RFC 1860 (rfc1860) - Page 1 of 3

Variable Length Subnet Table For IPv4

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Network Working Group                                         T. Pummill
Request for Comments: 1860                                       Alantec
Category: Informational                                       B. Manning
                                                                     ISI
                                                            October 1995


                 Variable Length Subnet Table For IPv4

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This document itemizes the potential values for IPv4 subnets.
   Additional information is provided for Hex and Decmial values,
   classfull equivalents, and number of addresses available within the
   indicated block. We appreciate inputs from Bruce Pinsky (cisco) and
   Daniel Karrenberg (RIPE).

Table

   The following table lists the variable length subnets from 1 to 32,
   the CIDR representation form and the Decmial equivalents.

   Mask value:
   Hex            CIDR   Decimal           #of add    Classfull
   80.00.00.00    /1     128.0.0.0         2048 M     128 A
   C0.00.00.00    /2     192.0.0.0         1024 M      64 A
   E0.00.00.00    /3     224.0.0.0          512 M      32 A
   F0.00.00.00    /4     240.0.0.0          256 M      16 A
   F8.00.00.00    /5     248.0.0.0          128 M       8 A
   FC.00.00.00    /6     252.0.0.0           64 M       4 A
   FE.00.00.00    /7     254.0.0.0           32 M       2 A
   FF.00.00.00    /8     255.0.0.0           16 M       1 A
   FF.80.00.00    /9     255.128.0.0          8 M     128 B
   FF.C0.00.00   /10     255.192.0.0          4 M      64 B
   FF.E0.00.00   /11     255.224.0.0          2 M      32 B
   FF.F0.00.00   /12     255.240.0.0       1024 K      16 B
   FF.F8.00.00   /13     255.248.0.0        512 K       8 B
   FF.FC.00.00   /14     255.252.0.0        256 K       4 B
   FF.FE.00.00   /15     255.254.0.0        128 K       2 B
   FF.FF.00.00   /16     255.255.0.0         64 K       1 B
   FF.FF.80.00   /17     255.255.128.0       32 K     128 C
   FF.FF.C0.00   /18     255.255.192.0       16 K      64 C



Pummill & Manning            Informational
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