Providing telephony services to terminals behind a firewall and/or a network address translator

• US 20070094412A1
• Filed: 11/17/2006
• Published: 04/26/2007
• Est. Priority Date: 06/14/2001
• Status: Active Grant

• Current Assignee: RPX Clearinghouse LLC (RPX Corporation)
• Original Assignee: Nortel Networks Limited (Nortel Networks Corporation)
• Inventors: Sollee, Patrick
• Granted Patent: US 8,244,876 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2517 using port numbers
• CPC Class Codes: H04L 61/2539 Hiding addresses; Keeping addresses anonymous
• CPC Class Codes: H04L 61/255 Maintenance or indexing of mapping tables
• CPC Class Codes: H04L 61/2553 Binding renewal aspects, e.g. using keep-alive messages
• CPC Class Codes: H04L 61/2564 for a higher-layer protocol, e.g. for session initiation protocol [SIP]
• CPC Class Codes: H04L 61/2578 without involvement of the NAT server
• CPC Class Codes: H04L 63/0227 Filtering policies mail message filtering H04L51/212
• CPC Class Codes: H04L 63/0236 Filtering by address, protocol, port number or service, e.g. IP-address or URL
• CPC Class Codes: H04L 63/0254 Stateful filtering
• CPC Class Codes: H04L 63/029 Firewall traversal, e.g. tunnelling or, creating pinholes
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 65/1043 Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• 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: H04L 65/65 Network streaming protocols, e.g. real-time transport protocol [RTP] or real-time control protocol [RTCP]
• CPC Class Codes: H04L 9/40 Network security protocols
• 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
• CPC Class Codes: H04M 7/0078 Security; Fraud detection; Fraud prevention

Abstract

A method and apparatus is provided to allow telephony or other types of media communications and services to be provided for a device (24) having a private network address that resides behind a firewall and network address and port translation (NAPT) module (which is not aware of the underlying protocol for the communications and services). Examples of the underlying protocol includes the Session Initiation Protocol (SIP) and Real-Time Protocol (RTP). A path through the firewall and NAPT module is defined by use of keep-alive messages communicated through the firewall and NAPT module. Addresses that are allocated by the firewall and NAPT module are associated with the device (24) for both signaling and media communications. A feature of the firewall that enables the provision of telephony and media communications through the firewall that is protocol-unaware is that the firewall allows responses to messages initiated by the device back through the firewall.

Claims

1. A method for use in communications involving a first terminal that is coupled to one side of a firewall and network address translator, the method comprising:

sending, by the first terminal, a message identifying the first terminal to a node on another side of the firewall and network address translator;

receiving, by the first terminal, another message from the node, wherein the messages between the first terminal and the node causes creation of a path through the firewall and network address translator;

repeatedly sending keep-alive messages to maintain the path through the firewall and network address translator; and

exchanging messages, by the first terminal, with the node over the path maintained through the firewall and network address translator to establish a call session.

2. The method of claim 1, further comprising receiving a call request, by the first terminal, from the node over the path maintained through the firewall and network address translator.

3. The method of claim 1, wherein repeatedly sending the keep-alive messages is based on a timer in the first terminal.

4. The method of claim 1, wherein sending the identifying message comprises sending a registration message to register the first terminal with the node.

5. The method of claim 4, wherein sending the registration message comprises sending a Session Initiation Protocol REGISTER message.

6. The method of claim 5, wherein sending the registration message comprises sending the registration message to a Session Initiation Protocol proxy, the node comprising the Session Initiation Protocol proxy.

7. The method of claim 1, wherein sending the identifying message and receiving the another message are used to perform registration of the first terminal, and

wherein repeatedly sending the keep-alive messages to maintain the path through the firewall and network address translator is performed for a duration of the registration of the first terminal.

8. The method of claim 1, wherein maintaining the path through the firewall and network address translator comprises maintaining a signaling path between the first terminal and the node through the firewall and network address translator.

9. The method of claim 1, wherein repeatedly sending the keep-alive messages to maintain the path through the firewall and network address translator causes a mapping table to be maintained by the firewall and network address translator, the mapping table containing a mapping between an internal address of the first terminal and an external address of the first terminal.

10. The method of claim 9, wherein timing of repeatedly sending the keep-alive messages is controlled by a timer, and wherein repeatedly sending the keep-alive messages is performed at a periodic interval sufficient to prevent closing of the mapping caused by time-out in the firewall and network address translator.

11. A method for use in communications involving a first terminal that is coupled to one side of a firewall and network address translator, the method comprising:

sending, by the first terminal, a message identifying the first terminal to a node on another side of the firewall and network address translator;

receiving, by the first terminal, another message from the node, wherein the messages between the first terminal and the node causes creation of a path through the firewall and network address translator;

repeatedly sending keep-alive messages to maintain the path through the firewall and network address translator,

wherein maintaining the path comprises maintaining a Session Initiation Protocol (SIP) signaling path between the first terminal and the node through the firewall and network address translator.

12. A device capable of being used in communications through a firewall and network address translator, the device comprising:

an interface adapted to exchange messages with a node on another side of the firewall and network address translator, the exchange of messages with the node to create a signaling path through the firewall and network address translator; and

a controller adapted to repeatedly send keep-alive messages to maintain the signaling path through the firewall and network address translator, wherein the controller repeatedly sends keep-alive messages to maintain the signaling path through the firewall and network address translator between the device and node, wherein the signaling path comprises a Session Initiation Protocol (SIP) signaling path.

13. The device of claim 12, further comprising a timer to determine timing of the keep-alive messages.

14. The device of claim 12, wherein the interface is adapted to exchange messages with the node to perform registration of the device, and

the controller repeatedly sends the keep-alive messages to maintain the signaling path through the firewall and network address translator for a duration of the registration of the device.

15. The device of claim 12, wherein the controller repeatedly sending keep-alive messages to maintain the signaling path through the firewall and network address translator causes a mapping table to be maintained by the firewall and network address translator, the mapping table containing a mapping between an internal address of the device and an external address of the device.

16. The device of claim 15, further comprising a timer to determine timing of the keep-alive messages, wherein the timer causes the keep-alive messages to be sent at a periodic interval sufficient to prevent closing of the mapping caused by a time-out in the firewall and network address translator.