...
Q: What traffic is routed through the DC?
A: There are two choices:. See diagrams in AWS Direct Connect Routing Diagrams.
RFC1918 Routing
For Cornell AWS accounts with DC configured for RFC1918 routing, only 10-space traffic (specifically 10.0.0.0/8) is routed from on-campus 10-space to 10-space addresses in Cornell Standard AWS VPCs. This means that traffic from servers and clients with (only) public campus IP addresses cannot access the 10-space networks in a Cornell Standard AWS VPC.
...