What is the difference between Spectrum attributes ifAlias (0x117fe) and Internal_If_Alias (0x11f82) and X_ifAlias (0x13224)?

Products

• Spectrum
• Network Observability

Issue/Introduction

What is the difference between Spectrum attributes IfAlias (0x117fe), Internal_If_Alias (0x11f82) and X_ifAlias (0x13224)?

As an example, if I want to create a Global Collection, how would I know which ifAlias to use?

Environment

All Supported Releases

Resolution

• Internal_If_Alias (0x11f82) is an internal value stored in the database.
• ifAlias (0x117fe) is an external value read on the actual device. In general, once it is read this value is copied to the Internal_If_Alias (0x11f82) (internal) attribute unless the device supports Cisco Catalyst functionality.  Spectrum also writes the value to X_ifAlias 0x13224.  Either way, ifAlias (0x117fe) is not stored in the DB.
• X_ifAlias (0x13224) is an internal attribute but is only populated on SpectroSERVER startup or by triggering the update action. Please reference knowledge article "Spectrum's Internal_If_Alias attribute does not match the devices actual ifAlias entry for ports"
  It would normally be recommended to use the internal Internal_If_Alias (0x11f82) attribute value as requires less work because it does not have to do an external read of the attribute ifAlias (0x117fe) on the device however it may not match the actual ifAlias.
• The Internal_If_Alias (0x11f82) internal attribute may not always be the most recent value depending on when it was last read and will not reflect actual IfAlias if the device supports Cisco Catalyst functionality.
• If you require the most current attribute value, then you should use the external attribute ifAlias (0x117fe).
• It should be noted however that if using the external ifAlias (0x117fe) attribute is very "expensive" as Spectrum needs to query every port for the value.  It will involve more server work, will be slower and could potentially fail if the device was to be unreachable.
• We recommend using X_ifAlias (0x13224) if you can.