BGP Configuration Guide for Cisco 8000 Series Routers, Cisco IOS XR Releases

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BGP-RIB feedback mechanisms for update generation

Updated: February 28, 2026

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Overview

Introduces BGP-RIB feedback mechanisms, emphasizing best practices for advertising BGP routes only after FIB confirmation and provides instructions to configure BGP to wait for RIB feedback before sending updates.

The BGP-RIB feedback mechanisms for update generation are BGP route control mechanisms that

  • ensure routes are installed locally before advertising them to neighbors

  • track which route versions the forwarding information base (FIB) has consumed, and

  • send updates only for routes confirmed installed in the FIB to prevent premature advertisements.

These mechanisms help you avoid traffic loss caused by premature route advertisements after events like router reloads, line card online insertion and removal (LC OIR), or link flaps when alternate paths become available

You configure BGP to wait for routing information base (RIB) feedback before sending updates by using the update wait-install command in the router address-family IPv4 or router address-family VPNv4 configuration mode. This command ensures that BGP sends updates only after routes are confirmed installed in the forwarding information base (FIB), preventing premature route advertisements.

You can verify this configuration using the following commands:

  • show bgp

  • show bgp neighbors

  • show bgp process performance-statistics

This configuration helps you avoid traffic loss caused by premature route advertisements after events such as router reloads, line card online insertion and removal (LC OIR), or link flaps when alternate paths become available.

Guidelines for BGP-RIB feedback mechanisms

To prevent traffic loss and ensure reliable routing, always advertise BGP routes only after they are confirmed as installed in the Forwarding Information Base (FIB) via the BGP-RIB feedback mechanism.

  • ensure that BGP installs routes in the Routing Information Base (RIB) and waits for feedback from the RIB about installation in the FIB.

  • confirm that the RIB tracks which route versions are in the FIB using the BCDL feedback mechanism.

  • send BGP update messages only for routes confirmed as installed in the FIB, preventing premature advertisements that could cause packet loss or blackholing.

Configure BGP to wait for RIB feedback before sending updates

Enable BGP to delay advertising updates until routes are confirmed as installed in the FIB, preventing premature updates and possible traffic loss.

Use this configuration to enhance BGP routing reliability by ensuring updates are sent only after successful RIB-to-FIB installation confirmation.

Before you begin

  • Verify you have administrator access to the router.

  • Identify the AS number and desired address family (e.g., IPv4 unicast, VPNv4).

Follow these steps to configure BGP to wait for RIB feedback:

Procedure

1.

Enter router configuration mode for the desired address family.

Example:

Router# configure
Router(config)# router bgp 1
Router(config-bgp)# address-family ipv4 unicast
Router(config-bgp-af)# update wait-install
2.

Save the configuration.

Example:

Router#(config-bgp-af)# commit
3.

Use the show bgp process command to view the delay of the BGP process update since the last router reload.

Example:

Router# show bgp process
Wed Aug 24 00:40:48.649 PDT

BGP Process Information:
BGP is operating in STANDALONE mode
Autonomous System number format: ASPLAIN
Autonomous System: 100
Router ID: 192.168.0.2 (manually configured)
Default Cluster ID: 192.168.0.2
Active Cluster IDs:  192.168.0.2
------------------------------
------------------------------
Update wait-install enabled:
  ack request 2, ack rcvd 2, slow ack 0
  startup delay 10 secs

BGP on the router now delays advertising route updates until RIB confirms that routes are installed in the FIB, ensuring reliable route propagation and preventing traffic loss.

What to do next

Monitor BGP updates and verify network stability after applying the configuration.