New network tier with routing preference is now available in preview
Published date: 19 May, 2020
Routing preference is a new option for Azure customers, allowing them to choose routing between their Azure resources and clients on the Internet. Optimal consumption of apps is critical and so is the ability to architect the delivery. The two routing options are (1) routing via Microsoft Global Network, which is the default and (2) routing via the public Internet. These options are also referred to as “cold potato routing” and “hot potato routing” respectively.
Default routing via Microsoft global network: Traffic from users is accepted closest to the user and routed on the Microsoft global network to resources in Azure. The return traffic from Azure follows the same path and exits Microsoft network closest to the user. The traffic is kept on the Microsoft network for as long as possible, ensuring least number of hops, best performance and availability (cold potato).
Public Internet routing: Traffic from users is traversing the public Internet (ISP network) and enters Microsoft network closest to the region hosting the service accessed. The return traffic from Azure exits the Microsoft network in the same region and takes the public Internet route back to the user. Traffic spends the majority of the time on the public Internet (hot potato routing). The end-to-end network performance over the public Internet will be mainly be dominated by ISP and network provider performance.
Egress pricing will vary based on the routing network selection. You are able to select routing preference when creating a public IP address, which can be attached to an Azure resource such as a virtual machine, virtual machine scale set or Internet facing load balancer. Additionally, you can select routing preferences for Azure storage resources.