HT201577: AirPort Express frequently asked questions (FAQ)

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Mary T. Carter

Q: Will Apple Airport Express work with a Comcast Combination Modem/Router

WE currently have an Apple AirPort Extreme Router but it is not working correctly with Comcast's new 2X speed upgrade. They recommended using their combination Modem/Router but we need to be able to use our Airport Express extender. Would appreciate any help with this. Thank you!

MacBook Pro, OS X Yosemite (10.10.1)

Posted on Jun 11, 2015 3:51 PM

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Q: Will Apple Airport Express work with a Comcast Combination Modem/Router

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  • by BobHarris,

    BobHarris BobHarris Mar 25, 2016 6:31 AM in response to CARWILCAT
    Level 6 (19,272 points)
    Mac OS X
    Mar 25, 2016 6:31 AM in response to CARWILCAT

    My suspicion is the Netgear switch.  It is the common denominator, and the outage affected all devices.

     

    But that does not rule out a device jamming the switch, so did you...

     

    ... disconnect just 1 Airport Extreme to see if the problem cleared up?  Then the other?  If it happens again, swapped which one is disconnected 1st and check.

     

    Have you tried disconnecting any of the other devices 1 at a time to see if the problem clears up.

     

    This kind of experiment can be very time consuming, especially if you are trying to confirm disconnecting just 1 does the trick and then verifiy it is the only one you need to disconnect.

     

    I am weak on the following, but it is my understanding that if somehow you create a Ethernet loop, bad things can happen.  I think this would require you to have an Ethernet connection from the switch to say one of the Airport Extremes and then an Ethernet connection back to the switch.  I suspect you did not anything like this, but I'll ask.  NOTE: I would not rule out Ethernet to Airport Extreme, WiFi to a device that is ALSO Ethernet connected, and that feeds back to the switch.  Again, I do not suspect this, just throwing ideas out to see if it rings any bells.

     

    I do not suspect the Comcast router, but if you want to try disabling it, I would only do it as an experiment and maybe see if you could limp along with just one Airport Extreme upstairs and one in the basement as a proof of concept, so you do not need to spend any money up front for an experiment.

     

    NOTE:  If you happen to have 2 Ethernet connections close enough to 1 of the existing Airport Extremes, you could do what I do.  Ethernet from Comcast router in bridge mode straight upstairs to the WAN port of one of my Airport Extremes.  This Airport Extreme is configured as my router.  Then an Ethernet from that Airport Extreme's switched ports back to the basement into my 16-port Ethernet switch, which then redistributes the routed LAN to other rooms in my house, including another Airport Extreme in Bridge mode.

     

    Even if you have 2 Ethernet ports close enough to one of the Airport Extremes such that you have to run an Ethernet cable along the baseboard from one bedroom to another for a few days/weeks until you prove/disprove the experiment.  Buying a long Ethernet cable if you do not have one is cheaper than a new Airport Extreme router.

  • by CARWILCAT,

    CARWILCAT CARWILCAT Mar 25, 2016 1:00 PM in response to BobHarris
    Level 1 (4 points)
    Mar 25, 2016 1:00 PM in response to BobHarris

    Bob:

     

    Thank you for the quick and comprehensive response.  I should have mentioned that I experimented with directly connecting only one Airport Extreme to the 4 switch ports provided on the Comcast router to eliminate any potential problems in the Netgear switch powering the home network.  The observed outage continued with this direct connection and then came back online once disconnected.  That probably rules out the switch as the source of the issue - I think.  I am going to try your recommendation of re-configuring one of the Airport Extremes to be the router with a line back to the Netgear switch with Comcast in bridge mode.  I ran extra wires to this location when I built the house just in case.  Better lucky than smart.  I will let you know how it turns out.  Thanks again.  Your insights were very helpful.  Best, Jim

  • by BobHarris,

    BobHarris BobHarris Mar 25, 2016 5:32 PM in response to CARWILCAT
    Level 6 (19,272 points)
    Mac OS X
    Mar 25, 2016 5:32 PM in response to CARWILCAT

    There is also the possibility that the actual Ethernet cable is marginal.  It works most of the time, so it cannot be all bad, but if it is marginal, it might flake out under the right conditions.  Environmental stuff like temperature, humidity, ...

     

    NOTE:  I'm not saying there is anything wrong with the cable, just another item to consider.

  • by BobHarris,

    BobHarris BobHarris Mar 26, 2016 6:24 PM in response to CARWILCAT
    Level 6 (19,272 points)
    Mac OS X
    Mar 26, 2016 6:24 PM in response to CARWILCAT

    I want to ask some followup questions.

     

    How old are the Airport Extremes?  For example do you have one of the first 802.11n single radio models.  This is the first one to support 802.11n and 5GHz, but you had to choose between using either 2.4GHz or 5GHz as it just had a single radio.  Or is it even older, and of the flying saucer generation?


    The reason I ask is that if you have some really old units, that could be an issue, as Apple is most likely not providing any firmware updates for those units anymore, and that first 802.11n single radio unit is considered by some to be not the best Airport Extreme (then again, I own one [retired] and it did work for me for years, as in it was retired only a few months ago).

     

    My second question is just "How Many" devices do you have connected to the system all going through the Comcast router.  While many home routers claim they can handle up to 'n' devices, where 'n' is 25 or 50, that does not mean they will manage all of them well.

     

    If you have a lot of IoT (Internet of Things) devices, then you might consider configuring a separate LAN just for those things.  By IoT, I'm talking lights, thermostats, web cams, Ring.com doorbells, WiFi Toasters , etc...  Instead of putting a router into bridge mode, you allow it to be a router with an unique SSID and radio channels that you configure your IoT things to.  That way all of their traffic is managed by that router, and just becomes a single device to the Comcast router, thus reducing the unique number of devices the Comcast router needs to manage.

     

    Of course if you are security conscious, you would actually setup 3 routers in a Y configuration.  The base would talk to Comcast.  One of the top forks would take to the IoT devices, and the other top fork would take to your home computers, Apple TVs, Sonos, etc...  This is because many IoT devices are using very inexpensive and not well thought out security implementations, such that they may become vectors into your home network.  In a Y setup, the router servicing their LAN would block them sniffing the network for your computer traffic.  The router servicing your computer oriented LAN would block any attempts to send requests from IoT devices to your computers.

     

    Of course a Y setup in your home where you need 2 WiFi base stations to give you proper coverage, would mean you would have to double things to give coverage for IoT and coverage for computers.  So, I am NOT suggesting you go this route, but I felt that if I was going to mention a separate LAN for IoT devices, I needed to at least mention security concerns.

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