This is the index of the queue group that this MPLS Class Type (a DiffServ-TE bandwidth pool, CT0-CT7) has been mapped to for actual packet scheduling on the hardware. An admin traces this mapping to confirm that traffic admitted under a given class type is actually being scheduled through the intended hardware queue with its associated priority and shaping, rather than falling into a default queue. For example, class type 3 mapped to queue group index 12 tells the admin exactly which hardware queue's statistics to check when troubleshooting congestion for that traffic class.