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Physical link issues that result in rapid losses of signal strength, typically originating from faulty infrastructure (such as a failing optic, bad cable, or faulty patch panel), can result in an unrecoverable switch failure. When this occurs on platforms running Fabric OS (FOS) versions 9.2.0x, 9.2.1x, 9.2.2x, or 10.0.0x, the firmware is designed to intentionally fault the application-specific integrated circuit (ASIC).This faulty infrastructure can cause switch or blade faults after upgrading to FOS versions 9.2.0x, 9.2.1x, or 9.2.2x. In some cases, this has unnecessarily initiated hardware replacement procedures.NOTE: Replacing the switch or port blade alone willnotresolve the issue. If the faulty infrastructure is not remediated, new hardware will eventually fail and be faulted.In addition to causing physical link errors, the faulty infrastructure can produce rapid changes in signal strength. This is a new failure behavior being observed. Persistent, repeated failures can eventually result in specific failure conditions associated with attenuation in signal strength, creating a critical failure of the switch port and rendering it unable to correctly receive frames.SymptomsPrior to the critical switch or blade fault, excessive physical layer errors will be observed.Below is an example of an uncorrectable error (UNCOR ERR), which indicates physical errors on the link for port 60:Switch:admin> porterrshowPersistent, repeated failures can eventually result in specific failure conditions associated with attenuation in signal strength causing a critical failure of the switch port. A critical ASIC fault error code, "C4-1056," may also be displayed:2025/11/11-00:00:01 (GMT),[C4-1056], 1234567, CHASSIS, CRITICAL, G630, Chip in Slot 0, Chip 0 getting faulted with reason 53.2025/11/11-00:00:01 (GMT), [EM-1134], 1234568, FFDC | CHASSIS, ERROR, G630, Switch set to faulty, rc=20015.NOTE: The "C4-1056" critical ASIC fault error code is generally displayed for any critical failure detected by Fabric OS. The only clear signature for this failure is the switch or blade fault that accompanies excessive physical layer errors.
This issue is observed on the following HPE Storage switches or port blades running any version of Fabric OS (FOS) 9.2.0x, 9.2.1x or 9.2.2x:HPE Storage Fibre Channel Switch B-series SN6600B (switchType 162)HPE Storage Fibre Channel Switch B-series SN6650B (switchType 173)NOTE: SN6600B switchType 162 and SN6650B switchType 173 are affected by this specific failure condition. SN6600B switchType 183 and SN6650B switchType 184 are not at risk for this specific failure condition.This issue also occurs with the following port blades installed in an SN8600B or SN8700B switch running any patch version of FOS 9.2.0x, 9.2.1x, 9.2.2x, or 10.0.0x (for the SN8600B 32Gb SAN extension blade installed in an SN8600B or SN8700B only):HPE SN8600B 32Gb 48 Port Blade (Blade ID 178)HPE SN8600B 32Gb 64 Port Blade (Blade ID 204)HPE SN8600B 32Gb SAN Extension Blade (Blade ID 186)NOTE: These blades are also supported in the HPE SN8700B 8-slot Power Pack+ Director Switch and the HPE SN8700B 4-slot Power Pack+ Director Switch.
HPE recommends upgrading to a Fabric OS version that includes a more graceful handling mechanism, which faults only the affected port (Error Code C4-1060) instead of the entire ASIC:Fabric OS v9.2.2d (recommended)Fabric OS v9.2.2c1Fabric OS v9.2.1c3Fabric OS v9.2.0c5Proactive Workaround (if unable to upgrade):Enable Monitoring and Alerting Policy Suite (MAPS) alerts and Port Fencing.HPE strongly recommends enabling Monitoring and Alerting Policy Suite (MAPS) alerts and Port Fencing. (A Fabric Vision license is required for this feature.)The default conservative policy includes predefined threshold values designed to generate alerts only in response to excessive errors. If these values are not suitable for the specific environment, a custom policy can be created, and the thresholds can be adjusted.Below are sample commands to add FENCE action globally and enable "dflt_conservative_policy":Switch:admin> mapsconfig --actions "RASLOG,SNMP,FPIN,FENCE"Switch:admin> mapspolicy --enable dflt_conservative_policyFencing the port based on invalid transition word (ITW) thresholds can prevent the signal attenuation from reaching the point that causes an ASIC fault.NOTE: Port fencing immediately takes the port offline when configured thresholds in a given rule are exceeded.If the "FENCE" action is not desired, it is essential to ensure alerting is fully configured and that physical errors are addressed promptly to minimize overall risk.Recovery Procedure:Remediate: Replace the failing optic in the third-party device or repair the dense wavelength-division multiplexing (DWDM) line.Recover Switch: Manually reboot or power-cycle the faulted switch.Recover Blade: In a director, use the slotpoweroff command followed by the slotpoweron command for the affected slot.Revision HistoryDocument VersionRelease DateDetails6September 30, 2026Revised the Resolution section with updated Fabric OS information.5September 18, 2026In the Scope section, additional content was added to the existing Note regarding switchType 162 and 173.4August 28, 2026A note was added to the Scope stating SN6600B and SN6650B are not at risk of failure. In the Scope, X7-8/X7-4 was changed to SN8600B or SN8700B only and SN8700B was added to the list of port blades. The Resolution was replaced with additional content.3February 3, 2026Updated with the screenshot and specific metrics in the Description section, and clarified the fencing process in the Resolution section2January 8, 2026In the Resolution section, updated the second NOTE, and added content to clarify step 11December 5, 2025Original Document Release
Operating Systems Affected:Not Applicable
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