Policy engine in an internet protocol multimedia subsystem

1. A system comprising:

a memory device to:

store a plurality of associations of information, relating to subscribers, and rules relating to a communications network, the communications network providing at least one service to which the subscribers subscribe, the rules including a first type of rule and a second type of rule;

a network device to:

receive an update to one association of the plurality of associations stored in the memory device, and

forward the update based on receiving the update; and

a group of rule enforcement devices, the group of rule enforcement devices including a first rule enforcement device to enforce the first type of rule and a second rule enforcement device to enforce the second type of rule,

the first rule enforcement device being different than the second rule enforcement device,

at least one rule enforcement device, of the group of rule enforcement devices, being to:

receive the update from the network device,

store the update, and

process a received communication request based on the stored update,

the network device being further to:

forward, to the first rule enforcement device and not to the second rule enforcement device, the first type of rule,

forward, to the second rule enforcement device and not to the first rule enforcement device, the second type of rule,

the first type of rule being different than the second type of rule,

receive status information relating to the communications network,

update, based on receiving the status information, at least one rule of the rules, and

forward, based on updating the at least one rule, the updated at least one rule to a rule enforcement device of the group of rule enforcement devices, and

the rule enforcement device being to:

receive the updated at least one rule from the network device,

store the received updated at least one rule, and

process a different communication request using the updated at least one rule.

2. The system of claim 1 , where the subscribers include subscribers to an Internet Protocol Multimedia Subsystem (IMS).

3. The system of claim 1 , where the updated at least one rule relates to a network resource identified in the status information.

4. The system of claim 1 , where the group of rule enforcement devices correspond to rule decision points.

5. The system of claim 1 , where

the first type of rule includes a resource rule,

the second type of rule includes a service level agreement,

the first rule enforcement device is implemented in a serving call session control function (S-CSCF), and

the second rule enforcement device is implemented in one or more of a proxy call session control function (P-CSCF), a breakout gateway control function (BGCF), a break in gateway control function (BIGCF), an access session border controller (A-SBC), or an internetworking session border controller (I-SBC).

6. The system of claim 1 , where

the first rule enforcement device is implemented in a gateway-related device of the communications network, and

the second rule enforcement device is implemented in a core of the communications network.

7. A system comprising:

a network device in a communications network that includes a plurality of rule enforcement devices, the plurality of rule enforcement devices including a first rule enforcement device and a second rule enforcement device that is different from the first rule enforcement device, the network device comprising:

a memory to store information associating each of a plurality of subscribers with one or more rules relating to the communications network, the communications network providing at least one service to which the subscribers subscribe, the plurality of rules including a first type of rule and a second type of rule,

the first type of rule being different than the second type of rule; and

a processor to:

receive status information relating to the communications network,

update, based on receiving the status information, at least one rule of the plurality of rules stored in the memory,

determine whether the at least one rule is the first type of rule or the second type of rule, and

select a particular one of the first rule enforcement device or the second rule enforcement device based on determining whether the at least one rule is the first type of rule or the second type of rule, the processor, when selecting the particular one of the first rule enforcement device or the second rule enforcement device being to:

select the first rule enforcement device based on determining that the at least one rule is the first type of rule, and

select the second rule enforcement device based on determining that the at least one rule is the second type of rule;

forward, based on updating the at least one rule and to the selected particular one of the first rule enforcement device or the second rule enforcement device, information identifying that the at least one rule was updated, the processor, when forwarding the information identifying that the at least one rule was updated being to:

forgo forwarding the at least one rule to the other rule enforcement device, of the first rule enforcement device and the second rule enforcement device, based on determining whether the at least one rule is the first type of rule or the second type of rule,

the selected particular one of the first rule enforcement device or the second rule enforcement device being to:

receive the updated at least one rule from the network device,

store the received updated at least one rule, and

process a communication request using the updated at least one rule.

8. The system of claim 7 , where the status information identifies one or more resources of the communications network.

9. The system of claim 7 , where the first rule enforcement device includes at least one of a border gateway function, a serving call session control function (S-CSCF), a proxy call session control function (P-CSCF), a breakout gateway control function (BGCF), or a break in gateway control function (BIGCF).

