I have a windows NT Service that opens a ServiceHost object. The service host context is per-session so for each client a new worker thread is created. What I am trying to do is have each worker thread make calls to the thread that started the service host. The NT Service needs to open a VPN connection and poll information from a device on the remote network. The information is stored in a SQL database for the worker threads to read. I only want to poll the device if there is a client connected, which will reduce network trafic. I would like the worker threads to tell the service host thread that they are requesting information and start the polling and updating the database. Everything is working if the device is alway being polled and the database being updated.