IZ51286: SWITCH STITCHER CAN'T CREATE THE CONNECTIONS BETWEEN DEVICES WHEN REMOTE NEIGHBOR IS MISSING MAC ADDRESS INFORMATION

IBM Tivoli Network Manager IP 3.8.0 Fix Pack 7, 3.8.0-TIV-ITNMIP-FP0007

APAR status

• Closed as program error.

Error description

• v3.7.0.25 - Linux
  
  Switch stitcher (SwitchFdbToConnections.stch) can not create
  connections when one of the device is missing MAC address
  information from FDB data.
  
  Though the connectivity information is available under CDPLayer
  and its being dropped by switchTopology during layer merge due
  to higher precedence by default.
  
  Solution should be:
  
  Modify switch stitcher to make use of available CDP
  information to allow the link to get through into the
  fullTopology.
  

Local fix

• Test fix provided
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All platforms. May occur on any network with CDP enabled.
  ****************************************************************
  PROBLEM DESCRIPTION:
  Layer 2 topology (Physical topology) incorrect in GUI.
  Investigation of the discovery databases shows link is correct
  in CDP layer, but incorrect in switch layer (IP is not resolved
  to the device name in the switch stitcher).
  Such bad links occur where CDP data is discovered by the switch
  agent for the problematic link but FDB data is not AND the CDP
  data refers to a remote interface that lacks a MAC address.
  ****************************************************************
  RECOMMENDATION:
  Upgrade to fix pack containing this fix.
  | fix pack | 3.7.0-ITNMIP-FP0008
  | fix pack | 3.8.0-ITNMIP-FP0002
  ****************************************************************
  

Problem conclusion

• Fixed in 3.7.
  The switch stitcher will now correctly handle such cases and
  where there is insufficient link data will allow the CDP layer
  link through. This will ensure the physical topology is correct.
  

Temporary fix

• Move the CDPLayer be be higher that the SwitchTopology when
  Merging Layers. This however may result in other topology
  issues.
  

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

  NC/PREC DISCOVY

• Fixed component ID

  5724O52DS

Applicable component levels

• R370 PSN

     UP