By Paul Allen

In a previous post, I described the standard VPC configuration we use for Cornell AWS accounts requiring network connectivity back to the campus network. This post is to share minor updates of that configuration. Differences from the original are:

• Using AWS Direct Connect instead of a VPN to establish network connectivity between campus and AWS VPCs. Our current primary DC connection is 1Gbs, and our secondary connection is 100Mbs.
• Continued allocation of a /22 CIDR block (1024 addresses) to the VPC, but no longer allocating all of those addresses to subnets within the VPC. This allows for future customization of the VPC without having to vacate and delete /24 subnets as was necessary for VPC customization with the original design.
• Reducing the size of the four subnets to /26 CIDR blocks (64 addresses) instead of /24 CIDR blocks (256 addresses). This allows the flexibility described above, while still allowing /24 subnets to be created as part of VPC customizations.