Ref: https://learn.cantrill.io/courses/1820301/lectures/41301590

• Summary:
• Contents:

R53 Geolocation Routing - Architecture

Diagram: https://github.com/acantril/aws-sa-associate-saac03/blob/main/1200-ROUTE53/00_LEARNINGAIDS/Route53GeolocationRouting-1.png

• 🔧 Multiple records with the same host name, each record is tagged with a location

  • Location tag can be (from smallest to biggest):
    1. subdivision (❗ Only for US states!)
    2. country (uses ISO standard country codes)
    3. continent (uses ISO standard continent codes)
    4. default (optional to have one)
  • When DNS query comes in, R53 returns the most specific record for the user location
    • R53 searches first subdivision, then country, then continent, then default. If it finds a record at any point, it returns that record and doesn't look further.
    • ❗ If no location matches and there's no default record, “NO ANSWER” is returned!

• Example: for a given host name, there's R53 records for Texas, United States, Argentina, South America and Europe. There's no default record. The following clients will receive:

  Client location	Receives record tagged with
  Houston, Texas, USA	Texas
  Sacramento, California, USA	United States
  Buenos Aires, Argentina	Argentina
  Porto Alegre, RS, Brazil	South America
  Toronto, Ontario, Canada	NO ANSWER
  Munich, Bavaria, Germany	Europe
  Tokyo, Japan	NO ANSWER
  Brisbane, Queensland, Australia	NO ANSWER

  • If there was a defined record tagged with default, those who receive "NO ANSWER” would receive the default record instead

• ‼️ Do NOT confuse with R53 Geoproximity Routing! Geolocation routing is NOT about proximity!!!

  • Return records based on where they are (location), NOT how close they are (proximity)!
  • e.g. if client is based in the UK but there's only records for France and for Europe, even if the Europe record is hosted in Poland, that's the record that will be returned. It's impossible for UK clients to get records tagged for France or Canada.

• Useful for routing traffic based on the location of your customers

  • Content restriction (e.g. content for US market only)
  • Language specific content
  • Load balancing across regional endpoints based on customer location