BridgeQuery polls a device which respond to SNMP Bridge Table queries and generates a hash reference with each polled MAC address as the key and the associated port as the value. The specific MIBs that are polled are described in RFC1493. SNMP::BridgeQuery requires Net::SNMP in order to function. Devices can be switches, bridges, or most anything that responds as a OSI Layer 2 component. Layer 3 devices do not generally respond and will cause an error. If an error is generated, it will return a hash reference with a single element ('error') which can be tested for.