Patent ID: 7574736

Claim:
A computer-implemented process for receiving from a plurality of sending clients media packets across a firewall sent to a single destination address and a single destination port of a firewall, each media packet not including an unencrypted Synchronization Source Identifier (SSRC) but including an encrypted Synchronization Source Identifier, comprising the process actions of: establishing a plurality of security associations (SAs) for dialogs between sending clients and receiving clients, each SA including source information of a sending client and an indication of a receiving client; receiving from a sending client an encrypted media packet sent using Real-time Transport Protocol (RTP) message format at a media-relay server, the encrypted media packet being sent to the destination address and the destination port; determining whether the sending client's Security Association (SA) exists using the sender's source information received with the media packet the sender's source information being unencrypted and including a source address; if no SA exists, dropping the media packet at the media-relay server; and if a SA does exist, decrypting the media packet including decrypting a media packet Synchronization Source Identifier included in the media packet; obtaining obtained Synchronization Source Identifier from the SA; comparing the media packet Synchronization Source Identifier included in the decrypted media packet with the obtained Synchronization Source Identifier obtained from the SA; if the media packet Synchronization Source Identifier included in the decrypted packet does not match the obtained Synchronization Source Identifier obtained from the SA, dropping the media packet; and if the media packet Synchronization Source Identifier in the decrypted packet matches to the obtained Synchronization Source Identifier obtained from the SA, forwarding the packet to a receiving client indicated in the SA based on the sender's source information wherein a plurality of sending clients send media packets with different encrypted Synchronization Source Identifiers to the destination address and the destination port.