Communication system, computer, and method for determining a communication protocol to be used in a communication system

A method for determining a communication protocol to be used in a communication system having at least one first communication network designed for communication according to a first protocol, at least one second communication network designed for communication according to a second protocol, at least one third communication network designed for communication according to the first and the second protocol, where the at least one first communication network and/or the at least one second communication network and/or the at least one third communication networks are coupled to one another for the exchange of messages, a mobile computer designed for communication according to the first and the second protocol, a target computer that is designed for communication according to the first and/or second protocol and is a computer of the first or of the second or of the third communication network, said method comprising:

• determining, when the mobile computer is connected to a network connection computer of the third communication network, the protocol to be used for communication with the network connection computer before the establishment of a communication connection to the target computer,
• wherein the determining comprises transmitting a query message by a sending computer to the target computer using a hop-by-hop message transmission mechanism, transmitting a reply message by the target computer to the sending computer and evaluating by the sending computer, the sending computer being either the mobile computer or the network connection computer.

An apparatus that can be connected to a communication system having at least one first communication network designed for communication according to a first protocol, at least one second communication network designed for communication according to a second protocol, at least one third communication network designed for communication according to the first and the second protocol, wherein the at least one first communication network and/or the at least one second communication network and/or the at least one third communication networks are coupled to one another for the exchange of messages, a target computer that is designed for communication according to the first and/or second protocol and is a computer of the first or of the second or of the third communication network, said apparatus comprising:

• a system computer capable of communication according to the first and the second protocol and when connected to a network connection computer of the third communication network, the protocol used for communication with the network connection computer is determined before the establishment of a communication connection to the target computer,
• wherein the determination comprises a query message being transmitted by a sending computer to the target computer using a hop-by-hop message transmission mechanism, and at least one reply message being transmitted by the target computer to the sending computer and evaluated by the sending computer, the sending computer being either a mobile computer or the network connection computer.

A computer program product which is stored on a computer-compatible and computer readable medium for controlling the computer, comprising:

• computer-readable program capability which causes a computer, when connected to a communication networks designed for communication according to a first and a second protocol, to perform a parallel or sequential communication in the first and the second protocol to a target computer;
• computer-readable program capability which causes the computer to receive respective reply messages of the target computer to the query messages transmitted in the first and the second protocol;
• computer-readable program capability which causes the computer to evaluate the messages received according to the first and the second protocol with regard to the respective transmission path of the messages over the network;
• and
• computer-readable program capability which causes the computer to establish a communication path according to the first or the second protocol to the target computer for further communication,
• wherein the establishment comprises a query message being transmitted by a sending computer to the target computer using a hop-by-hop message transmission mechanism, and at least one reply message being transmitted by the target computer to the sending computer and evaluated by the sending computer, the sending computer being either a mobile computer or a network connection computer.