Cisco APIC Layer 3 Networking Configuration Guide, Release 6.2(x)

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Cisco APIC Layer 3 Networking Configuration Guide, Release 6.2(x)

Route reflectors

Updated: April 17, 2026

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Describes how MP-BGP route reflectors distribute external routes across an ACI fabric and provide redundant connectivity between fabric leaf switches and external networks.

An ACI fabric route reflector is a spine switch that

  • uses MP-BGP to distribute external routes throughout the fabric

  • requires you to select spine switches for the route reflector role

  • requires an autonomous system number, and

  • provides redundancy when you configure at least two spine switches as route reflectors in each pod.

External connectivity and route distribution

After you enable route reflectors, configure L3Outs on leaf switches to connect the fabric to external networks. Leaf switches that provide this connectivity are called border leaf switches.

Each border leaf switch exchanges routes with external devices through dynamic routing protocols or static routes. The spine route reflectors then distribute these routes to all leaf switches in the fabric.

Note

For the maximum number of routes supported on each leaf switch, refer to the Verified Scalability Guide for Cisco APIC for your release.

Configure MP-BGP route reflector using the GUI

Procedure

  1. From the menu bar, choose System > System Settings.

  2. In the Navigation pane, right-click BGP Route Reflector, and choose Create Route Reflector Node.

  3. In the Create Route Reflector Node dialog box, choose the spine switch that you want to configure from the Spine Node drop-down list, and click Submit.

    Note

    Repeat the node-creation process for each additional spine switch.

    The APIC designates the spine switch as a route reflector.

  4. In the BGP Route Reflector properties area, enter the autonomous system number in the Autonomous System Number field, and click Submit.

    Note

    If the external router uses BGP, the autonomous system number must match the autonomous system number configured on the router connected to the leaf switch. If the fabric learns routes through static routing or OSPF, you can enter any valid autonomous system number.

  5. From the menu bar, choose Fabric > Fabric Policies > Pods > Policy Groups.

  6. In the Navigation pane, right-click Policy Groups, and choose Create Pod Policy Group.

  7. In the Create Pod Policy Group dialog box, enter a name for the pod policy group in the Name field.

  8. From the BGP Route Reflector Policy drop-down list, choose the BGP route reflector policy, and click Submit.

    The APIC associates the BGP route reflector policy with the pod policy group and enables the BGP process on the leaf switches.

  9. From the menu bar, choose Fabric > Fabric Policies > Profiles > Pod Profile default > default.

  10. In the Work pane, choose the pod policy group that you created from the Fabric Policy Group drop-down list, and click Submit.

    The APIC applies the pod policy group to the fabric policy group.

Verify the MP-BGP route reflector configuration

Procedure

  1. Verify the MP-BGP process on each leaf switch.

    1. Use Secure Shell (SSH) to log in to each leaf switch as an administrator.
    2. Enter the show processes | grep bgp command and verify that the process state is S.

      A state of NR indicates that the process is not running and that the configuration was unsuccessful.

  2. Verify the autonomous system number on each spine switch.

    1. Use SSH to log in to each spine switch as an administrator.
    2. Enter these commands in the shell:

      Example:

      cd /mit/sys/bgp/inst
								grep asn summary

    The command displays the configured autonomous system number. A value of 0 indicates that the configuration was unsuccessful.