Emulex Blog: Emulex Labs

Taking NVGRE to the Next Level

Posted June 13th, 2012 by Brandon Hoff

TechED is Microsoft’s premier technology conference for IT professionals and developers, offering the most comprehensive technical education across Microsoft’s current and soon-to-be-released suite of products, solutions, tools, and services.  We are excited to be here to talk about Microsoft technologies such as RSS, Single Root I/O Virtualization (SR-IOV), virtual machine queue (VMQ), Receive Segment Coalescing (RSC), and many more for the upcoming Windows Server 2012 features.  We also have one more thing …

We are showing the first results of new technology called Network Virtualization using GRE or NVGRE, based on our joint RFC submission to the IETF.  Emulex, Microsoft, and others submitted NVGRE to address new networking requirements for virtualized environments.  According to the draft RFC:

“We describe a framework for policy-based, software controlled network virtualization to support multitenancy in public and private clouds using Generic Routing Encapsulation (GRE). The framework outlined in this document (the RFC) can be used by cloud hosters, enterprise data centers, and enables seamless migration of workloads between    public and private clouds.”

At TechEd 2012, Emulex is showing a prototype FPGA technology demonstration of NVGRE.  This is an important next step for NVGRE to become a viable solution.  Microsoft published a call to action at their Build Conference in September of 2011 for NIC vendors to “implement GRE compatible hardware offloads.”

The Emulex prototype FPGA technology demonstration of NVGRE is shown below.

The demo is simple. All we do is set up the virtual machines (VMs) without NVGRE enabled, with the configuration above, and the VMs cannot communicate.  This is shown when a simple PING operation doesn’t work.  Then we enable NVGRE through PowerShell scripts and set up the policies for the two different virtual networks.  Once the NVGRE is configured, the VMs on a specific TNI (Tennant Network Identifier) can see each other.  An interesting piece of complexity is that the IP addresses for the VMs are identical, which can easily happen in multi-tenant environments.  Even with duplicate IP addresses, traffic flows on the correct Virtual Segment.  Bottom line, the VMs believe that they have their own physical fabric, but in reality, multiple virtual fabrics are running traffic over the same physical infrastructure.

The industry has been talking about the need for hardware offloads to reduce the impact of Overlay Networking techniques, such as NVGRE on CPU usage.  At conferences such as the Open Networking Summit, I have heard people talking about reducing CPU overhead by 10% to 20% with hardware offloads, and this is important to increase VM density and reduce the overall cost of a virtualized data center.  In this prototype FPGA technology demo, which is similar to the simple NVGRE demo described by Microsoft in this web page, Emulex is showing technology that is compatible with Microsoft’s deployment of NVGRE on one of the servers with software NVGRE on the second server.

What’s new is, we are also showing management layer using PowerShell scripts configuration policies in Windows Server 2012.  While we expect that management for Network Virtualization will take place in centralized controllers, PowerShell is an easy to use tool to demonstrate the technology.

If you are attending TechEd this week, stop by our booth #14 to see our demo, or you can check out these whitepapers for more information on overlay networking using NVGRE here or here.

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