Understanding Network Topologies for Oracle Database@AWS: A Practical, Real-World Guide

Deploying Oracle Database@AWS is not just about provisioning a database or choosing the right Exadata configuration. The foundation of a reliable deployment lies in selecting the right network topology. Network architecture determines latency, security, availability, cost, and long-term scalability.

Oracle Database@AWS gives cloud architects several ways to connect applications with the database layer, ranging from simple single–availability–zone deployments to multi-region and hybrid scenarios. Each topology is suited for a different business requirement—latency-sensitive workloads, multi-line-of-business architectures, DR architectures, or hybrid modernization programs.

This blog breaks down these topology options in clear, practical language so you can confidently choose the right architecture for your environment.

Why Network Topology Matters for Oracle Database@AWS

Before selecting a topology, it helps to understand how Oracle Database@AWS is organized.

A few core principles apply to all topologies:

• Each VM cluster belongs to a single ODB (Oracle Database@AWS) network in one availability zone.

• Multiple VM clusters—Autonomous or Exadata—can run within the same ODB network.

• An ODB network can be peered with only one VPC in the region.

• VM clusters cannot be moved between ODB networks after deployment.

• ODB networks can be shared across AWS accounts within the same organization.

• AWS Transit Gateway (TGW) or Cloud WAN may be used to connect multiple VPCs to ODB networks.

• IPs for the database cluster come from the CIDR assigned to the Client subnet.

CIDR ranges also require attention:

• Client subnet must be at least /27 (Oracle recommends /24 for future growth).

• Backup subnet for Autonomous DB should be at least /28.

• No CIDR block may overlap with any AWS VPC, OCI VCN, or external database clients.

These fundamentals are important because they influence which topology you can use and how traffic flows throughout the system.

Network Topology Options for Oracle Database@AWS

Oracle Database@AWS supports five primary network architectures:

1. Same availability zone connectivity

2. Same availability zone with multiple VM clusters

3. Cross-VPC connectivity in the same region (Hub-and-Spoke)

4. Cross-region connectivity (Hub-and-Spoke)

5. On-premises hybrid connectivity (Hub-and-Spoke)

Each model is explained below:

1. Same Availability Zone Connectivity

This is the most straightforward topology and provides the lowest latency because both the database and applications reside in the same AWS availability zone.

When to use this topology

• Latency-sensitive OLTP workloads

• Real-time financial or industrial applications

• Applications requiring extremely fast round-trip times

• Simpler deployments without multi-VPC complexity

How it works

• The Application VPC is in the same availability zone as the ODB network.

• An ODB peering connection links the VPC and the database.

• Applications in separate subnets connect directly to Oracle Database@AWS.

Why it works well

• No cross-zone charges

• No transit through Transit Gateway

• Lowest possible network latency

This is the recommended model whenever application and database can be colocated in the same AZ.

2. Same Availability Zone with Multiple VM Clusters

Some organizations need multiple isolated environments within the same availability zone. This may be for separating:

• Dev, QA, and Prod

• Multi-tenant customer environments

• Separate business domains

• Compliance and data segmentation requirements

How this topology functions

• Multiple VM clusters (Autonomous or Exadata) run on the same Exadata Infrastructure.

• Each VM cluster has its own ODB network.

• The same Application VPC may access multiple VM clusters if required.

• ODB networks can be shared across different AWS accounts, enabling strong isolation.

Benefits

• Logical and security isolation

• Can scale VM clusters independently

• Lower cost compared to separate dedicated hardware

This topology is popular for enterprises running many teams or separate product workloads.

3. Cross-VPC Connectivity in the Same Region (Hub-and-Spoke)

This is one of the most commonly used enterprise architectures.

Instead of connecting one VPC directly to the ODB network, multiple VPCs connect through a hub using AWS Transit Gateway or Cloud WAN.

Use cases

• Organizations with many application teams and VPCs

• Centralized access to a single database for multiple LoBs

• Traffic inspection via firewalls before reaching the database

• Multi-AZ application architectures needing a shared database backend

How it works

• A hub VPC peers with the ODB network.

