Assigned numbers
RFC 750

Document Type RFC - Historic (September 1978; No errata)
Obsoleted by RFC 755
Obsoletes RFC 739
Last updated 2013-03-02
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NWG/RFC  750                                  JBP 26-Sep-78 18:30  45500

Network Working Group                                          J. Postel
Request for Comments: 750                                        USC-ISI
NIC: 45500                                             26 September 1978

Obsoletes: 739,
604, 503, 433, 349

                            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


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 for the listed protocol.

                                                                [Page 1]

NWG/RFC  750                                  JBP 26-Sep-78 18:30  45500
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             [35,36,42,43,44]
      159-191   237-277   Measurements                              [28]
      192-195   300-303   Message Switching Protocol               [4,5]
      196-255   304-377   Experimental Protocols
      224-255   340-377   NVP                                     [1,39]

                                                                [Page 2]

NWG/RFC  750                                  JBP 26-Sep-78 18:30  45500
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 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

      Specific Assignments:

         Network Standard Functions

         Decimal   Octal     Description                      References
         -------   -----     -----------                      ----------
         1         1         Old Telnet                              [6]
         3         3         Old File Transfer                   [7,8,9]
         5         5         Remote Job Entry                     [1,10]
         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]
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