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Showing posts from December, 2019

AWS Transitive routing with Transit Gateways in the same region

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Gilles Chekroun
Lead VMware Cloud on AWS Specialist
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At the AWS Re:invent 2019 conference, the long waited TGW peering functionality was announced and available in a few AWS regions. This is an INTER-REGION peering only meaning that the Transit Gateways need to be in different regions.
Hoping that AWS will soon release an INTRA-REGION capability I discussed with a few AWS Solutions Architects in Las Vegas, among them Tom Adamski, about using a VPC as a bridge between two TGWs in the same region. Tom assured me that it is possible opening for the first time the transitive routing capability in AWS networking.

Well . . . I needed to test that and see by myself.
Test bed
For a simple test, I will use 2 TGWs in the same regions with 2 VPCs attached each and another VPC as "bridge" connected to both TGWs. Yes you can connect a VPC up to 5 TGWs.
The whole idea is to use this "bridging VPC" and point the default route of the TGWs to it. To do that I create 2 subnets on the bri…