Type,Description/Meaning,Reference 128,RTT Estimate,[RFC6323] 129-183,Unassigned, 184-190,Reserved for experimental and testing use,[RFC4342] 191,Unassigned, 192,Loss Event Rate,[RFC4342] 193,Loss Intervals,[RFC4342] 194,Receive Rate,[RFC4342] 195-247,Unassigned, 248-254,Reserved for experimental and testing use,[RFC4342] 255,Reserved,[RFC4342]