Subnets (was: [dba-Tech] Modems)

Expand away!

Drew
----- Original Message -----
From: "Foote, Chris" <Chris.Foote at uk.thalesgroup.com>
To: "'Discussion of Hardware and Software issues'"
<dba-tech at databaseadvisors.com>
Sent: Wednesday, August 20, 2003 6:30 AM
Subject: Subnets (was: [dba-Tech] Modems)


> A wonderful piece of work Drew, thank you!
>
> Could I just enlarge on subnets?
>
> Subnets (or subnetworks) are a way of subdividing a Local Area Network
(LAN)
> into smaller "groups". Subnets are formed by "borrowing" some of the
"host"
> part of the IP address.
>
> For example:
>
> Say you are using the private IP address 172.16.0.0 for your LAN. This
would
> give you useable host addresses from 172.16.0.1 to 172.16.255.254 (you
> cannot use 172.16.0.0 as a host as this is the network number, and you
> cannot use 172.16.255.255 as this is the broadcast address). This give you
> 65023 hosts.
>
> If you "borrow" three bits from the host part of the address to form
subnets
> you get the following binary address format:
>
> nnnnnnnn.nnnnnnnn.ssshhhhh.hhhhhhhh
>
> where "n" are "network number" bits, "s" are subnet number bits, and "h"
are
> host number bits.
>
> The subnet mask is used to signify which (if any) bits are used for subnet
> addressing.
>
> In the above example, the default subnet mask would be 255.255.0.0
> This shows that only the first 16 bits are used in the network address.
>
> If we "borrow" three bits for subnets the subnet mask will be
255.255.224.0,
> because 224 in binary is 11100000.
>
>
> Best regards!
> Chris Foote
>
>
> > -----Original Message-----
> > From: Drew Wutka [mailto:dbatech at wolfwares.com]
> > Sent: Wednesday, August 20, 2003 1:53 AM
> > To: Discussion of Hardware and Software issues
> > Subject: Re: [dba-Tech] Modems
> >
> >
> > Steve, you asked, so I'm gonna learn ya!
> >
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