Specifications

Understanding the Sessions of Roaming Users
7-8 Configuring and Managing Mobility Domain Roaming
Understanding the Sessions of Roaming Users
WhenawirelessclientsuccessfullyroamsfromoneAPtoanother,itssessionsareaffectedinthe
followingways:
•TheRoamAboutSwitchtreatsthisclientsessionasaroamingsessionandnotanewsession.
•RADIUSaccountingishandledasacontinuation ofanexistingsession,ratherthananewone.
•The
sessionwiththeroamed ‐fromAPisclearedfromtheRoamAboutSwitch,evenifthe
clientdoesnotexplicitlydisassociatefromtheAPandtheIEEE802.1Xreauthentication
periodhasnotexpired.
RoamingrequirescertainconditionsandcanbeaffectedbysomeoftheRoamAboutswitch’s
timers.Youcanmonitora
wirelessclient’sroamingsessionswiththeshowsessionsnetwork
verbosecommand.
Requirements for Roaming to Succeed
Forroamingtotakeplace,theroamingclient mustassociateorreassociatewithanAPinthe
MobilityDomainafterleavinganexistingsessiononadifferentAPintheMobilityDomaininone
ofthefollowingstates:
Inaddition,thefollowingconditionsmustexistforroamingtosucceed:
• MobilityDomain
communicationsmustbestable.
Generally,thecommunicationsrequiredfor roamingarethesameasthoserequiredforVLAN
tunneling.AclientcanalsoroamamongportsonaRoamAboutSwitchwhenaMobility
Domainisinaccessibleornotconfigured.
•Clientauthenticationandauthorizationontheroamed‐toAPmustbesuccessful
onthefirst
attempt.
Ifauthenticationorauthorizat ionfails,MSSclearstheclientsession.Dependingonwhenthe
failureoccurs,roamingcanbedisqualifiedordelayed.
•Theclientmustusethesameauthorizationparametersfortheroamed‐toAPasforthe
roamed‐fromAP.
Iftheclientchangesitsencryption
typeorVLANname,MSSmightrecordanewsession
ratherthanaroamedsession.
ACTIVE The normal state for a client that has left radio range without sending a request to
disassociate.
DEASSOCIATED The state of a client that has sent an 802.11 disassociate message, but has not
roamed or aged out yet.