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Microsoft has developed its own Linux. Repeat. Microsoft has developed its own Linux

Redmond reveals Azure Cloud Switch, its in-house software-defined networking OS

Sitting down? Nothing in your mouth?

Microsoft has developed its own Linux distribution. And Azure runs it to do networking.

Redmond's revealed that it's built something called Azure Cloud Switch (ACS), describing it as “a cross-platform modular operating system for data center networking built on Linux” and “our foray into building our own software for running network devices like switches.”

Kamala Subramaniam, Redmond's principal architect for Azure Networking, writes that: “At Microsoft, we believe there are many excellent switch hardware platforms available on the market, with healthy competition between many vendors driving innovation, speed increases, and cost reductions.”

(Translation: Microsoft partners, we mean you no harm.)

“However, what the cloud and enterprise networks find challenging is integrating the radically different software running on each different type of switch into a cloud-wide network management platform. Ideally, we would like all the benefits of the features we have implemented and the bugs we have fixed to stay with us, even as we ride the tide of newer switch hardware innovation.”

(Translation: Software-defined networking (SDN) is a very fine idea.)

But it appears Redmond couldn't find SDN code to fits its particular needs, as it says ACS “... focuses on feature development based on Microsoft priorities” and “allows us to debug, fix, and test software bugs much faster. It also allows us the flexibility to scale down the software and develop features that are required for our datacenter and our networking needs.”

ACS is designed to use the Switch Abstraction Interface (SAI), an OpenCompute effort that offers an API to program ASICs inside network devices.

Microsoft's post revealing ACS says a fair bit about its features, but doesn't explain the relationship between Microsoft and Linux. Perhaps the complexity of the world's switching ecosystem was the reason: Redmond says it has demonstrated ACS across with “four ASIC vendors (Mellanox, Broadcom, Cavium, and the Barefoot software switch), six implementations of SAI (Broadcom, Dell, Mellanox, Cavium, Barefoot, and Metaswitch), and three applications stacks (Microsoft, Dell, and Metaswitch).”

Subramaniam's post ends by letting us know: “We’re talking about ACS publicly as we believe this approach of disaggregating the switch software from the switch hardware will continue to be a growing trend in the networking industry and we would like to contribute our insights and experiences of this journey starting here.”

That experience clearly includes Linux, not Windows, as the path to SDN.

Satya Nadella's Microsoft is a very different animal, unafraid to use any technology if it gets the job done. But Microsoft building a Linux? Wow. Just wow. ®

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