BugZero | Cisco BugID CSCvn96821 - Stack adapter authentication failed

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BugZero | Cisco BugID CSCvn96821 - Stack adapter authentication failed

ODD
Cisco
CSCvn96821

Cisco - Defect ID: CSCvn96821

Stack adapter authentication failed

ODD
Cisco
CSCvn96821

Cisco - Defect ID: CSCvn96821

Stack adapter authentication failed

Last updated on September 29th, 2025

BugZero Risk Score
7.8 High

Overall: 7.8

Severity: 8.2

Lifecycle: 9.1

Popularity: 5.1

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Bug Details

Views: 13

Description

Symptom

Stack adapter authentication failed during boot time.

Conditions

The behavior is observed as stack adapter authentication failed because of act2 i2c chip read/write failure for 3650 switch in customer setup.

Workaround

Remove stack cables and reload the failure switches. then connect same/different stack cable and boot the switches.This might not work all the time.

Further Problem Description

As part of fix, act2 i2c write retries are increased to 3000, as some of the recent SKU's require more retry count. The write retry count are inherited from the default value and for the same reason SCC_MAX_I2C_RDWR_RETRY increased to 4000. Added PLATFORM_MGR_SCC_DEBUG and NG3k_SCC_DBG to NGWC_SCC_ERROR/DEBUG ,NGWC_SCCHW_DEBUG/ERR for visibility and logging purpose. The increased count of read / write for the i2c chip resolved the failure.

Change history

2025-09-29 Added: 16.11.1, 16.11.1a, 16.11.1b, 16.11.1c, 16.11.1s, 16.11.2, 16.12.1, 16.12.10, 16.12.10a, 16.12.11, 16.12.12, 16.12.13, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.1t, 16.12.1v, 16.12.1w, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2, 16.12.2a, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.12.8, 16.12.9, 16.3.10, 16.3.11, 16.3.8, 16.3.9, 16.6.10, 16.6.6, 16.6.7, 16.6.7a, 16.6.8, 16.6.9, 16.9.3, 16.9.3a, 16.9.3h, 16.9.3s, 16.9.4, 16.9.4c, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.2, 17.7.1, 17.7.1a, 17.7.1b, Gibraltar-16.12.1c

Relevant Products

Click on a version to see all relevant bugs

Affected versions:No known affected versions

Fixed versions: 16.11.1, 16.11.1a, 16.11.1b, 16.11.1c, 16.11.1s, 16.11.2, 16.12.1, 16.12.10, 16.12.10a, 16.12.11, 16.12.12, 16.12.13, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.1t, 16.12.1v, 16.12.1w, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2, 16.12.2a, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.12.8, 16.12.9, 16.3.10, 16.3.11, 16.3.8, 16.3.9, 16.6.10, 16.6.6, 16.6.7, 16.6.7a, 16.6.8, 16.6.9, 16.9.3, 16.9.3a, 16.9.3h, 16.9.3s, 16.9.4, 16.9.4c, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.2, 17.7.1, 17.7.1a, 17.7.1b, Gibraltar-16.12.1c

Relevant Products

Click on a version to see all relevant bugs

Affected versions:No known affected versions

Fixed versions: 16.11.1, 16.11.1a, 16.11.1b, 16.11.1c, 16.11.1s, 16.11.2, 16.12.1, 16.12.10, 16.12.10a, 16.12.11, 16.12.12, 16.12.13, 16.12.1a, 16.12.1c, 16.12.1s, 16.12.1t, 16.12.1v, 16.12.1w, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2, 16.12.2a, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.12.8, 16.12.9, 16.3.10, 16.3.11, 16.3.8, 16.3.9, 16.6.10, 16.6.6, 16.6.7, 16.6.7a, 16.6.8, 16.6.9, 16.9.3, 16.9.3a, 16.9.3h, 16.9.3s, 16.9.4, 16.9.4c, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.2, 17.7.1, 17.7.1a, 17.7.1b, Gibraltar-16.12.1c

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