Hybrid Cloud Connectivity Network
A hybrid connectivity design linking on-premises data centers to the cloud over a dedicated circuit with redundant VPN backup and BGP failover. It delivers private, resilient networking for migrations and hybrid workloads.
What and When
Hybrid connectivity links on-premises data centers to the cloud over private, predictable paths rather than the public internet. It is the backbone for migrations, hybrid applications, and workloads that must reach systems in both worlds. Build this when latency and bandwidth between sites matter, when compliance forbids sensitive traffic over the internet, or when a phased migration leaves systems running in both locations.
The design combines a dedicated circuit for performance with redundant VPN tunnels for resilience, joined by dynamic routing.
Components
- Direct Connect (or the provider equivalent) is a dedicated private circuit giving consistent bandwidth and low latency.
- VPN gateway provides encrypted tunnels over the internet as a backup path and for lower-volume sites.
- BGP routing dynamically advertises routes and fails over between the dedicated link and VPN automatically.
- Transit gateway is the cloud-side hub that connects on-premises to many cloud networks.
- Redundant circuits at separate locations remove single points of failure.
- DNS forwarding resolves names consistently across on-premises and cloud; a firewall inspects cross-boundary traffic.
Data Flow
Traffic from an on-premises system destined for the cloud enters the Direct Connect circuit and reaches the transit gateway, which routes it to the correct cloud network. BGP advertises reachable prefixes in both directions and, if the dedicated circuit fails, withdraws those routes so traffic shifts to the VPN tunnels automatically. DNS forwarding lets workloads resolve each other by name across the boundary, and the firewall inspects the flows.
Scaling and Resilience
The combination of a dedicated circuit plus VPN backup balances performance and resilience: normal traffic takes the fast private path, and failover to VPN keeps connectivity during a circuit outage. Provision redundant circuits at diverse locations to avoid a single facility failure. BGP makes failover automatic and fast. Size bandwidth for peak migration transfers, which can be far higher than steady-state traffic.
Security
Private circuits keep traffic off the public internet, but treat the link as untrusted under zero trust: encrypt sensitive flows even over Direct Connect, and inspect cross-boundary traffic with a firewall. Apply least-privilege routing so only required networks are reachable. Segment on-premises and cloud so a compromise on one side does not freely traverse to the other. Log and monitor the boundary for anomalies.
Trade-offs and Alternatives
Dedicated circuits cost more and take weeks to provision but deliver consistent performance the internet cannot guarantee. VPN-only connectivity is cheaper and faster to set up but is subject to internet variability and bandwidth limits. SD-WAN can simplify managing many sites. Use the dedicated-plus-VPN pattern when performance and resilience both matter; use VPN-only for small or temporary needs.