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Azure Accelerated Networking Support for Virtual Edges

Azure accelerated networking support is available for Virtual Edges from the 5.4 release and later. This document provides detailed instructions on how to enable, disable, and verify accelerated networking for Virtual Edges, as well as providing support and host servicing details.

Accelerated Networking is Azure's implementation of single root I/O virtualization (SR-IOV), a standard that allows a physical PCIE device to appear as multiple virtual devices (virtual functions). When Accelerated Networking is enabled on an interface of a VeloCloud Edge on Azure, SR-IOV support for Mellanox ConnectX-4 and ConnectX-5 Network Interface Cards (NICs) is automatically enabled in the Edge Virtual Machine (VM).

Note: The SR-IOV support for Mellanox ConnectX-4 and ConnectX-5 NICs is only available for the VeloCloud Edge on Azure in the 5.4 release.

Azure Instance Support

The following table lists instance types that support the Accelerated Networking functionality.

Table 1. Azure Instance Types Support
Software Version Instance Types
Edge Software 5.4 or later Standard_D3_v2
Standard_D4_v2
Standard_D5_v2
Standard_D4_v5
Standard_D8_v5
Standard_D16_v5

Enable or Disable Azure Accelerated Networking

This section provides links for detailed instructions on the different ways to enable and disable Azure Accelerated Networking.

Accelerated Networking can be enabled or disabled via the following locations:
  • Azure portal
  • Azure CLI or Azure PowerShell
Select the following section links for instructions on how to enable and disable Accelerated Networking via the Azure portal and the Azure CLI or Azure PowerShell.

Enable Accelerated Networking

Enable Accelerated Networking using the Azure portal or the Azure CLI.

Azure requires that an existing Virtual Machine (VM) be stopped or deallocated before enabling Accelerated Networking on any Network Interface Card (NIC). For additional information, see: Microsoft Accelerated Networking Reference

Enabling Accelerated Networking Using the Azure Portal

To enable Accelerated Networking on an interface of an existing VM, use the following the steps and refer to the image below for additional information.

  1. Stop or deallocate the VM
  2. Change the setting of accelerated networking to Enabled.
  3. Restart the VM.
    Figure 1. Enabling Accelerated Networking Through an Azure Portal
    Important: To fully benefit from the Accelerated Networking feature, enable it on all interfaces of the VM.
    After the VM restarts, if the NIC model type allotted to the interface does not use Mellanox ConnectX4 or ConnectX5, the Edge VM does not activate accelerated networking support for the interface. As a troubleshooting effort, change the NIC model, stop or deallocate the VM, and then restart the VM.
    Note: You must stop the VM before you enable the Accelerated Networking support.

Enable Accelerated Networking Using the Azure CLI

Follow these steps to enable Accelerated Networking using the Azure CLI. For additional information, reference the following: Enabling Accelerated Networking on VMs.

  1. Deallocate resources of the VM.

    az vm deallocate --resource-group myResourceGroup --name myVm

  2. Enable Accelerated Networking on the NIC.

    az network nic update \

    --name myNic \

    --resource-group myResourceGroup \

    --accelerated-networking true

  3. Restart the VM.

    az vm start --resource-group myResourceGroup --name myVm

Disable Accelerated Networking

There are two options to disable Accelerated Networking using the Azure portal or the Azure CLI.

Disabling Accelerated Networking using the Azure Portal

To disable Accelerated Networking on an interface of an existing Virtual Machine (VM):
  1. Stop/deallocate the VM.
  2. Change the setting of accelerated networking to disabled or false.
  3. Restart the VM.

