Per-Device Variable Mapping for Configuration Scripts

NetBrain configuration scripts today do not support a variable whose underlying value can differ by device while keeping the script logic uniform; when interface naming or other configuration elements vary across device types (for example, mgmt0 versus vlan161, or vendor-specific interface naming conventions), engineers must create separate scripts for each variation rather than a single reusable template. This enhancement would allow users to define a global variable and map it to distinct values for each device or device group, then reference that variable within a configuration script so the script automatically resolves to the correct value at execution time. Customers managing large, heterogeneous device fleets would be able to build standardized change templates that account for non-standard configurations across devices, reducing the need to maintain and distribute multiple versions of the same script.