RFC 739 HISTORIC META · REGISTRY
Assigned numbers
A registry of protocol numbers and reserved network addresses
RFC EDITOR
Postel, J., "Assigned numbers", RFC 739, DOI 10.17487/RFC0739, November 1977, <https://www.rfc-editor.org/info/rfc739>.
BIBTEX
@misc{rfc739,
series = {Request for Comments},
number = 739,
howpublished = {RFC 739},
publisher = {RFC Editor},
doi = {10.17487/RFC0739},
url = {https://www.rfc-editor.org/info/rfc739},
author = {J. Postel},
title = {{Assigned numbers}},
pagetotal = 11,
year = 1977,
month = nov,
} RFC text
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Network Working Group J. Postel
Request for Comments: 739 USC-ISI
NIC: 42341 11 November 1977
ASSIGNED NUMBERS
This Network Working Group Request for Comments documents the currently
assigned values from several series of numbers used in network protocol
implementations. This RFC will be updated periodically, and in any case
current information can be obtained from Jon Postel. The assignment of
numbers is also handled by Jon. If you are developing a protocol or
application that will require the use of a link, socket, etc. please
contact Jon to receive a number assignment.
Jon Postel
USC - Information Sciences Institute
4676 Admiralty Way
Marina del Rey, California 90291
phone: (213) 822-1511
ARPANET mail: POSTEL@ISIB
Most of the protocols mentioned here are documented in the RFC series of
notes. The more prominent and more generally used are documented in the
Protocol Handbook [1] prepared by the Network Information Center (NIC).
In the lists that follow a bracketed number, e.g. [1], off to the right
of the page indicates a reference to the protocol assigned that number.
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Link Numbers
ASSIGNED LINK NUMBERS
The word "link" here refers to a field in the original ARPANET
Host/IMP interface leader. The link was originally defined as an 8
bit field. Some time after the ARPANET Host-to-Host (AHHP) protocol
was defined and, by now, some time ago the definition of this field
was changed to "Message-ID" and the length to 12 bits. The name link
now refers to the high order 8 bits of this 12 bit message-id field.
The low order 4 bits of the message-id field are to be zero unless
specifically specified otherwise for the particular protocol used on
that link. The Host/IMP interface is defined in BBN report 1822 [2].
Link Assignments:
Decimal Octal Description References
------- ----- ----------- ----------
0 0 AHHP Control Messages [1,3]
1 1 Reserved
2-71 2-107 AHHP Regular Messages [1,3]
72-151 110-227 Reserved
152 230 PARC Universal Protocol
153 231 TIP Status Reporting
154 232 TIP Accounting
155-158 233-236 Internet Protocol [35,36]
159-191 237-277 Measurements [28]
192-195 300-303 Message Switching Protocol [4,5]
196-255 304-377 Experimental Protocols
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Socket Numbers
ASSIGNED SOCKET NUMBERS
Sockets are used in the AHHP [1,3] to name the ends of logical
connections which carry long term conversations. For the purpose of
providing services to all callers an Initial Connection Procedure ICP
[1,34] is used between the user process and the server process. This
list specifies the socket used by the server process as its contact
socket.
Socket Assignments:
General Assignments:
Decimal Octal Description
------- ----- -----------
0-63 0-77 Network Wide Standard Function
64-127 100-177 Hosts Specific Functions
128-223 200-337 Reserved for Future Use
224-255 340-377 Any Experimental Function
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Socket Numbers
Specific Assignments:
Decimal Octal Description References
------- ----- ----------- ----------
Network Standard Functions
1 1 Old Telnet [6]
3 3 Old File Transfer [7,8,9]
5 5 Remote Job Entry [10]
7 7 Echo [11]
9 11 Discard [12]
11 13 Who is on or SYSTAT
13 15 Date and Time
15 17 Who is up or NETSTAT
17 21 Short Text Message
19 23 Character generator or TTYTST [13]
21 25 New File Transfer [1,14,15]
23 27 New Telnet [1,16,17]
25 31 Distributed Programming System [18,19]
27 33 NSW User System w/COMPASS FE [20]
29 35 MSG-3 ICP [21]
31 37 MSG-3 Authentication [21]
33 41 DPS ICP [18,19]
35 43 IO Station Spooler
37 45 Time Server [22]
39 47 NSW User System w/SRI FE [20]
Host Specific Functions
65 101 Speech Data Base at LL-TX-2 [23]
67 103 Datacomputer at CCA [24]
69 105 CPYNET
71 107 NETRJS (EBCDIC) at UCLA-CCN [25]
73 111 NETRJS (ASCII) at UCLA-CCN [25]
75 113 NETRJS (TTY) at UCLA-CCN [25]
77 115 any private RJE server
79 117 Finger
81 121 Network BSYS
95 137 SUPDUP [33]
Experimental Functions
229 345 Garlick's Debugger
232-237 350-355 Authorized Mailer at BBN
239 357 Graphics [1,26]
241 361 NCP Measurement [27,28]
243 363 Survey Measurement [28,29,30]
245 365 LINK [31]
247 367 TIPSRV
249-255 371-377 RSEXEC [31,32]
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Network Numbers
ASSIGNED NETWORK NUMBERS
This list of network numbers is used in the internetwork protocols
now under development, the field is 8 bits in size.
