Running 9800 and 8510 WLC's in parallel for upgrading a site

[craiglebutt]

Upgrading Wireless network from 8500 to 9800.

Both have to run in parallel till APs are replaced

8500 is the RF leader, both WLCs in the same RF Group in the same subnet and in mobility.

Tested roaming between wlcs, seem to work no issue.

Have a couple of SSID that go to the DMZ WLC for BYOD, the SSID matches config and naming convention on both WLCs

My question is should client roaming work between 8500 -> 9800 and visa versa if the WLC is anchored to a WLC on the DMZ?

Testing seems to say no, ran captures on both WLCs

Attache crude layout, both internal WLC pointing to the same DMZ WLC P1 = pritority 1 for mobility settings

[Leo Laohoo]

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@craiglebutt wrote:
My question is should client roaming work between 8500 -> 9800 and visa versa if the WLC is anchored to a WLC on the DMZ?

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What is the exact model of the 9800?
What is the total amount of APs?
What is the daily wireless client numbers?

[craiglebutt]

swapping out 470

8500 - mix of 2600, 3700, 

C9800-L-F-K9 - 9120AXI-E

For that site looking aroun 2000 users at any one point.

[Leo Laohoo]

9800-L only has one WNCD.  And that is good news.  

I would, however, make the both the 8510 and the 9800 RF leaders.  

The 2600 will not be supported on the 9800.

[marce1000]

   - Note that you can have client debugs as attached in capture.txt analyzed with Wireless Debug Analyzer
     (you may want to use a longer debug session  for that)

                                                      >Upgrading Wireless network from 8500 to 9800.
   - In general always have a review of it's configuration with the CLI command show tech wireless and feed
      the output from that into Wireless Config Analyzer
                     ( do not use a simple show tech as input for this procedure , use the full command denoted in green)
     Consider this kind of mandatory when staging 9800 controllers , preparing for production and or afterwards,
     and when making configuration changes (e.g.)

    M.

[craiglebutt]

The cleint debug was me roaming from 9800 -> 8500 back to 9800, that was all that was captured for that time period of testing.  But the client didn't oam while connected to the BYOD ssid that is anchored to the DMZ WLC.

But when a client was conencted to an internal SSID the behviour was as should be it roamed from 9800 to 8500 and back, same test and route as above, the only differntce was the SSID was anchored to a WLC on DMZ, does the behavour act differently.

Or should the client still have roamed when there is already an ahcor to an othere WLC?

[marce1000]

               - I can only say that client roaming decisions are always autonomous , 

 M.

[Rich R]

You didn't mention what the DMZ WLC is.  The 2 possible scenarios are covered in the guide:
Configuring Inter Release Controller Mobility in Wireless Deployments supporting AireOS and Catalyst 9800 Controllers 

Note that seamless roaming between WLC1 (9800) and WLC3 (8500) for guest anchor clients is not supported if the DMZ WLC is AireOS.