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

Enhanced monitoring of BGP memory utilization

Updated: February 28, 2026

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Overview

Outlines advanced monitoring tools for BGP memory utilization and provides steps to monitor and analyze memory resources dedicated to BGP processes.

Enhanced monitoring of BGP memory utilization is a network monitoring feature that

tracks memory usage by the BGP process within a device,
provides periodic memory state checks and logs changes, and
triggers notifications when memory usage approaches critical thresholds.

This feature serves as an early warning system to help you maintain network stability and performance by proactively managing BGP memory consumption.

Table 1. Feature History Table
Feature Name	Release Information	Feature Description
BGP Link-State	Release 25.4.1	Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only) This feature is now supported on: 8011-32Y8L2H2FH 8011-12G12X4Y-A 8011-12G12X4Y-D
BGP Link-State	Release 25.1.1	Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only) This feature is supported on Cisco 8011-4G24Y4H-I routers.
BGP Link-State	Release 24.4.1	Introduced in this release on: Fixed Systems (8200 [ASIC: P100], 8700 [ASIC: P100, K100])(select variants only); Modular Systems (8800 [LC ASIC: P100])(select variants only) You can proactively maintain network stability and performance with early warnings about high BGP memory usage. This feature tracks BGP process memory, checks usage every 60 seconds, and logs changes in both the BGP trace log and a circular buffer. It records any memory increase over 1% of the set resource limit and sends syslog notifications at 85%, 90%, and 95% of the limit, enabling you to detect and address issues before they affect your network. This feature is supported on: 8212-48FH-M 8711-32FH-M 8712-MOD-M 88-LC1-36EH 88-LC1-12TH24FH-E 88-LC1-52Y8H-EM

Key features of enhanced monitoring of BGP memory utilizations:

Periodic Memory State Check: The system automatically monitors memory usage every 60 seconds to detect issues promptly while minimizing overhead.
Logging Mechanism: Memory changes are recorded in both the BGP trace log and a circular buffer, ensuring reliable data for troubleshooting.
Significant Change Detection: Any increase in memory usage exceeding 1% of the configured resource limit (rlimit) since the last report is logged to identify trends or spikes.
Resource Limit (rlimit): This predefined threshold limits the maximum memory BGP can use to prevent system instability caused by excessive memory consumption.
Syslog Notifications: Notifications are sent to syslog at 85%, 90%, and 95% of the resource limit, escalating in frequency as memory usage nears the limit to alert administrators effectively.

Monitor BGP memory utilization

Track BGP memory usage changes when utilization exceeds 1% of the configured resource limit (rlimit) to maintain network stability.

Use the show bgp memory history command to review BGP memory usage changes exceeding 1% of the resource limit for proactive monitoring.

Before you begin

Make sure you have appropriate access rights to run the show bgp memory history command on the device.

Follow these steps to monitor BGP memory utilization:

Procedure

Use the show bgp memory history command to view the data on memory utilization on the active router.

Example:


Router# show bgp memory history
History of memory changes recorded for a threshold greater than 1.0% of rlimit. 
Last shown record displays current values. 
Network information for default VRF. 

Time               Memory(MB)  Rlimit(%)  Memory diff(MB)  Networks  Paths     PathElems  Attributes 
Oct  2 16:30:37    152         1          152              400       400       400        9 
Oct  2 16:31:37    343         4          191              396952    396869    396952     725 
Oct  2 16:32:37    425         5          81               524567    513979    524567     8408 
Oct  2 16:42:38    741         9          316              1178605   1241533   1178604    10753 
Oct  2 16:43:38    985         12         243              1778234   1859254   1778234    11214 
Oct  2 19:42:39    901         11         -84              1800688   678607    1800688    10911 
Oct  2 19:45:39    766         9          -136             1332259   688784    1332259    10943

This command displays memory changes exceeding 1.0% of rlimit, with the last record showing current values and network information for the default VRF on the active router.

Use the show bgp memory history standby command to view the data on memory utilization on a standby router.

Example:


Router# show bgp memory history standby
History of memory changes recorded for a threshold greater than 1.0% of rlimit. 
Last shown record displays current values. 
Network information for default VRF. 

Time               Memory(MB)  Rlimit(%)  Memory diff(MB)  Networks  Paths     PathElems  Attributes  
Feb  9 03:39:04    98          1          98               0         0         0          0           
Feb  9 03:42:04    2913        35         2814             2372674   14546789  2372674    170613      
Feb  9 03:56:05    5832        71         138              3229253   35912290  3229253    387534      
Feb  9 03:57:05    5987        73         155              3229257   37416025  3229257    389403      
Feb  9 03:58:05    6133        74         145              3229257   38817868  3229257    390404      
Mar  2 00:26:46    6248        76         114              3229257   39991732  3229257    390551

This command displays memory changes exceeding 1.0% of rlimit, with the last record showing current values and network information for the default VRF on the standby router.

This table shows key fields from the show bgp memory history details output related to enhanced BGP memory utilization.

Table 2. Fields pertaining to enhanced monitoring of BGP memory utilization in the output of show bgp memory history details command
Field	Description
Time	Timestamp when the rmeasurement was taken.
Memory (MB)	Total memory in megabytes (MB) used by the routing process at the specified time.
Rlimit (%)	Percentage of the memory resource limit that is being used.
Memory diff (MB)	Quantity of memory usage in megabytes (MB) that has increased or decreased since the last report.
Networks	Number of network prefixes known to the router.
Paths	Number of distinct paths to various destinations.
PathElems	Number of path elements (such as AS numbers) involved in routing.
Attributes	Number of unique BGP attributes in use, such as local preference, and MED.

You obtain a detailed historical view of BGP memory usage for proactive monitoring of resource consumption.

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