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Level 4

1,015 points

How to set-up a DUAL BAND wireless network.

Lots of people are reporting problems caused by replacing an existing wireless network with the new Airport Extreme 802.11n base station.

* Xbox360 compatibility.
* Airtunes issues
* 802.11n slowed down by 802.11g devices

One workaround is to set-up a dual-band network. Your old 802.11g base station looks after the older "g" devices. And the new Airport Extreme looks after the 802.11n devices.

There are a number of benefits to this solution.
* Everything that did work, carries on working. No reconfiguring needed.
* Everything works at its fastest possible speed. You can use the full 270Mb 5Ghz band for n devices.
* 802.11g traffic does not interfere with 802.11n traffic at all.
* It's easy to set up.

The downside is
* There are two boxes. I want one.

This is the diagram (again)

Note that in this configuration, the new Airport Extreme base station is set-up in Bridging Mode.

Glyn

Mac Pro + Powerbook G4 + Intel Mac Mini + iMac G3, Mac OS X (10.4.8)

Posted on Feb 11, 2007 2:16 PM

165 replies

Glyn Williams1 Author

Level 4

1,015 points

Jun 15, 2007 11:53 AM in response to Dano Monticelli

Q#1 - security - when running an Airport base station
in bridge mode, are you restricted to WEP level of
security or can you still use WPA & WPA2? I've read
in other forums but cannot confirm that in bridge
mode you are restricted to WEP.

I am 99% certain that WPA is available with AEBSn in Bridged mode.

Q#2 - security - when running an Airport Express as
part of a WDS, are you restricted to WEP security?

The 802.11g side can have a different security setting to the 802.11n side.
But either or both sides can have WPA.

Q#3 - transfer speeds - Did you notice a drop in
speed when you changed from sharing the internet
connection via the AEBS(b/g) to sharing the internet
connection via the AEBS(n)? I've read elsewhere that
there is a hit on speed when using Internet sharing
via the WAN.

No.
NAT adds a overhead to traffic coming in from the internet via the WAN port. The processor has to re-address each incoming packet.
However it has to be a very very fast internet connection for this overhead to be significant.

I suspect the NAT overhead is even greater on older equipment.

Q#4 - Hardware/transfer speeds in the network - what
would be faster - an external HD firewired to a
client vs. an ethernet linked media server?

A local hard drive will always be faster than a networked device.
A media server accessed via 802.11n will be able to deliver data at 7-9 MegaBYTES per second. Which is more than enough for any media streaming application. But if you are editing uncompressed HD video ....

I have a Media library on a USB drive attached to the AEBSn.
It is "only" capable of about 5Megabytes per second. Which is plenty for me.

HOWEVER if you are sharing media VIA iTunes, it is better that the media be located on the client machine running iTunes.

Q#5: Signal str

Using iStumbler, in my relatively small European house.
802.11n network - Signal 44% Noise 13%
802.11g (Linksys) - Signal 59% Noise 13%

That's probably 20feet with two floors between me and the base stations.

bobdogg

Level 1

0 points

Aug 13, 2007 6:12 AM in response to Glyn Williams1

I need to connect two AEBS(n) wirelessly to extend my network (5 story house made of concrete in Asia, bad for wireless). I have mixed "n" and "b" devices. Can I use a dual band network with WDS on "a" to provide the WDS connect between the two ABES'. I believe this should give me greater range and throughput between the two AEBS'. How would I configure this?

tkx

Duane

Level 10

124,267 points

Aug 13, 2007 6:55 AM in response to bobdogg

bobdogg, Welcome to the discussion area!

If you want an 802.11b/g client to connect to an AirPort Extreme base station (AEBS) it must be operating in an 802.11b/g compatible mode.

If you wireless connect 2 AEBS and one of them is in an 802.11b/g compatible mode, both must be in an 802.11b/g compatible mode. Therefore the wireless link between them can not be 'a' but must be at 2.4 GHz.

Additionally, be aware that the AEBS sacrifices client bandwidth to support the wireless link between the base stations. Each WDS link cuts the available bandwidth in half.

bobdogg

Level 1

0 points

Aug 14, 2007 3:03 AM in response to Duane

Hi Duane- Thanks for the quick reply. I was under the impression that the AEBS could operate in "dual mode" trx on both the 2.4 (b/g) and 5 (a) GHz spectrum and that I could accomplish this by setting it to "a" and that would operate on both freq. I must be wrong.

bobdogg

lynch16

Level 1

0 points

Aug 27, 2007 7:11 AM in response to Glyn Williams1

Greetings, everyone.

Glyn's early note that his original topology requires the least re-configuration of existing wireless networks has a lot of appeal to me, but I wonder if, now that there's a gigabit ethernet version of the AEBS(n), we may have a "dual-band" wired option to consider too. Should we assume, for instance, that putting this new device in bridging mode (as shown in Glyn's excellent diagram) will route all wired gigabit traffic attached to it through the 10/100 ethernet connections to the "Old System" router and thus slow it to 10/100 ethernet speeds?

