在IPv4中，该字段IPv4包头中的protocol指定上层协议号，而IPv6中则由IPv6基本包头中的next head字段指定，该字段值固定8bit，因此取值范围为0-255，各取值代表不同的上层协议，就像二层Ethertype指定上层承载的协议一样。
比如我们比较常用的：
1为ICMP，2为IGMP，6为TCP协议，17为UDP协议,88为EIGRP，89为OSPF协议等，而4为IPv4协议号，41为IPv6协议号，47为GRE头。
而针对IPv6中，我们的各种扩展头也由此部分定义，比如IPv6中比较常用的几个扩展头为：
0为IPv6 hop-by-hop逐跳选项扩展头，43为IPv6路由扩展头，44为IPv6分片扩展头，50为ESP加密头，51为AH认证头，58为ICMPv6,59为no next head无下一个头部，60为IPv6目的选择扩展头。
以下列表为各字段的定义：
Decimal Keyword Protocol Reference
0 HOPOPT IPv6 Hop-by-Hop Option [RFC1883]
1 ICMP Internet Control Message [RFC792]
2 IGMP Internet Group Management [RFC1112]
3 GGP Gateway-to-Gateway [RFC823]
4 IPv4 IPv4 encapsulation [RFC2003]
5 ST Stream [RFC1190][RFC1819]
6 TCP Transmission Control [RFC793]
7 CBT CBT [Tony_Ballardie]
8 EGP Exterior Gateway Protocol [RFC888][David_Mills]
9 IGP any private interior gateway (used by [Internet_Assigned_Numbers_Authority]
Cisco for their IGRP)
10 BBN-RCC-MON BBN RCC Monitoring [Steve_Chipman]
11 NVP-II Network Voice Protocol [RFC741][Steve_Casner]
[Boggs, D., J. Shoch, E. Taft, and R. Metcalfe, "PUP: An Internetwork
12 PUP PUP Architecture", XEROX Palo Alto Research Center, CSL-79-10, July 1979; also in IEEE
Transactions on Communication, Volume COM-28, Number 4, April 1980.][[XEROX]]
13 ARGUS ARGUS [Robert_W_Scheifler]
14 EMCON EMCON [<mystery contact>]
15 XNET Cross Net Debugger [Haverty, J., "XNET Formats for Internet Protocol Version 4", IEN 158, October
1980.][Jack_Haverty]
16 CHAOS Chaos [J_Noel_Chiappa]
17 UDP User Datagram [RFC768][Jon_Postel]
18 MUX Multiplexing [Cohen, D. and J. Postel, "Multiplexing Protocol", IEN 90, USC/Information
Sciences Institute, May 1979.][Jon_Postel]
19 DCN-MEAS DCN Measurement Subsystems [David_Mills]
20 HMP Host Monitoring [RFC869][Robert_Hinden]
21 PRM Packet Radio Measurement [Zaw_Sing_Su]
["The Ethernet, A Local Area Network: Data Link Layer and Physical Layer
Specification", AA-K759B-TK, Digital Equipment Corporation, Maynard, MA. Also as:
"The Ethernet - A Local Area Network", Version 1.0, Digital Equipment Corporation,
22 XNS-IDP XEROX NS IDP Intel Corporation, Xerox Corporation, September 1980. And: "The Ethernet, A Local
Area Network: Data Link Layer and Physical Layer Specifications", Digital, Intel
and Xerox, November 1982. And: XEROX, "The Ethernet, A Local Area Network: Data
Link Layer and Physical Layer Specification", X3T51/80-50, Xerox Corporation,
Stamford, CT., October 1980.][[XEROX]]
23 TRUNK-1 Trunk-1 [Barry_Boehm]
24 TRUNK-2 Trunk-2 [Barry_Boehm]
25 LEAF-1 Leaf-1 [Barry_Boehm]
26 LEAF-2 Leaf-2 [Barry_Boehm]
27 RDP Reliable Data Protocol [RFC908][Robert_Hinden]
28 IRTP Internet Reliable Transaction [RFC938][Trudy_Miller]
29 ISO-TP4 ISO Transport Protocol Class 4 [RFC905][<mystery contact>]
30 NETBLT Bulk Data Transfer Protocol [RFC969][David_Clark]
[Shuttleworth, B., "A Documentary of MFENet, a National Computer Network",
31 MFE-NSP MFE Network Services Protocol UCRL-52317, Lawrence Livermore Labs, Livermore, California, June
1977.][Barry_Howard]
32 MERIT-INP MERIT Internodal Protocol [Hans_Werner_Braun]
33 DCCP Datagram Congestion Control Protocol [RFC4340]
34 3PC Third Party Connect Protocol [Stuart_A_Friedberg]
35 IDPR Inter-Domain Policy Routing Protocol [Martha_Steenstrup]
36 XTP XTP [Greg_Chesson]
37 DDP Datagram Delivery Protocol [Wesley_Craig]
38 IDPR-CMTP IDPR Control Message Transport Proto [Martha_Steenstrup]
39 TP++ TP++ Transport Protocol [Dirk_Fromhein]
