Apparatus and methods of assisting in NAT traversal

A method of maintaining a NAT bind for a real device in a private network, said real device having a private Internet Protocol address and port, said method comprising at predetermined time intervals:

• editing a data packet having an Internet Protocol header comprising source fields by altering its source fields to comprise the private Internet Protocol address and port of a real device;
• and
• sending the edited data packets from a private interface of an Internet Protocol faker through a NAT,
• wherein said time intervals are predetermined to be smaller than the timeout period set for the NAT.

A method of discovering a Cone NAT bind for a real device in a private network said real device having a private Internet Protocol address and port, said method comprising:

• editing a data packet having an Internet Protocol header comprising source fields by altering the source fields to comprise the private Internet Protocol address and port of the real device;
• sending the edited data packet from a private interface to a public interface of the Internet Protocol faker through a Cone NAT;
• receiving the edited data packet at the NAT from the Internet Protocol faker;
• reading the source fields of the edited data packet;
• opening a NAT bind for the private Internet Protocol address and port of the real device;
• forwarding the data packet to the public interface of the Internet Protocol faker;
• reading the source fields of the data packet received at the public interface of the Internet Protocol faker;
• and
• extracting a public Internet Protocol address and port assigned to the real device to determine the NAT bind.

A method of opening a NAT bind for a real device in a communications system comprising a signalling device and an Internet Protocol faker locatable in a signalling path of the signalling device and in parallel with a Cone NAT, said method comprising:

• receiving a communication initiation message from an external device;
• allocating the signalling device to handle the message;
• editing a data packet by altering its source fields to comprise a private Internet Protocol address and port of the signalling device;
• sending the edited data packet from a private to a public interface of the Internet Protocol faker, through the Cone NAT;
• analysing the source fields of the data packet received at the public interface of the Internet Protocol faker to determine a public Internet Protocol address of the Cone NAT bind;
• and
• sending a redirection message with the public Internet Protocol address of the NAT bind to the external device.

A communications system comprising:

• an Internet Protocol faker locatable on the boundary of a private and a public network and in parallel with a Cone NAT, said Internet Protocol faker having a private interface and a public interface, and operable to:
• edit a data packet by altering its source fields to comprise a private Internet Protocol address and port of a real device in a private network that said Internet Protocol faker is impersonating;
• and
• send the edited data packet from its private interface to its public interface through the Cone NAT.

An Internet Protocol faker having a private and a public interface, and operable to:

• receive a command to establish a NAT bind for a real device from a Network Element;
• edit a data packet by altering its source fields to comprise a private Internet Protocol address and port of the real device;
• send the edited data packet from its private interface to its public interface through a Cone NAT, said Cone NAT creating a NAT bind for the data packet;
• analyse the source fields of the data packet received at its public interface from the NAT to determine a public Internet Protocol address of the NAT bind;
• and
• send a reply to the Network Element with the public Internet Protocol Address of the NAT bind.

An Internet Protocol faker having a private and a public interface, and operable to:

• receive a communication initiation message from an external device;
• allocate a signalling device to handle the message;
• edit a data packet by altering its source fields to comprise a private Internet Protocol address and port of the signalling device;
• send the edited data packet from its private interface to its public interface through a Cone NAT, said NAT creating a Cone NAT bind for the data packet;
• analyse the source fields of the data packet received at its public interface from the Cone NAT to determine a public Internet Protocol address and port of the Cone NAT bind;
• and
• send a redirection message with the public Internet Protocol address of the Cone NAT bind to the external device.

A communications system comprising:

• a signalling device, and an Internet Protocol faker locatable in a signalling path of the signalling device and in parallel with a NAT, said NAT operable to create a NAT bind for a data packet, said Internet Protocol faker having a private and a public interface and operable to:
• receive a communication initiation message;
• allocate the signalling device to handle the message;
• edit a data packet by altering its source fields to comprise a private Internet Protocol address and port of the signalling device;
• send the edited data packet from its private interface to its public interface through the NAT;
• analyse the source fields of the data packet received at its public interface from the NAT to determine a public Internet Protocol address of the NAT bind;
• and
• send a redirection message with the public Internet Protocol address of the NAT bind.

A communications system comprising:

• an Internet Protocol faker locatable in a private network, said Internet Protocol faker having a private interface, and operable to:
• edit a data packet by altering its source fields to comprise the Internet Protocol address and port of a real device in a private network that said Internet Protocol faker is impersonating;
• and
• send the edited data packet from its private interface through a NAT.