Prevent Duplicate entries based on Multiple serial Nuimbers on a Network Switch
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3 weeks ago
I have a intergration with Cisco Catalyst. When the Service Now Mid Tier runs and comes across a device wth more than one serial Number it attempts to make them all individual CI's I have set he recon to run the switch apart from the Grand Parent which must use Serial Number for all devices to maintain uniqueness. Since we want Cisco to be the Primary Source or Truth we want Service Now Pattern matches to not use Serial but use Mac address as uniqueness and update where needed. Right now it is aborting becuase of the look up assocating Serial only. has anyone come across this condition and what did you do to get around it
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3 weeks ago
Hi @RaymondAlex ,
Catalyst devices often report multiple serial numbers (chassis, modules, line cards, etc.), and the default reconciliation logic tries to treat each one as a separate CI.
The Identification and Reconciliation Engine (IRE) is using serial number as the primary identifier.
Catalyst hardware reports multiple serials, so IRE thinks they’re different devices.
Since you’ve set serial as the uniqueness key, the reconciliation aborts when it sees duplicates.
1. Change the identification rule for network devices
Instead of using serial number as the primary key, configure the rule to use MAC address (or a combination like MAC + hostname).
This way, the device is recognized as one CI, even if multiple serials are reported.
2. Keep serials as attributes, not identifiers
Store all reported serial numbers as related attributes (e.g., in a child table or as additional properties).
Only the “grandparent” CI (the main switch) needs a unique serial for compliance, but the rest can be tracked as metadata.
3. Pattern customization
In the Discovery Pattern for Cisco Catalyst, adjust the identification section so that:
MAC address is the primary identifier.
Serial numbers are collected but not used for CI matching.
4. Governance decision
Since you want Cisco to be the “source of truth,” align your reconciliation rules so that ServiceNow updates based on Cisco data, but doesn’t fragment the CI record.
MAC address is generally the most stable unique identifier for network gear.
Serial numbers are useful for asset tracking but not reliable for CI uniqueness when multiple are reported.
Document this in your reconciliation policy so future admins know why serials aren’t used for uniqueness.
