Extending wireless...

[Ichinisan]

I am about to set up wireless for soemone, which I have done many times before for other people. In this case, it will be a bit different because the home is HUGE. The cable modem is on the third floor and there is a computer two floors down that will also need to access it. I might move the cable modem somewhere in the middle of the home, even though that would require purchasing a USB wireless adapter for both desktops instead of only one. Moving the modem might be difficult because I'll have to rewire the cable splitwork to bypass the amplifier and maintain an acceptable cable signal for the modem.

I see that some routers have a "RADIUS" option that I assume has something to do with networking between routers to allow seamless hopping between access points...? A long time ago, I used to see "range extender" products in retail stores like Best Buy and Circuit City. I no longer see these. Is it possible to use a few trusty Linksys WRT54G's to create a seamless network without buying specialized equipment? Do any third-party firmwares enable such functions? Does RADIUS require an existing hard-wired network?

Thanks for any help!

 

[skyking]

That is WDS in a nutshell

If you set up a few routers with WDS enabled, within range of each other, they will form and area of coverage for seamless wireless connectivity.
The SSID is the same.
The Class C network is the same.

 

[Ichinisan]

Do most router's support WDS? Is it likely to work if you mix brands? I would assume that the channel should be set differently so that they don't interfere with each other, right? It seems like such a feature would surely have to have support in the driver software...is it part of the 802.11x standard? The router that is installed for the purpose of extending range, it does not need a WAN connection at all?

 

[JackMDS]

Most Entry Level Routers can Not do WDS.

Of the Brand Names, Buffalo Tech., and some of the Belkin Do, WRT54G does it with 3rd party firmware.

Mix Brands is "iffy" might or might not work, better to stick with the same Brand on the Router/AP side. Mixing Brand of Client cards is OK within 802.11g mode (No Super etc.).

RADIUS mainly used to authenticate wireless client logon into a system controled by a server.

:sun:

 

[skyking]

same channel, same ssid, same brand, WDS enabled.
Each additional router down the chain cuts the throughput in half, but that is insignificant if they are being used for surfing the web.

If you have two or three WRT54G that are v4 or older, you can do it with third party firmware. I prefer the DD-WRT firmware.
If you want to do this and have the routers, everything you could need is found
here.

The new WRT54G is V5 and cannot be flashed to a serviceable state, and has a ton of problems.

 

[spidey07]

one quick note, they should all be on separate channels - 1, 6, 11 so as not to interferre with one another.

 

[skyking]

Originally posted by: spidey07
one quick note, they should all be on separate channels - 1, 6, 11 so as not to interferre with one another.

Not in my experiences.

"For Straight WDS mode between two WDS enabled devices, such as 2x WRT54G/GS's, the requirements are that both the 'Host Router' and the 'Client Router' to be in 'AP' mode and on the same Channel. Importantly to be on seperate SSIDs so the 'Client Router' can roam between the 'Host Router'. Both the 'Client Router' and 'Host Router' must have WDS 'Lan' entrys for there respective MAC addresses, and there is confusion here because the firmware status screen may report the WAN address instead of the WLAN, so its best to be checked by ssh/telnet'ing to the wrt and using ifconfig, On the 'Client router' firewalling and blocking of anon intenet requests must be turned off. Both the 'Host' & 'Client' SSID's do not need to be broadcasted, but I havnt confirmed this my self. No other WDS settings such as 'lazy WDS' or 'WDS subnet' are relevant to the straight kind of WDS setup described here. "

from the dd-wrt wiki
the AP all share the same channel, so as to broadcast the WAN traffic out the the single router connected to the WAN. That is why a large WDS system gets slow, since it must repeat the traffic over the same channel down the line. Each hop effectively halves the throughput, so large filesharing operations over the LAN are not recommended.
If you need to connect a network segment to another using wired clients at the far end, setting one router as a client to the AP will get full throughput.
Unfortunately, that is a constraint when using single radios like that. If you had a more sophisticated device that could forward traffic through on one radio and handle AP traffic on another, that would indeed be slick.

 

[spidey07]

sounds like a severe limitation in that implementation.

Good wireless design for roaming and maximum coverage/performance is to use separate channels for each wireless cell/coverage area.

 

[skyking]

consider a location next to another without any wan connection. That is what WDS is all about, with seamless, no IP change, same subnet roaming wireless between and around the two AP's.

 

[spidey07]

well it still sounds like bad design. Normally you have all APs wired and on different channels still allowing seamless roaming, no bandwidth sacrifices and maximum coverage.

If you can't get wired coverage then you use 802.11a as the link to other APs with B still on different channels. Otherwise your causing interferrence even more than the bandwidth halfing by having an AP act as an infrastructure AP and client (repeating the radio)

 

[skyking]

That works fine if you have the $$$.

 

[JackMDS]

Originally posted by: skykingImportantly to be on seperate SSIDs so the 'Client Router' can roam between the 'Host Router'.

Since it is better to use seperate SSID it might be better (as spidey said) to use sperate channels in order to reduce cross transmitting noise.

:sun:

 

[skyking]

think about it, Jack. how are the two routers going to communicate? telepathy?

 

[JackMDS]

Originally posted by: skyking
think about it, Jack. how are the two routers going to communicate? telepathy?

Sorry, you are Right, me bad.