Assigned Network Numbers
Decimal Octal Network
------- ----- -------
0 0 Reserved
1 1 BBN Packet Radio Network
2 2 SF Bay Area Packet Radio Network (1)
3 3 BBN RCC Network
4 4 Atlantic Satellite Network
5 5 Washington D.C. Packet Radio Network
6 6 SF Bay Area Packet Radio Network (2)
7-9 7-11 Not assigned
10 12 ARPANET
11 13 University College London Network
12 14 CYCLADES
13 15 National Physical Laboratory
14 16 TELENET
15 17 British Post Office EPSS
16 20 DATAPAC
17 21 TRANSPAC
18 22 LCS Network
19 23 TYMNET
20-254 24-376 Unassigned
255 377 Reserved
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Internet Message Versions
ASSIGNED INTERNET MESSAGE VERSIONS
In the internetwork protocols there is a field to identify the
version of the internetwork general protocol. This field is 4 bits
in size.
Assigned Internet Message Versions
Decimal Octal Version References
------- ----- ------- ----------
0 0 Old [35]
1 1 Current [36]
2-14 2-16 Unassigned
15 17 Reserved
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Internet Message Formats
ASSIGNED INTERNET MESSAGE FORMATS
In the internetwork protocols there is a field to identify the format
of the host level specific protocol. This field is 8 bits in size.
Assigned Internet Message Formats
Decimal Octal Format References
------- ----- ------ ----------
0 0 Reserved
1 1 raw internet
2 2 TCP-3 [36]
3 3 DSP [37,38]
2-254 2-376 Unassigned
255 377 Reserved
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
Assigned Internet Message Types
ASSIGNED INTERNET MESSAGE TYPES
In the internetwork old protocol there is a field to identify the
type of the message. This field is 4 bits in size.
Assigned Internet Message Types
Decimal Octal Type
------- ----- ----
0 0 Escape
1 1 TCP-2
2 2 Secure
3 3 Gateway
4 4 Measurement
5 5 DSP
6 6 UCL
7-12 7-14 Reserved
13 15 Pluribus
14 16 Telenet
15 17 Xnet
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
References
REFERENCES
[1] Feinler, E. "ARPANET Protocol Handbook," NIC 7104, Defense
Communications Agency, 1 April 1976.
[2] BBN, "Specifications for the Interconnection of a Host and an
IMP," Report 1822, Bolt Beranek and Newman, Cambridge,
Massachusetts, January 1976.
[3] McKenzie,A. "Host/Host Protocol for the ARPA Network," NIC
8246, January 1972.
[4] Walden, D. "A System for Interrprocess Communication in a
Resource Sharing Computer Network," RFC 62, NIC 4962,
3-Aug-70. Also published in Communications of the ACM volume
15, number 4, April 1972.
[5] Bressler, B. "A Proposed Experiment with a Message Switching
Protocol," RFC 333, NIC 9926, 15-May-72.
[6] Postel, J. "Telnet Protocol," RFC 318, NIC 9348, 3-April-72.
[7] McKenzie, A. "File Transfer Protocol," NIC 14333, RFC 454,
16-Feb-73.
[8] Clements, R. "FTPSRV -- Extensions for Tenex Paged Files," RFC
683, NIC 32251, 3-April-75.
[9] Harvey, B. "One More Try on the FTP," RFC 691, NIC 32700,
6-Jun-75.
[10] Bressler, B. "Remote Job Entry Protocol," RFC 407, NIC 12112,
16-Oct-72.
[11] Postel, J. "Echo Process," RFC 347, NIC 10426, 30-May-72.
[12] Postel, J. "Discard Process," RFC 348, NIC 10427, 30-May-72.
[13] Postel, J. "Character Generator Process," RFC 429, NIC 13281,
12-Dec-72.
[14] Neigus, N. "File Transfer Protocol," NIC 17759 RFC 542
12-July-73.
[15] Postel, J. "Revised FTP Reply Codes," NIC 30843 RFC 640
5-June-74.
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
References
[16] McKenzie, A. "Telnet Protocol Specifications," NIC 18639,
August 1973.
[17] McKenzie, A. "Telnet Option Specification," NIC 18640, August
1973.
[18] White, J. "A High Level Framework for Network-Based Resource
Sharing," RFC 707, NIC 34263, 14 January 1976. Also in NCC
Proceedings, AFIPS, June 1976.
[19] White, J. "Elements of a Distributed Programming System," RFC
708, NIC 34353, 28 January 1976.
[20] COMPASS. "Semi-Annual Technical Report," CADD-7603-0411,
Massachusetts Computer Associates, 4 March 1976. Also as,
"National Software Works, Status Report No. 1,"
RADC-TR-76-276, Volume 1, September 1976. and COMPASS. "Second
Semi-Annual Report," CADD-7608-1611, Massachusetts Computer
Associates, 16 August 1976.
