Internet Assigned Numbers Authority Internet Protocol Version 4 (IPv4) Parameters Last Updated 2018-05-03 Available Formats [IMG] XML [IMG] HTML [IMG] Plain text Registries included below * IP Option Numbers * IPv4 Router Alert Option Values * IP Time to Live Parameter * IP TOS Parameters * Type-of-Service Values IP Option Numbers Registration Procedure(s) Not defined Note The Internet Protocol (IP) has provision for optional header fields identified by an option type field. Options 0 and 1 are exactly one octet which is their type field. All other options have their one octet type field, followed by a one octet length field, followed by length-2 octets of option data. The option type field is sub-divided into a one bit copied flag, a two bit class field, and a five bit option number. These taken together form an eight bit value for the option type field. IP options are commonly referred to by this value. Available Formats [IMG] CSV Copy Class Number Value Name Reference 0 0 0 0 EOOL - End of Options List [RFC791][Jon_Postel] 0 0 1 1 NOP - No Operation [RFC791][Jon_Postel] 1 0 2 130 SEC - Security [RFC1108] 1 0 3 131 LSR - Loose Source Route [RFC791][Jon_Postel] 0 2 4 68 TS - Time Stamp [RFC791][Jon_Postel] 1 0 5 133 E-SEC - Extended Security [RFC1108] 1 0 6 134 CIPSO - Commercial Security [draft-ietf-cipso-ipsecurity-01] 0 0 7 7 RR - Record Route [RFC791][Jon_Postel] 1 0 8 136 SID - Stream ID [RFC791][Jon_Postel][RFC6814][1] 1 0 9 137 SSR - Strict Source Route [RFC791][Jon_Postel] 0 0 10 10 ZSU - Experimental Measurement [ZSu] 0 0 11 11 MTUP - MTU Probe [RFC1063][RFC1191][1] 0 0 12 12 MTUR - MTU Reply [RFC1063][RFC1191][1] 1 2 13 205 FINN - Experimental Flow Control [Greg_Finn] 1 0 14 142 VISA - Experimental Access Control [Deborah_Estrin][RFC6814][1] 0 0 15 15 ENCODE - ??? [VerSteeg][RFC6814][1] 1 0 16 144 IMITD - IMI Traffic Descriptor [Lee] 1 0 17 145 EIP - Extended Internet Protocol [RFC1385][RFC6814][1] 0 2 18 82 TR - Traceroute [RFC1393][RFC6814][1] 1 0 19 147 ADDEXT - Address Extension [Ullmann IPv7][RFC6814][1] 1 0 20 148 RTRALT - Router Alert [RFC2113] 1 0 21 149 SDB - Selective Directed Broadcast [Charles_Bud_Graff][RFC6814][1] 1 0 22 150        - Unassigned (Released 18 October 2005) 1 0 23 151 DPS - Dynamic Packet State [Andy_Malis][RFC6814][1] 1 0 24 152 UMP - Upstream Multicast Pkt. [Dino_Farinacci][RFC6814][1] 0 0 25 25 QS - Quick-Start [RFC4782] 0 0 30 30 EXP - RFC3692-style Experiment [2] [RFC4727] 0 2 30 94 EXP - RFC3692-style Experiment [2] [RFC4727] 1 0 30 158 EXP - RFC3692-style Experiment [2] [RFC4727] 1 2 30 222 EXP - RFC3692-style Experiment [2] [RFC4727] IPv4 Router Alert Option Values Registration Procedure(s) IETF Review Reference [RFC5350] Available Formats [IMG] CSV Value Description Reference 0 Router shall examine packet [RFC2113] 1-32 Aggregated Reservation Nesting Level [RFC3175] 33-64 QoS NSLP Aggregation Levels 0-31 [RFC5974] 65 NSIS NATFW NSLP [RFC5973] 66-65502 Unassigned 65503-65534 Reserved for experimental use [RFC5350] 65535 Reserved [RFC5350] IP Time to Live Parameter Registration Procedure(s) Not defined Note The current recommended default time to live (TTL) for the Internet Protocol (IP) is 64 [RFC791][RFC1122]. IP TOS Parameters Registration Procedure(s) Registrations no longer accepted Note This registry was deprecated following the publication of [RFC2474]. Type-of-Service Values Registration Procedure(s) Registrations no longer accepted Note This registry was deprecated following the publication of [RFC2474]. Contact Information ID Name Contact URI Last Updated [Andy_Malis] Andy Malis mailto:agmalis&gmail.com 2013-05-28 [Charles_Bud_Graff] Charles "Bud" Graff mailto:bud&fotlan.army.mil 1995-03 [Deborah_Estrin] Deborah Estrin mailto:Estrin&usc.edu 1994-10 [Dino_Farinacci] Dino Farinacci mailto:dino&cisco.com 1999-05 [Greg_Finn] Greg Finn mailto:Finn&isi.edu 1994-10 [Jon_Postel] Jon Postel mailto:postel&isi.edu 1994-10 Footnotes [1] obsoleted IP Option Number [2] It is only appropriate to use these values in explicitly-configured experiments; they MUST NOT be shipped as defaults in implementations. See RFC 3692 for details. Licensing Terms