초록

Methods, systems, and mediums for enabling clients to traverse firewall and Network Address Translation (NAT) installations by using probe packets between servers and clients to communication the addresses modified by the NAT.

대표청구항 ▼

The invention claimed is: 1. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private addr

The invention claimed is: 1. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; generating, at the traversal server, a probe definition that uniquely identifies a connection establishment event; sending a standard message according to a Session Initiation Protocol (SIP) for real-time multimedia communication from the traversal server to the private client, the standard message including the probe definition, the sending including receiving a standard SIP INVITE message at the traversal server from the private client via the persistent registration connection, the standard SIP INVITE message including at least one of a contact header and a record route header having an address of the private client, modifying at least one of the contact header or the record route header to include an address of the traversal server, forwarding the standard SIP INVITE message from the traversal server to a SIP registrar/proxy including at least one of a modified contact header and a modified record route header, receiving a standard SIP OK message at the traversal server from the remote client via the SIP registrar/proxy, adding a standard SDP parameter to the standard SIP OK message at the traversal server, adding the probe definition to the standard SIP OK message at the traversal server, the probe definition having been determined by the traversal server, and forwarding the standard SIP OK message including an added SDP parameter and an added probe definition to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 2. The method of claim 1, wherein the multimedia information includes a standard real-time protocol (RTP) based media information and the receiving a standard SIP INVITE message further comprises: receiving a standard SIP INVITE message that includes at least one media parameter set describing the RTP based media information. 3. The method of claim 1, wherein the receiving the probe packet further comprises: receiving the probe packet having a size less than 12 bytes. 4. The method of claim 1, wherein the transferring the multimedia information further comprises: receiving a standard SIP BYE message at the traversal server terminating the transferring the multimedia information; and releasing a resource at the traversal server associated with the transferring the multimedia information. 5. The method of claim 1, wherein the method further comprises: relaying SIP messages received at the private client from the traversal server to a further private client in the private address space; and relaying SIP messages received at the private client from the further private client to the traversal server. 6. The method of claim 1, wherein the establishing the persistent registration connection further comprises: establishing a standard Transport Layer Security (TLS) connection between the private client and the traversal server in the outside address space. 7. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a standard H.323 gatekeeper in the outside address space for multimedia information transfer with the private client, wherein said registering includes receiving a standard H.323 Registration Request message (RRQ) including a standard H.323 data parameter at the traversal server from the private client, modifying a timeToLive parameter in the standard RRQ message such that a subsequent RRQ message will be received from the private client prior to an expiration of a NAT binding for the persistent registration connection, removing the data parameter from the standard RRQ message, forwarding a modified standard RRQ message not having the data parameter to the gatekeeper, receiving a standard H.323 Registration Confirm (RCF) message at the traversal server from the gatekeeper, adding the data parameter to the RCF message, and forwarding the RCF message including the data parameter to the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 8. The method of claim 7, further comprising: receiving a standard H.323 lightweight Registration Request message (Lightweight RRQ) at the traversal server from the private client using a same source address as a source address of the RRQ message received from the private client; forwarding the Lightweight RRQ from the traversal server to the gatekeeper; and forwarding a standard H.323 lightweight RCF message received at the traversal server from the gatekeeper to the private client. 9. The method of claim 7, wherein the receiving the probe packet further comprises: receiving the probe packet having a size less than 12 bytes. 10. The method of claim 7, wherein the establishing the persistent registration connection further comprises: establishing the persistent registration connection using standard User Datagram Protocol (UDP) messages between the private client and the traversal server in the outside address space. 11. The method of claim 7, wherein the standard H.323 data parameter includes a NonStandardData parameter. 12. The method of claim 7, further comprising: storing a relationship between the source address of the probe packet and the probe; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP based on the relationship between the source address of the probe packet and the probe. 13. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 signaling message including a standard H.245 address at the traversal server from the standard communication registration server, adding the probe definition to a H.323 standard data parameter in the standard H.225 signaling message, modifying the H.245 address in the standard H.225 signaling message to form a modified H.245 address, and forwarding the standard H.225 signaling message having the modified H.245 address and the probe definition to the private client, wherein an address in a transport-request construct of the data parameter is the same as the modified H.245 address; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 14. