Internet numbers
RFC 997
Document | Type |
RFC - Unknown
(March 1987; No errata)
Updates RFC 990
|
|
---|---|---|---|
Authors | |||
Last updated | 2013-03-02 | ||
Stream | Legacy | ||
Formats | plain text html pdf htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 997 (Unknown) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group J. Reynolds
Request for Comments: 997 J. Postel
ISI
Obsoletes RFCs: 990, 960, 943, 923, 900, March 1987
870, 820, 790, 776, 770, 762, 758,
755, 750, 739, 604, 503, 433, 349
Obsoletes IENs: 127, 117, 93
INTERNET NUMBERS
Status of this Memo
This memo is an official status report on the network numbers used in
the Internet community. Distribution of this memo is unlimited.
Introduction
This Network Working Group Request for Comments documents the
currently assigned network numbers and gateway autonomous systems.
This RFC will be updated periodically, and in any case current
information can be obtained from Hostmaster.
Hostmaster
DDN Network Information Center
SRI International
333 Ravenswood Avenue
Menlo Park, California 94025
Phone: 1-800-235-3155
ARPA mail: HOSTMASTER@SRI-NIC.ARPA
Most of the protocols used in the Internet are documented in the RFC
series of notes. Some of the items listed are undocumented. Further
information on protocols can be found in the memo "Official
ARPA-Internet Protocols" [24]. The more prominent and more generally
used are documented in the "DDN Protocol Handbook" [11] prepared by
the NIC. Other collections of older or obsolete protocols are
contained in the "Internet Protocol Transition Workbook" [12], or in
the "ARPANET Protocol Transition Handbook" [13]. For further
information on ordering the complete 1985 DDN Protocol Handbook,
contact the Hostmaster.
In the entries below, the name and mailbox of the responsible
individual is indicated. The bracketed entry, e.g., [nn,iii], at the
right hand margin of the page indicates a reference for the listed
protocol, where the number ("nn") cites the document and the letters
("iii") cites the person. Whenever possible, the letters are a NIC
Ident as used in the WhoIs (NICNAME) service.
Reynolds & Postel [Page 1]
Internet Numbers RFC 997
Introduction
The convention in the documentation of Internet Protocols is to
express numbers in decimal and to picture data in "big-endian" order
[31]. That is, fields are described left to right, with the most
significant octet on the left and the least significant octet on the
right.
The order of transmission of the header and data described in this
document is resolved to the octet level. Whenever a diagram shows a
group of octets, the order of transmission of those octets is the
normal order in which they are read in English. For example, in the
following diagram the octets are transmitted in the order they are
numbered.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 1 | 2 | 3 | 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 5 | 6 | 7 | 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 9 | 10 | 11 | 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Transmission Order of Bytes
Whenever an octet represents a numeric quantity the left most bit in
the diagram is the high order or most significant bit. That is, the
bit labeled 0 is the most significant bit. For example, the
following diagram represents the value 170 (decimal).
0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+
|1 0 1 0 1 0 1 0|
+-+-+-+-+-+-+-+-+
Significance of Bits
Similarly, whenever a multi-octet field represents a numeric quantity
the left most bit of the whole field is the most significant bit.
When a multi-octet quantity is transmitted the most significant octet
is transmitted first.
Reynolds & Postel [Page 2]
Internet Numbers RFC 997
Network Numbers
NETWORK NUMBERS
The network numbers listed here are used as internet addresses by the
Internet Protocol (IP) [11,21]. The IP uses a 32-bit address field
and divides that address into a network part and a "rest" or local
address part. The division takes 4 forms or classes.
The first type of address, or class A, has a 7-bit network number
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