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New networking features in Windows Server 2012


When choosing a network adapter for use with Windows Server 2012 some considerations are important. The choice of a network card is ideal for virtualization, File Server, SQL or another function.

The table below demonstrates how the resources of network cards should be configured as the function that the physical server will play:


Find out how these features work may not be the desire of consumption of most IT Pros, but the performance gain is considerable and therefore become an item that must be configured.

Network cards for use in servers have a specific processor to develop fracture control tasks, Message Queuing and other functions that release the processor (CPU) of the computer you have to deal with network traffic.

Below we see the Interruptions (Ch0), where we can enable the plate processor to perform the multiple uses of the Control Board instead of the CPU. This happens, for example, at a time when many applications access the network. If the network card is offboard worth, if the card is onboard your CPU is less efficient than the computer’s CPU, and it would not be worth:


Large Offload capabilities allow you to indicate if the Board or the OS will do the packet processing frames. For example, if a given on is greater than the standard package of 1500 bytes (9000 in Jumbo Frame) it is divided into several packages. The offload capabilities will indicate that the Board is responsible for turning the package in frames. Turn on this feature for e-mail servers and streaming would not be indicated, since these types of package can of course be lost and retransmitted:


Already the RSS causes packets coming in on the same TCP/UDP connection are always processed by the main processor. In machines multi-process configurations or even multi-core this feature causes each connection is as loyal to that same processor, avoiding that a package is distributed between processors and will cause overload on the CPU.

For virtual machines and NIC Team the RSS feature is used automatically when you have enabled the SR-IOV in the Virtual Switch, which allows VMs on Windows to access physical resources of 2012 network cards natively, such as those already discussed.

The RSC Board feature small packages to create a single package. For example, it will add 3 packages of 400 bytes in a single package of 1500 bytes, saving headers and packets on the network. Obviously with this feature we improved the physical medium of communication, playing a smaller number of packets in the network cable.

The RDMA is a feature that enables and supports the SMB Direct, a new features of File Servers. This feature allows data in memory of a file server is transmitted directly to the network card, without the need for passing by the kernel of the operating system. Its performance is similar to Fibre Channel, which would be a dedicated controller (HBA). Without the RDMA the Hyper-V Cluster resource based on SMB (File Share) is committed to performance.

Important: When in iSCSI storage access boards the resources, RSS, and RDMA Offload must be disabled because they “hold” the data packets, causing packet loss and slow

I discussed some of the existing features and that can improve the performance of some functions as the table at the beginning of the article.

If you want details about the features, please visit the links and

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