[4382] in linux-net channel archive
Re: Subnets - Can you have more than one?
daemon@ATHENA.MIT.EDU (Marcos Assis Silva)
Sat Sep 14 16:32:52 1996
Date: Sat, 14 Sep 1996 16:45:58 -0300 (EST)
From: Marcos Assis Silva <assis@npd.uel.br>
To: Daniel Maldonado <danny@ct-ngnet.army.mil>
Cc: "'Linux-net@vger.rutgers.edu'" <Linux-net@vger.rutgers.edu>
In-Reply-To: <01BBA1C3.25EB68A0@DMC_HOME.ngctdpi>
On Fri, 13 Sep 1996, Daniel Maldonado wrote:
|o| Hi everyone,
|o| I met a guy at work the other day and started talking about
|o| subnetting. He said that two computers on the same network can have
|o| different subnet masks. For example one computer can have a subnet mask of
|o| 255.255.255.0 while another could have a 255.255.248.0 subnet. I was under
|o| the impression that there could only be one network number in ever network.
|o| He said that the computers with different subnets would not be able to see
|o| each other but they would both be able to share the network and find other
|o| computers with their same subnet. Is this true? Maybe when it was
|o| explained in the Cisco router class that I took I misunderstood the
|o| instructor. Can anyone verify this? I need this info for our Linux
|o| systems.
|o|
Hi
According to my own PRATICAL experience, the guy is absolutely right.
I've done this many times. As an exercise, it makes sense. But for production
environments, it's hard to guess a reason for resorting to such a thing. I,
personally, call it "subnet overloading" (of a physical wire) and the only
instance I found its use makes sense is when you have two small subnets (two
of 16 hosts, for example) and 24 hosts (to have a number to play with)
connected to the same wire, which ends up in a router (that allows ip
aliasing). This way you can apply both subnets to the same wire. The first
one serves some of our 24 hosts and the other one serves the remaining hosts.
So, I can have everybody happy without remodeling all my subnets to acomodate
those 24. The major disvantages: greater complexity (the router has two
interfaces to the same wire) and additional trafic (figure two of those 24
hosts trying to talk to each other being that one of them is in a subnet
different from the subnet of the other one). My 2 cents. Best regards ...
...
. . . -(o o)-
_.,-*b'`-`'d*-,._.,-*b'`-`'d*-,._.,-*b'`-`'d*-,._/----oOO--(_)--OOo-----
=
UNIVERSIDADE ESTADUAL DE LONDRINA - UEL .:. assis @ npd.uel.br
Nucleo de Processamento de Dados - NPD <*> Marcos Assis Silva
Gerencia de Software Basico - GSB ":" Analista de Suporte
Parana - Brasil o
. . . = .
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