Our monthly Q&A series offers advice to those seeking help with home or small business WLANs. This month our guru helps a reader straighten out virtual SSIDs and considers one of the more complicated Wi-Fi repeater situations he’s ever addressed on our pages.
Would you like to ask the guru a question? Write the editor.
Have you ever tried to debug a tech problem for a friend or family member by talking it through over the phone? Even for the experienced tech savvy person, the experience can be an exercise in frustration. “Try clicking cancel. What does it say now?” “Which window did you close? Are you looking at the browser now? Or the control panel?” With each question, and each ambiguous answer, you edge ever closer to an open window, hoping that maybe you’ll fall out before the ordeal is over.
Sometimes the person you are helping lacks the experience to provide you with useful narration. But sometimes the problem isn’t them at all, but the design of the product or software you’re trying to wrangle. Take the case of a Netgear wireless router, recently installed by a family member. He’d proudly setup the router himself, plugged in the cables, walked through the setup wizard, and yet the laptop did not see any available wireless network.
We walked through all the usual scenarios. Could the laptop be at fault? (No, it did see neighbors’ networks.) Could there be an issue with the wireless-n router talking to a wireless-g laptop? Could there be an issue with security? Exploring each step by phone ate up lots of minutes and got us nowhere. In a desperate measure, I suggested we poke around the “advanced” menu of the wireless router’s administration interface. There, like a glowing beacon, hid a most promising setting: “Enable wireless radio”. And it was…unchecked.
Guess what? Your wireless router needs to be enabled to actually work. Who would’ve guessed? My question is, why was it disabled in the first place, fresh out of the box? Why would a manufacturer of a wireless router consider enabling the wireless radio a special, advanced situation?
Using DD-WRT, which SSID do I want to connect to?
Q:When I want to connect to a wireless network using a repeater, I see two networks, the “physical” SSID, and the Virtual SSID from the repeater. On which one do I have to connect? – Stefan
A: When you follow the linked tutorial using DD-WRT to configure a wireless router as a repeater, the router needs to behave in two different modes at once. Normally, a wireless router behaves in broadcast mode, sending out wireless data to associated clients. In special configurations, a wireless router can behave in client mode, where it instead receives wireless data from another router. You can use this configuration to build a bridge, connecting physical devices to a wireless network even though they may not have a wireless adapter built-in.
In repeater mode, a wireless router needs to play both sides of the fence. Because the typical wireless router only has one radio, it can only behave in one mode or the other but not both at the same time. To get around this limitation, firmware like DD-WRT that supports repeater mode causes the router to alternate between modes, rapidly switching between receiving and broadcasting data. In setting up such a situation, you configure a “virtual SSID” which represents the network name of the broadcast mode. So when connecting to a repeater, it is the virtual SSID you want to use.
Note that when you setup a repeater, the throughput (network speed) available to associated clients is halved compared to clients using the primary router. This is because, by virtue of playing the roles of both client and broadcaster, the repeater router’s radio can only be used for each role half the time. For more on this situation, read on.
How do I extend a wireless network to a guest house all the way across my property?
Q:I’d like to extend and redistribute the wireless signal from my home to the guest house on the far corner of my property Basically, I want to repeat my wireless network at full speed (if I understand correctly, a wireless bridge/WDS would cut the speed in half; I need a WAP to distribute the signal wirelessly within the guest house). I cannot physically wire the guest house to the main house.
I have two Tomato-flashed Buffalo WHR-HP-54G routers I can put in the guest house, and a long-range yagi antenna I can connect to one. I want to use one wireless router as a client and cable it to the other wireless router working as an AP, like this:
The client router and antenna in the guest house connect to the main house with no problem. I need help configuring and wiring the AP so it can receive the signal from the client. – Bree
Note: Bree continues on with several specific questions, and I will address them each one-by-one below. We have printed Bree’s full description of her setup because it is a model example of a configuration that will work and may appeal to many readers who need to extend a wireless signal to a distant area of their property. The reason this configuration avoids the half-bandwidth problem described is because Bree is using two routers at the remote location; one to behave as the wireless client, and another to behave as the broadcaster. By doing this, no one radio needs to play both roles, therefore no significant speed is lost.
I think I want to connect the client’s LAN port to the AP’s WAN port, in effect substituting the client for a cable modem. Is this right, or should it be LAN to LAN?
A: In fact, both ways will work, but with different consequences.
In scenario one, you connect the wireless client (bridge) LAN port to the AP WAN port. Doing this will segment your network, meaning that everyone connected to the client router (visitors in your guest house) will essentially be on a separate network from the network in your main house.
By “separate network” I mean that the SSID, security settings, and IP addressing will be completely independent from your main network. These users should not be able to see clients in your main network, and will be behind whatever firewall settings you configure on the client router. So yes, this would be very much like substituting the wireless client for a cable modem. Presuming that you are renting your guest house to visitors, this is probably your most desirable configuration.
In scenario two, you would connect LAN ports on both routers, ignoring the WAN port. This would essentially extend the network from your main house into your guest house. Users in the guest house would share access to the same devices as in the main house. This would be desirable if you or trusted others were using the network from the guest house, but not so desirable otherwise.
2. Should the guest house AP’s network address be different from the network in the main house? (I’ll be running different SSIDs to avoid conflicts).
3. The client currently works with DHCP on, and I think I should probably turn DHCP off on the AP. Right?
A: The answers here are related to one another.
In scenario one (segmented network), your broadcast router (Buffalo 2 WAP) should enable DHCP and the configured IP address network should be different from the main house.
Suppose your main house router (WAP) is configured to the LAN address 192.168.1.1. This means its DHCP server hands out addresses in the 192.168.1.x range. On your guest house WAP, leave DHCP enabled and configure its LAN address to a different subject, for example 192.168.0.1, and its DHCP pool to addresses in the 192.168.0.x range.
Had you configured scenario two (unified network), you would basically do the opposite on the guest house WAP. Disable its DHCP server (because there should be only one on a unified network, and that is the main house router), and configure its LAN address to an address on the main router subnet; e.g. 192.168.1.2.
4. I plan to run WPA-2 and TKIP on the guest house AP, just as I do on the AP in the main house.
A: Absolutely fine. In either scenario one or two, you should be able to configure the wireless security (and SSID) on the guest house AP any way you want.
Note that in scenario two (unified network), setting identical security and SSID parameters for both the main router and the guest house WAP would allow seamless roaming between both locations. But since you presumably prefer the segmented network of scenario one, roaming is probably not the goal.
5. Finally, would I be better off running Buffalo 1 in Tomato’s bridge mode? I want to avoid cutting my connection speed, as with wireless bridging.
A: It seems to me that you are already running “Buffalo 1” as a bridge. When this router is configured for Tomato’s client mode, it is behaving as a receiver, picking up the signal from your main house WAP. It is passing data on to wired clients connected to any of the LAN ports on Buffalo 1, which includes Buffalo 2. This is what a bridge is. You should not lose any (significant) bandwidth this way because, as described above, the radio in Buffalo 1 is not being asked to play dual roles. It is receiving only, never broadcasting (that job is being done by Buffalo 2).
All in all, you are essentially using two routers networked together to play the role of a repeater. In my experience this is a solid solution compared to running a single router repeater, although that can be done. The downside, of course, is that you have to buy two routers, and if one ever goes belly-up, your repeater will be non-functional until it is replaced.
