Method of transmitting messages in communication networks

A method of discovering availability of information related to an external network in a wireless local area network, the method comprising:

• transmitting, by a requesting station, a request message to a responding station via a wireless channel, the request message including an advertisement identifier and requesting that the responding station retrieve information related to a media independent handover (MIH) information service (IS) from a server of the external network;
• receiving, by the requesting station, a query response message as a response to the request message from the responding station via the wireless channel, the query response message including the advertisement identifier and a fragmentation field, the fragmentation field indicating that a query response which the responding station receives from the server is fragmented;
• and
• receiving, by the requesting station, at least one fragmentation response message from the responding station via the wireless channel, the at least one fragmentation response message including the advertisement identifier, a more fragmentation field, a sequence number field, and a fragment of the query response,
• wherein the advertisement identifier identifies the server of the external network,
• wherein the more fragmentation field has one bit and indicates whether the fragment of the query response in a corresponding fragmentation response message is a last fragment,
• wherein the sequence number field has more than 3 bits and indicates a fragment number of a corresponding fragmentation response message, and
• wherein the method further comprises determining, by the requesting station, that any fragment of the query response is missing based on the sequence number field.