Path: utzoo!attcan!uunet!tut.cis.ohio-state.edu!ucbvax!AQUA.WHOI.EDU!mep
From: mep@AQUA.WHOI.EDU (Michael E. Pare)
Newsgroups: comp.protocols.tcp-ip
Subject: Re:  IP Addresses (Subnets)
Message-ID: <9006141239.AA15188@aqua.whoi.edu>
Date: 14 Jun 90 12:39:45 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 28

>I have a quick question, hopefully you will not flame to loudly with
>regard to  viewing RFCs.  I looked through RFC 950 to try to determine
>how to specify a host when using a subnet.  In my particular instance we
>have a class B network.  I am interested in how one would specify
>addresses when a subnet of 6 bits is used.

>Suppose I want the 300th host on the 1 subnet of a class B network with
>a netmask of 255.255.252!  Should I specify the IP address as
>128.38.1.300 or 128.38.253.44

>I guess my overall question is:  Should I specify the addressing using
>the 3rd octet field in the dot notation as the subnet or as the 3rd
>octet of the 32 bit field? 

>Thanks,
>  Bob Hott

The first subnet using 6 bits will be 4.  Decimal 300 in binary is
100101100. The rightmost 8 bits belongs to the first field and is 44.
The leftmost 1 is part of the next field.  The resulting binary format
for the first two fields will be :

			00000101 00101100
			------
			subnet|---------|
				host
The resulting decimal values are 5 and 44 respectively.  Thus the IP address
will be 128.38.5.44 for the 300th host of the first subnet.