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

BGP fast external fallover

Updated: February 28, 2026

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Overview

Guidelines for BGP fast external failover
Configure the eBGP session packet rate

Overview

Introduces BGP Fast External Fallover for rapid detection of eBGP neighbor failures, recommends increasing packet rates for large deployments, and guides configuration of eBGP session packet rate.

BGP fast external fallover is a routing feature that

automatically resets all BGP sessions of directly adjacent external peers when a link goes down
ensures immediate response to link failures affecting eBGP connections, and
can be disabled or re-enabled to favor either session stability or rapid convergence.

Guidelines for BGP fast external failover

To prevent eBGP session flapping when your node reaches 3500 eBGP sessions with BGP timer values set to 10 and 30, increase the packet rate. Use the lpts pifib hardware police location location-id command to raise the packet rate and support more than 3500 eBGP sessions.

Applies when managing high numbers of eBGP sessions on a node.

Increasing the packet rate prevents session instability caused by timer settings and session volume.

Ensures stable BGP session management under heavy session loads.

Configure the packet rate using the command lpts pifib hardware police location command.

Configure the eBGP session packet rate

This task instructs you on how to increase the packet rate for BGP traffic, which helps support a higher number of eBGP sessions and prevent session flapping in large-scale deployments.

Before you begin

Ensure you have access to the router’s global configuration mode and the necessary permissions to modify LPTS PIFIB hardware policing settings.

Procedure

To increase the packet rate for BGP traffic and support a higher number of eBGP sessions, configure the LPTS PIFIB hardware policing settings as follows

Example:

Router# configure
Router(config)# lpts pifib hardware police location 0/2/CPU0
Router(config-pifib-policer-per-node)# flow bgp configured rate 4000
Router(config-pifib-policer-per-node)# flow bgp known rate 4000
Router(config-pifib-policer-per-node)# flow bgp default rate 4000

This configuration helps prevent session flapping in large-scale deployments by allowing the router to handle increased BGP packet rates efficiently.

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