Using WLAN for media transport in cellular mobile networks

Method of operating a telecommunication network for setting up a call between a first and a second Wireless Local Area Network (WLAN)-enabled mobile terminal, said telecommunication network comprising a first switching node, a second switching node, a gateway switching node, a first WLAN Access Point (AP) serving said first WLAN-enabled mobile terminal and a second WLAN AP serving said second WLAN-enabled mobile terminal, wherein:

• said first WLAN AP inserts a local media transfer (LMT) indication into a Direct Transfer Application Part (DTAP) Setup message, indicating that media transfer may take place directly from the first WLAN AP;
• said first switching node receives said first DTAP Setup message from said first WLAN AP;
• said first switching node includes said LMT indication into a call establishment message, and sends said call establishment message to said gateway switching node;
• said gateway switching node receives said call establishment message from said first switching node and sends said call establishment message to said second switching node;
• said second switching node receives said call establishment message from said gateway switching node;
• said second switching node includes said LMT indication into a second DTAP Setup message, and sends said second DTAP Setup message to said second WLAN AP;
• said second WLAN AP receives said second DTAP Setup message, wherein said second WLAN AP inserts an acknowledge LMT indication in a first call confirm message if said second WLAN AP agrees to use local media transfer;
• said second WLAN AP sends said first call confirm message to said second switching node;
• said second switching node receives said first call confirm message from said second WLAN AP;
• said second switching node includes said acknowledge LMT indication into an info message, and sends said info message to said gateway switching node;
• said gateway switching node receives said info message from said second switching node and sends said info message to said first switching node;
• said first switching node receives said info message from said gateway switching node;
• said first switching node inserts said acknowledge LMT indication into a second call confirm message, and sends said second call confirm message to said first WLAN AP;
• said first WLAN AP uses information included in said acknowledge LMT indication received from said second WLAN AP, for media transport to and from said second WLAN AP;
• and,
• said second WLAN AP uses information included in said LMT indication received from said first WLAN AP, for media transport to and from said first WLAN AP.