This value, applicable only to preferred packet sizes on LLA-profile compressor contexts, indicates whether that preferred size is restricted to no-header packets (NHP), reduced-header packets (RHP), or usable for both. An admin fine-tuning LLA packet-size preferences would use this to understand why a given size might only be applied to headerless payload traffic and not to reduced-header traffic, which affects how consistently that size shows up on the wire. For instance, a preferred size flagged rhpOnly(2) means the compressor will only use that packet size for RHP packets, never for fully headerless NHP packets, even though the size is marked preferred.