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Cisco Bug: CSCuj27671 - QUAD SUP2T VSS Failover fails with tunnel path-mtu-discovery config

Last Modified

Apr 18, 2019

Products (4)

  • Cisco IOS
  • Cisco Catalyst 6500 Series Virtual Switching Supervisor Engine 720 with 10GE uplinks
  • Cisco Catalyst 6500 Series Supervisor Engine 2T
  • Cisco Catalyst 6500 Series Supervisor Engine 720 / MSFC3

Known Affected Releases


Description (partial)

Symptom: QUAD SUP VSS Fai-lover fails and goes into RPR mode with the below message.

*Sep 15 07:21:23.911: %ISSU-SW2-3-INCOMPATIBLE_PEER_UID: Setting image (s2t54-IPSERVICESK9-M), version (15.1(1)SY1) on peer uid (262) as incompatible
*Sep 15 07:21:23.911: SW2: Config Sync: Bulk-sync failure due to Servicing Incompatibility. Please check full list of mismatched commands via:
  show redundancy config-sync failures mcl

*Sep 15 07:21:23.911: SW2: Config Sync: Starting lines from MCL file:
interface Tunnel1
 ! <submode> "interface"
- tunnel path-mtu-discovery min-mtu 0
 ! </submode> "interface"

*Sep 15 07:21:23.919: %RF-SW2-5-RF_RELOAD: Peer reload. Reason: ISSU Incompatibility
Conditions: This symptom is observed under the following conditi1)QUAD SUP VSS Setup
2) Active Sup on switch 1 be in different slot from standby(HOT) slot in switch 2.
3) Tunnel should be configured with  "tunnel path-mtu-discover"
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