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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Slow Negotiated Speed for AP-515 Access Points

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  • 1.  Slow Negotiated Speed for AP-515 Access Points

    Posted Oct 04, 2019 11:44 AM

    We have recently deployed a new Instant cluster, based on AP-515 access points, running ArubaOS 8.5.0.2.

    We noticed that actual perceived speeds for clients were low, even though the signal was very good.

    Based on the client's association to the network, a client should be at 173Mbps (VHT, 2SS, 20Mhz, 256QAM, SGI).

    However, the maximum speed for -any- client, even those with an SNR of 50 or higher, never exceeds 86Mbps in the Instant UI.

    Setting the channel width to 40Mhz doubles the speed, but it's still much lower than what is should be: this time 173 instead of 400.
    Basically, it looks as if only 1 spatial stream is being utilized. But this conflicts from what we see in the association table.

     

    We tried downgrading to 8.4.0.4 to see if this fixes the issue (8.4 is the lowest supported for this type of AP), to no avail.

     

    We manage lots of IAP clusters, all with nearly identical configurations. The config of this cluster is based on a cluster of IAP-305s running 6.5.4.12.

    On any other cluster running 6.5.4.12, the speeds (both perceived as well as in the UI) are much better than on this new cluster with newer APs.

     

    Any ideas?

     



  • 2.  RE: Slow Negotiated Speed for AP-515 Access Points

    Posted Oct 04, 2019 01:23 PM

    @stevenjacobs wrote:

    We have recently deployed a new Instant cluster, based on AP-515 access points, running ArubaOS 8.5.0.2.

    We noticed that actual perceived speeds for clients were low, even though the signal was very good.

    Based on the client's association to the network, a client should be at 173Mbps (VHT, 2SS, 20Mhz, 256QAM, SGI).

    However, the maximum speed for -any- client, even those with an SNR of 50 or higher, never exceeds 86Mbps in the Instant UI.

     


    What channel width was it on initially when you observed this?

     



  • 3.  RE: Slow Negotiated Speed for AP-515 Access Points

    Posted Oct 05, 2019 04:50 AM

    Hello Colin,

     

    We had the cluster configured at 20Mhz from day one. Only yesterday we discovered this symptom after we received some complaints about the speeds.



  • 4.  RE: Slow Negotiated Speed for AP-515 Access Points

    Posted Oct 05, 2019 06:49 AM

    Do you have broadcast filtering enabled on all of your SSIDs?

    How many SSIDs do you have configured?

    How are your IAP-515s powered?



  • 5.  RE: Slow Negotiated Speed for AP-515 Access Points
    Best Answer

    Posted Oct 05, 2019 08:01 AM

    Hi Colin,

     

    They are powered by PoE+.

    And that's when the penny dropped... We forgot to enable LLDP.

     

    After enabling it I noticed the inline power went up from 15.4 to 30, and speeds went up as well.

     

    Once again, you saved the day! Cheers!