AARNet connects to 2 x Microsoft Enterprise Edge (MSEE) devices in each location (2 in Sydney, 2 in Melbourne). To take advantage of this redundancy, customers can purchase multiple AARNet4 VPN Services.
e.g. Customer provisions their Azure cloud services in Sydney ("Australia East" region). For redundancy, 2 x AARNet4 VPN services can be provided to the Sydney data centre. As another option, the customer may use their Internet connection with IPSec tunnel as the 2nd redundant connection. In this example, there is no reason to connect also to Melbourne.
e.g. For full IT Geo-redundancy, the Customer provisions their Azure cloud services in Sydney ("Australia East" region) and in Melbourne ("Australia Southeast" region). In this case, it is worth using multiple AARNet4 VPN services (up to 4 connections to Azure in total) to both Sydney and Melbourne.
Note that all connections must be active, so to control the path taken by traffic, BGP techniques need to be used - refer to: