For a better understanding of virtual network peering, you need to consider the following key points:
- Peered virtual networks do not need any encryption, public internet, or event gateways, as they use the Microsoft backbone network.
- Using virtual network peering provides a low-latency, high bandwidth connection between the resources in each virtual network.
- Virtual network peering can be used to migrate resources from one subscription/region to another, because Microsoft Azure supports the concept of peering virtual networks in different subscriptions/regions.
Peering for virtual networks located in different regions is currently in preview and is only available for the following regions: US West Central, Canada Central, and US West 2. Also, you need to register your subscription first to try this feature, otherwise, the peer creation will fail. For more information about the subscription registration for this feature, you can check out the following link: https://docs.microsoft.com/en-us/azure/virtual-network/virtual-network-create-peering#register.
- Virtual networks with different deployment models can be peered together.
- No disturbance occurs during the peering process. In other words, you can expect no downtime.
- Ensure that the peered virtual networks have non-overlapping IP address spaces.
- Ensure that you have added all the needed address spaces for your virtual networks before peering them, because once the peer is created, you can no longer add any address spaces.
- Do not expect a transitive relationship among the virtual networks. In other words, if you have virtual network 1, which is peered to virtual network 2, and virtual network B is peered to virtual network 3, that does not mean virtual network 1 and virtual network 3 are peered.
- If the peering status changed to Disconnected, that means the peering of one of the peered virtual networks has been deleted.