AWS Transit Gateway is used to simplify your AWS network architecture (topology) by allowing to have transitive peering between hundreds and thousands of VPC and on-premise data centers.
Transit Gateway is designed to simplify the network connections among VPCs and on-premise networks that are connected through VPC peering or Direct Connect (DX). It is a central hub that acts as a cloud router.
- A transit gateway implements a hub-and-spoke network topology.
- It can be used across multiple AWS accounts using Resource Access Manager (RAM).
- It can use route tables to control access among VPCs.
- It works with VPN and Direct Connect.
- It supports IP multicast.
- A transit gateway scales elastically based on the volume of network traffic. Routing through a transit gateway operates at layer 3, based on their destination IP addresses.