Hello and welcome to this lecture where I want to talk about why an organization would consider connecting their on-prem data center to AWS using an AWS Direct Connect. In my experience, even with the abundance of material extolling the benefits of AWS, many organizations begin their cloud journey by dipping their toes into AWS. Let me say clearly that there is nothing wrong with this approach. It's basic IT nature to view a new technology or service with a measure of healthy skepticism. Thus, it's perfectly acceptable for organizations to take careful and deliberate steps to validate AWS's ability to solve business challenges. I have seen several organizations begin their cloud journey by using Amazon S3 buckets to easily expand the storage capacity of their backup repositories to support long-term data retention goals.

Once this use case is tested and validated, this organization may expand its use of AWS by using infrastructure as code principles to deploy simple EC2 instances. Often, once EC2 instances are deployed, an organization will look to connect their AWS environment to their on-premises data center to support production applications by providing EC2 instances access to on-prem Active Directory domains, private DNS zones, database servers, file shares, Internet pages, anything, you name it. 

To securely facilitate this connectivity, an AWS site-to-site IPSec VPN tunnel can be created. Depending upon the configuration of the AWS environment and what resources must communicate with one another, organizations new to the cloud typically choose to do one of two things: deploy a virtual private gateway or deploy a transit gateway. A virtual private gateway is an AWS-managed VPN endpoint that includes redundancy and fail-over capabilities on the Amazon side of the site-to-site VPN connection.

A key point to remember, however, is that a virtual private gateway can only be attached and provide VPN access to a single AWS VPC. If an organization wishes to establish VPN connectivity from their on-premises data center to multiple AWS VPCs, they could choose to deploy a virtual private gateway in each of those VPCs or they could deploy a single AWS transit gateway. Like the virtual private gateway, the AWS transit gateway is an AWS-managed service which provides a highly available regional network transit hub. 

The transit gateway VPN attachment can be used as the VPN endpoint on the Amazon side of a site-to-site VPN connection, which will enable the interconnection of multiple AWS VPCs within the same AWS region and the on-premises network. There's no denying that the AWS virtual private gateway or transit gateway services are the easiest and quickest way to provision VPN IPSec connections to build a hybrid network between an on-premises data center and AWS.

However, as more and more resources and applications are deployed or migrated to AWS, the limitations of these VPN connections come into greater focus. For example, each VPN tunnel can achieve a maximum bandwidth of 1.25Gbps. Additionally, these VPN connections use the public Internet, which can have unpredictable and inconsistent performance, thus potentially making VPN connections unusable for latency-sensitive applications. Organizations needing to overcome the limitations of VPN connections in order to maximize the benefits of AWS will inevitably consider AWS Direct Connect.