sending data with GSM shield as a GSM-client


I want to use my Arduino GSM shield to send data to a certain internet address.
Every 5 minutes one block of data shall be sent.

I checked the example software for a GSM client which shows how to receive data from an internet address.
Can somebody support to me a piece of software how to send data?

Is it necessary to call client.stop() after every data block, like in the example for receiving data?

If no client.stop() has been called, will then any data be transferred in the 5 minutes pause?

Thank you for your tips in advance.