Your VPC has a DX connection that is advertising 99 routes. You have two more prefixes to add: 10.223.1.0/24 and 10.223.2.0/24. You have several locations, so you need to be as exact as possible with your routing. How would you do this?

September 14, 2021 by Admin

Your VPC has a DX connection that is advertising 99 routes. You have two more prefixes to add: 10.223.1.0/24 and 10.223.2.0/24. You have several locations, so you need to be as exact as possible with your routing.

How would you do this?

  • Add the prefixes; AWS allows for as many BGP routes as you need but not static.
  • Contact AWS to extend the number of prefixes you are allowed to advertise.
  • Summarize the routes into a 10.223.0.0/22 and advertise that route instead. 
  • Summarize the routes into a 10.223.0.0/12 and advertise that route instead.

Explanation:
BGP has a strict 100 prefix limit. 10.223.0.0/12 includes both routes but is not very specific. 10.223.0.0/22 is the proper summarization of both routes.

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