Method and apparatus for interleaving text and media in a real-time transport session

• US 7,656,861 B2
• Filed: 11/03/2004
• Issued: 02/02/2010
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Wildfeuer, Herbert Michael, Garakani, Mehryar Khalili, Kumar, Rajesh, Jones, Paul Edwin
• Primary Examiner(s): Pérez-Gutiérrez; Rafael
• Assistant Examiner(s): VIANA DI PRISCO, GERMAN
• Application Number:
  US10/982,620
• Publication Number:
  US 20060007916A1
• Time in Patent Office: 1,917 Days
• Field of Search: 370/389
• 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
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/34 ensuring sequence integrity, e.g. using sequence numbers
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1083 In-session procedures
• CPC Class Codes: H04L 65/1101 Session protocols

Abstract

Text is interleaved and transported along with media data over the same real-time Internet Protocol (IP) media transport session. A network processing device identifies text characters corresponding with text signaling. The identified text characters are formatted into text packets and sent over the same real-time IP media transport session used for real-time media transport. The media transport session can identify the sequence that the text characters are transmitted and can specify a maximum character transfer rate.

Claims

1. A method for transporting text in a real-time Internet Protocol (IP) media transport session, comprising:

receiving text signaling from a network or from a text generation device;

converting the text signaling into text characters;

formatting the identified text characters into Real Time Protocol (RTP) text packets that are associated with the real-time IP media transport session;

generating RTP media packets that are also associated with the same real-time IP media transport session;

receiving analog tones representing text characters;

extracting a digital meaning from the analog tones;

discarding other analog volume and duration signaling characteristics from the analog tones;

converting the digital meaning of the analog tones into a corresponding real text character;

formatting the real text character into a packet payload in one of the RTP text packets without sending the discarded volume and duration signaling characteristics from the analog tones

interleaving the RTP text packets with the RTP media packets;

assigning sequentially increasing packet numbers to each of the individual interleaved RTP text packets and RTP media packets that correspond to a sequential combined order that each of the interleaved RTP text packets and RTP media packets are sent on a packet switched network and that all correspond with the single same real-time IP media transport session;

sending the interleaved text packets and media packets over the packet switched network using the same single real-time IP media transport session.

2. The method according to claim 1 wherein:

the RTP text packets and the RTP media packets both include a payload identifier field, a timestamp field, a sequence number field, and a packet payload;

the same continuous sequential series of sequence numbers are used in the sequence number field according to an associated sequence of the interleaved RTP text packets and the interleaved RTP media packets;

the RTP text packets are distinguished from the RTP media packets by different values in the payload identifier field; and

an additional text counter field is used only in the RTP text packets to track a text character sequence contained in the RTP text packets.

3. The method according to claim 1 including adding a second text sequencing only to the RTP text packets that sequentially numbers the RTP text packets in an order transmitted in the IP media transport session independently of the sequential packet numbers used for the interleaved RTP media and RTP text packets.

4. The method according to claim 1 including specifying, in a media-signaling session prior to sending the RTP text packets, a character rate that controls a maximum rate that text characters can be transmitted in RTP text packets during the real-time IP media transport session as a preventative against dropping of text packets.

5. The method according to claim 1 including carrying the interleaved RTP media packets and RTP text packets over a same Real-time Transport Protocol (RTP) or Secure RTP (SRTP) real-time IP media transport session.

6. The method according to claim 5 including identifying the RTP text packets by using a RTP or SRTP payload type identifier in an RTP or SRTP packet header.

7. The method according to claim 5 including using a text counter field in an RTP or SRTP packet to identify a RTP text packet sequence during an RTP or SRTP session.

8. The method according to claim 1 including:

receiving the text signaling over a Public Switched Telephone Network (PSTN);

converting the text signaling into Internet Protocol (IP) text packets;

receiving media signaling over the PSTN network;

converting the media signaling into IP media packets; and

transporting the IP text packets and the IP media packets over the same real-time IP media transport session.

9. A network processing device, comprising:

a processor configured to;

convert media signaling into Internet Protocol (IP) media packets;

receive text signaling comprising different analog audio tones representing different alpha-numeric characters;

identify the alpha-numeric characters represented by the analog audio tones and generate digital values that represent the same identified alpha-numeric characters;

formatting the digital values into IP text packets absent analog signaling characteristics describing the audio tones; and

sending the IP media packets and the IP text packets in interleaved manner over an IP network using the same real-time IP transport session.

10. The network processing device according to claim 9 wherein the processor terminates the text signaling and generates digital values representing text characters identified in the text signaling.

11. The network processing device according to claim 9 including a Public Switched Telephone Network (PSTN) interface for receiving and transmitting the text and media signaling and an IP interface for sending and receiving the IP text and IP media packets.

12. The network processing device according to claim 9 wherein the processor transports the text packets such that the text packets share the same sequencing series as the media packets.

13. The network processing device according to claim 9 wherein the processor specifics a first sequentially increasing packet number sequencing for the combination of IP media and IP text packets in the real-time IP transport session and specifies a second different sequentially increasing packet number sequencing just for the IP text packets.

