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Cisco Wireless LAN Controller Configuration Guide
OL-9141-03
Chapter 11 Configuring Mobility GroupsWireless Device Access
Configuring Auto-Anchor Mobility
When a client first associates to a controller of a mobility group that has been preconfigured as a mobility
anchor for a WLAN, the client associates to the controller locally, and a local session is created for the
client. Clients can be anchored only to preconfigured anchor controllers of the WLAN. For a given
WLAN, you should configure the same set of anchor controllers on all controllers in the mobility group.
When a client first associates to a controller of a mobility group that has not been configured as a
mobility anchor for a WLAN, the client associates to the controller locally, a local session is created for
the client, and the controller is announced to the other controllers in the same mobility group. If the
announcement is not answered, the controller contacts one of the anchor controllers configured for the
WLAN and creates a foreign session for the client on the local switch. Packets from the client are
encapsulated through a mobility tunnel using EtherIP and sent to the anchor controller, where they are
decapsulated and delivered to the wired network. Packets to the client are received by the anchor
controller and forwarded to the foreign controller through a mobility tunnel using EtherIP. The foreign
controller decapsulates the packets and forwards them to the client.
Note
A 2000 series controller cannot be designated as an anchor for a WLAN. However, a WLAN created on
a 2000 series controller can have a 4400 series controller as its anchor.
Note
The IPSec and L2TP Layer 3 security policies are unavailable for WLANs configured with a mobility
anchor.
Guidelines for Using Auto-Anchor Mobility
Keep these guidelines in mind when you configure auto-anchor mobility:
•
Controllers must be added to the mobility group member list before you can designate them as
mobility anchors for a WLAN.
•
You can configure multiple controllers as mobility anchors for a WLAN.
•
You must disable the WLAN before configuring mobility anchors for it.
•
Auto-anchor mobility supports web authorization but does not support other Layer 3 security types.
•
The WLANs on both the foreign controller and the anchor controller must be configured with
mobility anchors. On the anchor controller, configure the anchor controller itself as a mobility
anchor. On the foreign controller, configure the anchor as a mobility anchor.
•
Auto-anchor mobility is not supported for use with DHCP option 82.
