This feature is implemented in t4.49 of JTAPI $rt->get_results_drv() [custom_drv] [custom_property] [property_name <name>] [expression_type [MATH | BOOL]] [equation] [depended_counters] [precision] [property_name] Specify the result property name. Note: * In order to return the custom property value in return result hash, user need to specify custom property in "properties" option. (The property name must be specified with "Custom.<property_name>") (Refer, the example below for reference.) * Custom return output: STC prepends 'Custom' before the specified property name. [Example, if property_name is specified as 'dropped' then return output name would be 'Customdropped'] [expression_type] Expression type for equation. Default: MATH [depended_counters] Specify result properties required to evaluate equation. [equation] Specify the equation that indicates how to evaluate the result property. Properties specified in 'depended_counters' only can be used in the equation. [precision] Specify the precision for result output. (Mainly used in MATH operation) Default: 2 Below is the sample code: my @customProperty = ({property_name => 'dropped1', expression_type => 'MATH', depended_counters => 'StreamBlock.TxFrameCount StreamBlock.RxSigFrameCount', equation => "StreamBlock.TxFrameCount - StreamBlock.RxSigFrameCount", precision => 2}, {property_name => 'dropped2', expression_type => 'BOOL', depended_counters => 'StreamBlock.TxFrameCount StreamBlock.RxSigFrameCount', equation => "StreamBlock.TxFrameCount == StreamBlock.RxSigFrameCount", precision => 4}); my $custom_drv1 = { properties =>'StreamBlock.StreamId StreamBlock.TxFrameCount StreamBlock.RxFrameCount StreamBlock.FrameConfig.ethernet:EthernetII.vlans.Vlan.1.id Custom.dropped1 Custom.dropped2', name => 'drv_vlan1', from => "$mystream1 [0]", where => 'StreamBlock.FrameConfig.ethernet:EthernetII.vlans.Vlan.1.id = 1', custom_property => \@customProperty}; my $res3 = $rt->get_results_drv(custom_drv=>$custom_drv1, size=>2000);