AWS Direct Connect is a service that enables dedicated and private network connections between your datacenter, office, or colocation environment and Amazon Web Services (AWS). These connections bypass the public Internet, providing a more reliable and consistent connection with higher bandwidth capacity and reduced latency. Direct Connect connections can be established using either a 1 Gbps or 10 Gbps network port at one of the many AWS Direct Connect locations worldwide.

A virtual interface (VIF) is a component of AWS Direct Connect that allows customers to create VLANs on their Direct Connect connection. By creating a VIF, customers can partition their Direct Connect connection into multiple, separate, and isolated connections to different AWS services or VPCs. There are two types of virtual interfaces: private VIFs and public VIFs. Private VIFs enable access to a specific VPC, while public VIFs provide access to AWS services accessible over the public internet such as Amazon S3, Amazon EC2 instances with Elastic IPs, or AWS Marketplace.

There are three connection models available for AWS Direct Connect: Dedicated Connections, Hosted Connections, and Hosted Virtual Interfaces. A Dedicated Connection is a physical Ethernet connection with a 1 Gbps or 10 Gbps port capacity, directly connecting your environment to AWS. Hosted Connection is a re-sold AWS Direct Connect service offered by the AWS Partner Network (APN) partners in a shared capacity. Hosted Virtual Interfaces, on the other hand, allow APN partners to create virtual interfaces for multiple customers using a single Direct Connect connection.

Direct Connect Gateway allows you to connect your on-premises networks to multiple Virtual Private Clouds (VPCs) across different AWS Regions using a single Direct Connect connection. This way, you can access resources in multiple VPCs without the need for multiple Direct Connect connections or VPC peering. Direct Connect Gateway is a global service, which simplifies multi-region connectivity management and provides a cost-effective solution for your hybrid cloud architectures.

A Link Aggregation Group (LAG) is a feature of AWS Direct Connect that allows you to bundle multiple connections to increase the total available bandwidth and provide redundancy to your network. LAGs can be created using multiple Direct Connect connections of the same capacity, which are then combined to create a single, logical, and aggregated connection. This feature enables you to scale your on-premises connectivity with AWS while also providing a higher level of fault tolerance and load balancing for your network traffic.

Dedicated connections are a type of AWS Direct Connect connection that provides a dedicated network circuit between your on-premises data center and AWS. This dedicated circuit ensures consistent network performance, improved security, and increased bandwidth. With a dedicated connection, you can establish a dedicated private connection between your organization and AWS, bypassing the public internet, improving privacy, and minimizing latency. As a result, you can reduce costs and increase performance for critical applications running in AWS. Dedicated connections are often requested by larger organizations with higher bandwidth requirements, strict compliance needs, or more complex networking scenarios.

Hosted Connections are a type of AWS Direct Connect connection that is provisioned through an AWS Direct Connect partner. Rather than establishing a dedicated network connection, Hosted Connections enable you to share the same physical connection with multiple AWS accounts. With Hosted Connections, customers can leverage the AWS Direct Connect partner's existing network infrastructure and connectivity to AWS, providing an easy way for smaller organizations to benefit from AWS Direct Connect without the need for dedicated network resources. Hosted connections are limited in terms of bandwidth compared to dedicated connections, but they offer a more cost-effective option for customers with lower bandwidth requirements or less stringent performance requirements.

Virtual interfaces (VIFs) are AWS Direct Connect components that allow you to connect your on-premises infrastructure to AWS services. Public and private VIFs describe two different types of virtual interface configurations that enable access to a variety of AWS resources. Public VIFs enable you to connect to AWS public resources such as Amazon S3, AWS global services, and public IPv4 and IPv6 IP addresses. Private VIFs enable you to connect your on-premises network with resources within one or more Amazon Virtual Private Clouds (VPCs). Choosing between public and private VIFs depends on your organization's requirements for accessing specific AWS services, security, and isolation in different network scenarios.

Direct Connect resiliency refers to the redundancy and availability of your AWS Direct Connect connections. To ensure high availability and fault tolerance, it is essential to design redundant and diverse network architectures. AWS Direct Connect supports resiliency by allowing you to deploy multiple connections and redundant virtual interfaces. For example, you can use multiple direct connect locations, diversely routed AWS Direct Connect circuits, or alternate paths through AWS Direct Connect partners. Creating a resilient network design using AWS Direct Connect helps you minimize downtime, maintain redundancy, and improve failover capabilities to ensure continuous operation of your applications and services hosted in AWS.

Transit Virtual Interfaces (transit VIFs) are a type of AWS Direct Connect virtual interface that enables you to use AWS Direct Connect to connect your on-premises network with AWS Transit Gateway resources. Transit VIFs provide a single interface for connecting multiple VPCs through the AWS Transit Gateway. By using Transit VIFs and Transit Gateway, you can centralize and simplify the management of inter-VPC routing, including Edge-to-Edge routing between VPCs, VPN connections, and your on-premises infrastructure. Transit VIFs make it easy to scale your network connectivity, support multi-account environments, and improve the security and manageability of your AWS hybrid cloud infrastructure.