METHODS AND APPARATUS FOR MAINTAINING CONNECTIVITY WITH AN INTERNET PROTOCOL PHONE OPERATING BEHIND A FIREWALL

• US 20100098061A1
• Filed: 12/24/2009
• Published: 04/22/2010
• Est. Priority Date: 06/25/2003
• Status: Active Grant

• Current Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property I LP (AT&T, Inc.)
• Inventors: Adams, Thomas Lee, Doherty, James M., Mueller, Steve
• Granted Patent: US 8,514,847 B2
• Time in Patent Office: Days
• US Class Current: 370/352
• CPC Class Codes: H04L 61/2582 through control of the NAT server, e.g. using universal plug and play [UPnP]
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4535 using an address exchange platform which sets up a session between two nodes, e.g. rendezvous servers, session initiation protocols [SIP] registrars or H.323 gatekeepers
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 65/1069 Session establishment or de-establishment
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/1104 Session initiation protocol [SIP]
• CPC Class Codes: H04M 7/006 Networks other than PSTN/ISDN providing telephone service, e.g. Voice over Internet Protocol (VoIP) , including next generation networks with a packet-switched transport layer H04L65/00 takes precedence; aspects not specific to the type of network H04M3/00; special services in those networks H04M3/42

Abstract

Methods and apparatus for maintaining connectivity with an Internet protocol (IP) phone operating behind a firewall are disclosed. An example method disclosed herein comprises registering the IP phone in response to receiving a first registration request from the IP phone, the first registration request including first registration information, the first registration information including a first public IP address associated with the firewall, storing the first registration information, reregistering the IP phone in response to receiving a second registration request from the IP phone, the second registration request including second registration information, the second registration information including a second public IP address associated with the firewall, the second public IP address different from the first public IP address, and reverting to the stored first registration information to process calls associated with the IP phone.

Claims

1. A method for a switch to maintain connection with an Internet protocol (IP) phone operating behind a firewall, the method comprising:

registering the IP phone in response to receiving a first registration request from the IP phone, the first registration request including first registration information, the first registration information including a first public IP address associated with the firewall;

storing the first registration information;

reregistering the IP phone in response to receiving a second registration request from the IP phone, the second registration request including second registration information, the second registration information including a second public IP address associated with the firewall, the second public IP address different from the first public IP address; and

reverting to the stored first registration information to process calls associated with the IP phone.

2. A method as defined in claim 1 wherein reverting to the stored first registration information to process calls associated with the IP phone occurs when a signaling channel at least one of is dropped or becomes not responsive.

3. A method as defined in claim 1 wherein reverting to the stored first registration information to process calls associated with the IP phone occurs when a subsequent registration is attempted without an existing registration being terminated.

4. A method as defined in claim 1 wherein the first information further includes an assigned phone number associated with the IP phone, an IP address associated with the IP phone, and a medium access control (MAC) address associated with the IP phone.

5. A method as defined in claim 4 wherein the second information also includes the assigned phone number associated with the IP phone, the IP address associated with the IP phone, and the MAC address associated with the IP phone.

6. A method as defined in claim 1 wherein the switch is a domain name system (DNS) switch and wherein storing the first registration information comprises storing the first registration information as a remote location record.

7. A method as defined in claim 1 further comprising setting a time to live (TTL) parameter in the remote location record to indicate a time period during which the first registration information is valid.

8. A tangible article of manufacture storing machine readable instructions which, when executed, cause a machine to:

register an Internet protocol (IP) phone operating behind a firewall with a switch in response to receiving a first registration request from the IP phone, the first registration request including first registration information, the first registration information including a first public IP address associated with the firewall;

store the first registration information;

reregister the IP phone in response to receiving a second registration request from the IP phone, the second registration request including second registration information, the second registration information including a second public IP address associated with the firewall, the second public IP address different from the first public IP address; and

revert to the stored first registration information to process calls associated with the IP phone.

9. A tangible article of manufacture as defined in claim 8 wherein the machine readable instructions, when executed, cause the machine to revert to the stored first registration information to process calls associated with the IP phone when a signaling channel is at least one of dropped or becomes not responsive.

10. A tangible article of manufacture as defined in claim 8 wherein the machine readable instructions, when executed, cause the machine to revert to the stored first registration information to process calls associated with the IP phone when a subsequent registration is attempted without an existing registration being terminated.

11. A tangible article of manufacture as defined in claim 8 wherein the first information further includes an assigned phone number associated with the IP phone, an IP address associated with the IP phone, and a medium access control (MAC) address associated with the IP phone.

12. A tangible article of manufacture as defined in claim 8 wherein the second information also includes the assigned phone number associated with the IP phone, the IP address associated with the IP phone, and the MAC address associated with the IP phone.

13. A tangible article of manufacture as defined in claim 8 wherein the switch is a domain name system (DNS) switch and wherein the machine readable instructions, when executed, further cause the machine to store the first registration information as a remote location record.

14. A tangible article of manufacture as defined in claim 13 wherein the machine readable instructions, when executed, further cause the machine to set a time to live (TTL) parameter in the remote location record to indicate a time period during which the first registration information is valid.

15. A switch to maintain connection with an Internet protocol (IP) phone operating behind a firewall, the switch comprising:

a memory; and

a processor programmed to;

register the IP phone in response to receiving a first registration request from the IP phone, the first registration request including first registration information, the first registration information including a first public IP address associated with the firewall;

store the first registration information in the memory;

reregister the IP phone in response to receiving a second registration request from the IP phone, the second registration request including second registration information, the second registration information including a second public IP address associated with the firewall, the second public IP address different from the first public IP address; and

revert to the first registration information stored in the memory to process calls associated with the IP phone.

16. A switch as defined in claim 15 wherein the processor is programmed to revert to the first registration information stored in the memory to process calls associated with the IP phone when a signaling channel is at least one of dropped or becomes not responsive.

17. A switch as defined in claim 15 wherein the processor is programmed to revert to the first registration information stored in the memory to process calls associated with the IP phone when a subsequent registration is attempted without an existing registration being terminated.

18. A switch as defined in claim 15 wherein the first information further includes an assigned phone number associated with the IP phone, an IP address associated with the IP phone, and a medium access control (MAC) address associated with the IP phone.

19. A switch as defined in claim 15 wherein the second information also includes the assigned phone number associated with the IP phone, the IP address associated with the IP phone, and the MAC address associated with the IP phone.

20. A switch as defined in claim 15 wherein the switch is a domain name system (DNS) switch and wherein the processor is further programmed to:

store the first registration information as a remote location record; and

set a time to live (TTL) parameter in the remote location record to indicate a time period during which the first registration information is valid.