System and method for establishing reliable communication in a connection-less environment

The establishment of reliable communication in particular in an environment of the mobile industry processor interface where communication is taking place based on the Unified Protocol is described. In this case based on the timer at the sender (IN) and based on maintaining an originator of a message at the receiver (TG) certain precautions are taken that messages are exchanged correctly and only once an acknowledgement is received from the sender, that a first and a second message have been exchanged correctly a maintained originator at the receiver is released. The same method can also be applied to sending a plurality of messages in sequence by using sequence numbers and replying to them in the same manner. In this case the timer is always restarted, once the message as a first type of message is sent from the sender side and an acknowledge is sent after the last second type of message with a highest sequence number has been received from the receiver side. With the method and the system according to the present invention it is possible to implement the configuration protocol of the Unified Protocol even in a case where a connection-less service which is faster to use is selected. The method according to the present invention may be triggered by a bit that is set in a protocol data unit as one of the reserved bits (310) in the header there.