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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Fragmented PAPI from controller to Airwave

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  • 1.  Fragmented PAPI from controller to Airwave

    Posted Nov 23, 2016 05:27 PM

    I noticed our firewall is dropping traffic from local controllers to Airwave because it is fragmented.

     

    The total packet size the controller is trying to send in this example is '32808 bytes', made up of 23 fragments, each with an IP payload of 1480 bytes.

     

    Anyone seen this before?

     

    It must be PAPI with AMON data, but strange that it is trying to send such a big packet?

     

    The path mtu between controller and Airwave is 1500 bytes, confirmed with ping w/ DF flag set.

     

    The below packet capture is showing the fragmented traffic:

    1.png



  • 2.  RE: Fragmented PAPI from controller to Airwave
    Best Answer

    Posted Nov 23, 2016 05:35 PM

    The AMON message size can be adjusted:  http://www.arubanetworks.com/techdocs/ArubaOS_65x_WebHelp/Web_Help_Index.htm#ArubaFrameStyles/1CommandList/amon_packet_size.htm?Highlight=amon

     

    There is no path MTU discovery for those packets.  It is quite possible that your version of ArubaOS is set to 32k: (arubaOS 6.5.0.1 release notes below)

    Screenshot 2016-11-23 at 16.34.25.png

     



  • 3.  RE: Fragmented PAPI from controller to Airwave

    Posted Nov 23, 2016 05:39 PM

    Cool, we're running 6.4.2.16 so that command isn't available - is there any way we can verify the current buffer size?



  • 4.  RE: Fragmented PAPI from controller to Airwave

    Posted Nov 23, 2016 07:03 PM

    EDIT:

    show amon msg-buffer-size