Source: https://patents.google.com/patent/US6954518B1/en
Timestamp: 2020-07-07 20:00:11
Document Index: 303848744

Matched Legal Cases: ['arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20', 'arty 20']

US6954518B1 - Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion - Google Patents
Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion Download PDF
US6954518B1
US6954518B1 US10/819,119 US81911904A US6954518B1 US 6954518 B1 US6954518 B1 US 6954518B1 US 81911904 A US81911904 A US 81911904A US 6954518 B1 US6954518 B1 US 6954518B1
US10/819,119
David William Geen
Narasimha K. Nayak
2000-01-07 Priority to US09/479,235 priority Critical patent/US6735288B1/en
2004-04-07 Application filed by Cisco Technology Inc filed Critical Cisco Technology Inc
2004-04-07 Priority to US10/819,119 priority patent/US6954518B1/en
2004-04-07 Assigned to CISCO TECHNOLOGY, INC. reassignment CISCO TECHNOLOGY, INC. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: GEEN, DAVID WILLIAM, NAYAK, NARASIMHA K.
2005-10-11 Publication of US6954518B1 publication Critical patent/US6954518B1/en
An IP telephony gateway and a voice mail resource enable a voice mail subscriber to place an outgoing call to a destination party from a voice mail session according to the voice over IP (H.323) protocol, and resume the voice mail session upon completion of the outgoing call with the destination party. The IP telephony gateway establishes a voice mail session for the voice mail subscriber with the voice mail resource across a first Real Time Protocol (RTP) data stream. The voice mail resource initiates a second RTP data stream to a destination party in response to reception of a prescribed command from the voice mail subscriber. Although an RTP bridge connecting the first and second RTP data streams can be maintained by the voice mail resource, the voice mail resource may also use the Empty Capability Set feature in the H.323 standard to cause the IP telephony gateway to close the first and second RTP data streams to the voice mail resource. The voice mail resource then issues Non-Empty Capability Set messages to the IP telephony gateway for the first and second RTP data streams, causing the IP telephony gateway to internally bridge the first and second RTP data streams. The voice mail resource monitors connections between the voice mail subscriber and the destination party, and upon detecting a disconnect by the destination party causes the IP telephony gateway to resume the voice mail session, by repeating the sequence of sending Empty Capability Set and Non-Empty Capability Set messages to the IP telephony gateway to break down the bridge and re-establish the connection between the voice mail subscriber and the voice mail resource.
FIGS. 1 and 2 are diagrams illustrating voice over IP voice mail systems configured for redirecting RTP data streams according to first and second embodiments of the present invention, respectively. Each system 10 includes an IP telephony gateway 12 configured for establishing Real Time Protocol (RTP) data stream connections according to H.323 protocol. Each system 10 also includes a voice mail resource 14 configured for controlling the establishment of the RTP data streams 16 by exchanging control and signaling commands across the H.245 channel 18. In particular, the voice mail resource 14 is implemented as an H.323 compliant software resource configured for executing voice mail applications; the voice mail resource 14 controls the IP telephony gateway 12 via the H.245 channel 18 for call setup and tear down, and redirecting of voice media traffic along the RTP data streams 16. Note that the voice mail resource 14 is illustrated as having discrete resources A and B for the sake of describing the RTP data streams 16 a, 16 b, 16 c, and 16 d although actual implementation of the voice mail resource may use a single instance of an H.323 resource. An exemplary implementation of the voice mail resource 14 is the commercially available Cisco Unified Open Network Exchange (Cisco uOne) (Products UONE-FOUND 4.1 S, and UONE-VOICEMSG4.1 S) from Cisco Systems, Inc.
According to the disclosed embodiment, the voice mail resource 14 initiates bridging of the RTP audio streams of the two call legs 22 a and 22 b while maintaining control of both legs. Hence, a voice mail subscriber 20 a may suspend his or her session with the voice mail resource 14 and call the destination party 20 b to respond to a voice mail message left by the destination party 20, and then return to the voice mail resource 14 upon completion of the call with the destination party 20 b.
The voice mail resource 14, during a voice mail session with the voice mail subscriber 20 a via the RTP stream 16 a, initiates in step 42 a second RTP data stream 16 b to the destination party 20 b in response to a prescribed command from the voice mail subscriber, for example the voice mail subscriber 20 a responding to a menu prompt to reply to a voice message. As part of the call setup and establishment of the second RTP stream 16 b, the voice mail resource 14 communicates with the H.323 resource within the IP telephony gateway 12 and stores the H.245 protocol capabilities (e.g., what codec to use, port number for sending media streams, etc.) from the IP telephony gateway 12 for the outbound call 22 b in step 44. The IP telephony gateway 12 then establishes a connection via the call leg 22 b and the second RTP stream 16 b between the destination party 20 b and the voice mail resource 14, enabling the voice mail resource 14 to determine whether the first RTP stream 16 a and the second RTP stream 16 b should be bridged.
