PDF《ISI》

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