This carries the DiffServ-TE class type (CT0 through CT7, representing different traffic priority classes for bandwidth reservation) whose admission threshold triggered this CAC notification. An admin needs this because different class types on the same interface have separate bandwidth pools, so knowing which class type is constrained tells them exactly which traffic priority is at risk of being blocked from new LSP admission. For example, a trap flagging class type 5 tells the admin that a specific, likely lower-priority, traffic class is the one running out of admittable bandwidth on this interface, while higher-priority classes may still have headroom.