A higher-layer protocol is identified with an 8-bit field within an IPv4 packet called Protocol. The IPv4 header format is shown in Figure B-1 with the Protocol field shaded. Figure B-2 shows the IPv6 header format where the protocol number is stored in the shaded Next Header field.
Table B-1 shows the registered IP protocol numbers, along with the protocol keyword (or acronym), the name of the protocol, and an RFC number (if applicable).
Table B-1. Registered IP Protocol Numbers, Keywords, Names, and Associated RFCs
Keyword Protocol References | Number |
---|
HOPOPT IPv6 Hop-by-Hop Option RFC 1883 | 0 |
ICMP Internet Control Message RFC 792 | 1 |
IGMP Internet Group Management RFC 1112 | 2 |
GGP Gateway-to-Gateway RFC 823 | 3 |
IP IP in IP (encapsulation) RFC 2003 | 4 |
ST Stream RFC 1190, RFC 1819 | 5 |
TCP Transmission Control RFC 793 | 6 |
CBT CBT | 7 |
EGP Exterior Gateway Protocol RFC 888 | 8 |
IGP Any private interior gateway IANA (used by Cisco for IGRP) | 9 |
BBN-RCC-MON BBN RCC Monitoring | 10 |
NVP-II Network Voice Protocol RFC 741 | 11 |
PUP PUP | 12 |
ARGUS ARGUS | 13 |
EMCON EMCON | 14 |
XNET Cross Net Debugger | 15 |
CHAOS Chaos | 16 |
UDP User Datagram RFC 768 | 17 |
MUX Multiplexing | 18 |
DCN-MEAS DCN Measurement Subsystems | 19 |
HMP Host Monitoring RFC 869 | 20 |
PRM Packet Radio Measurement | 21 |
XNS-IDP XEROX NS IDP | 22 |
TRUNK-1 Trunk-1 | 23 |
TRUNK-2 Trunk-2 | 24 |
LEAF-1 Leaf-1 | 25 |
LEAF-2 Leaf-2 | 26 |
RDP Reliable Data Protocol RFC 908 | 27 |
IRTP Internet Reliable Transaction RFC 938 | 28 |
ISO-TP4 ISO Transport Protocol Class 4 RFC 905 | 29 |
NETBLT Bulk Data Transfer Protocol RFC 969 | 30 |
MFE-NSP MFE Network Services Protocol | 31 |
MERIT-INP MERIT Internodal Protocol | 32 |
SEP Sequential Exchange Protocol | 33 |
3PC Third Party Connect Protocol | 34 |
IDPR Inter-Domain Policy Routing Protocol RFC 1479 | 35 |
XTP XTP | 36 |
DDP Datagram Delivery Protocol | 37 |
IDPR-CMTP IDPR Control Message Transport Protocol | 38 |
TP++ TP++ Transport Protocol | 39 |
IL IL Transport Protocol | 40 |
IPv6 Ipv6 | 41 |
SDRP Source Demand Routing Protocol | 42 |
IPv6-Route Routing Header for IPv6 | 43 |
IPv6-Frag Fragment Header for IPv6 | 44 |
IDRP Inter-Domain Routing Protocol | 45 |
RSVP Resource ReSerVation Protocol RFC 2205 | 46 |
GRE General Routing Encapsulation RFC 1701 | 47 |
MHRP Mobile Host Routing Protocol | 48 |
BNA BNA | 49 |
ESP Encap Security Payload RFC 2406 | 50 |
AH Authentication Header RFC 2402 | 51 |
I-NLSP Integrated Net Layer Security TUBA | 52 |
SWIPE IP with Encryption | 53 |
NARP NBMA Address Resolution Protocol RFC 1735 | 54 |
MOBILE IP Mobility RFC 2002 | 55 |
TLSP Transport Layer Security Protocol using Kryptonet key management | 56 |
SKIP SKIP | 57 |