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a H.225 standard Setup message at the traversal server from the standard communication registration server; sending a standard Registration Admission Status (RAS) message to the private client from the traversal server via the persistent registration connection requesting that the private client establish a Transport Control Protocol (TCP) connection to the traversal server, the RAS message including a standard data parameter and a probe token, establishing the TCP connection to the traversal server, receiving the probe token at the traversal server from the private client via the TCP connection, and forwarding the H.225 standard Setup message from the traversal server to the private client after receiving the probe token; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 15. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a H.245 standard message at the traversal server from the standard communication registration server using a TCP connection, sending a H.225 standard Facility message from the traversal server to the private client including a standard data parameter and an address on the traversal server to which the private client is to be connected and a probe token, establishing a TCP connection at the address on the traversal server from the H.225 standard Facility message, receiving the probe token at the traversal server from the private client via the TCP connection, and forwarding the H.245 standard message from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 16. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.245 OpenLogicalChannel message from the private client at the traversal server, adding an address of the traversal server to the OpenLogicalChannel message, forwarding the OpenLogicalChannel message including the address of the traversal server to the gatekeeper, receiving a standard H.245 OpenLogicalChannelAck message from the gatekeeper at the traversal server, adding a nonStandardData parameter to the OpenLogicalChannelAck message, the data parameter including a probe token and a traversal server address, and forwarding the OpenLogicalChannelAck message including the added-data nonStandardData parameter from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 17. The method of claim 16, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding the nonStandardData parameter further comprises: recording the traversal server address; modifying an address, in a H2250LogicalChannel parameter of the OpenLogicalChannelAck message, such that the multimedia information will be sent to the traversal server address; and adding probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannelAck message. 18. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.245 OpenLogicalChannel message from the gatekeeper at the traversal server, adding a data parameter to the OpenLogicalChannel message, the data parameter including a probe token and a traversal server address, and forwarding the OpenLogicalChannel message including the data parameter to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 19. The method of claim 18, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding the data parameter further comprises: recording the traversal server address; modifying an address, in a H2250LogicalChannel parameter of the OpenLogicalChannel message, such that the multimedia information will be sent to the traversal server address; and adding probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannel message. 20. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 Setup message at the traversal server from the private client, the H.225 Setup message including at least one set of transmit and receive addresses, modifying each set of transmit and receive addresses to be traversal server addresses, forwarding the standard H.225 Setup message including modified addresses to the gatekeeper, receiving a standard H.225 Alerting/Connect message at the traversal server from the gatekeeper, the H.225 Alerting/Connect message including a media destination address, recording the media destination address at the traversal server, modifying the media destination address in the H.225 Alerting/Connect message to be a traversal server address after recording the media destination address, and forwarding the H.225 Alerting/Connect message including a modified media destination address from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 21. A method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, said method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 Setup message at the traversal server from the gatekeeper, the standard H.225 Setup message including at least one set of transmit and receive addresses, adding a data parameter to the standard H.225 Setup message, the data parameter including a copy of an Rx-Probe-Info construct for each unique pair of offered transmit and receive addresses in the standard H.225 Setup message, forwarding the H.225 Setup message including the data parameter from the traversal server to the private client, receiving a standard H.225 Alerting/Connect message at the traversal server from the private client, the standard H.225 Alerting/Connect message including an answer to the offered transmit and receive addresses, modifying a transmit and receive address in the answer of the standard H.225 Alerting/Connect message to be a traversal server address, and forwarding the standard H.225 Alerting/Connect message from the traversal server to the gatekeeper; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 22. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; generating, at the traversal server, a probe definition that uniquely identifies a connection establishment event; sending a standard message according to a Session Initiation Protocol (SIP) for real-time multimedia communication from the traversal server to the private client, the standard message including the probe definition, the sending including receiving a standard SIP INVITE message at the traversal server from the private client via the persistent registration connection, the standard SIP INVITE message including at least one of a contact header and a record route header having an address of the private client, modifying at least one of the contact header or the record route header to include an address of the traversal server, forwarding the standard SIP INVITE message from the traversal server to a SIP registrar/proxy including at least one of a modified contact header and a modified record route header, receiving a standard SIP OK message at the traversal server from the remote client via the SIP registrar/proxy, adding a standard SDP parameter to the standard SIP OK message at the traversal server, adding the probe definition to the standard SIP OK message at the traversal server, the probe definition having been determined by the traversal server, and forwarding the standard SIP OK message including a added SDP parameter and an added probe definition to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 23. The computer readable storage medium of claim 22, wherein the real-time communication standard includes Session Initiation Protocol (SIP), the multimedia information includes a standard real-time protocol (RTP) based media information and the receiving a standard SIP INVITE message further comprises: receiving a standard SIP INVITE message that includes at least one media parameter set describing the RTP based media information. 