This read-only value reports the derived service category (cbr, vbr1, vbr2, ubr-abr, or unspecified) actually assigned to this ATM SVC in the forward direction, as determined by the switch's own classification logic based on the traffic parameters negotiated at call setup. This is distinct from the raw traffic descriptor fields, since it's the switch's summarized categorization of what kind of service the call ended up getting. An engineer verifying that a voice-bearer SVC correctly landed in the CBR service class rather than being downgraded would check that cktAtmSvcServiceCategory reports cbr(1) rather than ubr-abr(4).