:sun:

 

[Ichinisan]

A Linksys WRT54G does not seem to have WDS support without a third party firmware. There is no "AP Mode" because Linksys wants to sell the WAP54G for more $$$ even though it is a simpler piece of equipment.

 

[nweaver]

I am with Spidy, but I think him and I are pretty much cisco bigots....


although Cisco now supports roaming L3 roaming on their 1200 series

 

[mjia]

AP Mode is really just wireless router that does not do NAT or DHCP. Once you disable the DHCP service on the router, it will act just like an AP. It's sure that the WRT54G running on 3rd party firmware will allow you to disable the DHCP server.

 

[Mr N8]

Why not just try using high gain antenna's, instead? I get signal from my second floor WRT54-G in my basement on the standard antennas.

 

[Ichinisan]

Originally posted by: mjia
AP Mode is really just wireless router that does not do NAT or DHCP. Once you disable the DHCP service on the router, it will act just like an AP. It's sure that the WRT54G running on 3rd party firmware will allow you to disable the DHCP server.

In my experience, you must connect the modem/WAN to the LAN ports on the router *and* disable DHCP to function. Still, I've read that WDS requires manual association of AP's by MAC address in order to work.

How on earth can it work by simply setting the same SSID and channel? What about WPA encryption? I would actually prefer different SSID's and channels if possible so that I can tell while moving downstairs. If Windows would pop up and notify "now connected to BasementAP" without interrupting a download, that would be perfect!

 

[Kelemvor]

You can just get range extenders. You just plug them in and go. No configuring necessary. It just takes the existing signal and rebroadcasts it.

http://www.linksys.com/servlet/Satellit...name=Linksys%2FCommon%2FVisitorWrapper

 

[mjia]

Originally posted by: Ichinisan
In my experience, you must connect the modem/WAN to the LAN ports on the router *and* disable DHCP to function. Still, I've read that WDS requires manual association of AP's by MAC address in order to work.

How on earth can it work by simply setting the same SSID and channel? What about WPA encryption? I would actually prefer different SSID's and channels if possible so that I can tell while moving downstairs. If Windows would pop up and notify "now connected to BasementAP" without interrupting a download, that would be perfect!

You don't really have to have an actual WAN connection. If the router requires that there be something connected to the WAN port, you can loop back a wire from one of its own LAN ports into the WAN port. It will just obtain its address from the other DHCP server.

I have a hard time believing that this is really required though. What if your internet service from your ISP goes down temporarily? Would that mean that your entire network should be disabled as well?

Every router I've had has allowed me to disable the DHCP server. This makes sense for security, and is an easy option to implement.

I think that there is no way to move from one network to another without interrupting a transfer in progress. Furthermore, in order to implement such a design you would need 3 routers, 2 as APs and 1 as a bridge (or 1 PC as the bridge). You could alternatively join 2 wireless networks together using other types of networks though, eg. networks over power or phone line.

I don't suggest you do this though. WDS is realiable and easy to implement and use. It is not any more expensive than the other options either (they require 3 APs (one of which is cablable of bridging, or 2 APs plus a wireless NIC for a PC running as a bridge).

 

[nweaver]

Originally posted by: mjia

I think that there is no way to move from one network to another without interrupting a transfer in progress. Furthermore, in order to implement such a design you would need 3 routers, 2 as APs and 1 as a bridge (or 1 PC as the bridge). You could alternatively join 2 wireless networks together using other types of networks though, eg. networks over power or phone line.

incorrect, Cisco now has L3 roaming, allowing you to roam to a new AP that does not service that vlan, but remain attached and no hiccup in connection.

 

[spidey07]

and their normal WDS provides L3 roaming as well, you just have to have all the APs in the same VLAN/layer2 network.

I just assumed this was the case with any WDS access point because it isn't really that magical.

 

[Ichinisan]

Originally posted by: mjia

Originally posted by: Ichinisan
In my experience, you must connect the modem/WAN to the LAN ports on the router *and* disable DHCP to function. Still, I've read that WDS requires manual association of AP's by MAC address in order to work.

How on earth can it work by simply setting the same SSID and channel? What about WPA encryption? I would actually prefer different SSID's and channels if possible so that I can tell while moving downstairs. If Windows would pop up and notify "now connected to BasementAP" without interrupting a download, that would be perfect!

You don't really have to have an actual WAN connection. If the router requires that there be something connected to the WAN port, you can loop back a wire from one of its own LAN ports into the WAN port. It will just obtain its address from the other DHCP server.

I have a hard time believing that this is really required though. What if your internet service from your ISP goes down temporarily? Would that mean that your entire network should be disabled as well?

I was saying that the Internet connection (cable or DSL modem) must be connected to one of the LAN ports on the built-in 4-port switch. I've had to do this more than once with Linksys WRT54G's that had been fried by lightning damaging only the WAN port (I work for an ISP). If it sounded like I meant that it requires link on the WAN port, that's not what I meant. I leave the WAN port on the router completely disconnected. I was saying that it's the only way to have a WRT54G function as an AP instead of a router/gateway. Like I said, you can make it behave like an AP, but there is no "AP Mode" that will enable a WDS feature..

 

[mjia]

Sorry, I misread your post. Except I'm not completely clear on your setup now. Are you saying that you are obtaining multiple IPs from your ISP? Connecting the modem to a LAN port and disabling the DHCP server on the router would mean that all machines on the network (that use DHCP) will attempt to retrieve an IP from the ISP. How many machines do you have and how many IPs are you given?