40 IL IL Transport Protocol [Dave_Presotto]
41 IPv6 IPv6 encapsulation [RFC2473]
42 SDRP Source Demand Routing Protocol [Deborah_Estrin]
43 IPv6-Route Routing Header for IPv6 [Steve_Deering]
44 IPv6-Frag Fragment Header for IPv6 [Steve_Deering]
45 IDRP Inter-Domain Routing Protocol [Sue_Hares]
46 RSVP Reservation Protocol [Bob_Braden]
47 GRE General Routing Encapsulation [Tony_Li]
48 DSR Dynamic Source Routing Protocol [RFC4728]
49 BNA BNA [Gary Salamon]
50 ESP Encap Security Payload [RFC4303]
51 AH Authentication Header [RFC4302]
52 I-NLSP Integrated Net Layer Security TUBA [K_Robert_Glenn]
53 SWIPE IP with Encryption [John_Ioannidis]
54 NARP NBMA Address Resolution Protocol [RFC1735]
55 MOBILE IP Mobility [Charlie_Perkins]
56 TLSP Transport Layer Security Protocol [Christer_Oberg]
using Kryptonet key management
57 SKIP SKIP [Tom_Markson]
58 IPv6-ICMP ICMP for IPv6 [RFC1883]
59 IPv6-NoNxt No Next Header for IPv6 [RFC1883]
60 IPv6-Opts Destination Options for IPv6 [RFC1883]
61 any host internal protocol [Internet_Assigned_Numbers_Authority]
62 CFTP CFTP [Forsdick, H., "CFTP", Network Message, Bolt Beranek and Newman, January
1982.][Harry_Forsdick]
63 any local network [Internet_Assigned_Numbers_Authority]
64 SAT-EXPAK SATNET and Backroom EXPAK [Steven_Blumenthal]
65 KRYPTOLAN Kryptolan [Paul Liu]
66 RVD MIT Remote Virtual Disk Protocol [Michael_Greenwald]
67 IPPC Internet Pluribus Packet Core [Steven_Blumenthal]
68 any distributed file system [Internet_Assigned_Numbers_Authority]
69 SAT-MON SATNET Monitoring [Steven_Blumenthal]
70 VISA VISA Protocol [Gene_Tsudik]
71 IPCV Internet Packet Core Utility [Steven_Blumenthal]
72 CPNX Computer Protocol Network Executive [David Mittnacht]
73 CPHB Computer Protocol Heart Beat [David Mittnacht]
74 WSN Wang Span Network [Victor Dafoulas]
75 PVP Packet Video Protocol [Steve_Casner]
76 BR-SAT-MON Backroom SATNET Monitoring [Steven_Blumenthal]
77 SUN-ND SUN ND PROTOCOL-Temporary [William_Melohn]
78 WB-MON WIDEBAND Monitoring [Steven_Blumenthal]
79 WB-EXPAK WIDEBAND EXPAK [Steven_Blumenthal]
80 ISO-IP ISO Internet Protocol [Marshall_T_Rose]
81 VMTP VMTP [Dave_Cheriton]
82 SECURE-VMTP SECURE-VMTP [Dave_Cheriton]
83 VINES VINES [Brian Horn]
84 TTP TTP [Jim_Stevens]
85 NSFNET-IGP NSFNET-IGP [Hans_Werner_Braun]
86 DGP Dissimilar Gateway Protocol [M/A-COM Government Systems, "Dissimilar Gateway Protocol Specification, Draft
Version", Contract no. CS901145, November 16, 1987.][Mike_Little]
87 TCF TCF [Guillermo_A_Loyola]
88 EIGRP EIGRP [Cisco Systems, "Gateway Server Reference Manual", Manual Revision B, January 10,
1988.][Guenther_Schreiner]
89 OSPFIGP OSPFIGP [RFC1583][John_Moy]
[Welch, B., "The Sprite Remote Procedure Call System", Technical Report,
90 Sprite-RPC Sprite RPC Protocol UCB/Computer Science Dept., 86/302, University of California at Berkeley, June
1986.][Bruce Willins]
91 LARP Locus Address Resolution Protocol [Brian Horn]
92 MTP Multicast Transport Protocol [Susie_Armstrong]
93 AX.25 AX.25 Frames [Brian_Kantor]
94 IPIP IP-within-IP Encapsulation Protocol [John_Ioannidis]
95 MICP Mobile Internetworking Control Pro. [John_Ioannidis]
96 SCC-SP Semaphore Communications Sec. Pro. [Howard_Hart]
97 ETHERIP Ethernet-within-IP Encapsulation [RFC3378]
98 ENCAP Encapsulation Header [RFC1241][Robert_Woodburn]
99 any private encryption scheme [Internet_Assigned_Numbers_Authority]
