Microsoft's $26.2 billion LinkedIn acquisition hangs a big question mark over LinkedIn's ambitious plans to migrate its infrastructure to a private cloud. (See Microsoft Nabs LinkedIn for $26.2B.)

While both LinkedIn Corp. and Microsoft Corp. (Nasdaq: MSFT) are cloud providers with a strong commitment to open data center design and networking, they each have their own infrastructures. It's still unclear what Microsoft is going to do with LinkedIn's data center and network foundation, and whether the work LinkedIn engineers have done on their redesign will last. (See Microsoft & LinkedIn: Marriage Made in the Cloud.)

Neither Microsoft nor LinkedIn are saying. "LinkedIn will retain its distinct brand, culture and independence," noted a LinkedIn spokesperson. "After the acquisition closes and as we learn more about our two companies, we will explore opportunities for our teams to work together." Microsoft said something similar. We hear the situation is still up in the air -- LinkedIn isn't making any changes changes to its strategy and plans just yet, and the company hopes to be able to say more in three to four weeks.

LinkedIn laid out its infrastructure in a blog post in March. The LinkedIn Platform as Service architecture, launched two years ago, is designed to automate functions for developers and operations staff, including selecting hosts for new services and expanding and contracting services in reaction to traffic and other demands. (See LinkedIn Launches Private Cloud for Growth.)

Network topology decisions, on which services and jobs run where in the data centers, were previously done manually by network operators making judgment calls. Under LinkedIn Platform as a Service, that process is automated, using a process LinkedIn calls "Rain," resulting in a 50% resource savings.

Like other hypercloud providers, LinkedIn is building its infrastructure, rather than buying. (See Facebook Reinvents Data Center Networking and Google: 'Great' Data Center Networks Essential.)

Complementing LinkedIn Platform as a Service, Project Altair brings online a new data center and data center architecture.

LinkedIn is rebuilding its data centers and networks to turn its platform into a foundation for growth. The company plans to provide a variety of content and apps, including video and other content requiring significant bandwidth, for 5x to 10x network growth. The new Project Altair depends on 100,000 to 200,000 servers -- not Facebook- or Google-scale, but still pretty big. Additionally, LinkedIn has four smaller data center in the US and one in Singapore, with the Project Altair data center going up in Hillsboro, Ore.

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Light Reading CEO Steve Saunders talked with Saikrishna Kotha, who leads LinkedIn's infrastructure architecture strategy, for a video interview in December. Kotha said each profile page view taps hundreds of servers. He also discussed LinkedIn's commitment to open source -- both consuming and contributing -- including the Apache Kafka message broker. (See Meet the Architect Behind LinkedIn.)

LinkedIn also participates in the Open Compute Project , an initiative led by Facebook and other companies to develop open source data center and networking hardware designs.

I talked with Yuval Bachar, principal engineer, LinkedIn architecture and strategy, about the company's involvement with the OCP, for a March video interview. Bachar said he sees OCP as a means of getting high-end hardware server, storage, and networking without having to maintain a hardware engineering team, and focus instead on software. OCP lets LinkedIn collaborate with peers in a larger community, as an alternative to working one-on-one with vendors. (See LinkedIn on OCP & Data Center Innovation.)

Next page: The open source virtuous cycle

I spoke with Mike Schutz, Microsoft GM, cloud platform product marketing, for a video interview at the same conference. Like LinkedIn, Microsoft is an enthusiastic participant in OCP. Microsoft open sourced its cloud server design, the Open Cloud Server, two years ago; and in March donated its Software for Open Networking in the Cloud (SONIC), for switch management, to OCP. Bachar singled out SONIC as technology LinkedIn is interested in as well.

Like LinkedIn, Schutz sees a virtuous cycle of getting benefit from the open source community and giving back. (See Microsoft: Open Source Means Meeting Customers Where They Are.)

Microsoft is -- to put it mildly -- a whole heck of a lot bigger than LinkedIn. Where LinkedIn has four data centers, with a bigger one on the way, Microsoft's data center network, in which it has invested more than $15 billion, has more than 100 data centers and 1 million servers, powering more than 200 online services, including Office 365, Skype, Xbox Live, Skype, OneDrive and Microsoft Azure.

The company manages 24 regions in the US, Canada, Hong Kong, Singapore, Japan, Brazil, Australia and India, with eight more to come, including South Korea.

To help connect all that infrastructure, Microsoft and Facebook announced plans in May to build a transatlantic cable for cloud apps, with construction starting in August and finishing 14 months later. (See Microsoft, Facebook Building Transatlantic Cable.)

In March, Microsoft announced that it had developed a module plugging directly into data center switches to manage 80km links between data centers -- which Microsoft called its "sweet spot." The module eliminates the need for a dedicated DCI box. (See Microsoft Drops a Data Center Interconnect Bombshell.)

And last year, Microsoft open sourced SmartNIC, customized hardware it uses to offload networking processing loads from data center hosts. (See Microsoft Gives Software Networking a Hardware Boost.)

So how will Microsoft integrate LinkedIn's infrastructure into its own? We can only make a few guesses guided by information and experience.

In the short term, over the next months, the two companies will probably continue as before. Both CEOs -- Microsoft's Satya Nadella and LinkedIn's Jeff Weiner -- stressed that the two organizations will remain independent, with Weiner reporting to Nadella rather than a board of directors. The companies are looking to blend information on LinkedIn's 433 million members, and LinkedIn services, with Microsoft's own software and services. But the LinkedIn organization will report to Weiner, Microsoft's to Nadella, and presumably that includes both companies' IT groups.

As long as LinkedIn's existing data center and networks continue to work for it, they will almost certainly be allowed to stay online. But as LinkedIn's needs grow, capacity will likely come from Azure, rather than expanding LinkedIn's existing data center architecture and technologies.

On the other hand, expect Microsoft to pick the best of LinkedIn's technology and plans, and make it a part of Azure.

Over time, even if the application development and sales groups for Microsoft and LinkedIn remain independent for the long term, we may see core services organizations merge, including IT, data center operations and networking groups..

Beyond that, our crystal ball is cloudy. But this is a story we plan to stay on top of -- and we'll let you know what we find.

— Mitch Wagner, , Editor, Light Reading Enterprise Cloud.