VOICE-OVER-INTERNET TELECOMMUNICATION NETWORKS

摘要

When certain types of data, such as voice data, is sent over an IP-based network a problem can occur if this data passes a network address translator NAT, which is unable to identify and translate address information contained in the payload portion of a message. Voice-over-IP requires the initial establishment of a connection including the signalling of the address information for receipt of voice data. In accordance with the invention, a node (60) connected to a public network (50) is adapted to determine when address information received from a second node (10) in the payload portion of a voice-path-establishment message is different from the source address in the header of a voice packet received subsequently from the second node. A difference indicates that a NAT function is operating and the node (60) sends voice packets to the address identified in the voice packet header rather to that identified in the earlier message.