lunieri

Q: Airport Extreme 802.11ac extending network

I have 2 new Airport Extremes with 802.11ac capability. I know that the best way to use the two to extend my network is to place one in bridge mode and connect the two via ethernet cable. I would like to bridge them wirelessly but I want to make sure its via 802.11ac and not b/g or n. Is there anyway to do this?  How can I determine what type of wireless connection exists between the two.

AirPort Extreme 802.11n (5th Gen), Mac OS X (10.7.4)

Posted on Sep 6, 2014 8:59 AM

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Q: Airport Extreme 802.11ac extending network

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  • by Bob Timmons,

    Bob Timmons Bob Timmons Sep 6, 2014 9:40 AM in response to lunieri
    Level 10 (105,067 points)
    Wireless
    Sep 6, 2014 9:40 AM in response to lunieri

    The AirPort Extremes will extend "ac" signals if they are close enough to each other....and....there are no significant obstructions between them. So, think line-of-sight for best performance.

     

    The reason for this is that "ac" is delivered on the 5 GHz band, and that type of high frequency signal is much weaker than the lower frequency 2.4 GHz signals.

     

    Unfortunately, you will lose about half of the speed potential or a bit more on your network when you try to extend using wireless only, so the wired Ethernet cable connection is the best way to go by far, if you are interested in obtaining the best performance from your network.

     

    A wired connection will also allow you to locate the extending AirPort Extreme exactly where it will be needed. That is not the case when you try to extend using wireless only.....where the extending Extreme will need to be located where it can receive a really high quality signal from the main Extreme.

     

    As far as picking up an "ac" signal.......locate your Mac laptop close to the "main" AirPort and hold down the option key while you click on the AirPort icon at the top of the screen. Check the PHY Mode to see that you have an 802.11ac signal. If you see anything else.....then you are not getting "ac" at the location of the laptop.

     

    Power off the extending Extreme and perform the same test with your laptop to make sure that "ac" is being received at that location. Then, power up the extending device.

     

    Now, move the laptop further away to the extended area where you need more signal coverage and perform the same test again to confirm that you are receiving "ac" signals in that area.

     

    You may find that you need to locate the extending Extreme much closer to the main Extreme than you might think to get an "ac" signal extended effectively.  When I tried this as an experiment, I literally had to have line-of-sight between the two AirPorts for "ac" to extend.

  • by Tesserax,

    Tesserax Tesserax Sep 6, 2014 9:26 AM in response to lunieri
    Level 9 (54,427 points)
    Wireless
    Sep 6, 2014 9:26 AM in response to lunieri

    By default, when interconnected by wire or wireless, the 802.11ac AirPort will broadcast on all radio modes on both bands simultaneously. 802.11ac can ONLY operate on the 5 GHz band.

  • by Dæmon,

    Dæmon Dæmon Dec 25, 2014 12:01 PM in response to Tesserax
    Level 1 (15 points)
    Dec 25, 2014 12:01 PM in response to Tesserax

    I am very interested in this issue. I have an AE 802.11ac as "main" AirPort, and a 3rd generation Time Capsule (802.11n, simultaneous dual band, MIMO 3x3:3) as "extending" AirPort. If I don't set a different SSID for the 5 GHz WLAN, the TC insists on linking at 2,4 GHz, spectrum which is really crowded in my area. The resulting link offers 39-59 Mbps with RSSI 68 dBm. I think that the TC links at 2.4 GHz solely because it detects a stronger signal, ignoring all its disadvantages.

     

    In fact, using separate SSIDs I can force the TC to extend the 5 GHz WLAN. In this way I get a way better link: 122-162 Mbps and same 68 dBm RSSI). However this has some ugly consequences, since the TC creates another WLAN at 2.4 GHz, using the same SSID as the extended 5 GHz one.

     

    Now I am wondering: if I replace the TC by one of the newer 802.11ac models, would they prioritize linking using 5 GHz 802.11ac over 2.4 GHz 802.11n?

