IC90280: DELAY NEEDED IN STANDBY CONTROL AT INTERFACE-UP TIME, ALLOWING SPANNING TREE TO RECONVERGE, TO PREVENT UNNECESSARY TAKE OVER

APAR status

• Closed as program error.

Error description

• The following sequence of events might occur:
  * High priority device is active.
  * High device restarts or the interface is reconfigured.
  * Low device properly takes over after 10 second (hold time).
  * High device comes back.
  * High device gains link, but is still being blocked by spanning
  tree and thus has no connectivity.
  * High device becomes active.
  * Spanning tree unblocks the port, restoring connectivity.
  * High device is already active and sees another active device,
  so properly coups and forces an inappropriate takeover.
  * High device is Active again.
  * Low device is Standby again.
  

Local fix

Problem summary

• Affected are customers using the Standby Control feature
  in a network where routers are configured to use the non-rapid
  variant of the Spanning Tree protocol.
  
  Slow spanning tree reconvergence after an appliance restart
  might cause network instability, where more appliances in the
  standby group become Active at the same time.
  
  This fix adds anone minute delay for every (re)started
  interface,
  which must pass before the interface can negotiate for being
  Active. This prevents the interface from taking over the VIP
  before a worst-case time of the Spanning Tree protocol
  reconvergence.
  

Problem conclusion

• Fix is available in 4.0.2.13 and 5.0.0.8.
  
  For a list of the latest fix packs available, please see:
  
  http://www-01.ibm.com/support/docview.wss?uid=swg21237631
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  DATAPOWER

• Fixed component ID

  DP1234567

Applicable component levels

• R402 PSN

     UP

• R500 PSN

     UP