[21] NSW Protocol Committee, "MSG: The Interprocess Communication
Facility for the National Software Works," CADD-7612-2411,
Massachusetts Computer Associates, BBN 3237, Bolt Beranek and
Newman, Revised 24 December 1976.
[22] Harrenstien, K. "Time Server," RFC 738, NIC 42218, 31-Oct-77.
[23] Armenti, A., D. Hall, and A. Stone. "Lincoln Speech Data
Facility," SUR Note 37, NIC 10917, 14 July 1972.
[24] CCA, "Datacomputer Version 1 User Manual," Computer
Corporation of America, August 1975.
[25] Braden, R. "Interim NETRJS Specification," RFC 189, NIC 7133,
15-July-71.
[26] Sproull, R, and E. Thomas. "A Networks Graphics Protocol," NIC
24308, 16-Aug-74.
[27] Cerf, V., "NCP Statistics," RFC 388, NIC 11360, 23 August
1972.
[28] Cerf, V., "Formation of a Network Measurement Group (NMG),"
RFC 323, NIC 9630, 23 March 1972.
NWG/RFC# 739 JBP 11 Nov 77 42341
Assigned Numbers
References
[29] Bhushan, A., "A Report on the Survey Project," RFC 530, NIC
17375, 22 June 1973.
[30] Cantor, D., "Storing Network Survey Data at the Datacomputer,"
RFC 565, NIC 18777, 28 August 1973.
[31] Bressler, R., "Inter-Entity Communication -- An Experiment,"
RFC 441, NIC 13773, 19 January 1973.
[32] Thomas, R. "A Resource Sharing Executive for the ARPANET,"
AFIPS Conference Proceedings, 42:155-163, NCC, 1973.
[33] Crispin, M. "SUPDUP Protocol," RFC 734, NIC 41953, 7 October
1977.
[34] Postel, J. "Official Initial Connection Protocol," NIC 7101,
11 June 1971.
[35] Cerf, V. "Specification of Internet Transmission Control
Program -- TCP (version 2)," March 1977.
[36] Cerf, V. and J. Postel, "Specification of Internet
Transmission Control Program -- TCP-3," November 1977.
[37] Reed, D. "Protocols for the LCS Network," Local Network Note
3, Laboratory for Computer Science, MIT, 29 November 1976.
[38] Clark, D. "Revision of DSP Specification," Local Network Note
9, Laboratory for Computer Science, MIT, 17 June 1977.
AI ELI5
On this page
PROBLEMAs the ARPANET and early internet grew, protocols and applications needed unique identifiers for links, sockets, networks, and message types to avoid conflicts.
MECHANISMRFC 739 publishes a definitive list of all assigned numbers across multiple categories: ARPANET link assignments, socket assignments for standard functions and experimental uses, network numbers for interconnected networks, internet message versions and formats, and message types.
PROTOCOL NUMBER REGISTRYThis registry provided a central source of truth, preventing conflicts and allowing independent implementations to interoperate. It was kept current periodically and replaced by RFC 750.
§1Purpose and Scope
RFC 739 documents the currently assigned values from several series of numbers used in network protocol implementations. The RFC notes that it will be updated periodically, and current assignments can be obtained from Jon Postel at USC-ISI, who also handles new assignments. Developers building protocols or applications requiring link numbers, socket numbers, network numbers, or other standardized identifiers must contact Postel to receive assignments and avoid conflicts.
The network is growing and needs to organize which numbers mean what. This list says who is in charge of giving out numbers and what each one is used for.
§2Link, Socket and Network Numbers
The RFC assigns links (which refer to an 8-bit field in the ARPANET Host/IMP interface leader, now part of a 12-bit message-id) in ranges for different uses: AHHP control messages, regular messages, reserved ranges, experimental protocols and specialized services like PARC protocols and TIP (Terminal IMP) reporting. Socket numbers are assigned for network-wide standard functions (0-63), host-specific functions (64-127), reserved ranges (128-223), and experimental uses (224-255). Network numbers identify different physical networks in the growing internet, including the ARPANET, various packet radio networks, CYCLADES, TELENET and others.
Links, sockets and networks each get number ranges. Some numbers are for standard things like file transfer, others are for experiments, and some are reserved for later.
§3Message Versions and Types
The RFC specifies a 4-bit field identifying the version of the internet protocol (current version is 1, with 0 being older and 2-14 unassigned), and an 8-bit field identifying the format of the host-level protocol (raw internet, TCP-3, and DSP among the early formats). A separate 4-bit message type field distinguishes between different kinds of messages: escape, TCP-2, secure, gateway, measurement, DSP, UCL, and reserved types.
Messages need to say what version they use and what kind they are, so computers know how to read them.
§4References
[1]Feinler, E. "ARPANET Protocol Handbook," NIC 7104, April 1976.
[2]BBN, "Specifications for the Interconnection of a Host and an IMP," Report 1822, January 1976.