FIG. 1 illustrates one embodiment for redirecting RTP streams to perform outbound calls with return capability. Upon detecting across the H.245 channel that the IP telephony gateway 12 has established the call leg 22 b with the destination party 20 b, the voice mail resource 14 a initiates its own RTP bridge 16 c to connect the first RTP data stream 16 a and the second RTP data stream 16 b. At this point the voice mail subscriber 20 a may converse with the destination party 20 b. Once a disconnect condition is detected on the call leg 22 b, the voice mail resource 14 a terminates the bridge 16 c and continues the voice mail session with the subscriber 20 a.
One disadvantage of the arrangement in FIG. 1 is that the voice mail resource 14 a needs to set up the bridge 16 c, transfer the media streams of RTP streams 16 a and 16 b across the bridge 16 c, and tear down the bridge 16 c upon completion of the call between the voice mail subscriber 20 a and the destination party 20 b; hence, the processing burdens on the voice mail resource 14 a requires substantial central processing unit (CPU) resources, affecting the scalability of the system 10 a for a large number of voice mail subscribers.
According to the second embodiment described in detail below with respect to FIGS. 2 and 3B–3C, audio (RTP) transport responsibility is transferred from the voice mail resource 14 b to the IP telephony gateway 12, relieving the voice mail resource 14 b of RTP transport responsibilities while the calls are bridged. The voice mail resource 14 b, in response to reception of a prescribed command from the voice mail subscriber 20 a across a first RTP data stream (e.g., 16 a), initiates a second RTP data stream (e.g., 16 b) by the IP telephony gateway 12 in steps 42 and 44 for connection via the call leg 22 b to the destination party 20 b, similar to the arrangement of FIG. 1.
Upon determining in step 46 a prescribed condition at the destination party 20 b, for example detecting an off hook condition or in response to a prompt whether to connect the destination party 20 b to the voice mail subscriber 20 a, the voice mail resource 14 b initiates closing of the first RTP data stream 16 a and the second RTP data stream 16 b to the voice mail resource 14 b in step 48, and initiates in step 52 the connection of the data streams 16 a and 16 b to form the RTP bridge 16 d. Specifically, the voice mail resource 14 b in step 48 sends Empty Capability Set Messages for the RTP data stream 16 a and the RTP data stream 16 b via the H.245 channel 18 to the IP telephony gateway 12. According to H.323 protocol, if the IP telephony gateway 12 receives an Empty Capability Set Message (i.e., a capabilities message that does not specify capability information), the IP telephony gateway 12 is to reset and enter a Pause state. Hence, in response to receiving the Empty Capability Set Messages for the RTP streams 16 a and 16 b, the IP telephony gateway 12 in step 50 closes the RTP channels 16 a and 16 b to the voice mail resource 14 and enters a pause state, releasing the voice mail resource 14 b from the media streams 16 between the voice mail subscriber 20 a and the destination party 20 b.
After dropping the RTP connections 16 a and 16 b between the IP telephony gateway 12 and the voice mail resource 14 b, the voice mail resource 14 b initiates in step 52 the formation of the RTP bridge 16 to connect the RTP data stream 16 a and the RTP data stream 16 b internally within the IP telephony gateway 12. Specifically, the voice mail resource 14 b sends Non-Empty Capability Set Messages over the H.245 channels 18 for both the inbound call leg 22 a and the outbound call leg 22 b to the IP telephony gateway 12. The IP telephony gateway 12 in response connects the RTP media streams 16 a and 16 b according to H.323 protocol, effectively forming the RTP bridge 16 d, by resetting its H.245 state to an initialized state in step 54, performing Master Slave Determination in step 56, and Terminal Capabilities exchange in step 58; the IP telephony gateway 12 sends an Open Logical Channel (OLC) request in step 60, and the voice mail resource 14 b responds in step 62 with an acknowledgment that includes media stream addresses specifying the RTP port numbers for the RTP streams 16 a and 16 b. The IP telephony gateway 12 thus connects (i.e., “hairpins”) the media streams 16 a and 16 b in step 64, effectively forming the bridge 16 d.
Hence, the voice mail resource 14 b redirects RTP streams through the IP telephony gateway 12 by sending Empty Capability Set messages to the H.323 resource module within the IP telephony gateway 12, causing the IP telephony gateway 12 to drop existing RTP streams between the IP telephony gateway 12 and the voice mail resource 14 b; the voice mail resource 14 b can then redirect the RTP data streams by sending Non-Empty Capability Set messages for both the inbound and outbound call legs 22 a and 22 b, enabling the IP telephony gateway 12 to use its resources in managing the call flow between the voice mail subscriber 20 a and the destination party 20 b.
