Router Hardware Management Guide for Cisco 8000 Series Routers, Cisco IOS XR Release

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Router Hardware Management Guide for Cisco 8000 Series Routers, Cisco IOS XR Release

Power redundancy protection

Updated: July 1, 2026

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Describes the power redundancy protection feature, which raises an alarm when the required output power exceeds the total feed redundancy capacity, and explains the single-fault and dual-fault protection modes.

The power redundancy protection is a power management mechanism that

ensures continuous router operation during power supply failures
provides power feed redundancy through A and B feeds, and
triggers alarms when power requirements exceed capacity.

The Cisco 8000 Series Modular Routers utilize two primary redundancy mechanisms to maintain functionality during power supply failures:

PSU redundancy incorporates extra power supply units that takes over the load if a failure occurs.
Power feed redundancy divides input power into A and B feeds. When both feeds function normally, they share the power load equally. If one feed fails, the remaining feed scales up to its maximum capacity or the power supply unit operates with reduced input to maintain an uninterrupted power supply.

Table 1. Feature history table
Feature Name	Release Information	Feature Description
Power Redundancy Protection	Release 25.4.1	Introduced in this release on: Fixed Systems (8010 [ASIC: A100])(select variants only) This feature is supported on: 8011-32Y8L2H2FH 8011-12G12X4Y-A/D
Power Redundancy Protection	Release 25.1.1	Introduced in this release on: Fixed Systems (8700 [ASIC: K100], 8010 [ASIC: A100])(select variants only) This feature is supported on: 8011-4G24Y4H-I 8712-MOD-M
Power Redundancy Protection	Release 24.4.1	Introduced in this release on: Fixed Systems (8200 [ASIC: P100], 8700 [ASIC: P100])(select variants only); Modular Systems (8800 [LC ASIC: P100])(select variants only) *This feature is supported on: 8212-48FH-M 8711-32FH-M 88-LC1-36EH 88-LC1-12TH24FH-E 88-LC1-52Y8H-EM
Power Redundancy Protection	Release 24.1.1	You can now prevent power module exhaustion or failure due to power redundancy issues in the power feeds with the help of alarms that warn that the total output power required by the router exceeds the total feed redundancy capacity. You can configure either single-fault protection or dual fault protection, depending on whether you want to trigger alarms during redundancy failures in the power supply feed, PSU redundancy, or both. The feature introduces these changes: CLI: power-mgmt feed-redundancy The `Total feed redundancy capacity` field is added to the show environment command.

These options provide high reliability and minimize the risk of network downtime. The routers incorporate protection that triggers alarms for PSU and feed redundancy failures when the total output power required exceeds the total feed redundancy capacity.

The router supports two redundancy configuration modes:

Single fault protection - this mode monitors the router against a single power supply feed or PSU redundancy failure.
Dual fault protection - this mode monitors the router against a power supply feed and PSU redundancy failure simultaneously.

You can customize the PSU single feed capacity within a default power range to meet specific infrastructure requirements. The router determines the total feed capacity by selecting the lesser value between the feed redundancy capacity and the PSU redundancy capacity. The PSU redundancy capacity is the number of power supply units minus the redundant ones (N) multiplied by a dual feed capacity. On the other hand, the feed redundancy capacity is the total number of PSUs multiplied by a single feed capacity. In single-fault protection, the PSU refers to the total number of power supply units in the router units (N+1). In dual-fault protection, the PSU refers to the number of power supply units minus the redundant ones (N).

For example, consider a router that has a total of 9 PSUs with a default N + 1 power redundancy configuration. The PSU feed capacity with dual feed is 4800 W and the single feed capacity value is set 3200 W, then the total feed redundancy capacity would be:

Table 2. Total feed redundancy capacity example
Power Redundancy Protection	Total Number of PSUs	PSU redundancy	Number of PSUs minus the redundant ones (N)	Dual Feed Capacity	Single Feed Capacity	Feed Redundancy Capacity	PSU Redundancy Capacity	Total Feed Redundancy Capacity
Single fault protection	9	N+1	8	4800 W	3200 W	28800 W	38400 W	28800 W
Dual fault protection	9	N+1	8	4800 W	3200 W	25600 W	38400 W	25600 W

Guidelines and restrictions for power redundancy protection

By default, the router doesn't enable Power Redundancy Protection.
The Power Redundancy Protection feature doesn't impact the power budgeting in the routers.
For maximum power redundancy protection, use the dual fault protection.
For total feed redundancy capacity calculations, the router considers only the PSUs with A and B inputs. Both A and B inputs must be within the operating range in healthy conditions. If either feed is unavailable, the router excludes such PSUs from the calculations.
The router considers all PSUs, including redundant PSUs with two feeds (within the operating range in healthy condition) for feed redundancy capacity in single fault protection. However, the router excludes the redundant PSUs for feed redundancy capacity in dual fault protection. If the router has 8 PSUs and N+3 redundancy, single fault protection calculation considers all eight PSUs, whereas dual fault protection considers just 5 PSUs.

Configure single fault protection

Use the power-mgmt feed-redundancy command to configure the power redundancy protection mode and PSU single feed capacity.