If this is the case, I imagine it might make sense for anyone connecting wired gigabit devices to their network to make the AEBS(n)/gigabit the DHCP server, connect them to it directly, and put the Old System behind it configured as a bridge to both 11.g wireless and any 10/100 devices.

This isn't a topic I've been able to find discussion of so far. Any thoughts?

David

Duane

Level 10

124,267 points

Aug 27, 2007 7:51 AM in response to lynch16

lynch16, Welcome to the discussion area!

The extra complication is not necessary.

The Ethernet LAN ports on the AEBS are connected via internal Ethernet switch. Each port will get the connection it gets without affecting the other ports.

Therefore LAN port 1 can be connected to a 10/100 Mbps client and operate without affecting the 1 Gbps clients connected to LAN ports 2 and 3.

lynch16

Level 1

0 points

Aug 27, 2007 8:36 AM in response to Duane

Thanks for replying so quickly, Duane, and thanks for the welcome.

Hmm, well, I currently have a gigabit switch connecting my Mac Pro and a LaCie gigabit NAS to my (Buffalo) wireless 11.g router, and traffic between the NAS and the Pro appears to be limited to the router's 10/100 speed. Perhaps I'm mistaken--haven't done any rigorous testing. For some (or the same) reason, I've been unable to implement jumbo frames on this configuration, though all the gigabit devices, including the switch support them.

Mysteries . . .

David

Duane

Level 10

124,267 points

Aug 27, 2007 8:50 AM in response to lynch16

In your setup, the data must pass through the Buffalo router's 10/100 Mbps ports. So yes your data isn't going to run at Gigabit speeds.

Remember that the maximum bandwidth is going to be limited by the slowest pipe the data needs to be transferred through.

If you want to use the Gigabit capabilities of the AEBS, all of your Gigabit devices must be attached through Gigabit pipes to one of the LAN ports on the AEBS.

lynch16

Level 1

0 points

Aug 27, 2007 9:11 AM in response to Duane

That's what I thought too, Duane, so perhaps we agree that to take advantage of gigabit capabilities of the new AEBS(n) it should not be the bridge/slave to my old router, as shown in Glyn's original diagram? That's what I was trying to get at in my original post. Sorry if I wasn't clear.

Cheers, David

Duane

Level 10

124,267 points

Aug 27, 2007 9:32 AM in response to lynch16

No, it has no bearing on whether the 802.11b/g/n AEBS is the bridge/slave of the original router or not.

The important thing is that the Gigabit and 802.11n devices all connect directly to the 802.11b/g/n AEBS. This will move the data between these devices with the maximum bandwidth.

Any 10/100 Mbps or 802.11b/g devices should only connect to the old router.

lynch16

Level 1

0 points

Aug 27, 2007 10:47 AM in response to Duane

Thanks for the clarification--so in fact the new AEBS(n) won't behave like a switch (the term you use in your original reply), but like a router, even when it's in bridge mode? I'm not entirely clear on the technicalities. In any case, when my new AEBS(n)/gigabit arrives, I'll start with it as bridge as you suggest (simpler setup) and see what happens.

David

Duane

Level 10

124,267 points

Aug 27, 2007 10:52 AM in response to lynch16

It will act like a switch.

If the original router is connected to AEBS LAN Port 1, all traffic going through that port will be limited to 10/100 Mbps (the original router's Ethernet port speed).

Meanwhile all traffic between the other Ethernet ports on the AEBS will operate at Gigabit speeds. In addition the traffic between these Ethernet ports and the 802.11n clients will (have the potentional to) be at full 802.11n speeds.

lynch16

Level 1

0 points

Aug 27, 2007 1:14 PM in response to Duane

Aha--then I think we may agree? I'm assuming that, as shown in Glyn's original diagram (way back in February, way above), the 11.g wireless "original system" router is attached to the AEBS(n)'s WAN port, not one of its LAN ports. A final (I hope) question: assuming the configuration you describe above, where would you recommend attaching the cable modem, and which router would you set to bridging mode?

Thanks for your patience!

David

Duane

Level 10

124,267 points

Aug 27, 2007 1:22 PM in response to lynch16

...assuming the configuration you describe above, where would you recommend attaching the cable modem, and which router would you set to bridging mode?

It doesn't matter to which one you attach the cable modem. The cable modem is going to be the slowest link of all of them. I would probably attach it to the 802.11g router for no other reason that to group all of the slow interfaces together.

The router not attached to the cable modem should be in bridging mode.

Sep 21, 2007 8:54 PM in response to Glyn Williams1

Hi, I am just about to try and set up a duel band system. I looked at your diagram and I am going to follow it. Currently I have an Airport base station and several APE working in the house. What I was wondering was what utility do I use to set it up. . the one that comes with new AE or the older utility that is already working in my system? Please advise.

Regards,
DMS

How to set-up a DUAL BAND wireless network.