Symbol AP-51xx, Руководство по продукции, Страница: 41 / 622

Introduction 1-23
• Unassociated MU attempts to associate or reassociate with an available access point
• Supported rate changes or the MU finds a better transmit rate with another access point
• RSSI (received signal strength indicator) of a potential access point exceeds the current
access point
• Ratio of good-transmitted packets to attempted-transmitted packets falls below a threshold.
An MU selects the best available access point and adjusts itself to the access point direct-sequence
channel to begin association. Once associated, the access point begins forwarding frames addressed
to the target MU. Each frame contains fields for the current direct-sequence channel. The MU uses
these fields to resynchronize to the access point.
The scanning and association process continues for active MUs. This process allows the MUs to find
new access point’s and discard out-of-range or deactivated access point’s. By testing the airwaves,
the MUs can choose the best network connection available.
1.3.6 Operating Modes
The access point can operate in a couple of configurations.
• Access Point - As an Access Point , the access point functions as a layer 2 bridge (similar
to Symbol’s existing AP-4131 access point). The wired uplink can operate as a trunk and
support multiple VLANs. Up to 16 WLANs can be defined and mapped to access point
WLANs. Each WLAN can be configured to be broadcast by one or both access point radios
(unlike the AP-4131 model access point). An AP-5131 or AP-5181 can operate in both an
Access Point mode and Wireless Gateway/Router
mode simultaneously. The network
architecture and access point configuration define how the Access Point and Wireless
Gateway/Router
mode are negotiated.
• Wireless Gateway/Router - If operating as a Wireless Gateway/Router , the access point
functions as a router between two layer 2 networks: the WAN uplink (the ethernet port) and
the Wireless side. The following options are available providing a solution for single-cell
deployment:
• PPPoE - The WAN interface can terminate a PPPoE connection, thus enabling the
access point to operate in conjunction with a DSL or Cable modem to provide WAN
connectivity.
• NAT - (Network Address Translation) on the Wireless interface. Using NAT, the access
point router is able to manage a private IP scheme. NAT allows translation of private
addresses to the WAN IP address.
• DHCP - On the Wireless side, the access point can assign private IP addresses.