Notifications

Clicking the Notifications page menu entry opens the Data notification panel. This panel is a list of grouped settings, which makes you able to configure the DME Notification Framework. The notification framework is enabled or disabled in the field Status in the Process panel section (see Process).

Please note that special considerations apply to Apple iOS devices. See Notifications on iOS devices for more information.

The notification framework
The notification framework is the system by which DME scans the collaboration system and other systems for changes and lets the clients (devices) know that changes have occurred. This scan takes place periodically, and the frequency of the scan can be adjusted for each DME resource. DME operates with the following resources:

• E-mail (including e-mail folders)
• Calendar
• Contact
• To-do
• Notes (Journals)
• System information
• Files
• RSS

Each of these resources is described later.

The flags
The frequency, priority, and other settings for the scanning of a certain resource is called a scan scheme. For each scheme, and for each device, DME keeps track of when the system needs to scan for changes again. You can see the time of the next scan in the Schedule section of the individual devices in the Devices tab (see Schedule).

When a scan is run, a change may be found (as described in Scanning).

• If no change is found:

  The time of the next scan is calculated based on the scan scheme, and nothing more is done.

• If a change is found:

  A flag is raised for the device in question. The device now has a pending notification, which can be seen in the Pending panel section for all devices (see Pending), or in the Pending subtab of the Schedule section of the individual devices (see Schedule). The flag shows the type of the resource for which the scan was made, for instance a Sync. e-mail notification.

  Furthermore, the scan for the scheme in question requires minimum resources, as it only checks for the presence of the Pending flag and moves the time of the next scan into the future.

The Pending flag will be cleared in the following cases:

• When the device performs a synchronization of the same type as the pending flag (as mentioned above), either due to a scheduled sync., a push, or a manual sync. This is the regular way to clear a flag.
• When the flag's time to live (TTL) expires. In the field Process cache TTL in the Process panel section, you can set a maximum time to live for these pending flags. This is to clean up the list of pending notifications if the device for instance is turned off. If the same device keeps producing notifications which are not cleared by a synchronization, but only because the TTL expires, the system can be configured to not scan devices after a certain number of such notifications. When this happens, the pending flag becomes a permanent pending flag, and no more notifications are set for the device until the flag is cleared by a sync. See Process.
• If the synchronization scheme is reset. This is done by selecting the action Reset schedule(s) in the Schedule panel section, either in the Server tab (for all devices) or when editing a group (for a group of devices). See Schedule. See also below for reasons to reset the scheme.

After the flag has been cleared, the time of the next scan is calculated from the scan scheme, and the process starts over.

Suspension of notifications
The DME server may stop sending notifications for specific devices in the following events:

• If the device is roaming, and the setting Notification scan when roaming is set to Disabled.
• If the particular resource is disabled in the settings for the device. For instance: If a general scan scheme has been set up for Files, but the synchronization of files is disabled for the device, DME will scan for that resource much less frequently.
• If the maximum number of notifications has been reached (see Notification).

Note that the user will still be scanned, but no notifications will be sent to his or her device.

Error handling
Sometimes, an error may occur during scanning. This can for instance happen if the DME database cannot be reached, or the collaboration system is being restarted, or if DME cannot access a user's mailbox. DME distinguishes between two types of errors:

1. Login errors. This is when DME cannot log in to the collaboration system for some reason. In this case, the scan is suspended for 30 minutes. If the error arose because a user with credentials stored on the DME database could not log in, the credentials of the user in question are furthermore erased from the database. This is in order to prevent the scanner from accidentally shutting the user out of the collaboration system and, by extension, the network - which might happen in some types of setup if the scanner tries too many times without success. The scanner will automatically restart when the user synchronizes his or her device.
2. Other errors. If any of the subsystems are down, DME will attempt to scan again after 2 minutes, then after 4 minutes, then after 6 minutes, and finally DME will keep retrying the scan every 1 hour.

If an error condition has occurred, and you resolve the error, you do not have to wait for the scanner to discover this after perhaps a full hour. Instead you can select the action Reset schedule(s) in the Schedule panel section to force DME to restart the scanner immediately. The time of the next scan for the affected resources and devices is then recalculated, and the timer is started again. Note that this action is available at all levels (default in the Server tab and for groups and individual devices in the Devices tab).