The high-cost of vendor-locked optics has spawned a lot of ingenuity over the years as other ‘non-approved’ manufacturers build the same optics to the same spec and try to get them to work as a low-cost alternative to preferred ODMs. But the whitebox revolution has now leveled the playing field. Lower cost whitebox hardware can work with low-cost or high-cost optics, without discrimination based on manufacturer brand. In the case of a data center deployment, the cost savings of using lower cost optics can translate to millions of dollars.

As long as the box manufacturer and the optics manufacturer both build to industry standards — both formal and informal ones — optics from any manufacturer should be able to work on any box. Most of the implementation details are specified by standards. However, that doesn’t guarantee that you can pick any module on the internet, order a thousand units and have a successful deployment.

At Cumulus Networks, we do everything we can to ensure a smooth, easy deployment. We believe that one of the critical benefits of disaggregation is that it provides you with the ability to choose whatever hardware and software best suit your business needs.

When it comes to hardware, it is important to consider things like compatibility and interoperability well before it is time to deploy. We’ve put together this quick guide to use alongside our hardware compatibility list so that when you’re ready to go web-scale with Cumulus Linux, deployment will be a breeze.

Pluggable transceiver module considerations

Although Ethernet has become commonplace and simple to implement, in this new world of high-speed ethernet networking, the underlying physical infrastructure and technologies have become more and more complex. This section of the post covers the standard considerations for pluggable transceiver modules. After we set the playing field, I’ll go into the details about how Cumulus Networks approaches the subject.

Here is a quick overview of the four-dimensional pluggable transceiver module technology matrix to help make the differences clear.

pluggable transceiver module
Additionally there are other dimensions to the matrix that affect interoperability between modules and switches:

  • Module/port compatibility: The port has to support the module requirements. When an LR optical module is inserted, the port hardware must detect it and supply more power than for an SR module. Similarly, high speed technologies like Infiniband and FiberChannel come in SFP/QSFP form factors, but an Infiniband module may not also support Ethernet, causing compatibility problems.
  • Tx/Rx and control signalling: Innovations in the translation of the received signal from the SFP/QSFP back into an understandable and uncorrupted pattern of bits in the switch port have created several different electronics implementations inside the switch hardware. In our hardware compatibility list, there are various transmit and receive hardware technologies that accomplish this translation. Above that layer, Cumulus Networks currently supports ten different primary switching ASICs that influence the way that the port is configured and controlled. That adds two more dimensions to the Ethernet technology matrix that needs to be tested.
  • Manufacturer implementations of the standards: Each switch and module manufacturer has particular hardware implementations that might influence compatibility with other manufacturer implementations.

Because of the complexity of this matrix, nearly all traditional switch vendors support only a specific set of optics. Often the approved optics are branded with their own name. Some switch vendors use vendor locking — software checks that guarantee only their supported optics will work.
As I’ll explain shortly, at Cumulus Networks, we verify our products using a plethora of optics to ensure our software configures the switch properly. We believe in the benefits of disaggregation, and we do not limit our customers to only hardware we tested. That would not only completely go against what we stand for, it would also be a hinderance to many.

The Cumulus approach to pluggable transceiver modules

Cumulus embraces the power of choice, supporting many open networking switches and facilitating interoperability with any validated optics or pluggables. We conduct significant testing of our switch platforms using standard optics, but also give customers the freedom to choose any validated brand. Here are some of our hardware programs and policies to encourage both efficiency and choice:

  • The Cumulus Networks Hardware Compatibility List (HCL) provides a list of pluggables that are recommended for use with systems running Cumulus Linux. (For simplicity, this document refers to both transceiver modules and cables as “pluggables”). The list includes:
    • All Cumulus Express components
    • Pluggables qualified by Cumulus Networks Engineering
  • If a pluggable is on the HCL, but not listed as recommended for use with a particular platform on the HCL, then Cumulus has found that this specific combination is not recommended.
  • We recommend using hardware that is listed on our hardware compatibility list. However, some customers have successfully deployed with modules validated elsewhere. In these specific cases, the customers took on rigorous pre-deployment lab testing that included the hardware and software configurations that match the production deployment. If a customer decides to use a brand not on our verified list as seen in the HCL, we have a detailed set of deployment guidelines including a detailed test plan to help customers self-certify their particular modules in the switches that they plan to deploy.
  • We also offer a turnkey solution, Cumulus Express, that includes approved hardware and pluggables right in the box. It’s a completely plug and play experience so you do not have to worry about a thing.

With the fast-changing nature and proliferation of low-cost manufacturers, it’s close to impossible to test every single low-cost vendor. That said, at Cumulus Networks we do our best to ensure customers have all the information they need to choose hardware that best fits their needs. Our testing is focused on a variety of platforms that represent each switching ASIC and port hardware type (Tx/Rx and control signalling dimensions mentioned above), using a subset of ‘name-brand’ and ‘low-cost’ modules.

The beauty of disaggregation is that the choice is yours

In nearly all cases, whitebox switches and whitebox optics just work right out of the box. If you are concerned about compatibility issues derailing your deployment, check out our list of compatible pluggables and hardware on our hardware compatibility list.

Of course if you do not want to worry about compatibility, there is a streamlined way to go about deployment. Cumulus Express not only comes with Cumulus Linux installed and licensed, but it also comes with compatible hardware. Everything you need to deploy is there in the box — making deployment a breeze. Learn more about Cumulus Express.