N+1 C9800-40 with CW9800M

[Jalmeida]

N+1 C9800-40 with CW9800M

I'm participating in a project that will involve configuring N+1 between a 9800-40 (main site) and a CW9800M at the backup site.

In this case, the 9800-40 has image 17.9.3, as there's a controller for the guest network in the DMZ.

I looked at the CW9800M images, and they appear to be different.

I'm considering filing a case with the TAC, because as the aps migrate to the CW9800M, they'll update the image. But when they return to the 9800-40, there's a risk of a crash, as they'll have to revert back to the initial image.

I haven't studied it much yet, but it seems like this will cause an error. Has anyone encountered this scenario?

Any tips or links for study?

[Leo Laohoo]

If the WLC are running different firmware, I would not be configuring them as "secondary" unless the business units do not mind a 5 minute outage every time the AP flips to the 2nd firmware.

[Mark Elsen · Accepted solution]

  - @Jalmeida     Because CW9800M is a new hardware model , it is only supported starting from 17.14.1 (indeed)
                          It would indeed also advisable for N+1 redundancy that the controllers are on the same
                          software version. Also 17.9.x  is EOL.  Note however that from that version (17.14.1) and
                          onwards the older IOS-COS AP models are no longer supported

  M.
                           

[Jalmeida]

Thanks for the details.
I'll have to check for a 9800-40 version update. However, what will make things difficult is the DMZ guest network. The DMZ WLC is a 5508, which is only compatible with 17.9.3.
Thanks.

[Mark Elsen]

  - @Jalmeida    You may have some restrictions here indeed; advising to abandon the 5508 platform because it is
                          now completely EOS/EOL , software downloads and patches have been removed from
                          Cisco software downloads too

  M.

[Jalmeida]

Can you share the link with this information/recommendations?

[Mark Elsen]

  - @Jalmeida       FYI : https://www.cisco.com/c/en/us/products/collateral/wireless/5500-series-wireless-controllers/eos-eol-notice-c51-740221.html

                          As far as N+1 is concerned, running same software version on the controller is common sense
                          to avoid access points having to swap image versions. You can also have a look at :
                                     https://www.cisco.com/c/dam/en/us/td/docs/wireless/controller/9800/17-4/deployment-guide/c9800-n-plus-1-high-availability-wp.pdf

       More general info's : first release made available for the CW9800M:
                                             https://software.cisco.com/download/home/286330374/type/282046477/release/IOSXE-17.14.1
                                      Access point model compatibility info's amongst various versions :
                                             https://www.cisco.com/c/en/us/td/docs/wireless/compatibility/matrix/compatibility-matrix.html
                                      IOS-XE feature info's concerning various releases :
                                            https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/214855-ios-xe-wireless-feature-list-per-release.html

   M.