Method for transferring messages between communication terminals

1. A method for transferring messages between communication terminals, comprising:

transferring a token to a first communication terminal, which grants the first communication terminal authorization to transmit a message, and transferring a reservation message to a charging system, which asks the charging system to reserve resources for charging for the transfer of the message;

after receiving the token, transmitting the message from the first communication terminal, which is addressed to a second communication terminal;

transferring portions of the message which have been transmitted by the first communication terminal to a control computer and buffer-storing therein; and

after receiving a reservation confirmation message transferred to the control computer by the charging system upon successful reservation, transferring the message to the second communication terminal via the control computer.

2. The method as claimed in claim 1 , wherein the resources reserved are portions of a prepaid credit.

3. The method as claimed in claim 1 , wherein

the reservation confirmation message is used to transfer information about a confirmed period to the control computer, and

the control computer transfers the message to the second communication terminal until the transfer time reaches the confirmed period.

4. The method as claimed in claim 3 , wherein

a confirmed period associated with the first communication terminal is transferred to the control computer,

a confirmed period associated with the second communication terminal is transferred to the control computer, and

the control computer transfers the message to the second communication terminal until the transfer time reaches the confirmed period associated with the first communication terminal or until the transfer time reaches the confirmed period associated with the second communication terminal.

5. The method as claimed in claim 3 , wherein

information about a confirmed period is transferred, the confirmed period being longer than the transfer time required for transferring the message,

the control computer forms a difference between the confirmed period and the transfer time, and

the control computer retains a new confirmed period for transferring further messages, the new confirmed period corresponding to the difference.

6. The method as claimed in claim 5 , wherein

the control computer continuously checks whether further messages are being transmitted by the first communication terminal within a pre-selected idle time, and

if the messages are transmitted, the further messages are transferred and the transfer time required is determined, or

if the messages are not transmitted, a charging message is transferred to the charging system, the charging message being used to transmit information about the transfer time required up until then and a request to terminate reservation of the resources to the charging system.

7. The method as claimed in claim 6 , wherein the charging system transfers information about the length of the idle time to be used to the control computer.

8. The method as claimed in claim 6 , wherein the control computer stipulates the length of the idle time on the basis of a local setting.

9. The method as claimed in claim 6 , wherein receipt of the charging message prompts the charging system to charge for the transfer of the message using the reserved resources.

10. The method as claimed in claim 9 , wherein the charging system handles the charging message using a low priority.

11. The method as claimed in claim 10 , wherein the control computer uses the charging message to transfer information about the level of the priority to be applied for the charging message to the charging system.

12. The method as claimed in claim 6 , wherein charging for transfer of the message takes place using resources which are associated with the first communication terminal or its user and/or using resources which are associated with the second communication terminal or its user.

13. The method as claimed in claim 1 , wherein

shortly before the confirmed period expires, the control computer transfers a further reservation message to the charging system, which asks the charging system for further reservation of further resources for charging for the transfer of the message, and

upon successful further reservation, a further reservation confirmation message is transferred to the control computer.

14. The method as claimed in claim 1 , wherein a request message from the first communication terminal prompts transfer) of the token from the control computer to the first communication terminal.

15. The method as claimed in claim 1 , wherein the messages transferred from the control computer to the charging system are handled using a low priority.

16. The method as claimed in claim 1 , wherein the messages transferred from the control computer to the charging system are used to transfer information about the level of the priority to be applied for the messages to the charging system.

17. The method as claimed claim 1 , wherein the messages are transferred between the communication terminals in half-duplex mode.