The voice mail resource 14 b monitors the progress of the bridged call using the H.225/H.245 channel(s) 18. Upon detecting that the outbound call 22 b is dropped by the called party 20 b in step 66, the voice mail resource 14 b reissues an Empty Capability Set Message for the inbound call leg 22 a in step 68, causing the IP telephony gateway 12 to break down the RTP bridge 16 d and enter a pause state. The voice mail resource 14 b sends an acknowledgment on the outbound call leg 22 b in step 70 to clear the call, and repeats the process for setting up the RTP stream 16 a between the subscriber 20 a and the voice mail resource 14 b in step 72 by sending a Non-Empty Capability Set message for the inbound call leg 22 a.
According to the disclosed embodiment, a voice over IP voice mail system enables a voice mail subscriber to place an outbound call from a voice mail system, and then return to the voice mailbox after call completion. Use of the Empty Capability Set feature in the H.323 standard enables the redirect feature to be implemented in voice over IP systems with minimal effort. In addition, use of the voice over IP gateway to redirect the call and maintain the connections minimizes the resource requirements for the voice mail system, providing scalability as the number of users are increased.
US10/819,119 2000-01-07 2004-04-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion Expired - Lifetime US6954518B1 (en)
US09/479,235 US6735288B1 (en) 2000-01-07 2000-01-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion
US10/819,119 US6954518B1 (en) 2000-01-07 2004-04-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion
US09/479,235 Continuation US6735288B1 (en) 2000-01-07 2000-01-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion
US6954518B1 true US6954518B1 (en) 2005-10-11
ID=32230511
US09/479,235 Expired - Lifetime US6735288B1 (en) 2000-01-07 2000-01-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion
US09/606,692 Active 2021-10-19 US6930999B1 (en) 2000-01-07 2000-06-30 Scalable voice over IP system providing independent call bridging for outbound calls initiated by user interface applications
US10/819,119 Expired - Lifetime US6954518B1 (en) 2000-01-07 2004-04-07 Voice over IP voice mail system configured for placing an outgoing call and returning subscriber to mailbox after call completion
US11/155,498 Active 2023-10-04 US7729345B2 (en) 2000-01-07 2005-06-20 Scalable voice over IP system providing independent call bridging for outbound calls initiated by user interface applications
US (4) US6735288B1 (en)
US20080260116A1 (en) * 2007-04-20 2008-10-23 Microsoft Corporation Fully redundant call recording
AU3605000A (en) * 1999-02-26 2000-09-14 Bellsouth Intellectual Property Corporation Methods and systems for enabling a reply call to a voice mail message
DE10241179A1 (en) * 2002-09-05 2004-03-18 Siemens Ag Method for establishing a user data connection between end points in a VoIP arrangement
US8806020B1 (en) 2004-12-20 2014-08-12 Avaya Inc. Peer-to-peer communication session monitoring
US6269100B1 (en) * 1998-09-11 2001-07-31 Nortel Networks Limited Channel transfer with retrieve
2000-01-07 US US09/479,235 patent/US6735288B1/en not_active Expired - Lifetime
2000-06-30 US US09/606,692 patent/US6930999B1/en active Active
2004-04-07 US US10/819,119 patent/US6954518B1/en not_active Expired - Lifetime
2005-06-20 US US11/155,498 patent/US7729345B2/en active Active
ITU-T Recommendation H.323, "Packet-based multimedia communications systems", Series H: Audiovisual and Multimedia Systems, International Telecommunication Union, Sep. 1999.
Kotha, "Deploying H.323 Applications in Cisco Networks", Cisco Systems, Inc. White Paper (1998).
Purvis et al., "RE: Third party-initiated pause and re-routing", H.323 Implementors Archive for 1999.
Thom, "The Multimedia Communications Standard for local Area Networks", H.323 Summary (Aug. 29, 1997).
US8150007B2 (en) 2007-04-20 2012-04-03 Microsoft Corporation Fully redundant call recording
US7729345B2 (en) 2010-06-01
US6930999B1 (en) 2005-08-16
US6735288B1 (en) 2004-05-11
US20050232250A1 (en) 2005-10-20
US9661034B2 (en) 2017-05-23 Apparatus and method for computer controlled call processing applications for skills-based routing in packet switched telephone networks
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:GEEN, DAVID WILLIAM;NAYAK, NARASIMHA K.;REEL/FRAME:015193/0447