Service Differentiation in the IP Multimedia Subsystem Utilizing Context-Aware Signaling
First Claim
1. A method of service differentiation in an IP Multimedia Subsystem (IMS) network, said method comprising the steps of:
- defining a plurality of call classes of differing priorities for calls having different Quality of Service (QoS) profiles;
receiving a request from a User Equipment (UE) to establish a new call or join an ongoing call, said request including a requested call class;
granting by a call admission control mechanism, the UE'"'"'s request only if a traffic load for the requested call class would remain in compliance with a call admission policy following admission of the call; and
controlling by a media parameter control mechanism, formats of media streams exchanged in selected admitted calls in order to sustain the perceived media quality of the selected calls;
wherein utilization of network resources is optimized while satisfying the QoS profiles for admitted calls.
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Abstract
A system and method for service differentiation enabling a user to express the level of importance of a session being established and change the level during the session while satisfying QoS profiles. An extension of the 3GPP IMS architecture includes a Session Prioritization Function (SPF) in communication with a S-CSCF and a Context Information Base (CIB) which provides network contextual information. Upon receiving a session initiation or change request, the S-CSCF queries the SPF for a resource allocation/deallocation decision. The SPF consults session prioritization policies and the contextual information to make an informed decision. If the load on the IMS network is normal or light, the SPF utilizes an upper limit policy to limit resources for each service class. Otherwise, the SPF limits the size of multi-party sessions and utilizes soft and hard preemption to transfer network resources between classes. The SPF may trigger the S-CSCF to re-negotiate media-format parameters if network contextual information changes.
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Citations
22 Claims
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1. A method of service differentiation in an IP Multimedia Subsystem (IMS) network, said method comprising the steps of:
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defining a plurality of call classes of differing priorities for calls having different Quality of Service (QoS) profiles; receiving a request from a User Equipment (UE) to establish a new call or join an ongoing call, said request including a requested call class; granting by a call admission control mechanism, the UE'"'"'s request only if a traffic load for the requested call class would remain in compliance with a call admission policy following admission of the call; and controlling by a media parameter control mechanism, formats of media streams exchanged in selected admitted calls in order to sustain the perceived media quality of the selected calls; wherein utilization of network resources is optimized while satisfying the QoS profiles for admitted calls. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A system for service differentiation in an IP Multimedia Subsystem (IMS) network, said system comprising:
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a Session Prioritization Function (SPF) in communication with a Serving Call/Session Control Function (S-CSCF), wherein the SPF is adapted to make informed resource allocation/deallocation decisions when queried by the S-CSCF; and a Context Information Base (CIB) in communication with the SPF and with sources for network contextual information, wherein the CIB is adapted to obtain and store network contextual information and provide the contextual information to the SPF; wherein the SPF includes means for utilizing the network contextual information to make the informed resource allocation/deallocation decisions. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A Session Prioritization Function (SPF) for making informed resource allocation/deallocation decisions in an IP Multimedia Subsystem (IMS) network, said SPF comprising:
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means for receiving from a Serving Call/Session Control Function (S-CSCF), a request for a resource allocation/deallocation decision; means responsive to the request for obtaining network contextual information from a Context Information Base (CIB); means for utilizing the network contextual information to make an informed resource allocation/deallocation decision; and means for sending the informed resource allocation/deallocation decision to the S-CSCF. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A Session Prioritization Function (SPF) for making an informed resource allocation/deallocation decision in an IP Multimedia Subsystem (IMS) network, said SPF comprising:
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an interface to a Serving Call/Session Control Function (S-CSCF) for receiving from the S-CSCF, a request for a resource allocation/deallocation decision, and for sending the informed resource allocation/deallocation decision to the S-CSCF; an interface to a Context Information Base (CIB); an information access module for obtaining network contextual information from the CIB responsive to the request from the S-CSCF; a repository for session prioritization policies; and a control module for applying the network contextual information to the session prioritization policies to formulate the informed resource allocation/deallocation decision.
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Specification