2001-04-23 2023-02-03 Specification Required Unassigned There appears to be further breakdown: In the 8 LSBs, the range 0 to 127 is reserved for IETF standard-track specifications; the range 128 to 254 is available for other specifications that meet this requirement (such as Informational RFCs). The LSB value 255 is reserved for future extensibility of the present specification. 0x0000 ROHC uncompressed 0xnn00 Reserved 0x0001 ROHC RTP 0x0101 ROHCv2 RTP 0xnn01 Reserved 0x0002 ROHC UDP 0x0102 ROHCv2 UDP 0xnn02 Reserved 0x0003 ROHC ESP 0x0103 ROHCv2 ESP 0xnn03 Reserved 0x0004 ROHC IP 0x0104 ROHCv2 IP 0xnn04 Reserved 0x0005 ROHC LLA 0x0105 ROHC LLA with R-mode 0xnn05 Reserved 0x0006 ROHC TCP 0xnn06 Reserved 0x0007 ROHC RTP/UDP-Lite 0x0107 ROHCv2 RTP/UDP-Lite 0xnn07 Reserved 0x0008 ROHC UDP-Lite 0x0108 ROHCv2 UDP-Lite 0xnn08 Reserved 0x0009-0xnn7F To be Assigned by IANA 0xnn80-0xnnFE To be Assigned by IANA 0xnnFF Reserved