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I'm looking into upgrading my current Tomato ap to a 802.11n compliant access point initially using DD-WRT x86 until pfsense 2.2 alpha is out because pfsense 2.1 doesn't have 802.11n support. I'm currently using a gigabit pfsense machine that connects to PPPoE and acts as firewall, DHCP server etc. with a TL-SG1016 gigabit switch and a WRT54GL acting as a access point.

I'm thinking about a Pentium4 or a Celeron MicroATX machine with a gigabit card and a 802.11a/b/g/n PCI wireless card that supports both 2.4GHz and 5GHz (simultaneously!).

The question is: How can I achieve 2.4 & 5 simultaneously on the same SSID that support at least b/g/n at the same time without dropping all on 2.4 from 5 if a 2.4 client is connected?

Can it be done with a single PCI card, or even two without costing a small fortune. Are there PCI 802.11n cards? Because I only seem to be finding PCIe ones.

To clarify, I'm talking about having the wireless card inside the mentioned wireless access point machine I'm building and acting as a access point for BOTH 2.4GHz and 5GHz 11n and legacy 11a/b/g.

  |           |                |
(LAN)       (2.4GHz client)  (5GHz client)

  ^               ^                ^
(multiple pcs) (multiple clients both 2.4GHz and 5GHz connected on same SSID) 

Sorry if some variation of this question has already been asked, I have been looking for answers for a few days but I get lost in the many terms such as dual band/simultaneity/dual radio etc.

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You are not going to be able to connect to an access point on both frequencies. Most dual-band networking equipment when they support both 2.4Ghz and 5.0Ghz handle this by treating each one as a seperate access point. You also wouldn't double your speed as a client even if you did connect to both access points. – Ramhound Jan 13 '14 at 11:45
@Ramhound I'm not talking about doubling speeds or connecting to both at same time from same client, I'm talking about for example connecting a Galaxy phone on 5GHz 11n and a laptop on 2.4GHz 11g at same time to the same SSID/wireless card. – Edward A Jan 13 '14 at 12:26
So you want to make your wireless card into an access point? As I indicated you won't be able to have a single access point that both 2.4ghz and 5.0ghz devices can connect to. You would need to create two seperate virtual access points which would require the card to be not only a dual-band card but have enough radios to do that. Please update your question to reflect you want to use a wireless WiFi card to act serve as a virtual access point if thats the case. – Ramhound Jan 13 '14 at 12:56
Your not going to be able to connect to the same SSID on both frequencies. – Ramhound Jan 13 '14 at 13:42
I have that exact router. Each band has its own virtual access point. – Ramhound Jan 13 '14 at 15:12
up vote 1 down vote accepted

I'm not intimately familiar with pfSense, but in ddWRT, each radio is set up as a separate AP. To enable roaming you simply set the same SSID and security on both radios. End result: b/g/2.4n clients connect to the 2.4Ghz radio, and a/5n clients connect to the 5Ghz radio. a/b/g/n clients will connect to either, and may autodetect the best option based on their settings.

In some cases (I have severe 2.4Ghz congestion in my area), it may be beneficial to force a a/b/g/n client to use 5Ghz. Some have a setting for that, but in other cases you may need to give the 5Ghz radio a unique SSID and configure the client to prefer it.

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Dual-band operation works fine if you setup a parent interface under "Wireless" in assign interfaces.

Then add this one to the global interface list.

Here is a setup how it works:


Unfortunately these are in German, but Google translator is your friend. ;-)

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Welcome to Super User! Whilst this may theoretically answer the question, it would be preferable to include the essential parts of the answer here, and provide the link for reference. – Cfinley Sep 3 '14 at 17:55

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