Transit Gateway for Inter- and Intra-Regional Communication


Course Introduction
VPC Fundamentals
What is a VPC?
PREVIEW16m 20s
VPC Security and Control
VPC Connectivity
Introduction to AWS PrivateLink
VPC Sharing using the AWS Resource Access Manager
Understanding Direct Connect, Implementation and Configuration
Why Direct Connect?
5m 25s
Understanding AWS Direct Connect - Connectivity Options
7m 3s
Examining AWS Routing
AWS Default Routing

The course is part of this learning path

Start course
3h 55m

This section of the AWS Certified Solutions Architect - Professional learning path introduces you to the core networking concepts and services relevant to the SAP-C02 exam. We start with an introduction to the AWS Virtual Private Network (VPC) and networking services. We then understand the options available and learn how to select and apply AWS networking, DNS, and content delivery services to meet specific design scenarios relevant to the AWS Certified Solutions Architect - Professional exam. 

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Learning Objectives

  • Get a foundational understanding of VPCs, their security, and connectivity
  • Learn about VPC sharing using the AWS Resource Access Manager
  • Discover inter-regional and intra-regional communication patterns in AWS
  • Learn about AWS Direct Connect, along with its implementation, configuration, and connectivity options
  • Understand routing in AWS, including static and dynamic routing
  • Understand the basics of networking, including Elastic IP addresses, Elastic Network Interfaces, networking with EC2, VPC endpoints, and AWS Global Accelerator
  • Learn about the DNS and content delivery services Amazon Route 53 and Amazon CloudFront

In this lesson, we will discuss using transit gateways for inter and intra-regional communication. Transit gateway is an alternative to VPC peering. Instead of each VPC peering with other VPCs, each VPC attaches to a transit gateway. Transit gateway acts as a hub in a hub and spoke design. As well as allowing multiple VPCs to route to each other, transit gateways also allow attached VPCs to share a site-to-site VPN connection or a Direct Connect connection, as well as sharing a single route to the Internet. 

Transit gateways are a regional service. VPCs in the EU West 2 must be attached to a transit gateway in EU West 2. To connect VPCs in different regions, you can create a transit gateway in each region and then peer the two transit gateways. By peering the two transit gateways, the VPCs in each region will be able to reach to each other. Using transit gateway to connect your VPCs offers benefits and drawbacks when compared to VPC peering.

Benefits of using transit gateway instead of VPC peering include shared connections to on-premises and the Internet, increased scalability. When using VPC peering, you can have 50 active VPC peers per VPC. When you use a transit gateway, you can have to 5,000 attachments per gateway. When working with transit gateway, we can use multiple route tables to control the flow of traffic through the transit gateway. Each attachment is associated with one route table. Using multiple route tables means that we can control which VPC can route to each other. Transit gateway supports equal cost multi-path routing (ECMP). ECMP allows you to use active-active connectivity to your on-premises networks, allowing you to make full use of all the bandwidth available to you.

Transit gateway offers support for software-defined wide area network connectivity using a feature called AWS Transit Gateway Connect and the GRE protocol to simplify connectivity between your offices. Drawbacks of using transit gateway instead of VPC peering include: Cost; transit gateway is more expensive than VPC peering. When using transit gateway, you are charged per hour for each attachment to your transit gateway and a price per gigabyte of data processed. Like VPC peering, data found between VPCs attached to a transit gateway stays on the AWS backbone.


About the Author
Learning Paths

Danny has over 20 years of IT experience as a software developer, cloud engineer, and technical trainer. After attending a conference on cloud computing in 2009, he knew he wanted to build his career around what was still a very new, emerging technology at the time — and share this transformational knowledge with others. He has spoken to IT professional audiences at local, regional, and national user groups and conferences. He has delivered in-person classroom and virtual training, interactive webinars, and authored video training courses covering many different technologies, including Amazon Web Services. He currently has six active AWS certifications, including certifications at the Professional and Specialty level.