Apparatus (200, 300, 406) comprising: - a first interface (104, 202, 302) for communicating with a first communication network (102, 304, 402), - a second interface (118, 204, 306) for communicating with a second communication network (116, 308, 404) separate from the first communication network (102, 304, 402), - at least one processor (206, 310), - at least one memory (208, 312) containing computer program code (209, 313), and - at least one data memory (212, 312, 332, 334, 338), - wherein the at least one memory (208, 312) and the computer program code (209, 313) are configured to cause, with the at least one processor (206, 310), the device (200, 300, 406) to perform at least the following: - receiving an input message via the first interface (104, 202, 302), the input message having a first layer structure and containing an information piece associated with the top layer of the first layer structure, - extracting the information piece from the input message by passing the input message through a protocol stack associated with the first layer structure from bottom to top, - examining the extracted information piece to obtain an examination result, - buffering the information piece (105, 115) or an information piece generated based on the extracted information piece on the data memory (212, 332, 334, 338) as a function of the examination result, - generating an output message by passing the buffered information piece (105, 115) or an information piece generated on the basis of the buffered information piece through a protocol stack associated with a second layer structure from top to bottom; - obtaining an information request via the second interface (118, 204, 306) and - sending the output message via the second interface (118, 204, 306), - wherein the generating and/or the sending of the output message are performed as a function of the examination result and - wherein the sending of the output message is performed in response to the obtaining of the information request. - a first interface (104, 202, 302) for communicating with a first communication network (102, 304, 402), - a second interface (118, 204, 306) for communicating with a second communication network (116, 308, 404) separate from the first communication network (102, 304, 402), - at least one processor (206, 310), - at least one memory (208, 312) containing computer program code (209, 313), and - at least one data memory (212, 312, 332, 334, 338), - wherein the at least one memory (208, 312) and the computer program code (209, 313) are configured to cause, with the at least one processor (206, 310), the device (200, 300, 406) to perform at least the following: - receiving an input message via the first interface (104, 202, 302), the input message having a first layer structure and containing an information piece associated with the top layer of the first layer structure, - extracting the information piece from the input message by passing the input message through a protocol stack associated with the first layer structure from bottom to top, - examining the extracted information piece to obtain an examination result, - buffering the information piece (105, 115) or an information piece generated based on the extracted information piece on the data memory (212, 332, 334, 338) as a function of the examination result, - generating an output message by passing the buffered information piece (105, 115) or an information piece generated on the basis of the buffered information piece through a protocol stack associated with a second layer structure from top to bottom; - obtaining an information request via the second interface (118, 204, 306) and - sending the output message via the second interface (118, 204, 306), - wherein the generating and/or the sending of the output message are performed as a function of the examination result and - wherein the sending of the output message is performed in response to the obtaining of the information request. - receiving an input message via the first interface (104, 202, 302), the input message having a first layer structure and containing an information piece associated with the top layer of the first layer structure, - extracting the information piece from the input message by passing the input message through a protocol stack associated with the first layer structure from bottom to top, - examining the extracted information piece to obtain an examination result, - buffering the information piece (105, 115) or an information piece generated based on the extracted information piece on the data memory (212, 332, 334, 338) as a function of the examination result, - generating an output message by passing the buffered information piece (105, 115) or an information piece generated on the basis of the buffered information piece through a protocol stack associated with a second layer structure from top to bottom; - obtaining an information request via the second interface (118, 204, 306) and - sending the output message via the second interface (118, 204, 306), - wherein the generating and/or the sending of the output message are performed as a function of the examination result and - wherein the sending of the output message is performed in response to the obtaining of the information request.