If your application is hosted in multiple AWS Regions, you can improve performance for your users by serving their requests from the AWS Region that provides the lowest latency.
To use latency-based routing, you create latency records for your resources in multiple AWS Regions. When Route 53 receives a DNS query for your domain or subdomain (example.com or acme.example.com), it determines which AWS Regions you’ve created latency records for, determines which Region gives the user the lowest latency, and then selects a latency record for that Region. Route 53 responds with the value from the selected record, such as the IP address for a web server.
For example, suppose you have Elastic Load Balancing load balancers in the US West (Oregon) Region and in the Asia Pacific (Singapore) Region. You create a latency record for each load balancer. Here’s what happens when a user in London enters the name of your domain in a browser:
- DNS routes the query to a Route 53 name server.
- Route 53 refers to its data on latency between London and the Singapore Region and between London and the Oregon Region.
- If latency is lower between the London and Oregon Regions, Route 53 responds to the query with the IP address for the Oregon load balancer. If latency is lower between London and the Singapore Region, Route 53 responds with the IP address for the Singapore load balancer.
Latency between hosts on the internet can change over time as a result of changes in network connectivity and routing. Latency-based routing is based on latency measurements taken over a period of time, and the measurements reflect these changes. A request that is routed to the Oregon Region this week might be routed to the Singapore Region next week.
IP based Routing Policy
With IP-based routing in Amazon Route 53, you can fine-tune your DNS routing by using your understanding of your network, applications, and clients to make the best DNS routing decisions for your end users. IP-based routing gives you granular control to optimize performance or reduce network costs by uploading your data to Route 53 in the form of user-IP-to-endpoint mappings.
Geolocation and latency-based routing is based on data that Route 53 collects and keeps up to date. This approach works well for the majority of customers, but IP-based routing offers you the additional ability to optimize routing based on specific knowledge of your customer base. For example, a global video content provider might want to route end users from a particular internet service provider (ISP).
Some common use cases for IP-based routing are the following:
- You want to route end users from certain ISPs to specific endpoints so you can optimize network transit costs or performance.
- You want to add overrides to existing Route 53 routing types, such as geolocation routing, based on your knowledge of your clients’ physical locations.