Role of Dynamic Routing Gateway (DRG) in a Hybrid OCI Setup

In a hybrid cloud setup, where your enterprise workloads are split between on-premises data centers and Oracle Cloud Infrastructure (OCI), reliable and secure network connectivity is a must. The Dynamic Routing Gateway (DRG) is the backbone component that makes this connectivity work.

Let’s break down what DRG does, why it matters, and how it fits into a typical hybrid architecture.

What Is a DRG in OCI?

A Dynamic Routing Gateway (DRG) is a virtual router provided by OCI. It sits at the edge of your Virtual Cloud Network (VCN) and acts as the connection point between OCI and external networks, such as:

• On-premises data centers via IPSec VPN
• Dedicated connectivity via FastConnect
• Other VCNs in different regions via Remote Peering
• Third-party networks or SaaS environments

It supports dynamic routing protocols like BGP (Border Gateway Protocol), which enables route exchange and failover between your cloud and on-prem environment.

Key Functions of DRG in a Hybrid Setup

DRG in Action: A Common Hybrid Architecture

Imagine this setup:

• Your core ERP systems run on-premises
• Reporting, data lake, or AI workloads run on OCI
• A FastConnect link connects your data center to OCI

In this case, the DRG:

• Accepts the FastConnect connection
• Routes traffic between your VCN and your on-prem networks
• Enforces routing policies (e.g., traffic to specific subnets only)
• Supports dynamic BGP updates if routes change (failover, rerouting)

If your on-premises has dual routers and you set up multiple IPSec tunnels, DRG helps orchestrate failover and reroute automatically.

DRG Attachments and Routing

DRG uses a modular attachment model:

1. VCN Attachment: Connects the DRG to one or more OCI VCNs
2. IPSec Attachment: Connects to your VPN tunnel(s)
3. FastConnect Attachment: Used when connecting via private circuits
4. Remote Peering Attachment: Connects to other DRGs in different regions
5. Virtual Circuit Attachment: When using provider FastConnect

Each attachment is connected via route tables, so you can define granular routing behavior per connection.

Why DRG Is Crucial in Hybrid Cloud

• Centralized Network Control: DRG acts as the single routing gateway between OCI and external networks.
• Scalable Architecture: You can use one DRG to manage multiple VCNs, regions, or tunnels.
• Reduced Complexity: Instead of building NATs, proxies, or manual routes, DRG simplifies cross-network traffic.
• Redundancy and Failover: DRG supports route failover using BGP and multiple tunnels for enterprise-grade uptime.

Best Practices

• Use DRG route tables to control traffic between attachments (don’t assume everything is allowed by default).
• Enable BGP for dynamic route exchange and faster failover in VPN/FastConnect.
• Use Compartment-level segregation for DRG and route tables to maintain policy control.
• Use Monitoring and logging to watch for latency, route flapping, or tunnel downtime.
• When connecting to multiple regions, design your remote peering through DRGs for secure intra-region traffic.

In a hybrid cloud world, where cloud and on-prem must work together, the Dynamic Routing Gateway is your network bridge. It is flexible, secure, and scalable—designed to handle complex enterprise routing needs without the traditional network headache.

Whether you’re migrating workloads gradually, building DR sites in OCI, or extending data lakes to the cloud, DRG is your anchor point for hybrid network design.

Further Reading

• Oracle DRG Overview

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Brijesh Gogia

I’m an experienced Cloud and AI Architect with over 19 years in Oracle Applications, Databases, and Cloud ecosystems. My work spans large-scale, global projects where I’ve designed and optimized solutions across both Oracle and non-Oracle stacks—on-prem and in the cloud. Lately, my focus has shifted toward integrating AI into enterprise architectures, leveraging GenAI, automation, and data intelligence to drive performance, resilience, and modernization. I’m passionate about exploring emerging AI tools, agentic workflows, and practical use cases—and I'm fortunate that my role gives me space to experiment and share my learnings.

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