METHOD OF MEDIA STATE SYNCHRONIZATION

Abstract

A method of media state synchronization is described. An applicative entity sends a request to a rules control entity asking the rules control entity to dispatch a message to the applicative entity describing the state of the media controlled by this applicative entity and currently being used. On expiry of a default deadline or one contained in the request, the rules control entity sends the applicative entity a message in which the rules control entity describes the state of the media. Subsequent to the receipt of the message, the applicative entity does not undertake any action if the media list provided by the rules control entity is identical to that known to the applicative entity, or corrects its state of the media if a subset of the media of the list is different from the list of media known to the applicative entity, or requests the freeing of the session if the set of the media of the list is different from the list of media known to the applicative entity or if the session itself is unknown to the applicative entity.

Claims

1. A method of media state synchronization, the method comprising: sending a request from an application entity to a rules control entity, the request asking the rules control entity (PCRF) to send a message to the application entity describing the state of the media controlled by this application entity and currently in use, on expiry of a default time period or a time period contained in the request, receiving from the rules control entity a message in which the rules control entity describes the state of the media, and subsequent to the receipt of the message, the application entity: does not undertake any action if the media list provided by the rules control entity is identical to the media list known to the application entity, or corrects its state of the media if a subset of the media of the list is different from the media list known to the application entity, or requests the release of the session if the set of the media of the list is different from the media list known to the application entity or if the session itself is unknown to the application entity.

2. The method of claim 1, wherein the application entity indicates to the rules control entity a period on expiry of which the application entity wishes to receive the messages describing the state of the media.

3. The method of claim 1, wherein the request is presented by the application entity upon a request for media resources to the rules control entity.

4. The method of claim 1, wherein the exchanges between the application entity and the rules control entity comply with the Diameter protocol.

5. The method of claim 2, wherein the period is indicated in a dedicated Attribute-Value Pair (Media_State_Period) of an AA-Request Diameter message.

6. The method of claim 3, wherein the request is inserted into the Specific-Action Attribute-Value Pair of an AA-Request Diameter message.

7. The method of claim 4, wherein the message containing the state of the media is sent to the application entity by the rules control entity in an RA-Request Diameter message.

8. An application entity, the application entity configured to: send toward a rules control entity a request asking the rules control entity (PCRF) to send a message to the application entity describing the state of the media controlled by this application entity and currently in use, receive a message in which the rules control entity (PCRF) describes the state of the media, and subsequent to the receipt of the message: not undertake any action if the media list provided by the rules control entity is identical to the media list known to the application entity, or correct its state of the media if a subset of the media of the list is different from the media list known to the application entity, or request the release of the session if the set of the media of the list is different from the media list known to the application entity or if the session itself is unknown to the application entity.

9. The application entity of claim 8, the application entity further configured to indicate to the rules control entity (PCRF) a period on expiry of which the application entity wishes to receive the messages describing the state of the media.

10. The application entity of claim 8, the application entity further configured to implement the Diameter protocol.

11. The application entity of claim 8, wherein the application entity is associated with a P-CSCF server in an Multimedia Subsystem IP network.

12. A rules control entity, the rules control entity configured to: receive from an application entity a request asking the rules control entity to send a message to the application entity (AF) describing the state of the media controlled by this application entity and currently in use, and on expiry of a default time period or one contained in the request, send toward the application entity a message in which the rules control entity (PCRF) describes the state of the media.

13. The rules control entity of claim 12, wherein the rules control entity is further configured to implement the Diameter protocol.

14. A communication system, comprising the application entity of claim 8, and a rules control entity, the rules control entity configured to: receive from the application entity the request asking the rules control entity to send a message to the application entity describing the state of the media controlled by this application entity and currently in use, and on expiry of a default time period or one contained in the request, send toward the application entity the message in which the rules control entity describes the state of the media.

15. An irremovable, or partially or totally removable means of A non-transitory computer-readable storage medium having stored thereon instructions, which when executed by a processor, cause the processor to implement the method of claim 1.

16. A computer comprising a processor and a memory, the memory having stored thereon instructions which, when executed by the processor, cause the computer to implement the method of claim 1.

Description

[0060] Other aspects and advantages of the invention will become apparent on reading the description detailed hereinbelow of particular embodiments which are given by way of nonlimiting examples. The description refers to the figures which accompany it and in which:

[0061] FIG. 1, described hereinabove, represents a conventional PCC architecture, and

[0062] FIG. 2 schematically represents a system for the provision of multimedia services which is able to implement the invention.