  • by Bob Timmons,

    Bob Timmons Bob Timmons Dec 25, 2014 12:24 PM in response to Dæmon
    Level 10 (105,067 points)
    Wireless
    Dec 25, 2014 12:24 PM in response to Dæmon
    if I replace the TC by one of the newer 802.11ac models, would they prioritize linking using 5 GHz 802.11ac over 2.4 GHz 802.11n?

    No, since the TC and AirPorts prioritize by signal strength, not signal speed.

     

    If you really are after the best performance using two Apple routers, there is unfortunately only one way to accomplish this.....connect the devices using a permanent, wired Ethernet cable connection.

     

    Even if you can get the two devices to connect using 5 GHz over wireless, you will lose about half of the potential speed on the network by extending using wireless.

  • by Dæmon,

    Dæmon Dæmon Dec 26, 2014 3:11 PM in response to Bob Timmons
    Level 1 (15 points)
    Dec 26, 2014 3:11 PM in response to Bob Timmons

    Well, a friend of mine lent me his AirPort Extreme 802.11ac, and it works perfectly extending the WLAN created by my own AE 11ac. They always link using 802.11ac, with speeds in the range of 468-702 Mbps, and RSSI about 60 dBm. I made some file transfer tests and indeed the data rate is impressive. Just ordered another AE 11ac

  • by Bob Timmons,

    Bob Timmons Bob Timmons Dec 26, 2014 6:30 PM in response to Dæmon
    Level 10 (105,067 points)
    Wireless
    Dec 26, 2014 6:30 PM in response to Dæmon

    What you are telling us is that the AirPort Extreme that your friend lent to you was located where it could receive a good, strong signal from the "main" AirPort.

     

    If you locate the AirPort Extreme such that the signal has to go through several walls, the stronger 2.4 GHz signal will likely be picked up by the "extending" AirPort, since the 5 GHz signals.....which is where the "ac" signals operate.....are quite a bit weaker than 2.4 GHz signals.

     

    When I test here, with the signal having to pass through one wall,  I can usually get the extending Extreme to pick up enough of the 5 GHz signal to extend "ac". After the signal passes through 2 walls, no way that I can get "ac" to extend, since the 2.4 GHz signals are much stronger at that location.

     

    The only way that I could find to reliably extend the "ac" signal throughout the house was connect the AirPorts using permanent, wired Ethernet cable connection. Speeds improved as well when I did this.

     

    If you can make wireless work, that's great, but things will be even better if you can connect the AirPorts using Ethernet.  Here is what Apple says about that in their support document on extending.

     

    In the case of a wirelessly extended network, throughput may be reduced to less than 60 percent of that of a single device. The general rule is to keep the Wi-Fi network as simple as possible. You can accomplish this by using the minimum number of Wi-Fi base stations required to service the physical network area and by using Ethernet wherever possible.

     

    Extending the range of your Wi-Fi network by connecting Wi-Fi base stations together using Ethernet is always the best option, and will provide the best throughput.


    Wi-Fi base stations: Extending the range of your wireless network by adding additional Wi-Fi base stations - Apple Suppo…

  • by Dæmon,

    Dæmon Dæmon Dec 27, 2014 3:29 AM in response to Bob Timmons
    Level 1 (15 points)
    Dec 27, 2014 3:29 AM in response to Bob Timmons

    I replaced my TC with the lent AE 11ac exactly at the same location. Between the two AEs 11ac there are about 10 meters and two brick walls. Moreover, one of the walls has double width. I know about radio waves, and yes, I know that in the same circumstances the 5 GHz signal is more attenuated than the 2.4 GHz one. But 802.11ac offers an important feature: beamforming. Using beamforming the AE 11ac can concentrate more radiated energy in the direction of the connected devices; and the other AE 11ac can do the same. In this way, the 5 GHz signal, as received by each AE from the other one, can be (and, given the RSSI reported, in fact is) stronger than the 802.11n 2.4 GHz signal. Obviously your mileage may vary: beamforming may not be able to compensate the energy loss caused by too much distance or too many obstacles.

     

    The best way to increase WLAN coverage is to connect the APs via Ethernet. This is indisputable. But sometimes is unpractical (in my case very unpractical), and for that reason Wi-Fi extension exists.