System and method for reducing latency in call setup and teardown

• US 8,144,591 B2
• Filed: 07/07/2008
• Issued: 03/27/2012
• 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: Ghai, Rajat, TOWEY, Jim
• Primary Examiner(s): Rutkowski, Jeffrey M
• Application Number:
  US12/168,650
• Publication Number:
  US 20090141625A1
• Time in Patent Office: 1,359 Days
• Field of Search: 370230-235, 370/315, 370/328, 370/401, 370/352, 370/310, 370/374, 370/378, 370/381, 370/384, 370/395.31, 370/395.32, 370/395.72, 370/410, 709227-229, 709/231, 709/232, 709201-203, 709/212, 709213-219, 709/244, 455/448, 455/550.1, 455/556.1, 455/560, 726/1, 707/791, 707/793, 707/795, 707/797
• US Class Current: 370/235
• 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 agent that is configured to store in a computer readable memory policy information including local policy information and network policy information configured in a hierarchy, wherein the local policy information includes device-level policies and the network policy information includes network-level policies, and wherein the local policy information and the network policy include polices based on call session control function (CSCF) information;

a policy charging and enforcement function (PCEF) residing in the network device that is configured to manage at least one packet flow through the network device using a first policy information received from the policy agent;

a call session control function (CSCF) residing in the network device that is configured to handle call session setup and teardown and analyze requested media parameters against a second policy information received from the policy agent;

the policy agent in response to receiving a request to provide the first policy information to the PCEF, searching the computer readable memory to determine if the computer readable memory stores the first policy information;

if the computer readable memory stores the first policy information, retrieving the first policy information from the computer readable memory and providing the first policy information to the PCEF; and

if the computer readable memory does not store the first policy information, receiving the first policy information from a policy server, storing the first policy information in the computer readable memory, and providing the first policy information to the PCEF.

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

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

5. The network device of claim 1, wherein the PCEF is implemented as a PDN gateway (PGW) and the policy server is implemented as a policy charging and rules function (PCRF).

6. The network device of claim 1, wherein the policy agent authorizes a media request received at the CSCF and provides this policy information to the CSCF and the policy agent authorizes quality of service (QoS) resources at the PCEF.

7. The network device of claim 1, wherein the policy agent tracks quality of service (QoS) for each flow for a subscriber at the policy agent and checks the policy agent when a resource reservation protocol (RSVP) message is received at the network device.

8. The method of claim 1, wherein the local policy information includes policies based on a CSCF service subscription and a network operator'"'"'s CSCF service configuration.

9. The method of claim 1, wherein the network policy information includes user policy information.

10. A method of retrieving policies locally comprising:

receiving a request for a first session at a network device including a call session control function (CSCF), a policy agent, and a policy charging and enforcement function (PCEF);

retrieving policy information for a subscriber from a policy server if the policy information is unavailable locally at the network device from the policy agent;

storing the policy information at the network device in a computer readable memory accessible by the policy agent;

receiving a second request for a second session at the network device and checking if the policy information for the subscriber is available through the policy agent;

accessing the policy agent from the CSCF to obtain the policy information stored locally for the subscriber when setting up a packet flow;

accessing the policy agent from the PCEF to manage the packet flow using the policy information received from the policy agent;

storing through the policy agent the policy information including local policy information and network policy information in the computer readable memory configured in a hierarchy and wherein the local policy information and the network policy information include policies based on CSCF information; and

providing at the policy agent the local policy information providing device-level policies and the network policy information providing network-level policies.

11. The method of claim 10, further comprising accessing the policy agent locally when terminating the second flow for charging purposes rather than communicating with the policy server.

12. The method of claim 10, further comprising indexing the computer readable memory of the policy agent on a per subscriber basis and storing registration specific information for a subscriber.

13. The method of claim 10, further comprising accessing the policy agent from a PDN gateway (PGW) residing on the network device to obtain policy information.

14. The method of claim 10, further comprising refreshing the computer readable memory based on the determination of an aging mechanism.

15. The method of claim 10, further comprising authorizing at the policy agent a media request for the first flow and authorizing quality of service (QoS) resources.

16. The method of claim 10, further comprising tracking quality of service (QoS) for each flow for a subscriber at the policy agent and checking the policy agent when a resource reservation protocol (RSVP) message is received at the network device.

17. Logic encoded in one or more non-transient media for execution and when executed configured to:

receive a request for a first session at a network device including a call session control function (CSCF), a policy agent, and a policy charging and enforcement function (PCEF);

request policy information for a subscriber from a policy server if the policy information is unavailable locally at the network device from the policy agent;

store the policy information at the network device in a computer readable memory accessible by the policy agent;

receive a second request for a second session at the network device and checking if the policy information for the subscriber is available through the policy agent;

access the policy agent from the CSCF to obtain the policy information stored locally for the subscriber when setting up a packet flow;

access the policy agent from the PCEF to manage the packet flow using the policy information received from the policy agent;

store through the policy agent the policy information including local policy information and network policy information in the computer readable memory configured in a hierarchy and wherein the local policy information and the network policy information include policies based on CSCF information; and

provide at the policy agent the local policy information providing device-level policies and configured and the network policy information providing network-level policies.

18. The logic of claim 17, further comprising access the policy agent locally when terminating the second flow for charging purposes rather than communicating with the policy server.

19. The logic of claim 17, further comprising authorize a media request for the first flow and authorize quality of service (QoS) resources.

20. The logic of claim 17, further comprising track quality of service (QoS) for each flow for a subscriber at the policy agent and check the policy agent when a resource reservation protocol (RSVP) message is received at the network device.