Disabling Accelerated Networking Using the Azure CLI

  1. Deallocate resources of the VM.

    az vm deallocate --resource-group myResourceGroup --name myVm

  2. Disable Accelerated Networking on the Network Interface Card (NIC).

    az network nic update \

    --name myNic \

    --resource-group myResourceGroup \

    --accelerated-networking false

  3. Restart the VM.

    az vm start --resource-group myResourceGroup --name myVm

Verifying Accelerated Networking

To verify Accelerated Networking enabled on the Edge, log into the Edge Virtual Machine (VM) and run lspci from the command line:

edge:b1-edge1:~# lspci 
0000:00:00.0 Host bridge: Intel Corporation
440BX/ZX/DX - 82443BX/ZX/DX Host bridge (AGP disabled) (rev 03) 
0000:00:07.0 ISA bridge: Intel Corporation
82371AB/EB/MB PIIX4 ISA (rev 01) 
0000:00:07.1 IDE interface: Intel Corporation
82371AB/EB/MB PIIX4 IDE (rev 01) 
0000:00:07.3 Bridge: Intel Corporation
82371AB/EB/MB PIIX4 ACPI (rev 02) 
0000:00:08.0 VGA compatible controller:
Microsoft Corporation Hyper-V virtual VGA 
0fcd:00:02.0 Ethernet controller: Mellanox
Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80) 
8f67:00:02.0 Ethernet controller: Mellanox
Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80) 
9b19:00:02.0 Ethernet controller: Mellanox
Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80) 
9b46:00:02.0 Ethernet controller: Mellanox
Technologies MT27710 Family [ConnectX-4 Lx Virtual Function] (rev 80)

This feature does not support the Mellanox ConnectX-3 as it is not managed by the mlx5_core driver . If the Edge VM is assigned the ConnectX-3 Network Interface Cards (NICs) by Azure, the Edge will behave as it behaves today without the Accelerated Networking support.

Azure Host Servicing

The Azure Accelerated Networking support for Virtual Edges on Azure adds the DPDK failsafe/TAP/MLX PMD model. When Azure host maintenance is performed, the SR-IOV VFs might be temporarily removed and added back later.

Reference the following for additional information: Microsoft Azure Host Servicing

The events are logged by the kernel and can be viewed in the output of dmesg. They can also be viewed in /var/log/messages:

edge:b3-edge1:~# egrep 'VF registering|VF unregistering' /var/log/messages
2023-07-25T22:06:11.903 INFO kern kernel:[ 11.091250] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1: VF registering: eth5 
2023-07-25T22:06:12.049 INFO kern kernel:[ 11.237233] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2: VF registering: eth6
2023-07-25T22:06:12.208 INFO kern kernel:[ 11.396127] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3: VF registering: eth7 
2023-07-25T22:06:12.362 INFO kern kernel:[ 11.549624] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4: VF registering: eth8
2023-07-25T22:30:09.188 INFO kern kernel:[ 1448.376507] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3-hv: VF unregistering: eth7 
2023-07-25T22:30:14.390 INFO kern kernel:[ 1453.577954] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4-hv: VF unregistering: eth8 
2023-07-25T22:30:19.380 INFO kern kernel:[ 1458.568168] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1-hv: VF unregistering: eth5 
2023-07-25T22:30:26.555 INFO kern kernel:[ 1465.742626] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2-hv: VF unregistering: eth6

The HOTPLUG OUT events are reported on the VeloCloud Orchestrator.

Figure 2. Monitor HOTPLUG OUT Events

The Edge continues running during the Azure Host maintenance and the Paths remain active.

When you add the SR-IOV VFs back after Azure host maintenance completes, the events can be viewed in the output of dmesg or in /var/log/messages.

edge:b3-edge1:~# egrep 'VF registering|VF unregistering' /var/log/messages 
... 
2023-07-25T22:31:23.137 INFO kern kernel:[ 1522.324791] hv_netvsc 000d3a92-2dba-000d-3a92-2dba000d3a92 eth1-hv: VF registering: eth5 
2023-07-25T22:31:28.381 INFO kern kernel:[ 1527.568576] hv_netvsc 000d3a92-2178-000d-3a92-2178000d3a92 eth3-hv: VF registering: eth6
2023-07-25T22:31:33.416 INFO kern kernel:[ 1532.604181] hv_netvsc 000d3a92-245f-000d-3a92-245f000d3a92 eth2-hv: VF registering: eth7 
2023-07-25T22:31:38.468 INFO kern kernel:[ 1537.656531] hv_netvsc 000d3a92-218a-000d-3a92-218a000d3a92 eth4-hv: VF registering: eth8

The HOTPLUG IN events are reported on the VeloCloud Orchestrator.

Figure 3. Monitor HOTPLUG IN Events