Wireless Access

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Access network design for branch, remote, outdoor and campus locations with Aruba access points, and mobility controllers.
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Concerns on APs and PoE

  • 1.  Concerns on APs and PoE

    Posted Apr 09, 2019 09:34 AM



    I want to buy number of Aruba APs, switches etc , but I have concerns on the below, so kindly help me with the below so I can take a decision either to buy Aruba APs or not:


    -  If an AP has 2 ports, can I use the second port to connect one AP to another AP, or the 2 ports can be used only for failover?


    - If I connect the AP through PoE, do both the USB and LAN ports become disabled automaitcally once the AP is connected via PoE, or not?


    Is the second port POE (can power another network device from it) ?
    If yes, is that limited to that fact that the AP is powered through an injector ?


    Appreciate your help.



  • 2.  RE: Concerns on APs and PoE

    Posted Apr 09, 2019 02:04 PM

    What AP model(s) are you considering? Answers may vary based on the model. The AP datasheet will cover most of the questions around what feature(s) may be affected based on available power draw, but knowing what functionality you require we can direct answers appropriately.

  • 3.  RE: Concerns on APs and PoE

    Posted Apr 09, 2019 07:52 PM

    right now, the only AP we have that provides PSE on the second ethernet port is the AP-303P. In that case, if you supply the 303P with BT power, the power out will be AT. If you supply AT in, the 303P will supply AF out. If you supply AF in, no POE out will occur. 


    As Charlie mentions, the data sheets are the place to go, some of them with dual interfaces will do POE redundancy, and some model will do combining (AF + AF = AT or AT + AT = BT kind of thing).


    You can generally connect a second AP to ENET1 of the dual-eth AP models to connect another AP, but if they are not the 303P, you will have to supply power to the second, daisy-chained AP via DC power or power injector). It's not recommended due to the daisy chain aspect, and if you use contorller based APs it can create issues with GRE tunnels if configured wrong (nested tunnels can create MTU issues that are hard to resolve). 


  • 4.  RE: Concerns on APs and PoE

    Posted Apr 09, 2019 08:01 PM

    303H can do that as well (except for 802.3bt support).

    And you can power + daisy-chain a second AP from the 203RP as well (but no POE in).

    Daisy chaining has the restrictions mentioned by others, but the capability is generally supported on all APs with more than one ethernet port.

    POE combining is supported on the new 530 and 550 series only, and given that we can only guarantee a worst-case 65/35 power balance, AF + AF results in "just" ~21W total combined (so not quite AT). Two AT sources can deliver at least 39W using the same logic.