Re: Wireless Network Design
- From: Stephen <stephen_hope@xxxxxxxxxxxx>
- Date: Mon, 11 Aug 2008 18:25:20 GMT
On Sun, 10 Aug 2008 11:16:19 -0500, Bob Simon <nobody@xxxxxxxxxxx>
wrote:
On Sat, 9 Aug 2008 14:12:46 -0700 (PDT), Merv <merv.hrabi@xxxxxxxxxx>
wrote:
My ISP provides a single public static IP address to the WAN port of
the DSL modem. But since this modem does NAT, it should be able to
handle mulitple inside hosts with private addresses up to the limit of
its ability to handle translations without excessive delay. Right?
Are you able to configure the DSL modem ?
If for example the DSL modem is setup to only NAT 192.168.0..0/24 then
you might have an issue ....
If you can control its configuration so that it will NAT
192.168.0.0/16, then you should be okay
The modem is a Motorola/Netopia 2210-02. Motorola tech support said
it's been customized per ATT specs with some functionality stripped
out. I am able to configure it via the web interface plus via telnet,
which offers additional configuration granularity. There is no manual
available but the CLI offers help screens and command options. I only
see four NAT features:
mode -- NAT default server mode
mode (off) [ off | default-server | ip-passthrough ]
address -- NAT default server IP address
dhcp-enable -- NAT IP Passthrough DHCP enabled
host-hardware-address -- NAT IP Passthrough host hardware
Why would it be useful for the modem to be able to NAT for more than
one class c subnet? Wouldn't the following scenario work?
DSL Modem
WAN: public static
LAN: 192.168.0.1/24
Def GW: WAN port
NAT for 192.168.0.0/24 to public static IP
Wireless Rtr 1
WAN: 192.168.0.2/24
LAN: 192.168.1.1/24
Def GW: 192.168.0.1
NAT for 192.168.1.0/24 to 192.168.0.2
if you can disable NAT, then you should be able to get the clients on
W rtr 1 and w rtr 2 to talk directly.
Wireless Rtr 2
WAN: 192.168.0.3/24
LAN: 192.168.2.1/24
Def GW: 192.168.0.1
NAT for 192.168.2.0/24 to 192.168.0.3
Both routers would provide DHCP addresses for their respective
wireless clients. I presume roaming would not work because the client
would need to obtain a new IP address. But roaming doesn't work now
anyway as I mentioned yesterday.
OK. if rather than NAT these can work as real routers then you may be
able to make it work - but the modem would need to handle static
routes, RIP etc, since your LAN would comprise 3 subnets.
A better way (especially with only a few devices) is to structure it
as a single subnet.
But if the wireless routers just use no NAT, no routing and you have
DHCP for all devices from the "DSL modem" then a device should be able
to move across the 2 wireless links using the same IP address.
So if the address stays the same, you should be able to get roaming to
work.
hook a LAN port on each router to the modem.
Disable NAT / DHCP on each router (or run them in "AP mode" if they
support it).
Do not connect to the WAN ports on the routers.
If I'm missing some key point about network connectivity that requires
NAT for 192.168.0.0/16, I sure wish that someone would enlighten me.
Bob
if you remove 1 layer of NAT you end up witha system with a single
"LAN" and IP subnet, spread across the modem + 2 routers.
once you have that the connectivity between your devices is
unrestricted, and you have a chance to sort out roaming.
Note - if you want roaming to work, you need:
1. the same SSID / key phrase / wireless encryption mode on both
wireless routers.
2. devices where the wireless driver understand roaming (and
implements it correctly) - lots of flakey / broken drivers out
there...
3. A LAN that handles the logical move of a MAC address - this is
functions in the bridging within each wireless router + in the modem.
good luck
--
Regards
stephen_hope@xxxxxxxxxxxx - replace xyz with ntl
.
- References:
- Wireless Network Design
- From: Bob Simon
- Re: Wireless Network Design
- From: Stephen
- Re: Wireless Network Design
- From: Bob Simon
- Re: Wireless Network Design
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- Re: Wireless Network Design
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