New – Direct VPC Routing Between On-Premises Networks and AWS Outposts Rack

Today, we announced direct VPC routing for AWS Outposts rack. This enables you to connect Outposts racks and on-premises networks using simplified IP address management. Direct VPC routing automatically advertises Amazon Virtual Private Cloud (Amazon VPC) subnet CIDR addresses to on-premises networks. This enables you to use the private IP addresses of resources in your VPC when communicating with your on-premises network. Furthermore, you can enable direct VPC routing using a self-serve process without needing to contact AWS.

AWS Outposts rack

If you’re unfamiliar, AWS Outposts rack, a part of the Outposts family, is a fully-managed service that offers the same AWS infrastructure, AWS services, APIs, and tools to virtually any on-premises datacenter or co-location space for a consistent hybrid experience. They’re ideal for workloads that require low-latency access to on-premises systems, local data processing, data residency, and migration of applications with local system interdependencies. Once installed, your Outposts rack becomes an extension of your VPC, and it’s managed using the same APIs, tools, and management controls that you already use in the cloud.

With direct VPC routing, you now have two options to configure and connect your Outposts rack to your on-premises networks. Previously, to configure network routing between an on-premises network and an Outposts rack, you needed to use Customer-owned IP addresses (CoIP). During an Outposts rack installation, this involved providing a separate IP address range/CIDR from your on-premises network for AWS to create an address pool, which is known as a CoIP pool. When an Amazon Elastic Compute Cloud (Amazon EC2) instance on your Outposts rack needed to communicate with your on-premises network, Outposts rack would perform a 1:1 network address translation (NAT) from the VPC private IP address to a CoIP address in the CoIP pool. Using CoIP means that you must manage both VPC and CoIP address pools, without overlap, and configure route propagation between the two sets of addresses. When adding a subnet to a VPC, you also needed to follow several steps to update route propagation between your networks to recognize the new subnet addresses.

Managing IP address ranges for AWS cloud and onsite resources, as well as dealing with CoIP ranges on Outposts rack, can be an operational burden. Although the option to use CoIP is still available and will continue to be fully supported, the new direct VPC routing option simplifies your IP address management. Automatic advertisement of CIDR addresses for subnets, including new subnets added in the future, between the VPC and your Outposts rack, removes the need for you to reconfigure IP addresses. This also keeps route propagation up-to-date, thereby saving you time and effort. Furthermore, as mentioned earlier, you can enable all of this with a self-serve option.

Enabling Direct VPC Routing
You can select either CoIP or direct VPC routing approaches and utilize a new self-service API, CreateLocalGatewayRouteTable, to configure direct VPC routing for both new and existing Outposts racks. This eliminates the need to contact AWS to enable the configuration. To enable direct VPC routing, simply set the mode property in the CreateLocalGatewayRouteTable API’s request parameters to the value direct-vpc-routing. If you’re already using CoIP, then you must delete and recreate the route table that’s propagating traffic between the Outposts rack and your on-premises network.

The following example diagram, taken from the user guide, illustrates the setup for an Outposts rack running several Amazon EC2 instances and connected to an on-premises network, with automatic address advertisement. Note that private IP address ranges are utilized across the Outposts rack resources and the on-premises network.

Example of direct VPC routing

Get started with Direct VPC Routing today
The option to enable direct VPC routing is available now for both new and existing Outposts racks. As mentioned earlier, the option to use CoIP will continue to be supported, but now you can choose between direct VPC routing and CoIP based on your on-premises networking needs. Direct VPC routing is available in all AWS Regions where Outposts rack is supported.

Find more information on this topic in the AWS Outposts User Guide. More information on AWS Outposts rack is available here.

— Steve

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