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162 CHAPTER 8: CONFIGURING AND MANAGING MOBILITY DOMAIN ROAMING
Effects of Timers on
An unsuccessful roaming attempt might be caused by the following
timers. You cannot configure either timer.
Grace period — A disassociated session has a grace period of
5 seconds during which MSS can retrieve and forward the session
history. After 5 seconds, MSS clears the session, and its accounting is
MAC address search — If MSS cannot find the client’s MAC address
in a Mobility Domain within 5 seconds, it treats the session as a new
session rather than a roaming session.
In contrast, the 802.1X reauthentication timeout period has little effect
on roaming. If the timeout expires, MSS performs 802.1X processing on
the existing association. Accounting and roaming history are unaffected
when reauthentication is successful, because the client is still associated
with the same MAP. If reauthentication fails, MSS clears the session so it is
not eligible for roaming.
If the client associates with the same MAP, the session is recorded as a
new session. (To change the reauthentication timeout, see “Setting the
802.1X Reauthentication Period” on page 537.)
To monitor the state of roaming clients, use the display sessions
network verbose command. For example, the following command
displays information about the sessions of a wireless client who roamed
between the ports on a WX switch.
The output shows that the client SHUTTLE\2\exmpl roamed from the MAP
connected to port 3 to the MAP connected to port 6 on the same WX,
and then roamed back to the MAP connected to port 3.
WX1200> display sessions network verbose
User Sess IP or MAC VLAN Port/
Name ID Address Name Radio
------------------------------ ---- ----------------- --------------- -----
SHUTTLE2\exmpl 6* 10.3.8.55 default 3/1
Client MAC: 00:06:25:13:08:33 GID: SESS-4-000404-98441-c807c14b
State: ACTIVE (prev AUTHORIZED)
now on: WX 10.3.8.103, AP/radio 3/1, AP 00:0b:0e:ff:00:3a, as of 00:00:24 ago
from: WX 10.3.8.103, AP/radio 6/1, AP 00:0b:0e:00:05:d7, as of 00:01:07 ago
from: WX 10.3.8.103, AP/radio 3/1, AP 00:0b:0e:ff:00:3a, as of 00:01:53 ago
1 sessions total
(For more information about this command and the fields in the output,
see the Wireless LAN Switch and Controller Command Reference.)