Functionality; Sensor Discovery - Symbol WS5000 Series System Reference Manual

15-2
WS5000 Series Switch System Reference Guide

15.2 Functionality

In addition to the basic AP to sensor conversion it is also desirable that the switch provide some minimal
management capabilities for the sensors. You should be able to view the list of sensors, read and send sensors'
configuration and revert selected sensors back to AP.
AirDefense defines Layer 2 communication protocol that can be used to discover sensors connected to the
switch and to send commands to the sensors. A broadcast ping packet is used for sensor discovery, which
implies that the sensors must stay in the same broadcast domain as the switch after the conversion. This is
not an unreasonable expectation because AP adoption and subsequent conversion to a sensor would not be
possible without it.
This extended sensor management functionality has minimal potential impact on the core WS5000
functionality.The switch maintains the list of known sensors in a separate list that does not interfere with an
existing list of AP's.

15.2.1 Sensor Discovery

The switch discovers sensors by sending PINGREQUEST packets on all VLAN's connected to the switch. The
switch dynamically obtains the list of all known VLAN's from the switch Ethernet configuration. All sensors
that are reachable by the switch respond with PINGRESPONSE packet. The switch then sends
REQ_CONFIG command to all discovered sensors. The switch maintains the list of all sensors and their
configuration.The list is refreshed on a regular basis. The content of the list is returned to UI/CLI via an XML
command
15.2.2 Sensor Configuration
Sensor configuration consists of:
• DHCP or Static IP address
• IP/mask/gateway for Static IP
• Primary and secondary IP address of AirDefense server
The configuration is sent to a sensor after the initial conversion and at any other time based on user's request.
The switch persistently stores a single default configuration that is sent to every sensor immediately after the
conversion. The switch does not store per-sensor configuration. You can also interactively request for
configuration of an individual sensor, modify it and send it back to the sensor.
After the conversion, the switch continuously ping newly converted sensor by sending unicast
PINGREQUEST packets to the MAC address on the VLAN in which the AP300 has been created. After the
switch receives PINGRESPONSE from the sensor it sends CONFIG_UPDATE command to the sensor and
waits for an acknowledgement. That completes the initial configuration after the conversion. If the switch fails
to receive PINGRESPONSE after 10 seconds of conversion or if the switch fails to receive an acknowledgement
after the switch logs an error.
You can select one of the sensors to change its configuration.The switch issues REQ_CONFIG command and
waits for a response. The response contains current sensor's configuration and you can make changes in it.
After the changes are made the switch sends CONFIG_UPDATE command to the sensor and waits for an
acknowledgement. If the switch fails to receive an acknowledgement it logs an error.