24. The computer readable storage medium of claim 22, wherein the receiving the probe packet further comprises: receiving the probe packet having a size less than 12 bytes. 25. The computer readable storage medium of claim 22, wherein the transferring the multimedia information further comprises: receiving a standard SIP BYE message at the traversal server terminating the transferring the multimedia information; and releasing a resource at the traversal server associated with the transferring the multimedia information. 26. The computer readable storage medium of claim 22, wherein the method further comprising: relaying SIP messages received at the private client from the traversal server to a further private client in the private address space; and relaying SIP messages received at the private client from the further private client to the traversal server. 27. The computer readable storage medium of claim 22, the establishing the persistent registration connection further comprises: establishing a standard Transport Layer Security (TLS) connection between the private client and the traversal server in the outside address space. 28. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a standard H.323 gatekeeper in the outside address space for multimedia information transfer with the private client, wherein said registering includes receiving a standard H.323 Registration Request message (RRQ) including a standard H.323 data parameter at the traversal server from the private client, modifying a timeToLive parameter in the standard RRQ message such that a subsequent RRQ message will be received from the private client prior to an expiration of a NAT binding for the persistent registration connection, removing the data parameter from the standard RRQ message, forwarding a modified standard RRQ message not having the data parameter to the gatekeeper, receiving a standard H.323 Registration Confirm (RCF) message at the traversal server from the gatekeeper, adding the data parameter to the RCF message, and forwarding the RCF message including the data parameter to the private client, sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 29. The computer readable storage medium of claim 28, further comprising: receiving a standard H.323 lightweight Registration Request message (Lightweight RRQ) at the traversal server from the private client using a same source address as a source address of the RRQ message received from the private client; forwarding the Lightweight RRQ from the traversal server to the gatekeeper; and forwarding a standard H.323 lightweight RCF message received at the traversal server from the gatekeeper to the private client. 30. The computer readable storage medium of claim 28, wherein the receiving the probe packet further comprises: receiving the probe packet having a size less than 12 bytes. 31. The computer readable storage medium of claim 28, wherein the establishing the persistent registration connection further comprises: establishing the persistent registration connection using standard User Datagram Protocol (UDP) messages between the private client and the traversal server in the outside address space. 32. The computer readable storage medium of claim 28, wherein the standard H.323 data parameter includes a NonStandardData parameter. 33. The computer readable storage medium of claim 28, further comprising: storing a relationship between the source address of the probe packet and the probe; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP based on the relationship between the source address of the probe packet and the probe. 34. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 signaling message including a standard H.245 address at the traversal server from the standard communication registration server, adding the probe definition to a H.323 standard data parameter in the standard H.225 signaling message, modifying the H.245 address in the standard H.225 signaling message to form a modified H.245 address, and forwarding the standard 1-1.225 signaling message having the modified 1-1.245 address and the probe definition to the private client, wherein an address in a transport-request construct of the data parameter is the same as the modified H.245 address; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 35. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a H.225 standard Setup message at the traversal server from the standard communication registration server, sending a standard Registration Admission Status (RAS) message to the private client from the traversal server via the persistent registration connection requesting that the private client establish a Transport Control Protocol (TCP) connection to the traversal server, the RAS message including a standard data parameter and a probe token, establishing the TCP connection to the traversal server, receiving the probe token at the traversal server from the private client via the TCP connection, and forwarding the H.225 standard Setup message from the traversal server to the private client after receiving the probe token; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 36. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a H.245 standard message at the traversal server from the standard communication registration server using a TCP connection, sending a H.225 standard Facility message from the traversal server to the private client including a standard data parameter and an address on the traversal server to which the private client is to be connected and a probe token, establishing a TCP connection at the address on the traversal server from the H.225 standard Facility message, receiving the probe token at the traversal server from the private client via the TCP connection, and forwarding the H.245 standard message from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 37. