You would like to know how the licensing in Symantec DLP works for different detection servers and also endpoint agents, how does DLP measure/count the usage of the installed licenses.
DLP products are offered under perpetual or subscription-based licensing model on a per Managed Device or Managed User basis (refer to Symantec.com for the official definition):
• MANAGED USER: An individual person who has access to a network that is managed, monitored and/or protected by the Licensed Software.
• MANAGED DEVICE: A device that is managed, monitored or protected by the Licensed Software but that may not actually be running the Licensed Software itself.
• APPLIANCE: An individual piece of virtualized or physical machine with software installed to provide a specific computing resource.