Wireless Networks

"There are two definitions for wireless LAN roaming:
Internal Roaming (1): The Mobile Station (MS) moves from one access point (AP) to another AP within a home network because the signal strength is too weak. An authentication server (RADIUS) performs the re-authentication of MS via 802.1x (e.g. with PEAP). The billing of QoS is in the home network. A Mobile Station roaming from one access point to another often interrupts the flow of data among the Mobile Station and an application connected to the network. The Mobile Station, for instance, periodically monitors the presence of alternative access points (ones that will provide a better connection). At some point, based on proprietary mechanisms, the Mobile Station decides to re-associate with an access point having a stronger wireless signal. The Mobile Station, however, may lose a connection with an access point before associating with another access point. In order to provide reliable connections with applications, the Mobile Station must generally include software that provides session persistence.
External Roaming (2): The MS (client) moves into a WLAN of another Wireless Internet Service Provider (WISP) and takes their services (Hotspot). The user can independently of his home network use another foreign network, if this is open for visitors. There must be special authentication and billing systems for mobile services in a foreign network." [Wireless LAN. Wikipedia]
This Cisco roaming wireless local area network diagram example was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Cisco Network Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.

"A wireless local area network (WLAN) links two or more devices using some wireless distribution method (typically spread-spectrum or OFDM radio), and usually providing a connection through an access point to the wider Internet. This gives users the ability to move around within a local coverage area and still be connected to the network. Most modern WLANs are based on IEEE 802.11 standards, marketed under the Wi-Fi brand name. WLANs were once called LAWNs (for local area wireless network) by the Department of Defense." [Wireless LAN. Wikipedia]
The example "Wireless network diagram - Ultra high performance WLANs" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Wireless Networks solution from the Computer and Networks area of ConceptDraw Solution Park.