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

Enhanced next hop monitoring

Updated: February 28, 2026

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Overview

Explains key concepts behind next hop monitoring enhancements for improved network path validation and diagnostic accuracy.

Enhanced next hop monitoring is network monitoring feature that

track changes in BGP next hop metrics and reachability,
provide detailed event data including counters and timestamps, and
aggregate statistics globally to assess network health dynamically.

This feature closely integrates BGP with the Routing Information Base (RIB) to receive notifications about next hop status changes, which trigger recalculations of optimal routing paths. This monitoring helps you identify root causes of network variations, especially during high routing activity or instability, which can strain CPU resources.

Table 1. Feature History Table
Feature Name	Release Information	Feature Description
Enhanced next hop monitoring	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
Enhanced next hop monitoring	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.
Enhanced next hop monitoring	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) Enhanced next hop monitoring dynamically assesses network health by tracking changes in BGP next hop metrics and reachability. It provides detailed event data, including counters and timestamps, and aggregates statistics globally. This feature integrates BGP with the Routing Information Base (RIB) to receive notifications about next hop status changes, triggering recalculations of optimal routing paths. This monitoring helps identify root causes of network variations, especially during high routing activity or instability, which can strain CPU resources. 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

These key monitoring functions provide detailed insights into next hop status changes and overall network health, enabling effective tracking and analysis:

Event counter tracking: Counts key events per next hop such as reachable, unreachable, metric increases, and decreases.
Event history logging: Records the last five events with timestamps for each next hop.
Recent event tracking: Logs transitions of next hops to reachable or unreachable states with precise timing.
Global aggregation: Summarizes event counters by Address Family Identifier (AFI) for overall network health insight.
Temporal counter analysis: Continuously updates event counts and reports changes over 1, 3, and 5-minute intervals, providing a dynamic view of network stability and routing effectiveness.

By using these monitoring capabilities, you can proactively manage BGP next hop changes, improving network reliability and performance.

Verify enhanced next hop monitoring

Use these commands to monitor BGP next-hop reachability, metric changes, and event counters to analyze routing dynamics and network stability.

This feature helps you promptly identify and analyze routing path changes, which is essential for maintaining network stability and performance, especially in large-scale environments. By using specific show commands, you can obtain detailed insights into next-hop status, event counters, and historical event data, enabling effective troubleshooting and optimization of routing decisions.

Before you begin

Before you begin, make sure that you have proper access rights and privileges to run BGP-related show commands on the router.

Follow these steps to monitor BGP enhanced next hop monitoring:

Procedure

Use the show bgp nexthops command to verify the details of nexthop reachability and metric change counters.

Example:

Router# show bgp nexthops
....
Next Hop        Reachable   Unreachable   MetricIncrease   MetricDecrease 

0.0.0.0 
10.10.10.1              1             0                0                0 
203.0.113.1             2             1                0                0 
192.168.0.3             1             0                1                2 
192.168.0.5             1             0                0                0 

.....

Use the show bgp nexthops wide command to verify detailed information about BGP next-hop processing times, status codes, event counters, and metrics for each gateway address family.

Example:

Router# show bgp nexthops wide
....
Next Hop            Status      Metric    Tbl-ID        Notf      LastRIBEvent    RefCount     R     U    MI    MD 

0.0.0.0                                                                                25/3 
10.10.10.1           [R][C][NL]       0      e0000000         1/0    00:14:52 (Cri)    17/20        1     0     0     0 
203.0.113.1          [R][NC][NL]      2      e0000000         0/0    00:02:06 (Reg)     5/7         1     0     0     0 
192.168.0.3          [R][NC][NL]      3      e0000000         0/0    00:02:06 (Reg)    12/246       1     0     0     0 
192.168.0.5          [R][NC][NL]      2      e0000000         1/0    00:14:17 (Cri)    16/270       1     0     0     0 

.....

Use the show bgp nexthops ipaddress command to verify detailed BGP next-hop information for the IP address 10.10.10.1, including VRF, nexthop ID, flags, advertising neighbors, RIB details, event history, and reference counts.

Example:

Router# show bgp nexthops wide
.....
Reachable Notifications:        2 (last at Sep 11 16:04:56.738) 
     Unreachable Notifications:         1 (last at Sep 11 16:04:36.520) 
     Metric Increase Notifications:     2 
     Metric Decrease Notifications:     1 
     Most Recent Events: 
      Time                      Event Type      Metric 
      Sep 11 16:04:36.520       Unreachable          - 
      Sep 11 16:04:56.738       Reachable            2 
      Sep 11 16:30:38.402       Reachable           21 
      Sep 11 16:31:23.548       Reachable           16 
      Sep 11 16:34:59.460       Reachable          101 
.....

This table shows key fields from the show bgp nethops output related to enhanced next hop monitoring, including next-hop IP address, status, metric, notification counts, last RIB event time, reference counts, and event counters for reachability and metric changes, enabling effective tracking and optimization of routing path stability in large-scale networks

Table 2. Fields pertaining to Enhanced Next Hop Monitoring in the output of show bgp nexthops command

Next Hop	The IP address of the next-hop router in the BGP network.
Status	A set of codes indicating the reachability and other status details about the next hop (e.g., Reachable, Unreachable, etc.).
Metric	The metric value used by BGP to determine the best path to the next hop. Lower values are preferred.
Tbl-ID	The unique identifier for the table in which the next-hop information is stored.
Notf	Notifications received/sent related to the next hop, often indicating BGP updates or state changes
LastRIBEvent	The time elapsed since the last Routing Information Base (RIB) event that pertained to this next hop.
RefCount	Reference count, which can indicate how many routes are using this next hop.
R (Reachable)	Event counter for the number of times the next hop has been marked as reachable.
U (Unreachable)	Event counter for the number of times the next hop has been marked as unreachable.
MI (Metric Increased)	Metric value for a particular route that has increased compared to the previous metric value.
MI (Metric Decreased)	Metric value for a particular route that has decreased compared to the previous metric value.
Reachable Notifications	The number of times a route has become reachable, that is a valid route to a destination is available, and the time of the last such notification.
Unreachable Notifications	The number of times a route has become unreachable, that is a previously valid route is no longer available, and the time of the last such notification.
Metric Increase Notifications	The number of times the metric for a route has increased, which typically makes the route less preferred.
Metric Decrease Notifications	The number of times the metric for a route has decreased, which usually makes the route more preferred.
Most Recent Events	List of individual routing events, including the time they occurred, the type of event, and the metric associated with the event. This also indicates the relative desirability of the route, with lower metrics being more preferred.
Unreachable	Indicates a loss of route.
Reachable	Indicates that a route is available.

You have verified BGP next-hop reachability and analyzed event counters, supporting efficient routing stability assessment and troubleshooting.

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