SYSTEM AND METHOD FOR REDUCING LATENCY IN CALL SETUP AND TEARDOWN

• US 20090141625A1
• Filed: 07/07/2008
• Published: 06/04/2009
• Est. Priority Date: 07/05/2007
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: TOWEY, Jim, GHAI, Rajat
• Granted Patent: US 8,144,591 B2
• Time in Patent Office: Days
• US Class Current: 370/230
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/782 Hierarchical allocation of resources, e.g. involving a hierarchy of local and centralised entities
• CPC Class Codes: H04L 47/808 User-type aware
• CPC Class Codes: H04L 47/824 Applicable to portable or mobile terminals
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

Systems and methods for reducing latency in call setup and teardown are provided. A network device with integrated functionalities and a cache is provided that stores policy information to reduce the amount of signaling that is necessary to setup and teardown sessions. By handling various aspects of the setup and teardown within a network device, latency is reduced and the amount of bandwidth needed for setup signaling is also reduced.

Claims

1. A network device providing integrated functionality comprising:

a policy charging and enforcement point (PCEF) residing in the network device that manages packet flows through the network device using policies;

a call session control function (CSCF) residing in the network device that handles call session setup and teardown and analyzes requested media parameters against policy information; and

a policy agent residing in the CSCF that stores in a computer readable medium policy information about a subscriber, wherein the network device receives policy information from a policy and charging rules function (PCRF) for use locally with the policy agent.

2. The network device of claim 1, wherein the computer readable medium is part of the CSCF local cache.

3. The network device of claim 2, wherein the computer readable medium of the policy agent is a database that is indexed on a per subscriber basis and stores registration specific information for a subscriber.

4. The network device of claim 2, wherein the computer readable medium includes an aging mechanism to refresh the cache.

5. The network device of claim 2, where the policy agent reviews policies in a hierarchical fashion.

6. The network device of claim 1, wherein the PCEF is a PDN gateway.

7. A method of retrieving policies locally comprising:

receiving a request for a new session at a network device implementing a call session control function (CSCF);

retrieving policy information for a subscriber from a policy and charging rules function (PCRF);

caching the policy information at the network device in a policy agent computer readable medium;

accessing the policy agent computer readable medium and installing an uplink flow for the new session;

sending a session termination message to the PCRF to teardown the new session;

accessing the policy agent computer readable medium to remove the uplink flow for the new session upon teardown of the session;

receiving a second request for a second session at the network device and checking if the policy information for the subscriber is included in the cache;

finding the policy information for the subscriber in the cache;

accessing the policy information for the subscriber to install a second uplink flow;

accessing the cache to teardown the second session and removing flows from the cache.