Mal,
If you have the LabVIEW Operator Interace, you can place your TCP/IP Vi anywhere you want. Either at the beginning of the execution, when a particular sequence is running, when a user logs in, etc. Since you have the LV code, you can just add your TCP/IP as a subVI in the right place. You could also place a button in the front panel that will allow you to CONNECT/DISCONNECT by calling your VIs.
Does this help?
Azucena