two routers on one Lan?

M

mdb

I do the network support in a school where there are about 40 computers all
getting their IP's via wired connections back to some stacked switches and a
Belkin router. They're in an old building constructed of heavy concrete with
true plaster walls (meaning wire mesh under plaster). The librarian has
asked about the feasibility of installing a wireless network in the library.
Her library is downstairs and at the opposite end of the school from the
current modem/router/switch location. My point here is that a wireless
signal will not reach from the current location to the library. I've always
said that a network can have only one DHCP server but I wondered if I might
be wrong. Could I connect a wireless router to the current wired network
drop in the library but have it pass out IP addresses in a different private
ip address range than the IPs given out by the primary router upstairs? I
suppose another way to do this would be to relocate the modem/router down to
the library and have all computers acquire an address from the router there.
But that recabling would be pretty expensive.

The purpose of the wireless connection in the library is just to allow the
librarian to move about the room with her laptop, freeing her from staying
at her desk when she's giving lessons. This is an elementary school. Is
there a way to make the wired connection that her desktop has available to
her laptop? perhaps via Internet Connection Sharing?

Does anyway see a good way to do this? I also considered access points
between the current router and the library but we'd need so many because of
the construction and the distance involved.

Thanks.
 
A

Axel Hammerschmidt

mdb said:
I do the network support in a school where there are about 40 computers all
getting their IP's via wired connections back to some stacked switches and a
Belkin router. They're in an old building constructed of heavy concrete with
true plaster walls (meaning wire mesh under plaster). The librarian has
asked about the feasibility of installing a wireless network in the library.
Her library is downstairs and at the opposite end of the school from the
current modem/router/switch location.

You could plug an access point into one of the ethernet connections in
the library.
My point here is that a wireless signal will not reach from the current
location to the library. I've always said that a network can have only one
DHCP server but I wondered if I might be wrong.

Indeed. You are not wrong in that assumption.
Could I connect a wireless router to the current wired network drop in the
library but have it pass out IP addresses in a different private ip
address range than the IPs given out by the primary router upstairs?

You could do that as well. The wireless router (with its DHCP server)
would ensure, that there is still only one DHCP server on that network.
Because the router will act as a gateway between the two networks.
I suppose another way to do this would be to relocate the modem/router
down to the library and have all computers acquire an address from the
router there. But that recabling would be pretty expensive.

Here again, you could use an access point. An AP works like a switch/hub
giving wired access to the wireless clients.
The purpose of the wireless connection in the library is just to allow the
librarian to move about the room with her laptop, freeing her from staying
at her desk when she's giving lessons. This is an elementary school. Is
there a way to make the wired connection that her desktop has available to
her laptop? perhaps via Internet Connection Sharing?

No need to use ICS. Just use an access point or wireless router.
Does anyway see a good way to do this? I also considered access points
between the current router and the library but we'd need so many because
of the construction and the distance involved.

Are you here thinking of extending the wireless network? There is no
need to do that, when there is a wired "drop" in the library already.
Just use an AP/wireless router connected to the wire cable.
 
K

Kurt

mdb said:
I do the network support in a school where there are about 40 computers all
getting their IP's via wired connections back to some stacked switches and a
Belkin router. They're in an old building constructed of heavy concrete with
true plaster walls (meaning wire mesh under plaster). The librarian has
asked about the feasibility of installing a wireless network in the library.
Her library is downstairs and at the opposite end of the school from the
current modem/router/switch location. My point here is that a wireless
signal will not reach from the current location to the library.


I've always
said that a network can have only one DHCP server but I wondered if I might
be wrong.
Indeed, a second DHCP server is a Mocrosoft recommendation in case one
fails. The rule is they can't be giving out IP addresses in the same
scope (but they can give out address on the same subnet).

Could I connect a wireless router to the current wired network
drop in the library but have it pass out IP addresses in a different private
ip address range than the IPs given out by the primary router upstairs?

Or even in the same address space as long as the addresses are excluded
from the other DHCP server.

I
suppose another way to do this would be to relocate the modem/router down to
the library and have all computers acquire an address from the router there.
But that recabling would be pretty expensive.

The purpose of the wireless connection in the library is just to allow the
librarian to move about the room with her laptop, freeing her from staying
at her desk when she's giving lessons. This is an elementary school. Is
there a way to make the wired connection that her desktop has available to
her laptop? perhaps via Internet Connection Sharing?

As far as Internet goes, yes. But not for two-way connectivity to the
main network. ICS is functionally a NAT router. But if you wanted the
library to be on its own network, you could use a real router and a
wireless access point. The real router in the library would have a
default gateway of the main network's router, and the main network's
router would have a static route to the Library's subnet via the
Library's router.
Does anyway see a good way to do this? I also considered access points
between the current router and the library but we'd need so many because of
the construction and the distance involved.

Think of a wireless access point as a wireless switch. You can have
multiple wireless (or wired) connections to it as long as each
connection has it's own IP address. You wouldn't need a second DHCP
server, since an access point functions as a bridge (switch).

From Main Network
|
|
Small Switch
| \
| \
Teacher Comp WAP
/
\
/
Wireless Clients


....kurt
 

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