Systems and methods of sharing information between protocol layers

1. A device comprising:

memory; and

a processor configured by instructions retrieved from the memory to:

implement a publishing protocol layer, which specifies a control attribute and an associated value to be shared, the control attribute being one of a plurality of attributes;

implement a subscribing protocol layer; and

implement an information exchange service, the information exchange service configured to receive the control attribute and the associated value from the publishing protocol layer and to store the control attribute and the associated value in a storage of the device, and further configured to supply the stored associated value to the subscribing protocol layer responsive to a request from the subscribing protocol layer,

wherein the subscribing protocol layer is configured to adapt behavior based on the stored associated value of the control attribute supplied by the information exchange service.

2. The device of claim 1 , wherein the information exchange service is further configured to maintain multiple control attributes and associated values.

3. The device of claim 1 , wherein the information exchange service is further configured to periodically provide the associated value to the subscribing protocol layer.

4. The device of claim 1 , wherein the information exchange service is further configured to periodically provide the associated value to the subscribing protocol layer and to receive an indication from the publishing protocol layer of an expiration time for the associated value.

5. The device of claim 1 , wherein the information exchange service is further configured to receive a rule registration that includes a condition of one of the control attributes, and to notify the subscribing protocol layer when the condition is satisfied.

6. The device of claim 1 , wherein the information exchange service is further configured to evict the control attribute from the storage when the storage is full.

7. The device of claim 6 , wherein the information exchange service is further configured to apply a least-recently-used policy for eviction.

8. The device of claim 2 , wherein the information exchange service is further configured to select one of the control attributes for eviction based on a sticky bit associated with the corresponding attribute.

9. The device of claim 2 , wherein the information exchange service is further configured to communicate with a peer information exchange service in another device, and to handle multiple queries from the peer for one of the control attributes.

10. The device of claim 9 , wherein the information exchange service is further configured to determine if overlap exists among the multiple queries and if overlap does exist, to share a result of the overlapping queries.

11. A method for using an exchange intermediary to communicate between a publishing layer and a subscribing layer in a protocol stack residing in a computing device, the method comprising the steps of:

the publishing layer in the computing device specifying, to the exchange intermediary, an attribute and an associated value to be shared with a layer in the protocol stack, the attribute being one of a plurality of attributes;

the subscribing layer in the computing device adapting behavior based on the attribute;

the exchange intermediary implemented by a processor in the computing device storing the specified attribute and the associated value;

the exchange intermediary implemented by the processor in the computing device receiving a subscribe request, from the subscribing layer, specifying the published attribute; and

the exchange intermediary implemented by the processor in the computing device providing the associated value of the published attribute to the subscribing layer in response to the subscribe request.

12. The method of claim 11 , further comprising the step of: storing multiple attributes and associated values, described by an XML-based description.

13. The method of claim 11 , further comprising the step of periodically providing the associated value of the published attribute to the subscribing protocol layer.

14. The method of claim 11 , further comprising the step of:

receiving an indication from the publishing layer of an expiration time for the associated value of the attribute to be shared.

15. The method of claim 11 , further comprising the steps of:

receiving a rule registration that includes a condition of the attribute; and

notifying the subscribing protocol layer when the condition is satisfied.

16. The method of claim 11 , further comprising the steps of:

storing multiple attributes and associated values in a storage within the computing device, responsive to respective publication requests from the publishing layer; and

evicting a selected one of the attributes from the storage when the storage is full.

17. The method of claim 11 , further comprising the steps of:

communicating with a peer information exchange service in another computing device; and

receiving multiple queries from the peer information exchange service for one of the attributes.

18. The method of claim 11 , further comprising the steps determining if overlap exists among the multiple queries; and

if overlap does exist, sharing a result of the overlapping queries.

19. The method of claim 11 , further comprising the steps of:

storing multiple attributes and associated values, responsive to respective publication requests from the publishing layer; and

selecting one of the attributes for eviction based on a sticky bit associated with the corresponding attribute.