Configuring an InterLink

Once your InterLink has been created and the provisioning process is complete, you must complete a number of configuration steps to enable traffic to flow across the InterLink.

This document explains the process in full, and gives tips for troubleshooting any potential issues.

Configuration overviewLink to this anchor

The diagram above shows the four configuration steps necessary for an InterLink. Only when all steps have been completed can traffic flow across the InterLink, connecting the Scaleway VPC to the external (on-premises) infrastructure.

Read more about each step, and possible errors at each stage, in the following sections.

1. Create the InterLinkLink to this anchor

Creating an InterLink is itself a multi-step process, that requires action on both the Scaleway side, and on the partner side. This process is explained in full in Provisioning an InterLink.

You must wait until the InterLink has reached Active status before you can continue with the following configuration steps.

2. Attach VPCLink to this anchor

Attaching an InterLink to a VPC allows you to complete the connection from your external infrastructure, across the InterLink, to the Scaleway resources in the selected VPC.

The VPC must be in the same region as the InterLink. An InterLink can only be attached to one VPC at a time, but you are free to detach the VPC and attach a different one whenever you like.

Follow the instructions for attaching a VPC via the console, or use the Attach a VPC endpoint of the API.

3. Attach routing policyLink to this anchor

InterLink uses Border Gateway Protocol to exchange routing information between the customer’s infrastructure and the Scaleway VPC. Each side advertises IP prefixes for its own internal subnets and resources, to allow the other side to dynamically learn and update its internal routes, facilitating efficient traffic flow. However, by default, all routes across an InterLink are blocked. You must create and attach a routing policy aka routing policy, to set IP prefix filters for the route advertisements you want to whitelist. This facilitates traffic flow across the InterLink.

Follow the instructions and tips for creating a routing policy, via the console. Alternatively, you can create and attach routing policies via the API.

See our dedicated documentation on using BGP communities to influence route priority for InterLink traffic.

4. Activate route propagationLink to this anchor

Once you have attached a VPC and defined the routing policy, you must activate route propagation to allow traffic to flow over the InterLink. This enables all prefixes whitelisted in your routing policy to be announced in the BGP session, so that traffic can flow along these routes. See the documentation for activating route propagation via the API or the console

You can deactivate route propagation at any time. When you do this, all routes are blocked and removed from the VPC’s route table. No traffic can flow across the InterLink until route propagation is reactivated.