high available wireless (WLC in local site Another in Remote Site)

[HNETENG]

If I have a local site with LAN Network that has one WLC and couple of Wireless Access Points. This LAN network is connected to the internet through firewall and router. And there is a remote site over the internet which has another secondary WLC.

Can I have a high available wireless scenario by registering the AP to the local WLC on the same LAN and in case the local WLC goes off, then the AP can join the remote WLC over the internet?

[marce1000]

  - In that case you should fall back to N+1 mode of high availability (where APs get configured with a primary and fallback controller)

 M.

[HNETENG]

If we considered that the internet link has a RTT of 200ms to 400ms. in which mode the AP should be operating in this case? local mode or flexconnect mode ? 

[marce1000]

 - Capwap is limited to 200ms ; you should then go for flexconnect ,

  M.

[Rich R]

Cisco guideline is 300ms:
https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-9/config-guide/b_wl_17_9_cg/m_vewlc_flex_connect.html#restrictions-for-flexconnect-specific-details
but this is not an absolute number because it depends on how the WLANs are configured.
As Marce says the APs should definitely be in flexconnect mode.

"Round-trip latency must not exceed 300 milliseconds (ms) between the access point and the controller, and CAPWAP control packets must be prioritized over all other traffic. In scenarios where you cannot achieve the 300-ms round-trip latency, configure the access point to perform local authentication."

[Leo Laohoo]

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@HNETENG wrote:
If I have a local site with LAN Network that has one WLC and couple of Wireless Access Points.

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A WLC for only a "couple" of APs?  Wow!  Someone really went to town and then overboard.  

[HNETENG]

Just for the sake of discussion, you can consider 200 APs. 

[Leo Laohoo]

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@HNETENG wrote:
Can I have a high available wireless scenario by registering the AP to the local WLC on the same LAN and in case the local WLC goes off, then the AP can join the remote WLC over the internet?

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In that case, tell us more about the two controllers?  

What are the model?  What firmware are they on?  How many APs are on WLC 1 and WLC 2?

[HNETENG]

WLC : C9800-CL-K9

AP :  C9136I-ROW

Version : latest version. 

All 200 AP will be registering on the local WLC on the local LAN. and in case the local WLC goes down they will switch and register to the WLC hosted on the internet