# US 7,613,170 B1 · Method and apparatus for PSTN-based IP active call recovery and re-routing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,613,170 B1 - Document ID: US7613170B1 - Status: Granted - Kind: B1 - Application number: 10/880,686 - Filed: 2004-06-29 - Granted: 2009-11-03 - Earliest claimed: 2004-06-29 - Assignees: 3Com Corporation - Inventors: David A. Grabelsky; Michael Homeier - Web page: https://patentgrep.com/patent/US7613170B1 ## CPC - H04L 65/80: Responding to QoS - H04L 12/5692: {Selection among different networks} - H04L 47/70: Admission control; Resource allocation - H04L 65/1053: IP private branch exchange [PBX] functionality entities or arrangements (circuit switched PBXs H04M3/00) - H04L 65/1083: In-session procedures - H04M 7/0057: {Services where the data services network provides a telephone service in addition or as an alternative, e.g. for backup purposes, to the telephone service provided by the telephone services network} - H04M 7/121: {Details of network access arrangements or protocols} - H04M 7/1225: {Details of core network interconnection arrangements} - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) ## Abstract A method and system for rerouting IP telephony call information. The system includes an existing IP telephony call, the telephony call originating at a first IP telephony phone. A second IP telephony phone receiving the IP telephony call from the first IP phone and a network routing condition, the routing condition causing the IP telephony call to be rerouted. A switchover instruction, the switchover instruction initiating a switchover of the existing IP telephony call to a PSTN. ## Claims ### Claim 1 A method of re-routing an existing IP telephony session, said method comprising the steps of: originating an IP telephony session between a first IP client and a second IP client; monitoring a network condition of said IP telephony session; interrupting said IP telephony session based in part on said monitoring of said network condition; initiating a re-route of said IP telephony session to a PSTN, and transmitting a notify signal to said first IP client, said notify signal initiating a switchover logic. ### Claim 2 (depends on 1) The invention of claim 1 wherein said network condition comprises a network bandwidth. ### Claim 3 (depends on 1) The invention of claim 1 wherein said network condition comprises a network policy decision. ### Claim 4 (depends on 1) The invention of claim 1 wherein said network condition comprises a data priority decision. ### Claim 5 (depends on 1) The invention of claim 1 wherein said network condition comprises a hardware failure. ### Claim 6 (depends on 1) The invention of claim 1 wherein said network condition comprises a software failure. ### Claim 7 (depends on 1) The invention of claim 1 further comprising the step of re-routing said IP telephony session to said PSTN. ### Claim 8 (depends on 1) The invention of claim 1 wherein said step of monitoring said network condition comprises: transmitting a first heartbeat signal, said first heartbeat signal transmitted between a first boundary element in a first local network of said first IP client and a second boundary element in a second local network of said second IP client. ### Claim 9 (depends on 8) The invention of claim 8 above wherein the first heartbeat signal comprises a message that contains information indicative of the network condition being monitored. ### Claim 10 (depends on 8) The invention of claim 8 above wherein said first boundary element comprises a packet routing device. ### Claim 11 (depends on 8) The invention of claim 8 further comprising the step of transmitting a second heartbeat signal, said second heartbeat signal transmitted between said second packet routing device in said second local network of said second IP client and said first packet routing device in said first local network of said first IP client. ### Claim 12 (depends on 11) The invention of claim 11 wherein the second heartbeat signal comprises a message containing information indicative of the network condition being monitored. ### Claim 13 (depends on 8) The invention of claim 8 wherein said second heartbeat signal is transmitted after said first heartbeat signal. ### Claim 14 (depends on 1) The invention of claim 1 further comprising the step of: determining whether said first IP client originated said IP telephony session to said second IP client. ### Claim 15 (depends on 1) The invention of claim 1 further comprising the step of: determining whether said first client terminated said IP telephony session initiated by said second client. ### Claim 16 (depends on 1) The invention of claim 1 wherein said IP telephony session comprises an IP multimedia session. ### Claim 17 (depends on 1) The invention of claim 1 wherein said first IP client device comprises an IP phone. ### Claim 18 (depends on 1) The invention of claim 1 wherein said first IP client device resides in an IP Centrex Local Area Network (LAN). ### Claim 19 (depends on 1) The invention of claim 1 wherein said first IP device resides in an IP PBX Local Area Network (LAN). ### Claim 20 (depends on 1) The invention of claim 1 wherein said IP telephony session comprises voice data. ### Claim 21 (depends on 1) The invention of claim 1 wherein said IP telephony session comprises video data. ### Claim 22 (depends on 1) The invention of claim 1 wherein said IP telephony session comprises multimedia data. ### Claim 23 (depends on 1) The invention of claim 1 wherein said IP telephony session is initiated using a Session Initiation Protocol (SIP). ### Claim 24 (depends on 1) The invention of claim 1 wherein said first IP device comprises a Session Initiation Protocol (SIP) phone. ### Claim 25 (depends on 1) The invention of claim 1 wherein a signaling component is utilized to select said re-route of said IP telephony session to a PSTN. ### Claim 26 (depends on 25) The invention of claim 25 wherein said signaling component comprises a SIP Proxy. ### Claim 27 (depends on 1) The invention of claim 1 wherein said IP telephony session is initiated using a H.323 protocol. ### Claim 28 (depends on 1) The invention of claim 1 further comprising the step of providing an audio announcement to said first IP client device alerting a user of said IP client device that session re-routing is being initiated. ### Claim 29 (depends on 1) The invention of claim 1 further comprising the step of providing an audio announcement to said second IP client device alerting a user of said IP client device that session re-routing is being initiated. ### Claim 30 (depends on 1) The method of claim 1 further comprising the step of utilizing a SIP NOTIFY message to initiate a new call. ### Claim 31 An IP telephony system, said system comprising: a first IP telephony device; a second IP telephony device in communication with said first IP telephony device; an IP telephony session taking place between said first and said second IP telephony device; a means for monitoring a parameter of said IP telephony session; a means for interrupting said IP telephony session taking place between said first and said second IP telephony device; a means for transmitting a notify signal to said first IP telephony device, said notify signal initiating a switchover logic; and a means for switching over said IP telephony session between said first and said second IP telephony device to a PSTN. ### Claim 32 (depends on 31) The system of claim 31 wherein said IP telephony session comprises a Session Initiation Protocol IP telephony session. ### Claim 33 (depends on 31) The system of claim 31 wherein said first IP telephony phone comprises a Session Initiation Protocol IP phone. ### Claim 34 (depends on 31) The system of claim 31 wherein said IP telephony session comprises a H.323 protocol IP telephony session. ### Claim 35 (depends on 31) The invention of claim 31 wherein said parameter comprises a network bandwidth. ### Claim 36 (depends on 31) The invention of claim 31 wherein said parameter comprises a network policy decision. ### Claim 37 (depends on 31) The invention of claim 31 wherein said parameter comprises a data priority decision. ### Claim 38 (depends on 31) The invention of claim 31 wherein said parameter comprises a hardware failure. ### Claim 39 (depends on 31) The invention of claim 31 wherein said parameter comprises a software failure.