Signaling state management system for packet network gateways

• US 6,188,760 B1
• Filed: 06/29/1998
• Issued: 02/13/2001
• Est. Priority Date: 05/08/1998
• Status: Expired due to Term

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Oran, David R., Rowett, Kevin J.
• Primary Examiner(s): SMITH, CREIGHTON H
• Application Number:
  US09/107,071
• Time in Patent Office: 960 Days
• Field of Search: 379/229, 379/230, 379/221, 379/207, 379/201
• US Class Current: 379/230
• CPC Class Codes: H04L 65/104 in the network
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: H04M 7/0069 comprising a residential gateway, e.g. those which provide an adapter for POTS or ISDN terminals
• CPC Class Codes: H04M 7/125 Details of gateway equipment
• CPC Class Codes: H04Q 2213/1309 Apparatus individually associated with a subscriber line, line circuits
• CPC Class Codes: H04Q 2213/13176 Common channel signaling, CCS7
• CPC Class Codes: H04Q 2213/13196 Connection circuit/link/trunk/junction, bridge, router, gateway
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13216 Code signals, frame structure
• CPC Class Codes: H04Q 2213/13345 Intelligent networks, SCP
• CPC Class Codes: H04Q 2213/13405 Dual frequency signaling, DTMF

Abstract

A signal state management (SSM) system avoids both the overhead of maintaining call state and complex signaling in a packet network gateway, while simultaneously providing a more scalable system by not placing too great a state or processing burden on the signaling or call processing server. The SSM system sends an event/action table from a call agent to the gateway that directs the gateway to detect and accumulate specified signaling events generated by a telephone. The gateway accumulates the signaling events according to the event/action table and notifies the call agent only when the signaling events specified in the event/action table are detected. The call agent then sends a new event/action table to the gateway that commands the gateway to detect and accumulate a new set of signaling events. After notifying the call agent, the gateway operates in a quarantine where all signaling events are queued. The gateway remains in the quarantine state until the new event/action table is received from the call agent.

Claims

1. A method for managing signaling states in a packet network, comprising:

sending a signaling state from a call agent to a gateway that directs the gateway to detect and accumulate specified signaling events generated by a telephone;

detecting and accumulating signaling events at the gateway according to the signaling state;

notifying the call agent when the gateway detects the signaling events specified in the signaling state by sending the detected signaling events to the call agent;

acknowledging the sent signaling events by sending a new signaling state from the call agent to the gateway that directs the gateway to detect signaling events specified by the new signaling state;

detecting the signaling events at the gateway according to the new signaling state; and

notifying the call agent when the gateway detects the signaling events specified in the new signaling state.

2. A method according to claim 1 including discontinuing the signaling state and operating the gateway in a quarantine state after notifying the call agent and remaining in the quarantine state until the new signaling state is received from the call agent, the quarantine state accumulating all signaling events received from the telephone.

3. A method according to claim 1 wherein the signaling state commands the gateway to perform the following actions:

ignore signaling events specified in the signaling state;

accumulate signaling events specified in the signaling state by adding the specified signaling events to a list and sending the list of signaling events to the call agent when a specific one of the signaling events is detected; and

send one signaling event specified in the signaling state plus all previously accumulated events to the call agent.

4. A method according to claim 1 including the following:

sending a digit map with the signaling state;

combining signaling events together in the gateway to form a dial string;

comparing the dial string with the digit map;

adding additional signaling events to the dial string when the dial string is underqualified and only partially matches the digit map; and

sending the dial string to the call agent when the dial string completely matches the digit map.

5. A method according to claim 4 including sending different digit maps according to the signaling state.

6. A method according to claim 1 including sending an event/action table with each processing state that directs the gateway to detect tones, on hook transitions and telephone digits.

7. A method according to claim 6 wherein the event/action table commands the gateway to take specified actions when events identified in the event/action table are detected.

8. A method according to claim 7 wherein the specified actions in the event/action table include the following:

notifying the call agent;

accumulating signaling events;

processing the signaling events according to a digit map;

ignoring the signaling events.

9. A method according to claim 3 wherein the signaling state directs the gateway to reassign a current audio output to a next audio source in a list when a hook-flash is detected.

10. A system for managing signaling states in a packet network, comprising:

a gateway coupled between the packet network and a telephone for receiving signaling events from the telephone; and

a call agent sending a state table to the gateway that directs the gateway to accumulate signaling events and notify the call agent only when signaling events specified in the control table are detected and accumulated by the gateway, the call agent acknowledging the notification by sending a new state table to the gateway that changes which signaling events the gateway detects, accumulates and notifies to the call agent.

11. A system according to claim 10 wherein the gateway discontinues using the state table after notifying the call agent and queues all signaling events from the telephone until the call agent acknowledges the notification with the new state table.

12. A system according to claim 10 wherein the state table comprises an event/action table that specifies which telephone signaling events are detected or accumulated by the gateway and notified to the call agent.

13. A system according to claim 12 wherein the event/action table further specifies what actions that the gateway takes when the specified telephone signaling events are detected or accumulated.

14. A system according to claim 12 wherein the event/action table commands the gateway to do the following:

notify the call agent immediately after detecting one of the specified signaling events;

add a next one of the signaling events to a list and send the list to the call agent when a next one of the signaling events is a send event; and

ignore the specified signaling events.

15. A system according to claim 10 wherein the state table includes a digit map that specifies which signaling events are batched together and sent to the call agent as one message.

16. A system according to claim 15 wherein the signaling events specified in the digit map comprise digits, letters and timers.

17. A method for processing signaling events from a telephone in a packet network, comprising:

receiving an event/action state from a call agent that includes telephone signaling state information;

detecting and accumulating signaling events from the telephone according to the event/action state received from the call agent;

notifying the call agent when the signaling events identified by the event/action state have been detected;

discontinuing accumulation and detection of the signaling events according to the event/action state and automatically changing into a quarantine state after notifying the call agent, the quarantine state queuing up all call signaling events from the telephone;

receiving a new event/action state from the call agent including new telephone signaling state information; and

accumulating and detecting the queued up signaling events from the quarantine state and new signaling events from the telephone according to the new event/action state.

18. A method for controlling how signaling events from a telephone are processed in a packet network, comprising:

sending a signaling control state to a gateway that controls how the gateway detects and accumulates telephone signaling events;

receiving notification from the gateway when all the signaling events specified in the signaling control state have been detected or accumulated and receiving in the notification as a batch message any signaling events accumulated by the gateway;

generating a new signaling control state according to the received notification; and

sending the new signaling control state to change how the detects and accumulates signaling events.