networking - DD-WRT and 2 virtual interfaces with each dedicated to N or G

Can virtual interfaces be setup with DD-WRT to be dedicated to a specific protocol? I have a Wireless G printer and I've noticed that when my router is set to "compatibility mode" my throughput tanks. I'm curious if I got a router with DD-WRT if I could dedicate one virtual interface for G and stick the printer on it and have another for wireless N devices that won't kill my performance.

If necessary I'd be willing to use a dual/quad-band router.

Nope. At least on a TP-LINK TL-WDR4300, the network mode is assigned per radio, not per virtual interface.

Your best bet would be to either abandon the wireless part (run a cable) or get a cheap dedicated access point - and place it on a different channel.

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It should be possible to do it, but I can only test it with a one-card DD-WRT router because that's all I have.

After your router has booted, its hostapd.conf file is visible in /tmp/ath0_hostapd.conf for my one-NIC router. You can check your two-NIC situation by means of

   ps | grep hostapd

which, in my case, returns

   ps | grep hostapd
   730 root      1792 S    hostapd -B -P /var/run/ath0_hostapd.pid /tmp/ath0_hostap.conf 
   14911 root      1320 S    grep hostapd 

showing where its conf file is located. In my case the file does not contain the instruction

   hw_mode=g 

so what I need to do is to add it to the conf file and restart hostapd on boot. In your GUI, go to Administration -> start command field, and type:

  echo "hw_mode=g" >> /tmp/ath0_hostapd.conf
  killall hostapd
  hostapd -B -P /var/run/ath0_hostapd.pid /tmp/ath0_hostapd.conf

You will have to adapt the above to a two-NIC router and to the hw_mode you are interested in, but it looks trivial. Do not expect too much, my router, a fantastic Buffalo WZR-HP-G300NH2, still runs on madwifi, not nl80211.