Procedure

	1.	Enter the global configuration mode. Example: `Router# configure`
	2.	Configure single fault protection with PSU single feed capacity set to 2400 Watts. Example: `Router(config)# power-mgmt feed-redundancy single-fault-protection capacity 2400`
	3.	Save the changes. Example: `Router(config)# commit`
	4.	Use the show run power command to check the running configuration. Example: `Router# show run power … power-mgmt feed-redundancy single-fault-protection capacity 2400 …`
	5.	Use the show environment power command to verify the total power required and the total feed capacity for single fault protection. Example: Router# show env power ================================================================================ CHASSIS LEVEL POWER INFO: 0 ================================================================================ Total output power capacity (N + 1) : 28800W + 4800W Total output power required : 6679W >>>>> 1 Total power input : 2394W Total power output : 2066W Total feed redundancy capacity (Single Fault) : 16800W >>>>> 2 //The router triggers feed redundancy loss alarm when 1 > 2.*// ================================================================================ Power Supply -------Input-------- -----Output--- Status Module Type Volts A/B Amps A/B Volts Amps ================================================================================ 0/PT0-PM0 PSU4.8KW-DC100 62.8/62.7 2.6/2.5 55.2 5.3 OK 0/PT0-PM1 PSU4.8KW-DC100 62.7/62.7 2.7/2.6 55.3 5.3 OK 0/PT0-PM3 PSU4.8KW-DC100 61.0/62.7 2.6/2.5 55.2 4.8 OK 0/PT1-PM0 PSU4.8KW-DC100 67.3/67.3 2.7/2.5 55.3 5.2 OK 0/PT1-PM1 PSU4.8KW-DC100 67.3/67.2 2.8/2.7 55.3 5.7 OK 0/PT1-PM2 PSU4.8KW-DC100 67.3/67.4 2.7/2.7 55.2 5.6 OK 0/PT1-PM3 PSU4.8KW-DC100 67.3/67.3 2.6/2.5 55.3 5.5 OK Total of Power Modules: 2394W/36.7A 2066W/37.4A

Configure dual fault protection

Use the power-mgmt feed-redundancy command to configure the power redundancy protection mode and PSU single feed capacity.

Procedure

	1.	Enter the global configuration mode. Example: `Router# configure`
	2.	Configure dual fault protection with PSU single feed capacity set to 2400 Watts. Example: `Router(config)# power-mgmt feed-redundancy dual-fault-protection capacity 2400`
	3.	Save the changes. Example: `Router(config)# commit`
	4.	Use the show run power command to check the running configuration. Example: `Router# show run power … power-mgmt feed-redundancy dual-fault-protection capacity 2400 …`
	5.	Use the show environment power command to verify the total power required and the total feed capacity for dual fault protection. Example: Router# show env power ================================================================================ CHASSIS LEVEL POWER INFO: 0 ================================================================================ Total output power capacity (N + 1) : 28800W + 4800W Total output power required : 6679W >>>>> 1 Total power input : 2394W Total power output : 2066W Total feed redundancy capacity (Dual Fault) : 14400W >>>>> 2 //The router triggers feed redundancy loss alarm when 1 > 2.*// ================================================================================ Power Supply -------Input-------- -----Output--- Status Module Type Volts A/B Amps A/B Volts Amps ================================================================================ 0/PT0-PM0 PSU4.8KW-DC100 62.8/62.7 2.6/2.5 55.2 5.3 OK 0/PT0-PM1 PSU4.8KW-DC100 62.7/62.7 2.7/2.6 55.3 5.3 OK 0/PT0-PM3 PSU4.8KW-DC100 61.0/62.7 2.6/2.5 55.2 4.8 OK 0/PT1-PM0 PSU4.8KW-DC100 67.3/67.3 2.7/2.5 55.3 5.2 OK 0/PT1-PM1 PSU4.8KW-DC100 67.3/67.2 2.8/2.7 55.3 5.7 OK 0/PT1-PM2 PSU4.8KW-DC100 67.3/67.4 2.7/2.7 55.2 5.6 OK 0/PT1-PM3 PSU4.8KW-DC100 67.3/67.3 2.6/2.5 55.3 5.5 OK Total of Power Modules: 2394W/36.7A 2066W/37.4A
	6.	You can use the show alarms brief command to view the power redundancy alarm. Example: Router# show alarms brief system active ---------------------------------------------------------------------------------------------------------------------- Active Alarms ---------------------------------------------------------------------------------------------------------------------- Location Severity Group Set Time Description ---------------------------------------------------------------------------------------------------------------------- 0 Major Environ 11/27/2023 12:55:08 UTC Power Module redundancy feed mode lost Note The router triggers the `Power Module redundancy feed mode lost` alarm only when Total output power required exceeds Total feed redundancy capacity.
	7.	View system log messages for power redundancy loss. Example: Syslog message created while power redundancy loss (total output power exceeds total feed redundancy capacity): `RP/0/RP0/CPU0:Dec 15 10:24:29.489 UTC: envmon [123]: %PKT_INFRA-FM-3-FAULT_MAJOR : ALARM_MAJOR :Power Feed redundancy lost :DECLARE :0`

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Power redundancy protection

Guidelines and restrictions for power redundancy protection

Configure single fault protection

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Configure dual fault protection

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