Designing for proper Networking and Scalability is a key task in building out an AWS platform. This should be done in a test or sandbox environment first, to develop the approach based on your use cases and requirements. A detailed Networking and Solution-Scalability design is an Agile-Iterative process involving subject matter experts including networking, security, application and databases and testing.
Virtual Private Cloud (VPC)
DNS and PrivateLink
Load Balancing and Route 53
LB is essentially for scalability and security. You can have Application LBs or Network LBs (or both).
R53 DNS failover schema explained.
Caching and Content Delivery Network (CloudFront)
CloudFront content delivery network to cache the content close to end users. Often used with WAF.
Building Scalable Automated Solutions