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.245 OpenLogicalChannel message from the private client at the traversal server, adding an address of the traversal server to the OpenLogicalChannel message; forwarding the OpenLogicalChannel message including the address of the traversal server to the standard message communication registration server, receiving a standard H.245 OpenLogicalChannelAck message from the standard message communication registration server at the traversal server, adding a nonStandardData parameter to the OpenLogicalChannelAck message, the data parameter including a probe token and a traversal server address, and forwarding the OpenLogicalChannelAck message including the nonStandardData parameter from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 38. The computer readable storage medium of claim 37, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding the nonStandardData parameter further comprises: recording the traversal server address; modifying an address, in a H2250LogicalChannel parameter of the OpenLogicalChannelAck message, such that the multimedia information will be sent to the traversal server address; and adding probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannelAck message. 39. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the steps comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.245 OpenLogicalChannel message from the gatekeeper at the traversal server, adding a data parameter to the OpenLogicalChannel message, the data parameter including a probe token and a traversal server address, and forwarding the OpenLogicalChannel message including the data parameter to the private client, receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 40. The computer readable storage medium of claim 39, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding the data parameter further comprises: recording the traversal server address; modifying an address, in a H2250LogicalChannel parameter of the OpenLogicalChannel message, such that the multimedia information will be sent to the traversal server address; and adding probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannel message. 41. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 Setup message at the traversal server from the private client, the H.225 Setup message including at least one set of transmit and receive addresses, modifying each set of transmit and receive addresses to be traversal server addresses, forwarding the standard H.225 Setup message including modified addresses to the standard communication registration server, receiving a standard H.225 Alerting/Connect message at the traversal server from the standard communication registration server, the H.225 Alerting/Connect message including a media destination address, recording the media destination address at the traversal server, modifying the media destination address in the H.225 Alerting/Connect message to be a traversal server address after recording the media destination address, and forwarding the H.225 Alerting/Connect message including a modified media destination address from the traversal server to the private client; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 42. A computer readable storage medium storing computer program instructions which when executed by a computer cause the computer to implement a method for transferring multimedia information over Internet protocol (IP) between a private client in a private address space created by a Network Address Translation (NAT)/firewall device and a remote client in an outside address space separate from the private address space, the method comprising: establishing a persistent registration connection between the private client and a traversal server in the outside address space, the persistent registration connection passing through the NAT/firewall device; registering with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; sending a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, said sending includes receiving a standard H.225 Setup message at the traversal server from the standard communication registration server, the standard H.225 Setup message including at least one set of transmit and receive addresses, adding a data parameter to the standard H.225 Setup message, the data parameter including a copy of an Rx-Probe-Info construct for each unique pair of offered transmit and receive addresses in the standard H.225 Setup message, forwarding the H.225 Setup message including the data parameter from the traversal server to the private client, receiving a standard H.225 Alerting/Connect message at the traversal server from the private client, the standard H.225 Alerting/Connect message including an answer to the offered transmit and receive addresses, modifying a transmit and receive address in the answer of the standard H.225 Alerting/Connect message to be a traversal server address, and forwarding the standard H.225 Alerting/Connect message from the traversal server to the gatekeeper; receiving a probe packet including a probe based on the probe definition at the traversal server from the private client, a source address of the probe packet having been translated by the NAT/firewall device; and transferring the multimedia information between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 43. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a generating unit configured to generate a probe definition that uniquely identifies a connection establishment event; a standard message sending unit configured to send a standard message according to a communication standard for real-time multimedia communication to the private client, the standard message including the probe definition, the standard message sending unit including a receiving unit configured to receive a standard SIP INVITE message from the private client via the persistent registration connection, the standard SIP INVITE message including at least one of a contact header and a record route header having an address of the private client, a processor configured to modify at least one of the contact header or the record route header to include the traversal server address, a forwarding unit configured to forward the standard SIP INVITE message to a SIP registrar/proxy including at least one of a modified contact header or a modified record route header, the receiving unit further configured to receive a standard SIP OK message from the remote client via the SIP registrar/proxy, an adding unit configured to add a standard SDP parameter including the probe definition to the standard SIP OK message and to add the probe definition to the standard SIP OK message, the probe definition having been determined by the traversal server, and the forwarding unit further configured to forward the standard SIP OK message including an added SDP parameter and a added probe definition to the private client; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 44. The traversal server of claim 43, wherein the real-time communication standard includes Session Initiation Protocol (SIP), the multimedia information includes a standard real-time protocol (RTP) based media information and the receiving unit is further configured to receive a standard SIP INVITE message that includes at least one media parameter set describing the RTP based media information. 