• All other VPCs (spokes) route traffic to the hub using TGW or Cloud WAN.

• Optionally, a firewall cluster in the hub can inspect inbound database connections.

Design considerations

• Latency increases slightly due to TGW routing

• Ensure Transit Gateway route tables are configured correctly

• Keep the TGW attachments in the same AZ for best performance

This topology is ideal for regulated industries and large enterprise environments where segmentation and central governance are critical.

4. Cross-Region Connectivity (Hub-and-Spoke Across Regions)

Some organizations operate across multiple AWS regions and still require centralized or synchronized access to Oracle Database@AWS.

This topology connects multiple regions using:

• A Transit Gateway in each region

• A peering connection between the Transit Gateways

Use cases

• Cross-region data replication

• DR/BCP architecture

• Region-to-region analytics and reporting

• Centralized management of databases from a remote region

Key design points

• Latency varies by geography—validate application performance

• Cross-region bandwidth charges may apply

• Cloud WAN can replace TGW for global connectivity

• A consistent routing strategy is critical for multi-region deployments

This is the preferred design for global enterprises running workloads in multiple regions with centralized data operations.

5. On-Premises (Hybrid) Connectivity Using Hub-and-Spoke

Hybrid connectivity is essential for organizations not fully migrated to AWS, or for those maintaining critical workloads on-premises.

This topology extends on-prem connectivity to the ODB network through a Transit Gateway hub.

Use cases

• Gradual migration of Oracle workloads to cloud

• Hybrid DR strategy (on-prem primary, cloud DR or vice versa)

• Applications that must remain on-prem due to compliance

• Mixed-mode deployments during modernization

How it works

• On-prem connects to AWS through VPN or Direct Connect

• Transit Gateway routes traffic between on-prem and ODB network

• Database access is uniform across cloud and on-prem environments

Oracle recommendations

• Use Direct Connect for predictable performance

• Place the TGW attachment in the same AZ as the ODB network

• Validate latency-sensitive workloads before production cutover

This is the architecture many organizations adopt initially and gradually evolve toward fully cloud-native designs.

Key Components Across All Topologies

While the topology may change, the core infrastructure components remain the same.

Amazon VPC -Defines your virtual network and IP ranges.

Subnets- Dedicated IP ranges for compute, services, and database connectivity.

AWS Direct Connect Gateway- Enables secure, low-latency connectivity from on-premises to multiple VPCs.

AWS Transit Gateway- Connects multiple VPCs and hybrid networks through a central hub.

AWS Cloud WAN- Provides a global network backbone for cross-region and hybrid architectures.

ODB Network- Oracle-managed private network that hosts Oracle Database@AWS within an availability zone.

These components form the building blocks for each deployment pattern.

Selecting the Right Topology: Practical Guidance

Choosing the best network model depends on:

1. Latency requirements

If the application is extremely latency-sensitive, choose same availability zone.

2. Number of VPCs

If multiple teams need access, use hub-and-spoke in the same region.

3. Multi-region footprint

For global deployments, use cross-region connectivity.

4. Hybrid workloads

If workloads need both on-prem and cloud access, choose hybrid hub-and-spoke.

5. Compliance and isolation

If strict segmentation is required, choose multiple VM clusters in the same AZ.

The goal is not just connectivity—it is to ensure predictable performance, governance, and future scalability.

Final Thoughts

Oracle Database@AWS brings Oracle’s high-performance Exadata and Autonomous Database capabilities directly into AWS environments, but the network topology you choose defines the success of the deployment. A well-designed architecture ensures low latency, secure access, smooth scaling, and operational consistency.

Whether you are modernizing an existing workload, building a new multi-VPC application tier, extending hybrid connectivity, or architecting for multi-region resilience—Oracle Database@AWS provides the flexibility to support each scenario through clear and powerful networking patterns.

Understanding these topologies empowers teams to build deployments that are not only functional but future-ready.