Map Foreign Controller interface to Anchor Controller vs use interfaces defined on Anchor Controller

[fujovoris]

In Cisco guest WLAN architecture, regardless LWA & CWA variations, have Foreign Controller and Anchor Controller to configure.

I'm confused with some configuration variations in terms of guest interfaces used on the Anchor Controller:

Scenario 1:

Foreign WLC: WLC management
Anchor WLC: a dedicated dynamic interface named "guest" created and used, no Foreign Controller interface mapping

Scenario 2:

Foreign WLC: WLC management
Anchor WLC: a dedicated dynamic interface named "guest" created and used, but still use WLC management, Foreign Controller interface mapped to the "guest" interface

Both configurations actually work, but I'd like to know the logic behind, in which condition we should call for the interface directly (Scenario 1), or do interface mapping (Scenario 2)

[Haydn Andrews]

Fromhttps://www.cisco.com/c/en/us/td/docs/wireless/controller/8-1/Enterprise-Mobility-8-1-Design-Guide/Enterprise_Mobility_8-1_Deployment_Guide/WirelessNetwork_GuestAccessService.html

The default interface used by the foreign WLC for the guest WLAN is the management interface. If the EoIP tunnel cannot be established with the anchor, the foreign controller will disassociate any wireless clients that were previously associated with the unreachable anchor and then assign new clients and reassociate clients to the interface configured under the guest WLAN of the foreign itself. Therefore, it is recommended to link the guest WLAN on the foreign to a non-routable network, or alternatively configure the DHCP server of the management interface with an unreachable IP address. If the anchor becomes unreachable, this prevents the guest clients to gain access to the management network.

So from that the foreign interface should be a non routable interface.

[fujovoris]

Thanks for the recommendation. Actually I’m talking about the
configuration on Anchor Controller, which we could either do mapping
or use the guest subnet directly under the guest WLAN

[fujovoris]

via "Foreign Controller Interface Mapping"

[Rasika Nayanajith · Accepted solution]

Hi Jovoris,

If you have multiple foreign controllers and you need to map each foreign WLC guest traffic to different dynamic interfaces (or subnets) then you use foreign mapping feature. Otherwise you can simply using one dynamic interface in Anchor WLC for guest traffic without any mappings.

https://mrncciew.com/2013/03/24/auto-anchor-foreign-mapping/ 

HTH

Rasika

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[fujovoris]

Thank you very much, Rasika. Now the doubts are cleared:-)