Internet Assigned Numbers Authority Address Resolution Protocol (ARP) Parameters Last Updated 2023-05-19 Note Reverse Address Resolution Protocol Operation Codes The Reverse Address Resolution Protocol (RARP) specified in [RFC903] uses the "Reverse" codes below. DYNAMIC REVERSE ARP The Dynamic Reverse Address Resolution Protocol (DRARP) uses the "DRARP" codes below. For further information, see [RFC1931]. INVERSE ADDRESS RESOLUTION PROTOCOL The Inverse Address Resolution Protocol (IARP) specified in [RFC2390] uses the "InARP" codes below. Available Formats [IMG] XML [IMG] HTML [IMG] Plain text Registries included below • Operation Codes • Hardware Types • Protocol Type Operation Codes Registration Procedure(s) IETF Review or IESG Approval Reference [RFC826][RFC5494] Available Formats [IMG] CSV Number Operation Code (op) References 0 Reserved [RFC5494] 1 REQUEST [RFC826][RFC5227] 2 REPLY [RFC826][RFC5227] 3 request Reverse [RFC903] 4 reply Reverse [RFC903] 5 DRARP-Request [RFC1931] 6 DRARP-Reply [RFC1931] 7 DRARP-Error [RFC1931] 8 InARP-Request [RFC2390] 9 InARP-Reply [RFC2390] 10 ARP-NAK [RFC1577] 11 MARS-Request [Grenville_Armitage] 12 MARS-Multi [Grenville_Armitage] 13 MARS-MServ [Grenville_Armitage] 14 MARS-Join [Grenville_Armitage] 15 MARS-Leave [Grenville_Armitage] 16 MARS-NAK [Grenville_Armitage] 17 MARS-Unserv [Grenville_Armitage] 18 MARS-SJoin [Grenville_Armitage] 19 MARS-SLeave [Grenville_Armitage] 20 MARS-Grouplist-Request [Grenville_Armitage] 21 MARS-Grouplist-Reply [Grenville_Armitage] 22 MARS-Redirect-Map [Grenville_Armitage] 23 MAPOS-UNARP [Mitsuru_Maruyama][RFC2176] 24 OP_EXP1 [RFC5494] 25 OP_EXP2 [RFC5494] 26-65534 Unassigned 65535 Reserved [RFC5494] Hardware Types Expert(s) Carlos Pignataro Reference [RFC826][RFC5494] Available Formats [IMG] CSV Range Registration Procedures Note requests for values below 256 Expert Review requests for more than one value Expert Review requests for one value greater than 255 First Come First Served requests for one value, no value specified First Come First Served can only be assigned a two-octet value (i.e., a value greater than 255) Number Hardware Type (hrd) Reference 0 Reserved [RFC5494] 1 Ethernet (10Mb) [Jon_Postel] 2 Experimental Ethernet (3Mb) [Jon_Postel] 3 Amateur Radio AX.25 [Philip_Koch] 4 Proteon ProNET Token Ring [Avri_Doria] 5 Chaos [Gill_Pratt] 6 IEEE 802 Networks [Jon_Postel] 7 ARCNET [RFC1201] 8 Hyperchannel [Jon_Postel] 9 Lanstar [Tom_Unger] 10 Autonet Short Address [Mike_Burrows] 11 LocalTalk [Joyce_K_Reynolds] 12 LocalNet (IBM PCNet or SYTEK LocalNET) [Joseph Murdock] 13 Ultra link [Rajiv_Dhingra] 14 SMDS [George_Clapp] 15 Frame Relay [Andy_Malis] 16 Asynchronous Transmission Mode (ATM) [[JXB2]] 17 HDLC [Jon_Postel] 18 Fibre Channel [RFC4338] 19 Asynchronous Transmission Mode (ATM) [RFC2225] 20 