Microsoft announced a new routing preference feature for Azure customers that allows them to control which underlying routing networks they use for traffic to and from Azure.
Azure routing preference, available now worldwide, let customers choose a routing network based on the need for higher-quality performance, lower cost or other factors.
Mahesh Nayak, principal program manager at Microsoft, wrote in a blog post, “You can choose between routing via the Microsoft global network or routing via the Internet that uses transit Internet Service Provider (ISP) network. While the routing via Microsoft global network delivers traffic over an exceptionally reliable private global network, the transit ISP network option gives you a cost optimized choice with performance predominantly dominated by transit ISP. These routing options are also referred to as cold potato and hot potato routing respectively.”
Still, Microsoft made a good argument for routing via the Microsoft global network, a 165,000 mile fiber network with more than 180 edge points of presence (PoPs) made up of fibers fully owned or leased by Microsoft. The software giant conducted a performance report with ThousandEyes that showed its network offered the best latency option for routing Azure traffic.
Microsoft’s network uses SD-WAN for routing optimization and traffic management, and remains the default routing method for all Azure traffic. It also has redundant fiber paths to handle multiple simultaneous failures and boasts automatic physical layer encryption. Microsoft's own services connected to Office365, Teams, Xbox, Bing and others use this network.
However, Nayak stated that Microsoft understands that some customers may have varying cost, performance and security requirements for all the different workloads that they are bringing in and out of Azure.
“While Microsoft will always default to the best performing and most secure option of carrying the traffic across our global network from source to destination, the new competitive egress tier adds a second option for solutions that do not require the premium predictability and performance of Microsoft's global network,” he wrote. “Instead, it will allow the routing of traffic to the Internet via transit ISP network.”
Microsoft has posted some separate documentation from last month that details which services can be supported by the internet routing option, but as examples Nayak said users can choose their preferred routing “when creating a public IP address and then associate it to resources such as virtual machines (VMs), internet-facing load balancers, and more.”
Also, the ISP can be selected as a routing preference for storage accounts that give an additional endpoint to access services such as blobs, files, web, and Azure Data Lakes over the Internet, he stated. Customers also can enable both routing options for some services. For example, internet routing can be chosen for some virtual machines, while others use the Microsoft global network.