WLC 9800-80 SSO in VSS

[piotrPaszk]

Hello,

I am going to install 9800-80 for the first time but I am confused about SSO. I found this guide https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/213915-configure-catalyst-9800-wireless-control.html which tell about SSO with back-to-back connectivity.

Whereas the presentation from Cisco PVT in amsterdam tells that it is IMPORTANT: connect RP port to the VSS switch and not back to back!

What is a proper way to do it with 9800 ?

[omz · Accepted solution]

Hi 

Have a look at this guide - 

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/8-8/b_c9800_wireless_controller_ha_sso_dg.html#id_89553

"To support the active and standby WLCs in different data centers, in release 7.5, back-to-back redundancy port connectivity between peers is no longer mandatory and the redundancy ports can be connected via switches such that there is L2 adjacency between the two controllers."

https://www.cisco.com/c/en/us/td/docs/wireless/controller/technotes/7-5/High_Availability_DG.html#pgfId-43271

[Ven Taylor]

I got the same response from TAC, but I don't understand the logic.

From TAC:

Note: In IOS-XE 16.10 to 16.12, it is recommended to connect the 9800s Redundancy Port to the same switch where the management connection of the 9800 is connected to. This is because there is no verification for the gateway reachability yet in these versions. Connecting back-to-back will work but will cause higher chances of 9800 controllers being active-active when connected that way

However, from a L2 perspective, I don't see any difference between how the 9800s see one another via back-to-back or via the switch.

I'm currently running back-to-back with two 9800-80s and have no issues.  I'm moving it to the switch connection this weekend.  I have no idea how the HA pair is going to respond to moving the connection.

[Scott Fella]

This is the same for AireOS, ideally they would like to have a single switch in between if not using a back to back cable. Now I have had the RP port connected to two different switches because the co trollers were in different closets but was L2 connected. It comes down to what they will support when you open a TAC case. So the choice is up to you, test it and if it works, then that’s good, but also know that if you run into any SSO issues, it will not be support.