The value of tnOamTrCtlServiceId specifies the service ID of the service being tested. The applicability of tnOamTrCtlServiceId varies with the test type, as shown in the following table. tnOamTrCtlTestMode Applicability Related Virtual Router Object 'icmpTraceRoute' optional tnOamTrCtlVRtrID 'macTraceRoute' mandatory none 'mcastTraceRoute' optional tnOamMcastTrCtlVRtrID 'vprnTraceRoute' mandatory none otherwise not applicable none When tnOamTrCtlServiceId is mandatory, a non-zero value must be provided. When tnOamTrCtlServiceId is optional, it is used to specify a VPRN service. The test must use the VPRN service's virtual router. When a related virtual router object is shown, the interaction is described in the DESCRIPTION clause of the listed object. Service IDs larger than 2147483647 are internal, so they are excluded from the range. The default value is the null service ID.