Crossroads

Direct Connect with VPN backup

The problem A common AWS connectivity design is to have a direct connect (DX) connection with a VPN backup. There are some routing concerns to consider when implementing this design to make sure that traffic prefers the DX circuit and only uses the backup VPN path if the DX is unavailable. Traffic from AWS transit gateway (TGW) will always prefer the direct connect gateway (DXGW) path, but traffic in the other direction (to AWS) is dependent on the customer gateway (CGW) routing policy. ...

April 27, 2021 · 3 min · Jason Lavoie
Multi-region dual-stack TGW/DXGW design

Where AWS IPv6 networking fails

Introduction AWS has made much progress over the years with IPv6 support. From S3, EC2, Cloudfront, Route53, and EC2 support back in 2016, to more recent updates to NLB and the EC2 API, I’ve appreciated every advancement and patiently waited for the next. Unfortunately, there are still pieces missing that prevent me from making full use of IPv6 in my employer’s current environment. Existing architecture The architecture is modeled after one of AWS’s recommended connectivity designs. VPCs attach to a per-region transit gateway (TGW) for access to each other, shared services, on-prem network, our Azure VNets, and Internet access. In practice, a set of TGW route tables (common, campus, etc.) allow association and propagation with and to these various routes. ...

April 15, 2021 · 4 min · Jason Lavoie