TN TPA initialization service

TN TPA initialization service
When this service is really executed?
Only one time when TPA is defined?
Every time TN receives a transaction from respective partner?


It is not recommended to use the initService as it populates the default EDITPA variables.


Thanks ramesh,
But when this init service is actually executed? Its role in TPA life cycle?
Is this executed each time when we receive a document to TN from matching Partner?