The power of the open compute model for data center networking

For data centers, there’s an evolving need to increase the bandwidth over networks without needing to install more cable. Dense Wavelength Division Multiplexing (DWDM) has become the solution of choice for transporting large amounts of data efficiently between sites. DWDM can carry different data streams simultaneously over a single optical fiber, which helps optimize the existing network investment.

It’s an effective system, but it was designed primarily for large telco applications, not for data center networking. This means they tend to be large, complex, and vertically integrated platforms that are costly to own and operate, take up a significant amount of space, and require staff with levels of DWDM knowledge that wouldn’t otherwise be required within a data center. The scale, design and functionality of these centers can be designed in a way that is more efficient, cost-effective, and with a level of complexity that is appropriate for the non-telco scale.

In addition to size, there’s a more fundamental problem with traditional DWDM solutions, especially in the corporate and mega-data centers, and that’s the very rigid approach to data center networking. The telco systems require transponders to convert the output of the Ethernet and Fibre Channel switches to DWDM signals. These transponders are usually in the form of traffic dependent line cards. This means that for every individual Ethernet or Fibre Channel service, the system needs an individual line card that then takes the output of the switch and converts it to a DWDM signal. The user also needs to set up additional monitoring and control cards to perform various tasks on these traffic signals.

19” fixed DWDM Telco system with vertical plug in cards

Symmetrical networks limit the flexibility

There’s another limiting factor with these traditional transponder based DWDM solutions. They are typically restricted to symmetrical network architectures, which means that two switches or sites that are to be connected together also need to have identical equipment installed. For example, if there is a chassis system with traffic cards at one site, a chassis system with traffic cards is required also at the other sites.  The exact same chassis-based transponder system will then need to be placed at all sites in the network, regardless of the actual data transportation need, making the solution overly complex and expensive.

In reality not all networks and not all sites within a network require a transponder to convert the Ethernet output to DWDM. In some scenarios the optimal solution could be to place a DWDM transceiver directly in to the switch. Or in the case of an ISP offering LAN and cloud extension services, an asymmetrical solution for data center networking makes much more sense. Here, a transponder at the customer site gives the operator control and visibility as required, but at the operator’s site, an embedded DWDM signal based on standard transceivers delivers an efficient asymmetrical solution. It leverages the advantage of DWDM optical transceivers but in a much more cost-effective and flexible way.

Harnessing the power of open line DWDM networking

In the beginning, the telco system vendors made the rules and requirements for data center design and functionality. But today, these solutions are holding organizations back by relying on assumptions that data centers need to be vertically integrated, symmetrical, and suit one kind of data networking need. The Open Compute community (www.opencompute.org) designs and shares approaches to data center networking that caters to a variety of organizations, by type, by size, and by specific needs.

Because of the open source movement’s transparent approach, organizations can build world-class custom networks designed specifically around their needs, not those designed for telcos. In an open system, users should have the freedom and choice to select the connections and architectures that suit their traffic and demands best. In many cases, this is a mixture of transponders or DWDM interfaces directly embedded into switches and routers, and with these flexible approaches, all organizations can get the best-of-breed solution they need.

It’s not realistic for any organization – including telcos – to install new fiber every time data traffic increases. Moreover, the evolving data traffic and transport needs aren’t just about traffic volumes or data speeds, which is why it’s more important than ever to have a variety of approaches that optimize new and existing network investments. On top of the transparency and flexibility of the Open Compute Model, the open source approach enables a company like Smartoptics to offer flexible, scalable, and cost-effective solutions to data center networking.

To find out more about flexible, cost-efficient 21^st-century solutions to data center networking, download the Smartoptics guide to simplifying connectivity.