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Subnetting on the same Physical Network
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| Myrt Webb 2003-08-25, 6:23 pm |
| My 216 studies have demonstrated that it is possible to
have two or more subnets on the same physical network.
What puzzles me is why anyone would want to do that?
Enlightment would be appreciated.
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| Consultant 2003-08-25, 6:23 pm |
| separation of users
separation of workstations from servers
etc
etc
"Myrt Webb" <myrtwebb@centurytel.net> wrote in message
news:034101c36b51$02400960$a60
1280a@phx.gbl...
> My 216 studies have demonstrated that it is possible to
> have two or more subnets on the same physical network.
>
> What puzzles me is why anyone would want to do that?
>
> Enlightment would be appreciated.
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| Gary - US 2003-08-25, 10:25 pm |
| To keep different workgroups on separate subnets would be one reason.
--
Semper Fi & God Bless America,
Gary-US MCNGP #20 & retired Jarhead
http://www.mcngp.tk
The MCNGP Team - We're here to help
** Kindly Do The Needful **
"Myrt Webb" <myrtwebb@centurytel.net> wrote in message
news:034101c36b51$02400960$a60
1280a@phx.gbl...
> My 216 studies have demonstrated that it is possible to
> have two or more subnets on the same physical network.
>
> What puzzles me is why anyone would want to do that?
>
> Enlightment would be appreciated.
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| Herb Martin 2003-08-29, 12:24 pm |
| It's call a "Multi-net".
It is done for a variety of reasons including:
1) Running out of address on the original subnet
2) Some public, some private addresses
3) Combined two (or more) physical segments and
didn't feel like re-architecting
etc.
You might need "superscopes" if using DHCP and you
will have to consider ROUTING to get things working
correctly.
Two approaches to routing (different difficulty, different
results, different efficiency):
1) Give the gateway an address on BOTH subnets
and set each group of machines' default gateway to
the appropriate address
2) Give every machine an explicit route to the "other"
subnet using their own IP address as the "gateway"
(it's a convention, my address as gateway means
"dump the traffic right onto the wire" without using a
formal gateway.)
#1 is quick to setup and can even be used to prevent the
sets of machine from talking (directly). But any traffic
from group one to group two much traverse the wire TWICE
in each direction -- to the gateway and back.)
#2 A lot more trouble for the admin as the number of stations
grows but gives direct communication without the gateway
being needed for all machine on the local SEGMENT.
--
Herb Martin
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