WLC code compatibility with AP C9136I-B

[Najib Akbari]

Hi,

I have bunch of AP C9136I-B on C9800 code 17.12.6a and the controller warning message saying the current code does not support 2nd radio to be enabled. i can only upgrade up to 17.12.7a for a while as we have 3700 APs too.

I need your advise :

- is the second radio very important on performance and coverage to be enabled? elaborate a bit on the fundamental of this type of radio

- whats best to do? a work around or something?

[balaji.bandi]

If the upgrade is a dependency due to the AP model, that is perfectly understandable.

As I know -

• Slot 0: 2.4 GHz radio (4x4).
• Slot 1: Primary 5 GHz radio.
• Slot 2: Secondary 5 GHz radio.
• Slot 3: 6 GHz radio (4x4).

5 GHz radio is critical for performance and coverage; it is likely not critical for your environment right now, and leaving it disabled is a perfectly valid operating state

https://www.cisco.com/c/en/us/td/docs/wireless/access_point/technical-reference/cat9136-series-ap-deployment-guide.html

Are you in the migration path ?

[Najib Akbari]

Thanks. not sure about migration, but if activating 2nd 5G radio is critical then we should upgrade those 3700 APs

[Mark Elsen]

  - @Najib Akbari                Ref : https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214855-ios-xe-wireless-feature-list-per-release.html#toc-hId-1595855825
                                         >...
                                         >Quad-radio mode support for 9136 AP

      So you would need 17.13.1 at minimum; in practice 17.15.5 which is adviced
      17.13.1 is not a release for long term use

   Added    : benefits are    - two live, simultaneous client-serving 5 GHz cells — not a fallback radio
                                            more clients possible

  M. 

[Najib Akbari]

My appologies - i made a mistake on my initial post. i should have put 3700 and not 2700. i edited now

[Najib Akbari]

So I have tested before at a different setup the 17.15.5 and WLC shows unsupported AP for AIR-CAP3702I. now im checking the matrix and seems supported ?! maybe it was my mistake and though its not?

[Mark Elsen]

  - @Najib Akbari             3700 series is only officially supported till 17.12.3 
                                       Ref : https://www.cisco.com/c/en/us/td/docs/wireless/compatibility/matrix/compatibility-matrix.html
                                      >...

Cisco IOS XE Dublin 17.12.3

17.12.3.31

15.3(3)JPQ2

Cisco Catalyst APs: 9105AX (I/W), 9115AX (I/E), 9117AX (I), 9120AX (I/E/P), 9130AX (I/E), 9136 (I), 9162 (I), 9163 (E), 9164 (I), 9166 (I/D1) Cisco Aironet APs: 1815 (I/W/M/T), 1830 (I),1840 (I), 1852 (I/E), 1700 (I), 1800i, 2700 (I/E), 2800 (I/E), 3700 (I/E/P), 3800 (I/E/P), 4800 (I)

[Najib Akbari]

this is the email I got from the case i opened with TAC and it does not recommend to enable 2nd radio ! :

[Mark Elsen]

  - @Najib Akbari           Poor answer,  it's there for a reason and they should also mention from which
                                                           release it can be used,

  M.

[Leo Laohoo]

---

@Najib Akbari wrote:
we have 3700 APs too

---

2700/3700 is "un-officially" (or accidentally) supported in 17.13.1.

[Najib Akbari]

Yep, strange. I have a setup with 17.12.7a and bunch of 2600s and works even though they are not included in the compatibility matrix

[Rich R · Accepted solution]

@Najib Akbari that is not possible/believable in my opinion.  While a 2600 could theoretically run the same IOS image as the 2700/3700 the controller would not allow it to join because it's not on the list of supported APs (in fact they were end of support after AireOS 8.5 so cannot even join a WLC running 8.10 AireOS).  As Leo says the Wave 1 APs (1700/2700/3700) were left in 17.13.1 by mistake - but you should not use that release.  So stick with 17.12.x for now until you replace your 3700 APs.

Regarding the response you got from TAC (that looks like a reply from the AI bot Sherlock):  it's talking about the 2 modes you can use for the 5 GHz radios on the 9136.  Either combined operating as a single radio (with more spatial streams) or as 2 separate radios each with half the spatial streams. The former is the default in your current software release.  The latter only becomes possible in the future release.  So you are already using both 5GHz radios but they look like a single 8x8 radio.  Splitting them into two 4x4 radios means they would operate on different channels and the AP would create a small cell on one channel (clients close to the AP) and a larger cell on the AP (clients further from the AP) which can possibly accommodate more clients in a high density deployment.  In practice very few people will need this capability and it will require specialist survey and design and also complicates the channel allocations because you need twice as many channels with adequate channel separation (two 5 GHz radios in same AP one will always be on a low channel while the other is always on a high channel).  This is why Sherlock is saying TAC would almost never recommend it.  So stop worrying about it and keep using your APs as they are today.

From the datasheet: https://www.cisco.com/c/en/us/products/collateral/wireless/catalyst-9100ax-access-points/nb-06-cat9136-access-point-ds-cte-en.html

Flexible Radio Assignment (FRA) with quad-radio mode (with future software SW upgrade)

FRA allows the access points to intelligently determine the operating mode of serving radios based on the RF environment and traffic demands. The access points can operate in the following modes: ●  Tri-radio mode: One 4x4 6-GHz radio, one 8x8 5-GHz radio, and one 4x4 2.4-GHz radio. ●  Quad-radio mode: One 4x4 6-GHz radio, Dual 4x4 5-GHz radios, and one 4x4 2.4-GHz radio. With four total 4x4 radios (quad-radio) inside the access point, client device capacity can be increased on demand. The access point’s default mode is tri-radio with 8x8 5-GHz and 4x4 for 6-GHz and 2.4-GHz. It has the ability to split the 8x8 radio into two separate 4x4 5-GHz radios through a future software upgrade, thereby enabling the benefits of FRA while allowing the 2.4- and 6-GHz radios to remain active.

[Najib Akbari]

Thanks so much for the details, specially about 5Ghz dual radio elaboration. I will eventually go for 17.15.5 ( let me know if you advise a different image ) but nevertheless will stick to one 8X8 5G radio. 

yes its from Sherlock!!!!!!! i did not know its a bot!!!!!! hhahahhah good catch

[Najib Akbari]

this is another site with 17.12.7a and associated 1700 and 2700 even thou they are not listed in compatibility matrix ...!

[Mark Elsen]

  - @Najib Akbari         Note the 2700 ,3700 models (e.g.)   are officially supported till 17.12.3
                                   They work with any 17.12.x version ; the reason for that is that the IOS-XE
                                   code after 17.12.3 was no longer tested on these older access points.

  M.