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Network topology

Network topology provides a visual representation of your virtual network in Azure. It helps you understand the relationships between your network resources, including virtual machines, virtual network gateways, load balancers, and more. This visual map aids in troubleshooting and comprehending the overall network architecture.

Understanding the Network Topology View

The Network topology view displays your Azure virtual network resources and their connections. You can see:

  • Virtual Machines (VMs) and their network interfaces (NICs).
  • Virtual Network Gateways (VPN and ExpressRoute).
  • Load Balancers (Azure Load Balancer and Application Gateway).
  • Peered virtual networks.
  • Network Security Groups (NSGs) associated with NICs and subnets.
  • Public IP addresses.
Azure Network Watcher Topology Example

Figure 1: An example of a Network Watcher topology view.

Key Features and Benefits

  • Visual Clarity: Gain a clear, graphical understanding of your network infrastructure.
  • Relationship Mapping: See how different resources are connected and interact.
  • Troubleshooting Aid: Quickly identify potential bottlenecks or misconfigurations by observing the network flow.
  • Resource Management: Easily access details about individual resources directly from the topology map.
  • Compliance and Auditing: Provides a snapshot for understanding network configurations for compliance purposes.

How to Access Network Topology

You can access the Network topology feature through the Azure portal:

  1. Navigate to Network Watcher in the Azure portal.
  2. Under the Network monitoring section, select Topology.
  3. Choose the subscription, resource group, and virtual network you want to visualize.
  4. Click Display topology.

Interacting with the Topology View

  • Resource Details: Click on any resource in the map to open a pane with its properties and related configurations.
  • Filtering: You can filter the view to show specific types of resources or connections.
  • Drill Down: For complex networks, you can often drill down into subnets or specific resource groups to get a more granular view.

Example Use Case: Diagnosing Connectivity Issues

Imagine a VM can't connect to an external service. By viewing the network topology, you can:

  1. Locate the VM and its associated NIC.
  2. Check the connected subnet and its NSG rules.
  3. Verify if the VM is behind a firewall or NAT gateway.
  4. Examine connections to any load balancers or VPN gateways that might be involved.

This visual approach significantly speeds up the diagnostic process compared to reviewing configuration settings individually.

Best Practices

  • Keep your virtual network architecture organized and documented.
  • Regularly review your network topology to ensure it aligns with your security and performance requirements.
  • Utilize the topology view in conjunction with other Network Watcher tools like Connection Monitor and Packet Capture for comprehensive network analysis.

For more detailed information on specific resource types and their representation in the topology, please refer to the individual documentation pages for each service.

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