Mac Layer Bridging; Media Types - Motorola AP-7131 Product Reference Manual

1-22 AP-7131 Access Point Product Reference Guide

1.2.2 MAC Layer Bridging

The access point provides MAC layer bridging between its interfaces. The access point monitors
traffic from its interfaces and, based on frame address, forwards the frames to the proper destination.
The access point tracks source and destination addresses to provide intelligent bridging as MUs roam
or network topologies change. The access point also handles broadcast and multicast messages and
responds to MU association requests.
The access point listens to all packets on its LAN and WAN interfaces and builds an address database
using MAC addresses. An address in the database includes the interface media that the device uses
to associate with the access point. The access point uses the database to forward packets from one
interface to another. The bridge forwards packets addressed to unknown systems to the Default
Interface (Ethernet).
The access point internal stack interface handles all messages directed to the access point. Each
stores information on destinations and their interfaces to facilitate forwarding. When a user sends
an ARP (Address Resolution Protocol) request packet, the access point forwards it over all enabled
interfaces except over the interface the ARP request packet was received.
On receiving the ARP response packet, the access point database keeps a record of the destination
address along with the receiving interface. With this information, the access point forwards any
directed packet to the correct destination. Transmitted ARP request packets echo back to other MUs.
The access point removes from its database the destination or interface information not used for a
specified time. The AP refreshes its database when it transmits or receives data from these
destinations and interfaces.

1.2.3 Media Types

The access point radio interface conforms to IEEE 802.11 specifications. The access point supports
multiple-cell operations with fast roaming between cells. Within a direct-sequence system, each cell
can operates independently. Adding cells to the network provides an increased coverage area and
total system capacity.
The serial port provides a Command Line Interface (CLI) connection. The serial link supports a direct
serial connection. The access point is a Data Terminal Equipment (DTE) device with male pin
connectors for the RS-232 port. Connecting the access point to a PC requires a null modem serial
cable.