Global Accelerator (GA)

Global Accelerator is more focused on improving network performance for applications that require static IP addresses or fast regional failover.

A networking service that sends user's traffic through AWS's global network infrastructure via accelerators (it uses the AWS Backbone Network which is less congestioned of the public network.

It can increase performance and help deal with IP caching by leveraging Anycast IP.

Meant for TCP or UDP traffic! Major difference from CloudFront.

High-Level View:

• GA uses edge locations to help speed everything up.

• GA provides 2 static Anycast IP addresses for you accelerators.

• Dual-stack receives four static IP addresses (Two IPv4 and two IPv6)

• Static IP act as a single, fixed entry for ALL client traffic.

• Standard: traffic routed based on user location, health checks, and weights.

• Custom: Traffic routed to specified EC2 instances and ports in a VPC.

How Anycast IP addresses help solve IP caching issues

1. Understanding IP Caching Problem:

• DNS resolvers and clients cache IP addresses for performance

• If a server goes down, cached IPs still point to the failed server

• Users experience downtime until DNS TTL expires and cache refreshes

1. How Anycast IP Solves This:

• Multiple physical servers share the same IP address

• Network routers automatically direct traffic to the nearest available server

• If one server fails, traffic naturally routes to the next closest server

1. Key Benefits:

• No DNS cache issues because the IP address remains valid

• Automatic failover at the network layer

• Users connect to the closest working server without waiting for DNS updates

• Improved latency as users always reach the nearest point of presence

1. Real-world Example:

• CDNs like Cloudflare use Anycast extensively

• Same IP address works globally but routes to local edge servers

• If one edge server fails, connections seamlessly route to another

• No impact from cached DNS records

1. Additional Advantages:

• Simpler DNS configuration (single IP for multiple locations)

• Built-in DDoS mitigation (traffic gets distributed)

• Reduced latency through optimal routing

• Higher availability through automatic failover

The key point is that Anycast shifts failover handling from DNS to the network layer, eliminating issues with cached IP addresses entirely.