Information Technology Reference
In-Depth Information
Roaming and Mobility Groups
The primary reason to have wireless networks is roaming: the ability to access network re-
sources from common areas and in areas where it is difficult to run cabling. End clients
might want to move from one location to another. Mobility allows users to access the net-
work from several locations. Roaming occurs when the wireless client changes association
from one AP to another. The challenge is to scale the wireless network to allow client
roaming that is seamless and secure. Roaming can be intracontroller or intercontroller.
Key
To p i c
Intracontroller Roaming
Intracontroller roaming, shown in Figure 5-10, occurs when a client moves association
from one AP to another AP that is joined to the same WLC. The WLC updates the client
database with the new associated AP and does not change the client's IP address. If re-
quired, clients are reauthenticated, and a new security association is established. The
client database remains on the same WLC.
Data Traffic Bridge
onto VLAN
WLC
CAPWAP Tunnels
AP1
AP2
Pre-Roam
Data Path
Post-Roam
Data Path
Wireless Client
Roams from AP1 to AP2
Figure 5-10
Intracontroller Roaming
Layer 2 Intercontroller Roaming
Intercontroller roaming occurs when a client moves association from one AP to another