[0063] Although the present invention relates to any IP network making use of the DIAMETER protocol, a network architecture of IMS type, such as presented succinctly hereinabove, will now be considered by way of exemplary embodiment. This architecture is illustrated in FIG. 2.

[0064] The multimedia services offered by this IMS network 1 can comprise services in respect of telephony, video-telephony, content sharing, Presence, Instant Messaging, or television. These services are at the disposal of the user of a user equipment (or UE) 10 belonging to the network 1, which allows the user equipment 10 to exchange multimedia streams and session control signals conforming to the SIP protocol, for example with the user equipment (not represented) of a user belonging to an SIP network (not represented) linked to the network 1.

[0065] The user equipment 10 can be a fixed or mobile terminal, or a domestic or company gateway, having signaling means SIP and being able to comprise audiovisual content playback means.

[0066] As shown by FIG. 2, this IMS network 1 comprises, in addition to an IP transport infrastructure (not represented): [0067] at least one S-CSCF server; the S-CSCF server 27 manages notably the registration procedure in respect of the devices connected to the network 1; the S-CSCF server 27 also manages the routing of the signaling between the user equipment 10 and the servers for voice messaging VM 25, for Instant Messaging 26, and for telephony TAS 29; [0068] at least one I-CSCF server; the I-CSCF server 22 manages notably the routing toward other terminals managed by the same IMS network 1 and the routing of the signaling between this IMS network 1 and other networks (not represented); [0069] at least one P-CSCF server; the P-CSCF server 21 serves as entity for hooking up between the IMS core network and the access network used by the user equipment 10; [0070] at least one database server, of HSS type; the HSS server 24 contains the profile of the user of the user equipment 10 in terms of authentication and location data, and of subscribed services; [0071] at least one server VM 25 for message-summary; the server VM 25 manages the subscription of the user equipment 10 to the events of posting/consultation of the messages intended for the user equipment 10, and notifies the user equipment 10 upon the occurrence of these events; [0072] at least one Instant Messaging server IM 26; in case of subscription of the user of the UE 10 to the Instant Messaging service, this user can dialog instantly on-line with other subscribers to this service; and [0073] at least one telephone server TAS 29; the server TAS manages the telephone services to which the user of the terminal 10 has subscribed via his operator, such as number presentation or call return.

[0074] The message summary server VM 25, Instant Messaging server IM 26, and telephone server TAS 29 are examples of Applications Servers (AS).

[0075] Certain services, such as those of the server VM 25 and of the Instant Messaging server IM 26, rely on the subscription of the terminal 10 to predetermined events, as is explained hereinabove.

[0076] In FIG. 2, the dotted lines represent the real path followed by the SIP signals (between the UE 10 and the PCEF entity 31, and then between the PCEF entity 31 and the P-CSCF server 21). The hatched line (between the UE 10 and the P-CSCF server 21) represents the logical path of the SIP signaling. The PCRF entity 30 is connected to the PCEF entity 31 and to the P-CSCF server 21. Here, the P-CSCF server 21 plays the role of application entity AF according to the PCC architecture.

[0077] In a known manner, this architecture can implement the following steps.

[0078] During a step E1, the P-CSCF server 21 receives a session control message sent by the UE 10 and containing a media stream description compliant with the SDP (Session Description Protocol) protocol.

[0079] During a step E2, the P-CSCF server 21 sends a request for media stream reservation at the PCRF entity 30. This media stream reservation request is a Diameter resources control message AAR (for AA-Request) such as is defined in IETF document RFC 4005.

[0080] During a step E3, the PCRF entity 30 sends to the P-CSCF server 21 a message of acknowledgment of the stream reservation request. This acknowledgment message is a Diameter resources control message AAA (for AA-Answer) such as defined in document RFC 4005.

[0081] During a step E4, the PCRF entity 30 sends a message to the rules application entity PCEF 31 describing the rules to be installed in order to implement the media streams. This message describing the rules to be installed is a Diameter resources control message RAR (for RA-Request) such as defined in document RFC 4005.

[0082] During a step E5, the PCEF entity 31 sends to the PCRF entity 30 a message of acknowledgment of installation of the rules. This acknowledgment message is a Diameter resources control message RAA (for RA-Answer) such as defined in document RFC 4005.

