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Tx/EIRP reporting on AP 515

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  • 1.  Tx/EIRP reporting on AP 515

    Posted Nov 30, 2021 09:20 AM
    I am new to Aruba Wireless and have recently surveyed an AP-515 deployment inside a facility. Without granted access to the Controller, I had to rely on my analyzer's measurements and pcaps to find out information about the transmit powers. 
    Pcap shows there should be 3different sub-band limits, according to local regulatory domain EIRP limitations, but there is also the TPC Report showing "Transmit Power" as 18dBm for UNII-1,2&2e operating AP's and 14dBm for UNII-3 ones.
    As the individual integrated antenna has 4.6 dBi gain, according to the specs, this could only mean that AP is reporting its EIRP as Transmit Power. Please correct me if I am wrong!
    If it indeed reports the EIRP, why is it reporting 18dBm for the other sub-bands, where you could go up to 30dBm?  Could this only be a global EIRP limitation setting from the WLC (which I can't see without access)? I am curious how that works in the Aruba world.


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    Alex Vrabie
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  • 2.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Nov 30, 2021 02:33 PM
    In the Aruba controller all tx-power settings are in EIRP. So i believe it's the same in your PCAP.

    MD=Modolva (eastern of europe), so the rules should be the same as EU=Europe.
    In europe you can send max. eirp of 30dBm/1000mW in the U-NII-2c band.

    Also see the max. EIRP per regulatory domain per country for reference.

    Your AP working on 18dBm / 63mW EIRP. On the controller in ARM/Airmatch (radio resource management) decide the set value between a (min. tx-power and max. tx-power) EIRP value, this is configured on the controller.

    Hope this helps you!




    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 3.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 01, 2021 10:30 AM
    I am perfectly aware of that latest all-inclusive regulatory domain allocation table (gathered by K. Parsons), its interpretation and the whereabouts of my surveyed location. I am just new to Aruba wi-fi :p
    I was only wondering, without having access to the controller, what is the setting method of that 18dBm EIRP limit. Now I get it, there's a user defined range.
    Regarding TPC current settings advertised in the beacons, do you know if that reported value is in fact the current setting or just the max user set limit?
    Because I have reasons to suspect it's not reporting the actual operating Tx-Power.
    Thank you



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    Alex Vrabie
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  • 4.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Dec 01, 2021 07:45 PM
    Hi Alex,

    I did a quick test for you, the TPC value in the 802.11 beacon frame is the same as the EIRP in my Aruba Controller.




    In my controller configuration below you can see the min. 12dBm and max. 15dBm settings. The Aruba Airmatch feature on the Mobility Conductor collects 24x7 information from the access points and calculate the best EIRP value between 12 and 15 dBm EIRP. The new value is pushed out to the AP's everyday (Default) on 05:00am hour.

    rf dot11a-radio-profile "homelab-dot11a-radio-profile"
       min-channel-bandwidth 80MHz
       eirp-min 12
       eirp-max 15

    Hope this helps you!

    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 5.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 02:47 AM
    First of all, thank you for the trouble! Your point is partially proven from the attached info, but there are still some loose ends:
    1. Your AP is coincidentally emitting on maximum user set EIRP (15dBm), so there still might be a chance the TPC reported value is the max limit; Could you move your upper EIRP limit to a higher value, so that the 2 values have a chance of being different?
    2. Why is the Max EIRP 26.7 dBm in "show ap active" command? Shouldn't it be 30 dBm for U-NII-2c band in ETSI (NL)?
    3. I can see that EIRP is properly referred to as "EIRP" in the shell.  You wrote earlier that "in Aruba, all Tx-Power settings are in EIRP". Does that only apply to the GUI settings and beacon advertisements?
    4. How does this reference system work with external antenna AP's? For it to make sense, I suppose you'll first have to declare the antenna gains, but what if you forget or are not aware? Are there any default entered values, like with Cisco or other vendors?

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    Alex Vrabie
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  • 6.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Dec 02, 2021 03:56 AM
    Hi Max,

    Here my new configuration:
    rf dot11a-radio-profile "homelab-dot11a-radio-profile"
    am-scan-profile "homelab-dot11a-radio-profile_amscan_a_ui"
    min-channel-bandwidth 80MHz
    eirp-min 12
    eirp-max 32

    After that i run "airmatch runnow full" to recalculated an push the new vallues to the APs manually.

