False Trunk cable connection formed between two devices.

Products

• VMware Smart Assurance

Issue/Introduction

• False Trunk cable connection raising alerts in Smarts. 
• Smarts detect user access port as Trunk. 
• False STP connections are formed between Switches

Environment

Smarts 10.1.x

Cause

VSSSwitches exposing Virtual MACs when discovered in Smarts topology can form connection during post processing phase.

Resolution

As a workaround these MAC's need to be excluded in the tpmgr-param.conf using ExcludeVSSMACRange flag.

Follow the below steps to perform the same:

1. 1. Edit the tpmgr-param.conf file using sm_edit as follows:

      <BASEDIR>/IP/smarts/bin/sm_edit ../conf/discovery/tpmgr-param.conf

         
   2.  Search for ExcludeVSSMACRange, you will find below entry:

      # ExcludeVSSMACRange
      # ExcludeVSSMACRange This flag decides whether to exclude this VSS MAC Range during STP Post processing
      # If this flag is set to TRUE, then the MAC address specified in VSSMACRange will be excluded
      # during STP post processing.
      # By default this value is set to FALSE
      ExcludeVSSMACRange FALSE

   3. Change the value of the flag to TRUE.

      ExcludeVSSMACRange TRUE

   4. If we set this flag to TRUE, the "VSSMACRange" attribute present in the tpmgr-param.conf will be picked up and checked with the STPnodes BridgedMAC address and if there is match to any of the Identified virtualMAC patterns, then the connection creation will be avoided.

      Below is the list of such identified virtualMAC patterns, it can be found in tpmgr-param.conf:

      # VSSMACRange
      # VSSMACRange is the MAC address range reserved for VSSSwitch. This range of MAC address would be
      # excluded during STP post processing
      VSSMACRange 00-08-E3-FF-FC-*|00-08-E3-FF-FD-*|00-08-E3-FF-FE-*|00-08-E3-FF-FF-*|5C-45-27-1A-*   

   5. Please check if the virtual MAC which is responsible in creating the false connection is added in this VSSMACRange
   6. Save the file. 
   7. Reload the tpmgr-param.conf file using below command, run the command

      <BASEDIR>/IP/smarts/bin/sm_tpmgr -s <IP domain name> --load-conf=tpmgr-param.conf

   8. Rediscover the device or wait for full discovery to complete and check if false connection is removed.