z ‐ Different scenarios for VCN‐to‐VCN communication - SanjeevOCI/Ocidocs GitHub Wiki

1. VCN Peering (Local Peering)

Use Case:
To connect two VCNs within the same region and same tenancy.

Service Used:

  • Local Peering Gateway (LPG)

Key Points:

  • Low-latency, private communication.

  • Each VCN must have an LPG and a route rule to direct traffic to the other VCN.

  • Security list or NSG rules must allow traffic.


🔹 2. Remote VCN Peering

Use Case:
To connect VCNs in different regions but same tenancy.

Service Used:

  • Remote Peering Connection (RPC) with Dynamic Routing Gateway (DRG)

Key Points:

  • Enables cross-region private traffic.

  • Requires DRGs in both VCNs and a remote peering connection between them.


🔹 3. VCN Peering Across Tenancies

Use Case:
To connect VCNs in different tenancies (e.g., B2B, partner access).

Service Used:

  • Local or Remote Peering, depending on location.

  • Identity policies (IAM) must be configured for cross-tenancy access.

Key Points:

  • More secure and controlled sharing.

  • Requires collaboration between tenancy administrators.


🔹 4. Hub-and-Spoke Architecture

Use Case:
To manage multiple VCNs centrally, often in complex environments with many applications or business units.

Service Used:

  • DRG as a transit hub

  • VCN attachments to the DRG

  • DRG Route Tables and DRG Attachments

Key Points:

  • Centralizes connectivity and routing.

  • Simplifies management.

  • Supports inspection, logging, or security appliances between VCNs.


🔹 5. VPN or FastConnect Between VCNs

Use Case:
Less common, but sometimes used for special security controls or segmentation.

Service Used:

  • IPSec VPN or FastConnect

  • Could use on-prem as an intermediary

Key Points:

  • More complex setup.

  • Usually not recommended for intra-region VCN connections.


🔹 Summary Table

Scenario Same Region? Same Tenancy? Service Used
Local Peering Yes Yes Local Peering Gateway (LPG)
Remote Peering No Yes DRG + Remote Peering
Cross-Tenancy Peering Yes/No No LPG or DRG + IAM Policies
Hub-and-Spoke (Transit Routing) Yes/No Yes/No DRG + Attachments
VPN/FastConnect Between VCNs Optional Optional IPSec VPN / FastConnect
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