Network address translation for voice over internet protocol router

• US 7,346,044 B1
• Filed: 10/14/2002
• Issued: 03/18/2008
• Est. Priority Date: 10/12/2001
• Status: Expired due to Fees

• Current Assignee: SEVAK Ltd.
• Original Assignee: MediaRing Ltd. (Digilife Technologies Ltd.)
• Inventors: Noor, Halim Md, Chou, Chih-Hsiang, Lai, Poh Yoke, Reddy, Janardhana, Ow, Sin Ming, Tam, Wee Sin
• Primary Examiner(s): Ni; Suhan
• Application Number:
  US10/271,183
• Time in Patent Office: 1,982 Days
• Field of Search: 370352-356, 370/401, 370462-466
• US Class Current: 370/352
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

A network address translation apparatus and method within a Voice over Internet Protocol (VoIP) router is described. This apparatus and method operates within networking devices such as routers, switches, bridges, etc. These devices masks both source and destination addresses and may either replace or complement a firewall in providing security. According to one embodiment, network type information, corresponding to the gateways within connection, is embedded in a port number within a packet header. This network type information is extracted and analyzed to identify the network types of both gateways within the connection. According to another embodiment, a port number is assigned according to the network types of both gateways within a connection. Thus, this network type information may be identified by processing the port number on which a packet is received.

Claims

1. A network address translator for interfacing a first network and a second network, the network address translator comprising:

a voice connector configured to identify network type information corresponding to the first network and the second network and comprising a port initialization module configured to;

receive a call setup message from the first network;

provide routing information for the second network; and

assign a port for communications with at least one of the first network and the second network and wherein the port is assigned within a predetermined range corresponding to the network type information; and

a voice switch coupled to the voice connector configured to translate a packet using the network type information.

2. The network address translator of claim 1 wherein the routing information includes at least one of a network address and a port number.

3. The network address translator of claim 1 wherein the port initialization module is further configured to assign a port tuple for communications between the first network and the second network.

4. The network address translator of claim 1 wherein the voice connector further comprises:

a network pair table configured to store port configuration corresponding to the network type information.

5. The network address translator of claim 1 wherein the voice connector further comprises:

a network type table configured to associate a network type with a gateway operating on at least one of the first and the second networks.

6. The network address translator of claim 1 wherein the voice switch further comprises:

a packet translation module configured to adjust the packet for transmission from the first network to the second network; and

a network type identification module coupled to the packet translation module configured to identify the network type information.

7. The network address translator of claim 6 wherein the packet translation module translates Real Time Protocol (‘

RTP’

) packets traveling between the first network and the second network.

8. The network address translator of claim 6 wherein the network type identification module is further configured to identify network type information based on a port number.

9. The network address translator of claim 6 wherein network type information for the first network is extracted from a first field in the port number and network type information for the second network is extracted from a second field in the port number.

10. The network address translator of claim 1 wherein the voice switch masks the address of a first gateway on the first network from a second gateway on the second network.

11. The network address translator of claim 1 wherein the voice switch masks the address of a second gateway on the second network from a first gateway on the first network.

12. A network address translation method for connections between a first network and a second network, the method comprising:

receiving a packet from the first network;

identifying a network type corresponding to the first network;

determining a second network to which the packet should be forwarded;

identifying a network type corresponding to the second network;

translating the packet so that it may be transmitted to the second network;

receiving a call setup message from the first network and to provide routing information for the second network; and

assigning, within a predetermined range corresponding to the network type information, a port for communications with at least one of the first network and the second network.

13. The network address translation method of claim 12 further comprising:

assigning a port tuple for communications between the first network and the second network, wherein the port tuple includes a RTP stream and a RTCP stream.

14. The network address translation method of claim 12 wherein the translating further comprises:

adjusting a RTP packet traveling between the first and second networks.

15. The network address translation method of claim 12 further comprising:

masking the address of a first gateway on the first network from a second gateway on the second network.

16. The network address translation method of claim 12 wherein the network type of one of the first and second networks is identified based on a port number.

17. The network address translator method of claim 12 wherein network type information for the first network is extracted from a first field in the port number and network type information for the second network is extracted from a second.