You can now add routes in your AWS Outposts rack subnet route table to forward traffic between subnets within the same VPC spanning across disparate Outposts, using the Outpost local gateways (LGW). The LGW enables connectivity between your Outpost subnets and your on-premises network. With this enhancement, you can establish intra-VPC instance-to-instance IP communication across Outposts through your on-premise network, via direct VPC routing (DVR).
Source:: Amazon AWS