45. The traversal server of claim 43, wherein the probe packet receiving unit is further configured to receive the probe packet having a size less than 12 bytes. 46. The traversal server of claim 43, wherein the probe packet receiving unit is further configured to receive a standard SIP BYE message terminating a transfer of the multimedia information. 47. The traversal server of claim 43, wherein the client registration unit further comprises: a TLS unit configured to establish a standard Transport Layer Security (TLS) connection to the private client. 48. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server including a standard H.323 gatekeeper in the outside address space for multimedia information transfer with the private client, the server registration unit including a receiving unit configured to receive a standard H.323 Registration Request message (RRQ) including a standard H.323 data parameter from the private client, a processor configured to modify a timeToLive parameter in the standard RRQ message such that a subsequent RRQ message will be received from the private client prior to an expiration of a NAT binding for the persistent registration connection, a removing unit configured to remove the data parameter from the standard RRQ message, a forwarding unit configured to forward a modified standard RRQ message not having the data parameter to the gatekeeper, the receiving unit further configured to receive a standard H.323 Registration Confirm (RCF) message from the gatekeeper, an adding unit configured to add the data parameter to the RCF message, and the forwarding unit further configured to forward the RCF message including the data parameter to the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 49. The traversal server of claim 48, wherein the receiving unit is further configured to receive a standard H.323 lightweight Registration Request message (Lightweight RRQ) from the private client using a same source address as a source address of the RRQ message received from the private client, and the forwarding unit is further configured to forward the Lightweight RRQ to the gatekeeper and to forward a standard H.323 lightweight RCF message received from the gatekeeper to the private client. 50. The traversal server of claim 48, wherein the probe packet receiving unit is further configured to receive the probe packet having a size less than 12 bytes. 51. The traversal server of claim 48, wherein the client registration unit is further configured to establish the persistent registration connection using standard User Datagram Protocol (UDP) messages to the private client. 52. The traversal server of claim 48, wherein the standard H.323 data parameter includes a NonStandardData parameter. 53. The traversal server of claim 48, further comprising: a storing unit configured to store a relationship between the source address of the probe packet and the probe; and a transferring unit configured to transfer the multimedia information between the private client and the remote client through the NAT/firewall device over IP based on the relationship between the source address of the probe packet and the probe. 54. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a standard H.225 signaling message including a standard H.245 address from the standard communication registration server; an adding unit configured to add the probe definition to a H.323 standard data parameter in the standard H.225 signaling message, a processor configured to modify the H.245 address in the standard H.225 signaling message to form a modified H.245 address, and a forwarding unit configured to forward the standard H.225 signaling message having the modified H.245 address and the probe definition to the private client, wherein an address in a transport-request construct of the data parameter is the same as the modified H.245 address; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 55. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a H.225 standard Setup message from the standard communication registration server, a sending unit configured to send a standard Registration Admission Status (RAS) message to the private client via the persistent registration connection requesting that the private client establish a Transport Control Protocol (TCP) connection to the traversal server, the RAS message including a standard data parameter and a probe token, a TCP unit configure to establish the TCP connection to the private client, the receiving unit further configured to receive the probe token from the private client via the TCP connection, and a forwarding unit configured to forward the H.225 standard Setup message to the private client after receiving the probe token; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 56. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server that includes a gatekeeper in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a H.245 standard message from the gatekeeper using a TCP connection, a sending unit configured to send a H.225 standard Facility message to the private client including a standard data parameter and the traversal server address and a probe token, a TCP unit configured to establish a TCP connection at the traversal server address from the H.225 standard Facility message, the receiving unit further configured to receive the probe token from the private client via the TCP connection, and a forwarding unit configure to forward the H.245 standard message to the private client; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 57. