Last Updated on January 23, 2018 by Dishan M. Francis

Early January Microsoft announced general availability of Azure Accelerated Networking (AN). It is now available for all the regions. This will improve the VM’s performance as its offloading software-define networking from CPU to FPGA-based SmartNICs. To make it more interesting, it can provide up to 30Gbps networking throughput without any additional charge. 

How it works? 

If you worked with Hyper-V clusters, System Center virtualization manager (SCVMM) you may probably aware how virtual switches works. It works as a middle man between virtual machines and physical network to provide greater control over “Communication”. It allows to move workloads between physical hosts, control traffic and isolation using policies, flexible hardware upgrades etc. Azure also uses virtual switches similar to hyper-v. 

Image source: 
You also can read more about it using this link
As you can see in the above image without accelerate networking, traffic always need to pass through the virtual switch and physical hosts before it reaches the physical switch. When Accelerated networking in place, network traffic is directly handled by physical switch by bypassing host and the virtual switch. All the policies you used with virtual switches now can offload to hardware. As it removes the dependency of host to process the packet, we will be able to see lower latency. If there is no AN, Virtual switch process all the policies applying to network traffic. Since it is software based of cause it is need to handle by CPU. But the performance of it depend on the CPU utilization and number of policies. With AN, policies will no longer rely on CPU and it handle by the dedicated hardware. This will reduce jitter. 
There are few limitations applying to this feature. 
1. Can’t use with existing VMs – In order to use AN features, Virtual machines must be created with Accelerated Networking enabled. This feature cannot enable in existing VMs. 
2. A NIC with AN cannot attached to an existing VM –  A NIC with AN enabled only can attached during the VM creation process. It is not possible to attach it to existing VM. 
3. Azure Resource Manager only – This feature only can use with ARM. It can’t use in classic portal. 
Supported VM Instances 
Azure Accelerated Networking is supported on D/DSv2, D/DSv3, E/ESv3, F/Fs/Fsv2, and Ms/Mms Azure VM series. 

Supported Operating Systems
Azure Accelerated Networking is supported on both Linux and Windows operating systems such as, 
Windows Server 2016
Windows Server 2012R2
Ubuntu 16.04
Red Hat Enterprise Linux 7.4
CentOS 7.4
SUSE Linux Enterprise Server 12 SP3
This marks the end of this blog post. Hope this was useful. In next post I will demonstrate how to create VM with AN feature. If you have any questions feel free to contact me on also follow me on twitter @rebeladm to get updates about new blog posts.