Azure

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Azure hosts use ConnectX devices from Mellanox (now NVIDIA). ConnectX-4 needs the [https://docs.kernel.org/networking/device_drivers/ethernet/mellanox/mlx5.html mlx5_core] driver, while ConnectX-3 needs mlx4_en. It is not possible as of February 2023 to force allocation of one or the other for a given VM, and the NIC type can change if the VM is moved. Azure documentation typically refers to both classes as "SmartNICs".

The fundamental networking object in Azure is the VNet. VNets are manually created, scoped to a single region and subscription, and no larger than a /16. A VM's NICs are assigned to VNets. VNets ought use RFC 1918 or RFC 6598 addresses, and it is best practice to keep the addresses of your organization's VNets distinct. VNets can be peered together. ~~NICs can be assigned public IP addresses in addition to their private addresses with the VNet, and connecting into the VNet generally requires one or more such IPs.~~

The fundamental networking object in Azure is the VNet. VNets are manually created, scoped to a single region and subscription, and no larger than a /16. A VM's NICs are assigned to VNets. VNets ought use RFC 1918 or RFC 6598 addresses, and it is best practice to keep the addresses of your organization's VNets distinct. VNets can be peered together. VNets are <b>not a broadcast domain</b>, and indeed support neither broadcast nor multicast using typical mechanisms. ARP requests will be answered by the SDN, and never seen by the other VNet hosts. The reply will always contain the MAC address 12:34:56:78:9a:bc, which will make up most (if not all) of your neighbor table. The SDN does not answer for IPs not active in the VNet. MTUs within a VNet can be safely taken to around 8000 bytes. VNets can be further broken down into distinct subnets. NICs can be assigned public IP addresses in addition to their private addresses within some subnet (and thus VNet), and connecting into the VNet generally requires one or more such IPs.

VNets are <b>not a broadcast domain</b>, and indeed support neither broadcast nor multicast using typical mechanisms. ARP requests will be answered by the SDN, and never seen by the other VNet hosts. The reply will always contain the MAC address 12:34:56:78:9a:bc, which will make up most (if not all) of your neighbor table. The SDN does not answer for IPs not active in the VNet. MTUs within a VNet can be safely taken to around 8000 bytes.

===Accelerated Networking===

Azure: Difference between revisions

Dank (talk | contribs)

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 Azure hosts use ConnectX devices from Mellanox (now NVIDIA). ConnectX-4 needs the [https://docs.kernel.org/networking/device_drivers/ethernet/mellanox/mlx5.html mlx5_core] driver, while ConnectX-3 needs mlx4_en. It is not possible as of February 2023 to force allocation of one or the other for a given VM, and the NIC type can change if the VM is moved. Azure documentation typically refers to both classes as "SmartNICs".
-The fundamental networking object in Azure is the VNet. VNets are manually created, scoped to a single region and subscription, and no larger than a /16. A VM's NICs are assigned to VNets. VNets ought use RFC 1918 or RFC 6598 addresses, and it is best practice to keep the addresses of your organization's VNets distinct. VNets can be peered together. NICs can be assigned public IP addresses in addition to their private addresses with the VNet, and connecting into the VNet generally requires one or more such IPs.
+The fundamental networking object in Azure is the VNet. VNets are manually created, scoped to a single region and subscription, and no larger than a /16. A VM's NICs are assigned to VNets. VNets ought use RFC 1918 or RFC 6598 addresses, and it is best practice to keep the addresses of your organization's VNets distinct. VNets can be peered together. VNets are <b>not a broadcast domain</b>, and indeed support neither broadcast nor multicast using typical mechanisms. ARP requests will be answered by the SDN, and never seen by the other VNet hosts. The reply will always contain the MAC address 12:34:56:78:9a:bc, which will make up most (if not all) of your neighbor table. The SDN does not answer for IPs not active in the VNet. MTUs within a VNet can be safely taken to around 8000 bytes. VNets can be further broken down into distinct subnets. NICs can be assigned public IP addresses in addition to their private addresses within some subnet (and thus VNet), and connecting into the VNet generally requires one or more such IPs.
-VNets are <b>not a broadcast domain</b>, and indeed support neither broadcast nor multicast using typical mechanisms. ARP requests will be answered by the SDN, and never seen by the other VNet hosts. The reply will always contain the MAC address 12:34:56:78:9a:bc, which will make up most (if not all) of your neighbor table. The SDN does not answer for IPs not active in the VNet. MTUs within a VNet can be safely taken to around 8000 bytes.
 ===Accelerated Networking===