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a standard H.245 OpenLogicalChannel message from the private client, an adding unit configured to add an the traversal server address to the OpenLogicalChannel message, a forwarding unit configured to forward the OpenLogicalChannel message including the traversal server address to the standard communication registration server, the receiving unit further configured to receive a standard H.245 OpenLogicalChannelAck message from the standard communication registration server, the adding unit further configured to add a nonStandardData parameter to the OpenLogicalChannelAck message, the data parameter including a probe token and the traversal server address, and the forwarding unit further configured to forward the OpenLogicalChannelAck message including the nonStandardData parameter from to the private client; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 58. The traversal server of claim 57, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding unit further comprises: a recording unit configured to record the traversal server address; a modifying unit configured to modify an address, in a H2250LogicalChannel parameter of the OpenLogicalChannelAck message, such that the multimedia information will be sent to the traversal server address; and a probe token adding unit configured to add probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannelAck message. 59. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a standard H.245 OpenLogicalChannel message from the standard communication registration server, an adding unit configured to add a data parameter to the OpenLogicalChannel message, the data parameter including a probe token and the traversal server address, and a forwarding unit configured to forward the OpenLogicalChannel message including the data parameter to the private client; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 60. The traversal server of claim 59, wherein the multimedia information includes a real-time protocol (RTP) based media information and the adding unit further comprises: a recording unit configured to record the traversal server address; a modifying unit configured to modify an address, in a H2250LogicalChannel parameter of the OpenLogicalChannel message, such that the multimedia information will be sent to the traversal server address; and a probe token adding unit configured to add probe token information to rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannel message. 61. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a standard H.225 Setup message from the private client, the H.225 Setup message including at least one set of transmit and receive addresses, a processor configured to modify each set of transmit and receive addresses to the traversal server addresses, a forwarding unit configured to forward the standard H.225 Setup message including modified addresses to the standard communication registration server, a receiving unit configured to receive a standard H.225 Alerting/Connect message from the standard communication registration server, the H.225 Alerting/Connect message including a media destination address, a recording unit configured to record the media destination address, the processor further configured to modify the media destination address in the H.225 Alerting/Connect message to be a traversal server address in the traversal server addresses after recording the media destination address, and the forwarding unit further configured to forward the H.225 Alerting/Connect message including a modified media destination address to the private client; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 62. A traversal server in an outside address space configured to transfer multimedia information over Internet protocol (IP) between a private client in a private address space separate from the outside address space and a remote client in the outside address space, the private address space being created by a Network Address Translation (NAT)/firewall device, the traversal server comprising: a client registration unit configured to establish a persistent registration connection with the private client, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server in the outside address space for multimedia information transfer with the private client; a standard message sending unit configured to send a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server to the private client, the standard message including a probe definition, the standard message sending unit including a receiving unit configured to receive a standard H.225 Setup message from the gatekeeper, the standard H.225 Setup message including at least one set of transmit and receive addresses, an adding unit configured to add a data parameter to the standard H.225 Setup message, the data parameter including a copy of an Rx-Probe-Info construct for each unique pair of offered transmit and receive addresses in the standard H.225 Setup message, a forwarding unit configured to forward the H.225 Setup message including the data parameter from to the private client, the receiving unit further configured to receive a standard H.225 Alerting/Connect message from the private client, the standard H.225 Alerting/Connect message including an answer to the offered transmit and receive addresses, a processor configured to modify a transmit and receive address in the answer of the standard H.225 Alerting/Connect message to be the traversal server address, and the forwarding unit further configured to forward the standard H.225 Alerting/Connect message to the standard communication registration server; and a probe packet receiving unit configured to receive a probe packet including a probe based on the probe definition from the private client, a source address of the probe packet having been translated by the NAT/firewall device, wherein the multimedia information is transferred between the private client and the remote client through the NAT/firewall device over IP using the source address of the probe packet. 63. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server that includes a standard H.323 gatekeeper in the outside address space for multimedia information transfer, the server registration unit including a sending unit configured to send a standard H.323 Registration Request message (RRQ) including a standard H.323 data parameter to the traversal server, and a receiving unit configured to receive a standard H.323 Registration Confirm (RCF) message from the gatekeeper via the traversal server, the RCF message including the standard H.323 data parameter; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 64. The private client of claim 63, the server registration unit further comprising: a sending unit configured to send a standard H.323 lightweight Registration Request message (Lightweight RRQ) to the traversal server using a same source address as a source address of the RRQ message sent to the traversal server. 