Methods and apparatus for providing improved quality of packet transmission in applications such as internet telephony

• US 6,075,796 A
• Filed: 03/17/1997
• Issued: 06/13/2000
• Est. Priority Date: 03/17/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T, Inc.
• Inventors: Robinson, Bethany Scott, Katseff, Howard Paul
• Primary Examiner(s): MARCELO, MELVIN C
• Application Number:
  US08/819,617
• Time in Patent Office: 1,184 Days
• Field of Search: 370/466, 370/467, 370/471, 370/473, 370/474
• US Class Current: 370/466
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6427 Subscriber Access Module; Concentrator; Group equipment
• CPC Class Codes: H04L 2012/6472 Internet
• CPC Class Codes: H04L 2012/6475 N-ISDN, Public Switched Telephone Network [PSTN]
• CPC Class Codes: H04L 69/08 Protocols for interworking; Protocol conversion
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/164 Adaptation or special uses of UDP protocol
• CPC Class Codes: H04L 69/165 Combined use of TCP and UDP protocols; selection criteria therefor
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A digital data packet transmission process and system provides more efficient and higher quality of service in applications such as Internet telephony. In one aspect of this approach, transmission control protocol ("TCP") is used to send data from a first user or client over standard telephone lines to a local Internet service provider ("ISP"). At the ISP, the data packets are converted from TCP to user datagram protocol ("UDP"). The UDP packets are then transmitted, typically over a higher bandwidth link to another local ISP serving the recipient. The UDP packets are translated back to TCP packets and routed to the receiver. Because many existing systems currently employ UDP packets, the present approach is largely backwards compatible should a recipient be hooked up to an ISP that does not employ a TCP/UDP converter. A bidirectional TCP/UDP converter is preferable for two way communication such as Internet telephony.

Claims

1. A method for providing a voice connection utilizing digital data transmission in a packet-switched digital network, comprising the steps of:

establishing a data link between a server and a client;

establishing an Internet telephony connection utilizing said data link between said server and said client,

transmitting from said client to said server digital transmission control protocol (TCP) packets addressed to an addressee, said TCP packets being comprised of digitized Internet telephony voice data;

converting each TCP packet received from said client to user datagram protocol (UDP) format; and

routing each UDP-converted packet to the addressee.

2. The method of claim 1 wherein the step of establishing a data link between a server and a client further comprises the steps of:

establishing a data link between said client and a first modem;

establishing a data link between said server which is part of a local Internet service provider (ISP) and a second modem; and

establishing a dial-up data link between said first modem and said second modem utilizing standard telephone lines.

3. The method of claim 2 further comprising the step of:

utilizing the error correcting characteristics of said first modem and said second modem to minimize the latency of the TCP data link connection between said first and second modems.

4. The method of claim 1 further comprising the step of:

looking up the addressee'"'"'s address information in a calling destination database.

5. The method of claim 1 wherein the step of routing each UDP-converted packet to the addressee further comprises the step of routing each UDP-converted packet to a local Internet service provider (ISP), to which said addressee is connected.

6. The method of claim 5 wherein the step of routing each UDP-converted packet to a local ISP, to which said addressee is connected further comprises the step of establishing a connection over a high bandwidth data link connection.

7. The method of claim 5 further comprising the step of routing each UDP-converted packet from the local ISP, to which said addressee is connected to the addressee utilizing a modem and standard telephone lines.

8. The method of claim 1 wherein the step of routing each UDP-converted packet to the addressee further comprises the step of routing each UDP-converted packet through an Internet network to a local Internet service provider (ISP), to which said addressee is connected.

9. The method of claim 8 further comprising the step of receiving each UDP-converted packet at the addressee.

10. The method of claim 1 further comprising the step of establishing a calling destination database, said calling destination database comprising a lookup table of clients and Internet telephony addressees.

11. A packet converter for use in a packet-switched communication system, comprising:

a server for communicating with a plurality of clients and receiving transmission control protocol (TCP) packets from said clients;

a converter for converting said plurality of packets to user datagram protocol (UDP) packets;

a database for holding a lookup table associating the plurality of clients with addresses for the plurality of clients; and

a router for routing each of said packets to its addressee.

12. The packet converter of claim 11 wherein said server is further operable to receive from each of a plurality of remote servers a plurality of digital packets, each of said packets being formatted as a UDP packet, and the packet converter further comprises:

a converter for converting each of said received UDP packet to TCP format; and

a router for routing each of said converted packets to its addressee.

13. A packet-switched communication system comprising:

a first local server for communicating with a plurality of clients and receiving transmission control protocol (TCP) packets from said clients on an input;

a first converter for converting said TCP packets to user datagram protocol (UDP) packets;

a router to direct the converted UDP packets to a second local server for communicating with an addressee; and

a second converter for reconverting the converted UDP packets received by the second local server back to TCP packets.

14. The system of claim 13 further comprising a first client including a modem connected to a standard telephone line, said first client transmitting TCP packets representing digital data sampled from a voice of an Internet telephony user.

15. The system of claim 13 further comprising a memory for storing a calling destination database.

16. The system of claim 13 further comprising an active user registry server.

17. The system of claim 13 wherein the first converter further comprises an incoming network manager.

18. The system of claim 13 wherein the first and second local servers are part of local Internet telephony providers which are connected by a high bandwidth connection.

19. The system of claim 13 further comprising an addressee client which includes a modem for connecting the addressee client to the second local converter by way of a standard telephone line.

20. The system of claim 13 wherein the input of the first local server is connected to a standard telephony line.

21. The system of claim 13 wherein the second converter further comprises an incoming network manager.

22. A method for providing an Internet telephony connection utilizing a packet-switched digital network, comprising the steps of:

establishing a first data link between a first personal computer and a first ISP, said first data link comprising a dial-up modem connection between the first personal computer and the first ISP;

establishing a second data link between a second personal computer and a second ISP, said second data link comprising a dial-up modem connection between the second personal computer and the second ISP;

transmitting TCP packets of digitized voice data between the first personal computer and the first ISP;

converting said TCP packets to UDP packets at said first ISP;

looking up addressee routing information in a first calling destination database;

routing said UDP packets to a second ISP as specified in said first calling destination database;

converting said UDP packets to reconverted TCP packets at said second ISP; and

transmitting said reconverted TCP packets of digitized voice data between the second ISP and the second personal computer.

23. The method of claim 22, further comprising the steps of:

transmitting TCP packets of digitized voice data between the second personal computer and the second ISP;

converting said TCP packets to UDP packets at said second ISP;

looking up addressee routing information in a second calling destination database;

routing said UDP packets to the first ISP as specified in said second calling destination database;

converting said UDP packets to reconverted TCP packets at said first ISP; and

transmitting said reconverted TCP packets of digitized voice data between the first ISP and the first personal computer.

24. A two-way packet protocol converter for use in a packet switched communication system, comprising:

a first incoming network manager for communicating with a plurality of clients utilizing TCP packets;

a TCP to UDP packet converter;

a first outgoing network manager for communicating with a plurality of servers, said first outgoing network manager further comprising a calling destination database;

a second incoming network manager for communicating with a plurality of servers utilizing UDP packets;

a UDP to TCP packet converter; and

a second outgoing network manager for communicating with a plurality of clients, said second outgoing network manager further comprising a calling destination database.

25. The two-way packet protocol converter of claim 24, the first incoming network manager further comprising a bank of modems and the second outgoing network manager further comprising a bank of modems.