Improving Azure VM performance using accelerated networking

Accelerated Networking: Accelerated networking enables single root I/O virtualization (SR-IOV) to a virtual machine which improves the networking performance. This allows VM to directly talk to the network adapter by bypassing the virtualization transport layer .i.e. virtual switch.

This high-performance path bypasses the host from the datapath, reducing latency, jitter, and CPU utilization, for use with the most demanding network workloads on supported VM types.

Below diagram explains the traffic flow

Without accelerated networking, all networking traffic in and out of the VM traverses the host and the virtual switch. The virtual switch provides all policy enforcement, such as network security groups, access control lists, isolation, and other network virtualised services to network traffic.

With accelerated networking, network traffic arrives at the VM’s network interface (NIC), and is then forwarded to the VM. All network policies that the virtual switch applies are now offloaded and applied in hardware. Applying policy in hardware enables the NIC to forward network traffic directly to the VM, bypassing the host and the virtual switch, while maintaining all the policy it applied in the host.

You can enable this feature only on the selected list of Azure VMs. 

The supported series are: D/DSv2 and F/Fs &  D/DSv3, E/ESv3, Fsv2, and Ms/Mms.

It supports most of the flavours of Linux and in Windows it supports Windows Server 2012 R2 Datacenter & Windows Server 2016 Datacenter edition.

Once you enable accelerated networking on Windows Azure VM drivers are installed on the virtual machine. You may check the driver installed through Device Manager console in the VM. You will find it under the Network Adapter.

Mellanox ConnectX-3 Virtual Function Ethernet Adapter

Below is the screen shot for a VM without accelerated networking & a VM with accelerated networking.

The above screen shot is from the virtual machine without accelerated networking.

The above screen shot is from the virtual machine with accelerated networking enabled.

You may verify if the VM is enabled with accelerated networking.

You may enable accelerated networking while provisioning the Azure virtual machines.

I hope the article is helpful and thanks for reading!