IPv6-ICMP ICMP for IPv6 RFC 2463 | 58 |
IPv6-NoNxt No Next Header for IPv6 RFC 2460 | 59 |
IPv6-Opts Destination Options for IPv6 RFC 2460 | 60 |
Any host internal protocol IANA | 61 |
CFTP CFTP | 62 |
Any local network IANA | 63 |
SAT-EXPAK SATNET and Backroom EXPAK | 64 |
KRYPTOLAN Kryptolan | 65 |
RVD MIT Remote Virtual Disk Protocol | 66 |
IPPC Internet Pluribus Packet Core | 67 |
Any distributed file system IANA | 68 |
SAT-MON SATNET Monitoring | 69 |
VISA VISA Protocol | 70 |
IPCV Internet Packet Core Utility | 71 |
CPNX Computer Protocol Network Executive | 72 |
CPHB Computer Protocol Heart Beat | 73 |
WSN Wang Span Network | 74 |
PVP Packet Video Protocol | 75 |
BR-SAT-MON Backroom SATNET Monitoring | 76 |
SUN-ND SUN ND PROTOCOL-Temporary | 77 |
WB-MON WIDEBAND Monitoring | 78 |
WB-EXPAK WIDEBAND EXPAK | 79 |
ISO-IP ISO Internet Protocol | 80 |
VMTP VMTP RFC 1045 | 81 |
SECURE-VMTP SECURE-VMTP | 82 |
VINES VINES | 83 |
TTP TTP | 84 |
NSFNET-IGP NSFNET-IGP | 85 |
DGP Dissimilar Gateway Protocol | 86 |
TCF TCF | 87 |
EIGRP EIGRP CISCO | 88 |
OSPFIGP OSPFIGP RFC 2328 | 89 |
Sprite-RPC Sprite RPC Protocol | 90 |
LARP Locus Address Resolution Protocol | 91 |
MTP Multicast Transport Protocol | 92 |
AX.25 AX.25 Frames | 93 |
IPIP IP-within-IP Encapsulation Protocol RFC 1853 | 94 |
MICP Mobile Internetworking Control Protocol | 95 |
SCC-SP Semaphore Communications Sec. Pro. | 96 |
ETHERIP Ethernet-within-IP Encapsulation | 97 |
ENCAP Encapsulation Header RFC 1241 | 98 |
Any private encryption scheme IANA | 99 |
GMTP GMTP | 100 |
IFMP Ipsilon Flow Management Protocol | 101 |
PNNI PNNI over IP | 102 |
PIM Protocol Independent Multicast RFC 2362 (sparse mode) | 103 |
ARIS ARIS | 104 |
SCPS SCPS | 105 |
QNX QNX | 106 |
A/N Active Networks | 107 |
IPComp IP Payload Compression Protocol RFC 2393 | 108 |
SNP Sitara Networks Protocol | 109 |
Compaq-Peer Compaq Peer Protocol | 110 |
IPX-in-IP IPX in IP RFC 1234 | 111 |
VRRP Virtual Router Redundancy Protocol RFC 2328 | 112 |
PGM PGM Reliable Transport Protocol | 113 |
Any 0-hop protocol IANA | 114 |
L2TP Layer Two Tunneling Protocol RFC 2661 | 115 |
DDX D-II Data Exchange (DDX) | 116 |
IATP Interactive Agent Transfer Protocol | 117 |
STP Schedule Transfer Protocol | 118 |
SRP SpectraLink Radio Protocol | 119 |
UTI UTI | 120 |
SMP Simple Message Protocol | 121 |
SM SM | 122 |
PTP Performance Transparency Protocol | 123 |
ISIS over IPv4 | 124 |
FIRE | 125 |
CRTP Combat Radio Transport Protocol | 126 |
CRUDP Combat Radio User Datagram | 127 |
SSCOPMCE | 128 |
IPLT | 129 |
SPS Secure Packet Shield | 130 |
PIPE Private IP Encapsulation within IP | 131 |
SCTP Stream Control Transmission Protocol | 132 |
FC Fibre Channel | 133 |
Unassigned IANA | 134 to 254 |
Reserved IANA | 255 |