Device Triggers

Device triggers launch a profile when a device connects to or disconnects from a port.

The two types of device triggers are labeled device-detect and device-undetect in the software. Profiles that respond to these triggers are called device-detect profiles or device-undetect profiles.

Typically, a device-detect profile is used to configure a port for the device that has just connected.

Likewise, a device-undetect profile is used to return the port to a default configuration after a device disconnects. A variety of different devices can be connected to a port. When devices connect to the network, Universal Port helps provide the right configuration at the port.

Device triggers respond to the discovery protocols IEEE 802.1ab LLDP and ANSI/TIA-1057 LLDP-MED for Voice-over-IP (VoIP) phone extensions. A device-detect trigger occurs when an LLDP packet reaches a port that is assigned to a device-detect profile. A device-undetect trigger occurs when periodically transmitted LLDP packets are not received anymore. LLDP age-out occurs when a device has disconnected or an age-out time has been reached. LLDP must be enabled on ports that are configured for device-detect or device-undetect profiles. LLD P is described in LLDP Overview.

The combination of device triggers and LLDP enables the custom configuration of devices that connect to switch ports. For example, VoIP phones can send and receive information in addition to normal device identification information. The information sent through LLDP can be used to identify the maximum power draw of the device. The switch can then set the maximum allocated power for that port.

If the switch does not have enough PoE left, the switch can take action to lower the PoE loading and try again. The switch can also transmit additional VoIP files and call server configuration information to the phone so the phone can register itself and receive necessary software and configuration information.

There can only be one device-detect profile and one device-undetect profile per port. To distinguish between different connecting devices, you can use if-then-else statements in a profile along with detailed information provided through LLDP.