100 GMTP GMTP [[RXB5]]
101 IFMP Ipsilon Flow Management Protocol [Bob_Hinden][November 1995, 1997.]
102 PNNI PNNI over IP [Ross_Callon]
103 PIM Protocol Independent Multicast [Dino_Farinacci]
104 ARIS ARIS [Nancy_Feldman]
105 SCPS SCPS [Robert_Durst]
106 QNX QNX [Michael_Hunter]
107 A/N Active Networks [Bob_Braden]
108 IPComp IP Payload Compression Protocol [RFC2393]
109 SNP Sitara Networks Protocol [Manickam_R_Sridhar]
110 Compaq-Peer Compaq Peer Protocol [Victor_Volpe]
111 IPX-in-IP IPX in IP [CJ_Lee]
112 VRRP Virtual Router Redundancy Protocol [RFC3768][RFC5798]
113 PGM PGM Reliable Transport Protocol [Tony_Speakman]
114 any 0-hop protocol [Internet_Assigned_Numbers_Authority]
115 L2TP Layer Two Tunneling Protocol [Bernard_Aboba]
116 DDX D-II Data Exchange (DDX) [John_Worley]
117 IATP Interactive Agent Transfer Protocol [John_Murphy]
118 STP Schedule Transfer Protocol [Jean_Michel_Pittet]
119 SRP SpectraLink Radio Protocol [Mark_Hamilton]
120 UTI UTI [Peter_Lothberg]
121 SMP Simple Message Protocol [Leif_Ekblad]
122 SM SM [Jon_Crowcroft]
123 PTP Performance Transparency Protocol [Michael_Welzl]
124 ISIS over IPv4 [Tony_Przygienda]
125 FIRE [Criag_Partridge]
126 CRTP Combat Radio Transport Protocol [Robert_Sautter]
127 CRUDP Combat Radio User Datagram [Robert_Sautter]
128 SSCOPMCE [Kurt_Waber]
129 IPLT [[Hollbach]]
130 SPS Secure Packet Shield [Bill_McIntosh]
131 PIPE Private IP Encapsulation within IP [Bernhard_Petri]
132 SCTP Stream Control Transmission Protocol [Randall_R_Stewart]
133 FC Fibre Channel [Murali_Rajagopal]
134 RSVP-E2E-IGNORE [RFC3175]
135 Mobility Header [RFC3775]
136 UDPLite [RFC3828]
137 MPLS-in-IP [RFC4023]
138 manet MANET Protocols [RFC-ietf-manet-iana-07]
139 HIP Host Identity Protocol [RFC5201]
140 Shim6 Shim6 Protocol [RFC5533]
141 WESP Wrapped Encapsulating Security [RFC5840]
Payload
142 ROHC Robust Header Compression [RFC5858]
143-252 Unassigned [Internet_Assigned_Numbers_Authority]
253 Use for experimentation and testing [RFC3692]
254 Use for experimentation and testing [RFC3692]
255 Reserved [Internet_Assigned_Numbers_Authority]
该列表由IANA维护，最新数据可通过http://www.iana.org/assignments/protocol-numbers查看 |
IP卡
狗仔卡
提升卡
置顶卡
沉默卡
喧嚣卡
变色卡
显身卡