Windows Admin Center feature letting migrated VMs keep their IP addresses by stretching an on-premises subnet into Azure; two appliance VMs carry a VXLAN tunnel between them, and up to 250 addresses can be extended.
Also called extended network for Azure.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Azure Extended Network in context, with comparison tables and the common traps.
Terms in this definition
- Windows Admin Center
Browser-based management for Windows Server. Besides registering servers with Azure, its extensions can configure Azure Extended Network, Azure Network Adapter and Azure Backup (using MARS).
- Virtual machines
Infrastructure-as-a-service compute giving complete control of the operating system, making it a fit for lift-and-shift moves and for software relying on OS-level pieces like COM.
- Subnet
A segment of a VNet's address space from which resources receive private IPs. Azure holds back five addresses per subnet (the first four and the last), leaving 251 usable in a /24 and three in a /29, the smallest IPv4 subnet.
- VXLAN
Encapsulation of layer 2 frames in UDP on port 4789. Gateway Load Balancer chains NVAs with it, and Azure Extended Network uses it to carry a stretched subnet between its pair of appliances.
Related terms
- Azure Extended-Network Gateway
The appliance VM placed in Azure for Azure Extended Network. Its OS must be Windows Server 2022 Datacenter: Azure Edition, and it needs two NICs: one on the extended subnet, one on a routable subnet.
- Hyper-V
The hypervisor built into Windows. The VMs for the Azure Extended Network appliance require the Hyper-V role, using nested virtualisation, and an external virtual switch for each NIC.
- Nested virtualization
Hosting Hyper-V within a virtual machine. The appliance VMs of Azure Extended Network, for instance, need it so the Hyper-V role can be turned on.
- On-Premises Extended-Network Gateway
In Azure Extended Network, the VM appliance on the local side, running Windows Server 2019 or 2022 and connected to two subnets: one routable, the other the subnet being extended.