    Here you can see the AP is changed from 15dBm to 16dBm  (this a calculate value between 12 and 32 dBm)
    (mm01) [mynode] #show airmatch debug history ap-name HomeLAB-AP01
    5GHz radio mac d0:15:a6:bc:d8:f0 ap name HomeLAB-AP01
    ------------------------------------------------------------------------------------------------------------
    Time of Change Chan Bandwidth EIRP(dBm) Mode Source
    ------------------- ---------------- ------------ ------------ -------- -----------------------------
    2021-12-02 09:35:03 108 ->100 80 ->80 16.0 ->16.0 AP ->AP Solver
    2021-12-02 09:25:07 112 ->108 80 ->80 15.0 ->16.0 AP ->AP Solver
    2021-12-02 05:00:15 104 ->112 80 ->80 15.0 ->15.0 AP ->AP Solver
    2021-11-28 05:01:05 112 ->104 80 ->80 15.0 ->15.0 AP ->AP Solver

    (HomeLAB-MC02) [MDC] *#show ap active
    Name Group IP Address AP Type Flags Uptime Outer IP Cluster Role Radio 0 Band Ch/EIRP/MaxEIRP/Clients Radio 1 Band Ch/EIRP/MaxEIRP/Clients Radio 2 Band Ch/EIRP/MaxEIRP/Clients
    HomeLAB-AP01 HomeLAB 172.16.200.100 505 p2a 5d:14h:42m:47s N/A A/U AP:5GHz-HE:100E/16.0/26.7/4
    HomeLAB-AP02 HomeLAB 172.16.200.116 505 2a 11d:12h:55m:53s N/A A/U AP:5GHz-HE:108E/16.0/26.7/2
    \
    Here the new 802.11 beacon frame capture, where you see the same EIRP value.


    What you say about the MaxEIRP 26.7dBm limit a agree with you. Looks like al little strange and should be 1000mW/30dBM EIRP i this band i think. Maybe it's a bug or i not understand it either :). The AP-505 has internal 5.7dBi antennas following the datasheet.

    So the max radio tx-power should be 30dBm minus 5.7dBi =  24,3 dBm + some cable and connector loss. So i could be the MaxEIRP is wrongly noted and the value seems like radio tx-power and not EIRP. Think this is a bug and all other values are OK.

    @Onno Any clarification for this MaxEIRP value? Noted i use AP-505 on ArubaOS 8.9.0.0 which a very new version and could have some bugs. 

    An AP with external antennas you need the configure the antenna gain in the controller. If you don't, iam not sure but i think the ap dont come online.









    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 7.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 04:31 AM
    Thank you again for clarifying the TPC adverts part! At least now I know it reports the current EIRP.
    However, another question arises: Why are you allowed to set the upper limit to 32 dBm? That's 2 dB above regulations..
    As for that Max EIRP strange value, your calculations could be right, but the remaining 2.4 dB is a very high value for cable & connector loss, especially with integrated antennas. If I were Aruba, I would immediately change my RF pigtail supplier:)
    BTW: All these EIRP values refer to the per-chain or max aggregated (4x4) power? Maybe here lies the answer, although the aggregated power calculation method would be very strange (usually there should be a 3 dB addition for each chain doubling, therefore 6 dB from 1x1 to 4x4).

    ------------------------------
    Alex Vrabie
    ------------------------------



  • 8.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Dec 02, 2021 05:28 AM
    The max.EIRP is the regulatory domain maximum the AP can do. You can configure a higher value but the AP will never send more than the regulatory limitations. The max.EIRP shows what the AP maximum allowed is to transmit, its more a reminder for the engineer in the logging.