65. The private client of claim 63, wherein the probe packet sending unit is further configured to send the probe packet having a size less than 12 bytes. 66. The private client of claim 63, wherein the persistent registration unit is further configured to establish the persistent registration connection using standard User Datagram Protocol (UDP) messages to the traversal server in the outside address space. 67. The private client of claim 63, wherein the standard H.323 data parameter includes a NonStandardData parameter. 68. The private client of claim 63, further comprising: a storing unit configured to store a relationship between the source address of the probe packet and the probe, wherein the multimedia transferring unit is further configured to transfer the multimedia information to the remote client through the NAT/firewall device over IP based on the relationship between the source address of the probe packet and the probe. 69. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a receiving unit configured to receive a standard H.225 signaling message including a standard H.245 address, and the probe definition in a H.323 standard data parameter, wherein an address in a transport-request construct of the data parameter is the same as the H.245 address; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 70. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit, including a processor, configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a receiving unit configured to receive a standard Registration Admission Status (RAS) message from the traversal server via the persistent registration connection requesting establishment of a Transport Control Protocol (TCP) connection to the traversal server, the RAS message including a standard data parameter and a probe token, a TCP connection unit configured to establish the TCP connection to the traversal server, a probe token sending unit configured to send the probe token to the traversal server via the TCP connection, and the receiving unit further configured to receive a H.225 standard Setup message from the traversal server after sending the probe token; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 71. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a receiving unit configured to receive a H.225 standard Facility message from the traversal server including a standard data parameter and an address on the traversal server to which the traversal server is to be connected and a probe token, a TCP connection unit configured to establish a TCP connection to the traversal server at the address on the traversal server from the H.225 standard Facility message, a sending unit configured to send the probe token to the traversal server via the TCP connection, and the receiving unit further configured to receive a H.245 standard message from the traversal server; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 72. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a sending unit configured to send a standard H.245 OpenLogicalChannel message to the traversal server, and a receiving unit configured to receive an OpenLogicalChannelAck message including a nonStandardData parameter including a probe token and a traversal server address from the traversal server; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 73. The private client of claim 72, wherein the multimedia information includes a real-time protocol (RTP) based media information and the standard message receiving unit further comprises a recording unit configured to record the traversal server address. 74. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a receiving unit configured to receive a standard H.245 OpenLogicalChannel message from the traversal server, the OpenLogicalChannel message including a data parameter having a probe token and a traversal server address; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 75. The private client of claim 74, wherein the multimedia information includes a real-time protocol (RTP) based media information and the receiving unit is further configured to record the traversal server address and receive probe token information in rtp and rtcp parameters of a Tx-Probe-Info construct in the OpenLogicalChannel message. 76. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a sending section configured to send a standard H.225 Setup message to the traversal server, the H.225 Setup message including at least one set of transmit and receive addresses, receiving a standard H.225 Alerting/Connect message from the traversal server, the H.225 Alerting/Connect message including a media destination address that is a traversal server address; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet. 77. A private client for multimedia transfer in a private address space created by a Network Address Translation (NAT)/firewall device, said private client comprising: a persistent registration unit configured to establish a persistent registration connection to a traversal server in an outside address space separate from the private address space, the persistent registration connection passing through the NAT/firewall device; a server registration unit, including a processor, configured to register with a standard communication registration server in the outside address space for multimedia information transfer; a standard message receiving unit configured to receive a standard message according to a H.323 International Telecommunications Union (ITU) real-time multimedia communication from the traversal server, the standard message including a probe definition, said standard message receiving unit including a receiving unit configured to receive a standard H.225 Setup message from the traversal server, the standard H.225 Setup message including at least one set of transmit and receive addresses and a data parameter, the data parameter including a copy of an Rx-Probe-Info construct for each unique pair of offered transmit and receive addresses in the standard H.225 Setup message, and a sending unit configured to send a standard H.225 Alerting/Connect message to the traversal server, the standard H.225 Alerting/Connect message including an answer to the offered transmit and receive addresses; a probe packet sending unit configured to send a probe packet including a probe based on the probe definition to the traversal server; and a multimedia transferring unit configured to transfer the multimedia information to a remote client in the outside address space through the NAT/firewall device over IP using a source address of the probe packet.