WLC 9800 Redudency RMI - few topics

[RoeyF]

1. In cisco wlc 9800, is it possible to set the Rmi redudency port with different vlan then the WLC management vlan?

2. I understood that there are should be two management vlan addresses for each one of the controller and only the address of the active chassis is available , what's going on if the active WLC it is corrupt, the standby wlc become to be active and second management address will take over?

3. what's going to be if the redudency between the WLC's link is down? and the WLC's don't see each other?

[David Ritter]

My Mgnt/WMI ip is x.10 and my RMI ip is x.9.  this chassis is fully configured.  the prospective Standby chassis is then Mgmt ip x.12 and the RMI ip is x.11.  Got that?  my RMI is the lower of the pair.  When SSO is enabled on both chasses and the RPI ports linked, reboot..  The Master (Active) first, new Standby second.  The Master will duplicate itself on the Standby (secondary) the 2nd chasis lan mgnt ip becomes the same as Master. and shutdown.  Only the service port ip and the rmi ips ping, you can ssh/gui into the service ports of both

there is only 1 management IP that the AP's and DNS know.

if the Standby box looses heartbeet from Active, it will go active or something like that.

[Rich R]

1. No! From https://www.cisco.com/c/en/us/td/docs/wireless/controller/9800/17-9/config-guide/b_wl_17_9_cg/m_vewlc_high_availability.html Restrictions:
- Two HA interfaces (RMI and RP) must be configured on the same subnet, and the subnet cannot be shared with any other interfaces on the device.  

Refer to https://www.cisco.com/c/en/us/support/docs/wireless/catalyst-9800-series-wireless-controllers/220277-configure-high-availability-sso-on-catal.html

[David Ritter]

Like this?

[RoeyF]

thanks it's very helpful, I've seen couple of topics that i was interested.

• one thing that i mentioned and i don't understand is " 2. I understood that there are should be two management vlan addresses for each one of the controller and only the address of the active chassis is available , what's going on if the active WLC it is corrupt, the standby wlc become to be active and second management address will take over? "

Example, 

The active WLC management is 192.168.1.1 and the redun-port is 192.168.1.2

The standby WLC management is 192.168.1.4 and the redun-port is 192.168.1.3

my question is what's going to be if for some reason the two WLC don't see each other and the work link is up-

in this case the access points don't know who is the activate one and that's clear, but what's going on in the arp table in the wired network? i will see the Active WLC 192.168.1.1 address and the Standby WLC 192.168.1.4 as well,( two individual WLC) until the i will sync again, than the main WLC with the highest priority will take over and only one management address will be available?   

i hope i described it clearly 

[marce1000]

       >...my question is what's going to be if for some reason the two WLC don't see each other and the work link is up-
                  Confusing statements , at least for me (how do you define 'work link' ?)

 M.

[David Ritter]

lol what would be the management ip of the 2nd chassis was erased and replaced with the the IP of the 'stack' then the IP is disabled  to prevent ip confilicts.  thus the AP's never know which chassis is active.  As far as I can tell, the 2nd chassis has no idea what its original management IP was because its config is now the same as master.  Only the Service Port IP's remain the same  only way I can tell which is which.