Serial Line [Jon_Postel] 21 Asynchronous Transmission Mode (ATM) [Mike_Burrows] 22 MIL-STD-188-220 [Herb_Jensen] 23 Metricom [Jonathan_Stone] 24 IEEE 1394.1995 [Myron_Hattig] 25 MAPOS [Mitsuru_Maruyama][RFC2176] 26 Twinaxial [Marion_Pitts] 27 EUI-64 [Kenji_Fujisawa] 28 HIPARP [Jean_Michel_Pittet] 29 IP and ARP over ISO 7816-3 [Scott_Guthery] 30 ARPSec [Jerome_Etienne] 31 IPsec tunnel [RFC3456] 32 InfiniBand (TM) [RFC4391] 33 TIA-102 Project 25 Common Air Interface (CAI) [Jeff Anderson, Telecommunications Industry of America (TIA) TR-8.5 Formulating Group, , June 2004] 34 Wiegand Interface [Scott_Guthery_2] 35 Pure IP [Inaky_Perez-Gonzalez] 36 HW_EXP1 [RFC5494] 37 HFI [Tseng-Hui_Lin] 38 Unified Bus (UB) [Wei_Pan] 39-255 Unassigned 256 HW_EXP2 [RFC5494] 257 AEthernet [Geoffroy_Gramaize] 258-65534 Unassigned 65535 Reserved [RFC5494] Protocol Type Registration Procedure(s) The Ethertype space is administered as described in [RFC5342]. Reference [RFC826][RFC5494][RFC5342] Note These numbers share the Ethertype space. See [https://www.iana.org/assignments/ethernet-numbers]. No registrations at this time. Contact Information ID Name Contact URI Last Updated [Andy_Malis] Andy Malis mailto:agmalis&gmail.com 2013-05-28 [Avri_Doria] Avri Doria mailto:avri&peoteon.com 1994-12 [Geoffroy_Gramaize] Geoffroy Gramaize mailto:geoffroy.iana&gramaize.eu 2016-07-20 [George_Clapp] George Clapp mailto:meritec!clapp&bellcore.bellcore.com [Gill_Pratt] Gill Pratt mailto:gill%25mit-ccc@mc.lcs.mit.edu [Grenville_Armitage] Grenville Armitage mailto:gja&thumper.belcore.com 1995-04 [Herb_Jensen] Herb Jensen mailto:hwjensen&itt.com 1995-02 [Inaky_Perez-Gonzalez] Inaky Perez-Gonzalez mailto:inaky.perez-gonzalez&intel.com 2008-10-01 [Jean_Michel_Pittet] Jean-Michel Pittet mailto:jmp&gandalf.engr.sgi.com 1998-11 [Jerome_Etienne] Jerome Etienne mailto:jetienne&arobas.net 2000-06 [Jon_Postel] Jon Postel mailto:postel&isi.edu [Jonathan_Stone] Jonathan Stone mailto:jonathan&dsg.stanford.edu 1996-05 [Joyce_K_Reynolds] Joyce K. Reynolds mailto:jkrey&isi.edu [Kenji_Fujisawa] Kenji Fujisawa mailto:fujisawa&sm.sony.co.jp 1998-10 [Marion_Pitts] Marion Pitts mailto:marionp&vnet.ibm.com 1997-05 [Mike_Burrows] Mike Burrows mailto:burrows&src.dec.com [Mitsuru_Maruyama] Mitsuru Maruyama mailto:mitsuru&ntt-20.ecl.net 1997-03 [Myron_Hattig] Myron Hattig mailto:Myron_Hattig&ccm.jf.intel.com 1997-02 [Philip_Koch] Philip Koch mailto:Philip.Koch&dartmouth.edu [Rajiv_Dhingra] Rajiv Dhingra mailto:rajiv&ultra.com [Scott_Guthery] Scott Guthery mailto:sguthery&mobile-mind.com 2000-03 [Scott_Guthery_2] Scott Guthery mailto:sguthery&hidcorp.com 2008-09-25 [Tom_Unger] Tom Unger mailto:tom&citi.umich [Tseng-Hui_Lin] Tseng-Hui Lin mailto:tsenglin&us.ibm.com [Wei_Pan] Wei Pan mailto:tarzan.pan&huawei.com 2023-05-19 Licensing Terms