- LDM Messages
LDM messages are sent by the LDM client and can change the status of a workpoint at any time.
2. Switch Scans
Switch Scans occur at regularly scheduled intervals and can change the status of a workpoint if they detect that the device connected to a switchport at a workpoint has changed.
3. Scheduled Clean-up Tasks and Timeouts
Scheduled clean-up tasks happen at regularly scheduled intervals, and handle scenarios where an LDM client may have unexpectedly stopped sending messages, or a device has been unplugged from a switch port.
The LDM client will send the following types of messages. In addition to the message type, all LDM messages include the enabled ethernet and 802.11 MAC addresses of the client computer.
- User Active – When the LDM status check timer detects that the computer is active.
- User Active Logged On – When LDM starts.
- User Away – When the LDM status check timer detects that the user session is idle.
- User Away Logged Out – When the user logs out of their Windows session.
- User Away Application Closed – When LDM is closed.
- User Away Computer Asleep – When the power status changes to sleep.
- Ping Check – Sent at a regular time interval.
- Config Check – On startup and at regular intervals thereafter.
- MAC Changed – When the available network adapters change. This message will include network interfaces that were disabled as part of the MAC Changed, for example because a laptop has unplugged from a docking station.
Every LDM client will send these messages directly to MLS for immediate processing.
If the message is a MAC Changed message, then the last known computer name for each disabled MAC address in the LDM message will be compared to the computer name in the message. If they match, or if there is no previously known computer, then a User Unplugged type message will be generated and sent to WusCom.
If the message is a status message (any of User Active, User Active Logged On, User Away, User Away Application Closed, User Away Logged Out, or User Away Computer Asleep) or MAC Changed, then the last known user information for each active MAC address in the LDM message will be compared to the user information contained in the LDM message. If the information in the LDM message is different from the last known user information, or there is no previously known information for the user, then an update will be sent to WusCom.
If the message type was MAC Changed, it will be converted to User Active before sending to WusCom.
If the message is a Ping Check, then the last ping check time for the MAC Address will be updated and stored. This will be used later by the clean-up task.
Switch scans are performed at a regular interval to determine which MAC address is connected to which switch port. When changes are detected, it can result in updates to the workpoint status.
If a MAC address returned by a switch scan has no previously known locations or has one or more previously known locations and the previously known location with the fewest other devices connected is new for that MAC address on this scan, then an update will be sent to WusCom, using the last known status for the user and the new switch port of the device.
Scheduled clean up tasks and timeouts
Scheduled clean up handles the following:
Generating Faulty LDM type messages when no ping has been received for longer than a configured amount of time.
- Generating Unplugged type messages.
This task runs on a configurable schedule. In addition to the schedule that the task runs on, it accepts the following configuration:
- Unplug LDM Timeout
- Enable Unplug Check
- Enable Faulty LDM Check
- Location Cleanup Delay
- Ping Check Interval (from LDM configuration)
The unplug check is performed every time the cleanup task is run if Enable Unplug Check is configured to true.
In the unplug check, MLS looks at the last known user activity and location for each MAC address. If the last time MLS detected the MAC address at the switch port currently associated with that MAC, it is older than the last time MLS scanned that switch port and MLS either has no user activity for the MAC or the last user activity is older than the last switch scan, then MLS generates an Unplugged type message for that switch port. The Unplugged message includes the last known user and MAC address at that switch port.
Faulty LDM Check
Faulty LDM check is performed every time the cleanup task is run if Enable Faulty LDM Check is configured to true.
In the faulty LDM check, MLS looks at the last known user activity for each MAC address. If the following conditions are met, then a Faulty LDM type message will be generated for every switch port currently associated with that MAC address.
- Last LDM Message Time < Now - Ping Check Interval
- Last LDM Message Time < Now - Unplug LDM Timeout
- Last LDM Message Type is User Active, User Active Logged On, or User Away