14. The network processing device according to claim 9 wherein the processor specifies, in a media-signaling session prior to sending the text packets, a character rate that controls a maximum transfer rate for transferring characters in the IP text packets during the real-time IP media transport session as a preventative against dropping of text packets.

15. The network processing device according to claim 9 wherein the real-time IP transport session uses a Real-time Transport Protocol (RTP) or a Secure RTP (SRTP).

16. The network processing device according to claim 9 wherein the network processing device is a Public Switched Telephone Network (PSTN) to Internet Protocol (IP) network gateway.

17. The network processing device according to claim 9 wherein the network processing device is a IP device that communicates directly over an IP network without going through a gateway.

18. The network processing device according to claim 9 wherein the network processing device communicates over an IP network through a gateway.

19. The network processing device according to claim 9 wherein the text signaling is received over a PSTN network from a TTY/TTD text terminal.

20. A computer readable medium having a program for transporting text in a real-time Internet Protocol (IP) media transport session, the program when executed comprising:

receiving text signaling from a network or from a text generation device, the text signaling comprising tones representing text characters;

identifying the text characters represented by the tones;

formatting digital values representing the identified text characters into text packets while discarding other analog signaling characteristics from the tones; and

sending the text packets over the same real-time IP media transport session used for transporting media packets without sending the discarded analog signaling characteristics from the analog tones.

21. The computer readable medium according to claim 20 wherein the program when executed includes transporting the text packets such that the text packets share the same incrementing sequencing series with the media packets.

22. The computer readable medium according to claim 20 wherein the program when executed includes adding a different incrementing text sequencing to the text packets that identify a sequence that the text characters are transmitted in the IP media transport session.

23. The computer readable medium according to claim 20 wherein the program when executed includes specifying, in a media-signaling session prior to sending the text packets, a character rate that controls a maximum rate that text characters can be transmitted in text packets during the real-time IP media transport session as a preventative against dropping of text packets.

24. The computer readable medium according to claim 20 wherein the program when executed includes using Real-time Transport Protocol (RTP) or Secure RTP (SRTP) for the real-time IP media transport session.

25. The computer readable medium according to claim 24 wherein the program when executed includes identifying the text packets by using a RTP or SRTP payload type identifier in an RTP or SRTP packet header.

26. The computer readable medium according to claim 24 wherein the program when executed includes using a text counter field in an RTP or SRTP packet to identify a text packet sequence during an RTP or SRTP session.

27. The computer readable medium according to claim 20 wherein the program when executed includes:

receiving the text signaling over a Public Switched Telephone Network (PSTN);

converting the text signaling into Internet Protocol (IP) text packets;

receiving media signaling over the PSTN network;

converting the media signaling into IP media packets; and

transporting the IP text packets and the IP media packets over the same real-time IP media transport session.

28. The computer readable medium according to claim 20 wherein the program when executed includes processing TTY/TTD text signaling.

29. A system for transporting text in a real-time Internet Protocol (IP) media transport session, comprising:

means for receiving text signaling from a network or from a text generation device;

means for identifying text characters represented by the text signaling;

means for formatting the identified text characters into text packets; and

means for sending the text packets over the same real-time IP media transport session used for transporting media packets, wherein the text packets and media packets are assigned shared sequentially increasing packet numbers in a sequential incrementally increasing order that the combination of the test packets and media packets are each sent in the media transport session, wherein;

the text signaling includes analog tones representing the text characters;

said means for identifying extracts a digital meaning from the analog tones and discards other analog signaling characteristics from the analog tones;

said means for formatting converts the identified digital meaning of the analog tones into corresponding digital values that represent the text characters and formats the digital values into a packet payload in one of the text packets; and

said means for sending sends the text packets without including the other discarded analog signaling characteristics from the analog tones.

30. The system according to claim 29 including means for adding text sequencing to the text packets that identify a sequence that the text characters are transmitted in the IP media transport session.

31. The system according to claim 29 including means for specifying, in a media-signaling session prior to sending the text packets, a character rate that controls a maximum rate that text characters can be transmitted in text packets during the real-time IP media transport session as a preventative against dropping of text packets.

32. The system according to claim 29 including means for using Real-time Transport Protocol (RTP) or Secure RTP (SRTP) for the real-time IP media transport session.

33. The system according to claim 32 including means for identifying the text packets by using a RTP or SRTP payload type identifier in an RTP or SRTP packet header.

34. The system according to claim 32 including means for using a text counter field in an RTP or SRTP packet to identify a text packet sequence during an RTP or SRTP session.

35. The system according to claim 29 including:

means for receiving the text signaling over a Public Switched Telephone Network (PSTN);

means for converting the text signaling into Internet Protocol (IP) text packets;

means for receiving media signaling over the PSTN network;

means for converting the media signaling into IP media packets; and

means for transporting the IP text packets and the IP media packets over the same real-time IP media transport session.

36. The system according to claim 29 wherein the text signaling is TTY/TTD signaling.