabit Tomahawk 2.

Rochan SankarSuch product cycle times are proving beyond the optical module makers; if producing next-generation switch silicon is taking up to two years, optics is taking three, says Broadcom. 

“Right now, the problem with optics is that they are the laggards,” says Rochan Sankar, senior director of product marketing at switch IC maker, Broadcom. “The switching side is waiting for the optics to be deployable.”

The consequence, says Broadcom, is that in the three years spanning a particular optical module generation, customers have deployed two generations of switches. For example, the 3.2-terabit Tomahawk based switches and the higher-capacity Tomahawk 2 ones both use QSFP28 and SFP28 modules. 

In future, a closer alignment in the development cycles of the chip and the optics will be required, argues Broadcom.

Click to read more ...

400ZR will signal coherent’s entry into the datacom world

• 400ZR will have a reach of 80km and a target power consumption of 15W 
• The coherent interface will be available as a pluggable module that will link data-centre switches across sites    
• Huawei expects first modules to be available in the first half of 2020
• At OFC, Huawei announced its own 250km 400-gigabit single-wavelength coherent solution that is already being shipped to customers

Coherent optics will finally cross over into datacom with the advent of the 400ZR interface.  So claims Maxim Kuschnerov, senior R&D manager at Huawei.

Maxim Kuschnerov400ZR is an interoperable 400-gigabit single-wavelength coherent interface being developed by the Optical Internetworking Forum (OIF) {add link}.

The 400ZR will be available as a pluggable module and as on-board optics using the COBO specification {add link}. The IEEE is also considering a proposal to adopt the 400ZR specification, initially for the data-centre interconnect market. “Once coherent moves from the OIF to the IEEE, its impact in the marketplace will be multiplied,” says Kuschnerov. 

But developing a 400ZR pluggable represents a significant challenge for the industry. “Such interoperable coherent 16-QAM modules won’t happen easily,” says Kuschnerov. “Just look at the efforts of the industry to have PAM-4 interoperability, it is a tremendous step up from on-off keying.” 

Despite the challenges, 400ZR products are expected by the first half of 2020.

Click to read more ...

Rockley Photonics showcases its in-packaged design at OFC

Rockley Photonics has showcased its in-packaged optics design to select customers and development partners at the OFC show being held in San Diego this week.

The packaged design includes Rockley's own 2 billion transistor layer 3 router chip, and its silicon photonics-based optical transceivers. The layer 3 router chip, described as a terabit device, also includes mixed-signal circuits needed for the optical transceevers' transmit and receive paths.

 Source: Rockley Photonics (annotated by Gazettabyte).Rockley says it is using 500m-reach PSM4 transceivers for the design and that while a dozen ribbon cables are shown, this does not mean there are 12 100-gigabit PSM4 transceivers. The company is not saying what the total optical input-output is. 

Click to read more ...

New MSA to enable four-lambda 400-gigabit modules

A new 100-gigabit single-wavelength multi-source agreement (MSA) has been created to provide the industry with 2km and 10km 100-gigabit and 400-gigabit four-wavelength interfaces.

Mark NowellThe MSA is backed by 22 founding companies including Microsoft, Alibaba and Cisco Systems.

The initiative started work two months ago and a draft specification is expected before the year end.

“Twenty-two companies is a very large MSA at this stage, which shows the strong interest in this technology,” says Mark Nowell, distinguished engineer, data centre switching at Cisco Systems and co-chair of the 100G Lambda MSA. “It is clear this is going to be the workhorse technology for the industry for quite a while.”

Click to read more ...

COBO targets year-end to complete specification

Part 3: 400-gigabit on-board optics

• COBO will support 400-gigabit and 800-gigabit interfaces 
• Three classes of module have been defined, the largest supporting at least 17.5W 

The Consortium for On-board Optics (COBO) is scheduled to complete its module specification this year.

A draft specification defining the mechanical aspects of the embedded optics - the dimensions, connector and electrical interface - is already being reviewed by the consortium’s members.

Brad Booth“The draft specification encompasses what we will do inside the data centre and what will work for the coherent market,” says Brad Booth, chair of COBO and principal network architect for Microsoft’s Azure Infrastructure.

COBO was established in 2015 to create an embedded optics multi-source agreement (MSA). On-board optics have long been available but until now these have been proprietary solutions. 

“Our goal [with COBO] was to get past that proprietary aspect,” says Booth. “That is its true value - it can be used for optical backplane or for optical interconnect and now designers will have a standard to build to.” 

Click to read more ...