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Browse Prior Art Database

Address mappings (RFC0796)

IP.com Disclosure Number: IPCOM000003845D
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2004-Aug-15
Document File: 13 page(s) / 11K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Postel: AUTHOR

Abstract

This memo describes the relationship between address fields used in the Internet Protocol (IP) [1] and several specific networks.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 20% of the total text.

Network Working Group                                          J. Postel

Request for Comments:  796                                           ISI

Replaces: IEN 115                                         September 1981

                            ADDRESS MAPPINGS

                            ----------------

Internet Addresses

------------------

   This memo describes the relationship between address fields used in

   the Internet Protocol (IP) [1] and several specific networks.

   An internet address is a 32 bit quantity, with several codings as

   shown below.

   The first type (or class a) of address has a 7-bit network number and

   a 24-bit local address.

                           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

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      |0|   NETWORK   |                Local Address                  |

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                             Class A Address

   The second type (or class b) of address has a 14-bit network number

   and a 16-bit local address.

                           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 0|           NETWORK         |          Local Address        |

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                             Class B Address

   The third type (or class c) of address has a 21-bit network number

   and a 8-bit local address.

                           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 1 0|                    NETWORK              | Local Address |

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                             Class C Address

   The local address carries information to address a host in the

   network identified by the network number.  Since each network has a

Postel                                                          [Page 1]

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