The priority should reflect the severity of the reported case. The default priority is Low. The assessment of severity applies to incidents, but can be used on support tickets if there is a danger of a negative operational impact if the issue is not resolved swiftly.
Low - Routine case. Default value for tickets. Insignificant operational impact - (C - Normal)
Medium - Service instabilities. Inconvenient but operational, with risk of failure. Insignificant operational impact - (C - Normal)
High - Service degraded and no immediate workaround. Important requests with high quantifiable value for business operation - (B - Important)
Urgent - Service down and no immediate workaround. Critical for continued business operation, need immediate attention - (A - Business critical)
The correspondence to previous three category structure is referenced with the A, B, and C.