How to constraint variables with randc.(random-cyclic)?Am unable to get proper behavior of randc

In reply to Rao.Bee:

The randc directive only works on the same object randomized with the same constraints. The uvm_do macro creates a new object each time its used. You can either avoid using the uvm_do macro (See Sequences/Generation | Verification Academy) or you will have to build a list of previous pkt_length values and add another constraint
!(pkt_length inside {list};
.