[0083] Finally, during a step E6, the PCEF entity 31 implements said rules and authorizes the media streams.

[0084] According to one embodiment of the invention, during said step E2, the P-CSCF server sends, destined for the PCRF, through the interface Rx, a request in which the P-CSCF server asks to be notified of the state of the media controlled by this P-CSCF server and currently in use.

[0085] Accordingly, the P-CSCF server can for example, advantageously, apply the procedure indicated in Sections 4.4.6.4 and 5.3.13 of the aforementioned document TS 29.214, as well as in section B.1a of 3GPP document TS 29.213: this request for notification then takes the form of a Diameter message AAR setting an Attribute-Value Pair (AVP) field called Specific-Action. More precisely, there is proposed to this effect a new value of the Specific Action AVP, which will be called PERIODIC_MEDIA_STATE.

[0086] Moreover, in the absence of a default period, the P-CSCF server indicates to the PCRF a period on expiry of which it wishes to be notified of the state of the media which are currently in use. The periodicity of these notifications can be indicated in a dedicated AVP, which will be called Media_State_Period. The period must be neither too short (so as not to needlessly overload the interface), nor too long (so as to allow effective cleaning of the orphan components). This Media_State_Period AVP can, likewise, be inserted by the P-CSCF into the resources request message AAR mentioned hereinabove; the P-CSCF thus indicates to the PCRF a time period on expiry of which the PCRF must send a message describing the current state of the media to the P-CSCF.

[0087] Preferably, the request for notification remains valid for the entire duration of the session; thus, it will not be necessary to renew it.

[0088] On expiry of the time period indicated in the Media_State_Period AVP, the PCRF sends the P-CSCF server a message in which it indicates the current state of the media controlled by this P-CSCF server and currently in use. Preferably, this message is an RAR Diameter message (Re-Auth-Request) comprising the value PERIODIC_MEDIA_STATE, mentioned hereinabove, of the Specific Action AVP, so as to make the link with the Specific Action of the AAR at the origin of the present message RAR (from among, if relevant, other Specific Actions in progress) and thus to avoid risks of confusion. To describe the current state of the media, the PCRF may optionally use a grouped AVP Flows (that it is possible, conventionally, to insert into the RAR Diameter messages).

[0089] Subsequent to the receipt by the P-CSCF server of such an RAR Diameter message:

[0090] either the media list provided by the PCRF is identical to that known to the P-CSCF server, and then the P-CSCF server does not undertake any action as a consequence,

[0091] or a subset of the media of the list is different from those known, and then the P-CSCF server corrects its state of the media currently in use,

[0092] or the set of the media of the list is unknown for this session, and then the P-CSCF server requests the release of the session by sending an STR (Session Termination Request) Diameter message,

[0093] or the session itself is unknown, and then the P-CSCF server requests its release (STR message).

[0094] Generally, the present invention can be implemented within the nodes of an IP network, for example rules control entities or application entities, by means of software components and/or hardware components.

[0095] The software components will be able to be integrated into a conventional computer program for network node management. This is why, as indicated hereinabove, the present invention also relates to a computerized system. This computerized system comprises in a conventional manner a central processing unit controlling through signals a memory, as well as an input unit and an output unit. Moreover, this computerized system can be used to execute a computer program comprising instructions for the implementation of any one of the methods of synchronization according to the invention.

[0096] Indeed, the invention also envisages a computer program downloadable from a communication network comprising instructions for the execution of the steps of a method of synchronization according to the invention, when it is executed on a computer. This computer program can be stored on a support readable by computer and can be executable by a microprocessor.

[0097] This program can use any programming language, and take the form of source code, object code, or of code intermediate between source code and object code, such as in a partially compiled form, or in any other desirable form.

[0098] The invention also envisages an irremovable, or partially or totally removable information support, readable by a computer and comprising instructions of a computer program such as is mentioned hereinabove.

[0099] The information support can be any entity or device capable of storing the program. For example, the support can comprise a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a magnetic recording means, such as a hard disk, or else a USB key (USB flash drive in English).

[0100] Moreover, the information support can be a transmissible support such as an electrical or optical signal, which can be conveyed via an electrical or optical cable, by radio or by other means. The computer program according to the invention can be in particular downloaded over a network of Internet type.

[0101] As a variant, the information support can be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of any one of the methods of synchronization according to the invention.