10. The system of claim 7 , where

the communications network includes an Internet Protocol Multimedia Subsystem (IMS), and

the memory stores a copy of all rules used in the IMS.

11. The system of claim 7 , where the processor forwards the update to the first rule enforcement device using an extensible markup language (XML) protocol.

12. The system of claim 7 , where

the at least one rule includes a resource rule, and

the first rule enforcement device is implemented in a serving call session control function (S-CSCF).

13. The system of claim 7 , where

the at least one rule includes a resource rule, and

the first rule enforcement device is implemented in a device in a core of the communications network.

14. The system of claim 7 , where the processor is further to:

receive an update to particular information, stored in the memory, that associates a particular subscriber with a particular rule, and

forward the update to the particular information based on receiving the update,

where one rule enforcement device, of the plurality of rule enforcement devices, is to:

receive the update,

store the update, and

process a different communication request based on the stored update.

15. The system of claim 7 , where

the at least one rule is a first rule, and

the processor is further to:

update a second rule of the plurality of rules stored in the memory,

where the second rule is different from the first rule,

determine that the second rule is the second type of rule, and

forward, based on updating the second rule, information identifying that the second rule was updated to the second enforcement device and not to the first rule enforcement device, based on determining that the second rule is the second type of rule.

16. A method comprising:

storing, at a network device, information that associates each of a plurality of subscribers with one or more rules relating to a communications network, the communications network providing at least one service to which the subscribers subscribe, the rules including a first type of rule and a second type of rule,

the second type of rule being different than the first type of rule;

forwarding, by the network device, the first type of rule, of the rules, to a first rule device;

forwarding, by the network device, the second type of rule, of the rules, to a second rule device,

the second rule device being different than the first rule device;

receiving, by the network device, first information affecting the first type of rule, the first information including at least one of:

first status information relating to the communications network, or

a first update to the information that associates a first subscriber with a first rule that is the first type of rule;

identifying, by the network device, that the first information affects the first type of rule;

identifying, by the network device and based on identifying that the first information affects the first type of rule, that the first information is associated with the first rule device;

forwarding, by the network device and based on identifying that the first information is associated with the first rule device, an update to the first type of rule to the first rule device;

processing, by the first rule device, a received communication based on the update to the first type of rule;

receiving, by the network device, second information affecting the second type of rule, the second information including at least one of:

second status information relating to the communications network, or

a second update to information that associates a second subscriber with a second rule that is the second type of rule;

identifying, by the network device, that the second information affects the second type of rule;

identifying, by the network device and based on identifying that the second information affects the second type of rule, that the second information is associated with the second rule device;

forwarding, by the network device and based on identifying that the second information is associated with the second rule device, an update to the second type of rule to the second rule device; and

processing, by the second rule device, another received communication based on the update to the second type of rule.

17. The method of claim 16 , where one of the first status information or the second status information includes a resource status message identifying one or more resources.

18. The method of claim 16 , where

the communications network includes an Internet Protocol Multimedia Subsystem (IMS), and

each rule, of the one or more rules, relates to accessing the IMS.

19. The method of claim 16 , where

processing the received communication includes:

routing, via the first rule device, traffic through the communications network based on the update to the first type of rule; and

processing the received other communication includes:

routing, via the second rule device, traffic through the communications network based on the update to the second type of rule.

20. The method of claim 16 , where

the first type of rule includes a resource rule,

the second type of rule includes a service level agreement,

the first rule device is implemented in a serving call session control function (S-CSCF), and

the second rule device is implemented in one or more of a proxy call session control function (P-CSCF), a breakout gateway control function (BGCF), a break in gateway control function (BIGCF), an access session border controller (A-SBC), or an internetworking session border controller (I-SBC).

21. The method of claim 16 , where forwarding the first type of rule includes:

forwarding the first type of rule to the first rule device using an extensible markup language (XML) protocol.

22. The method of claim 21 , where forwarding the second type of rule includes:

forwarding the second type of rule to the second rule device using the XML protocol.