    I try put the configuration to min. 30 and max 32 dBm to see if Airmatch can set the 30dBm EIRP on the AP and the MaxEIRP is incorrect value.

    rf dot11a-radio-profile "homelab-dot11a-radio-profile"
    am-scan-profile "homelab-dot11a-radio-profile_amscan_a_ui"
    min-channel-bandwidth 80MHz
    eirp-min 30
    eirp-max 32

    But no, its is cut off again on 26dBm and cant even get a cut off on 26.7dBm :)))

    (HomeLAB-MC02) [MDC] *#show ap active

    Name Group IP Address AP Type Flags Uptime Outer IP Cluster Role Radio 0 Band Ch/EIRP/MaxEIRP/Clients Radio 1 Band Ch/EIRP/MaxEIRP/Clients Radio 2 Band Ch/EIRP/MaxEIRP/Clients
    HomeLAB-AP01 HomeLAB 172.16.200.100 505 p2a 5d:16h:23m:28s N/A A/U AP:5GHz-HE:108E/26.0/26.7/5
    HomeLAB-AP02 HomeLAB 172.16.200.116 505 2a 11d:14h:36m:34s N/A A/U AP:5GHz-HE:100E/26.0/26.7/1

    Off course we both known don't need or design or this tx-power levelsy. But its a good thing to understand the values.
    Hope @Onno have a clarification.






    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 9.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 05:42 AM
    Interesting...What if you switch to U-NII-1 band? There you should be limited at 23dBm and maybe the conclusion is more obvious.
    That is, if you have time to do all these tests :)

    ------------------------------
    Alexandru Vrabie | CWNA | Ekahau ECSE
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  • 10.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Dec 02, 2021 05:59 AM
    Intressting the max.EIRP is 22.7dBm in the UNII-1

    AP:5GHz-HE:36E/22.7/22.7/3

    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 11.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 06:08 AM
    Well, then something is definitely wrong, but now it's above any logical explanation!
    Better wait for the people in charge to figure this one out :)
    Thanks again for the effort

    ------------------------------
    Alexandru Vrabie | CWNA | Ekahau ECSE
    ------------------------------



  • 12.  RE: Tx/EIRP reporting on AP 515

    EMPLOYEE
    Posted Dec 02, 2021 02:18 PM
    Why would something be wrong? In addition to in-band limits, there are other regulatory limits (band-edge, OOB emissions, etc.) that may result in a lower max power on any given channel.

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    Onno Harms
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  • 13.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 02:33 PM
    :) Well, that's one way to safely put it (even though it would have been nice to mention that in the specs too)
    But I wonder why hadn't I seen these limitations with other dedicated vendors? Is Aruba the greenest of them all?!

    ------------------------------
    Alexandru Vrabie | CWNA | Ekahau ECSE | Wireless Site Survey Specialist
    ------------------------------



  • 14.  RE: Tx/EIRP reporting on AP 515

    EMPLOYEE
    Posted Dec 02, 2021 02:45 PM
    Can't comment on other vendors, but we take regulatory compliance very seriously at Aruba ;-)
    Not realistic to cover this in the datasheets. It varies by channel, bandwidth, rate, country, etc. We cover that by the statement "limited by local regulatory requirements" in our datasheet, which focuses on the generic capabilities of the platform.

    ------------------------------
    Onno Harms
    ------------------------------



  • 15.  RE: Tx/EIRP reporting on AP 515

    MVP EXPERT
    Posted Dec 02, 2021 03:05 PM
    Thanks Onno! Didn't known about the band-edge, OOB emissions, etc. I learned something :).
    Found some nice reference https://www.naic.edu/~phil/rfi/u_niiband_802.11_aug16.pdf


    ------------------------------
    Marcel Koedijk | MVP Guru 2021 | ACEP | ACMP | ACCP | ACDP | Ekahau ECSE | Not an HPE Employee | Opionions are my own
    ------------------------------



  • 16.  RE: Tx/EIRP reporting on AP 515

    Posted Dec 02, 2021 03:15 PM
    Slick!
    So,  a -27dBm/MHz oob emission limit in the Gaps between bands should make every serious vendor limit their in-band max EIRP to a value calculated according to their radio filters' quality  (in Aruba's case = 27.6 dBm)?! Shouldn't it be different with each channel?
    Unfortunately, since I don't know how to calculate that (yet), I will have to take your word for it.
    Cheers

    ------------------------------
    Alexandru Vrabie | CWNA | Ekahau ECSE | Wireless Site Survey Specialist
    ------------------------------