anchor.diff:  
   
           # vm
  -        vm = CTRexScRaw( [ STLVmFlowVar(name="ip_src", 
  +        vm = STLScVmRaw( [ STLVmFlowVar(name="ip_src", 
                                                 min_value="16.0.0.0", 
                                                 max_value="16.0.0.254", 
                                                 size=4, op="inc"),                     <1>
  
positive.code: 
  
          # vm
          vm = CTRexScRaw( [ STLVmFlowVar(name="fv_rand",                            <1>
                                          min_value=64, 
                                          max_value=len(base_pkt), 
                                          size=2, 
  
negative.code:                    src="2001:4860:0:2001::68")/
                UDP(dport=12,sport=1025)/ICMPv6Unknown()
  
          vm = STLScVmRaw( [ 
                              # tuple gen for inner Ipv6 
                              STLVmTupleGen ( ip_min="16.0.0.1", ip_max="16.0.0.2", 
                                              port_min=1025, port_max=65535,
  