FR3079382A1 - METHODS OF INITIATING DESENSEING AND DE-REGISTRATION OF A TERMINAL IN AN IP COMMUNICATION NETWORK, CORRESPONDING CONTROL ENTITIES AND COMPUTER PROGRAM. - Google Patents

Abstract

The invention relates to a method for initiating a de-registration of a previously registered terminal in an IP communication network, implemented by a first proxy-type control entity of said network, comprising: the detection (11) ) a communication problem with said terminal, and - the emission (13) of at least one message signaling said communication problem.

Description

Methods of initiating a deregistration and deregistration of a terminal in an IP communication network, control entities and corresponding computer program.

1. Field of the invention

The field of the invention is that of communications within an IP communication network, for example of the IMS type (in English “IP Multimedia Subsystem”, in French “IP multimedia subsystem”).

More specifically, the invention offers a solution for deregistering a terminal previously registered in an IP communication network, in the event of detection of a communication problem with the terminal.

The invention finds in particular, but not exclusively, applications in the field of IP telephony.

2. Prior art

When a terminal wishes to join a communication network, it must register with the network. For example, if we consider an IMS type network, this registration can be carried out by exchanging SIP requests between the terminal and an entity of the network responsible for registering the terminals.

Depending on the state of the terminal seen from the core network (i.e. registered or unregistered terminal), the mechanism used to reach the terminal is different. For example, if the terminal is not registered in the communication network, calls to the terminal can be directly forwarded to a mailbox. Conversely, if the terminal is registered in the communication network, the core network seeks to reach the terminal.

A problem appearing in IP telephony networks (VoLTE, VoWiFi for example) is linked to the persistent registration of a terminal when it is no longer reachable (for example because its battery is discharged , because it has left a coverage area, because its radio communication module is faulty, etc.).

This problem manifests itself in particular as follows:

the terminal of a client A, registered in an IMS network for example, becomes unreachable. The radio connection (in English "Bearer", or signaling path with the terminal) is then lost, and this is detected by the radio access network, which takes the necessary measures to completely destroy this radio connection in the various equipment of the access network;

the terminal of client A is not, however, deregistered by the IMS core network;

if client B tries to reach client A, as the terminal of client A is always seen as registered in the backbone, the latter will attempt to reach the terminal of client A. However, since there are no more radio connection, a call failure will occur.

This is detrimental to customers, because if customer A's terminal had been deregistered, certain accessible services "outside registration" could have been triggered (forwarding to a voicemail, broadcasting an announcement, immediate forwarding to another facility, etc. ).

This is also detrimental for the network operator, since resources are consumed unnecessarily (call signaling, recovery delay, etc.).

On the other hand, knowing the deregistered state of the terminal of client A on the “packet” network (IP), allows, when possible, to route the call to another network, in particular by using a network "circuit", which reduces PDD (in English "Post Dialling Delay", in French "timeout after dialing"), and improves the quality perceived by customer B.

A partial solution to this problem consists, during the processing associated with the call to the terminal of client A, in implementing additional procedures on the application server (“Application Server”) SCC-AS. These procedures make it possible to monitor the call progress at the level of the recipient of the call, in particular by arming a specific timer. If the call is rejected according to certain criteria, or if this timer expires while the call has not progressed, the SCC-AS initiates a procedure called "CS Fallback", that is to say it presents the call to the circuit domain. Client A's terminal is then reached via the circuit area to complete the call.

Unfortunately, this solution is not always usable, especially when the operator's network only has a "packet" network (LTE for example) and does not have a "circuit" network.

This problem also appears in fixed networks, although it occurs less frequently because the networks are more stable (permanent network resources, available energy, etc.): if the terminal of a client using fixed access does not is more reachable, it is desirable to be able to deregister it for the reasons explained above.

There is therefore a need for a new technique making it possible to deregister a terminal previously registered in an IP communication network, in the event of detection of a communication problem with the terminal.

3. Statement of the invention

The invention provides a new solution for initiating a deregistration of a terminal previously registered in an IP communication network, implemented by a first control entity, of the proxy type, of the network, comprising:

detecting a communication problem with said terminal, and sending at least one message signaling said communication problem.

Such a message is in particular intended for, or passes through, a second network control entity, responsible for registering the terminals.

The invention also relates to a method for deregistering a terminal previously registered in an IP communication network, implemented by a second network control entity responsible for registering the terminals, comprising:

receiving or intercepting at least one message sent by a first control entity, of the proxy type, from the network, and signaling a communication problem with the terminal, and initiating the deregistration of the network terminal.

The proposed solution thus allows a communication problem detected by a first control entity, of the proxy type, to be traced back to the core network, such as a loss of radio connection.

In this way, the second network control entity can receive or intercept this message signaling a communication problem, and initiate the deregistration of the terminal. It is in fact the second control entity of the network which manages the records and not the first proxy type control entity.

The second network control entity can thus be quickly informed of a communication problem with the terminal, and initiate the necessary actions, without waiting for the expiration of a timer for example, which allows in particular, according to at least one mode of implementation, to avoid consuming network resources unnecessarily (call signaling, recovery delay, etc.).

For example, the IP communication network is an IMS network, the first control entity is a P-CSCF type control entity, and the second control entity is an S-CSCF type entity (in English "Proxy / Serving Call Session Control Function ", in French" Mandatory Call Session Control Function / Waitress Call Session Control Function ").

In another embodiment, the invention relates to a proxy-type control entity of an IP communication network, known as the first control entity, comprising a reprogrammable computing machine or a dedicated computing machine configured for:

detect a communication problem with a terminal previously registered in said network, and send at least one message signaling said communication problem.

Such an entity is particularly suitable for implementing the method of initiating a deregistration described above. Thus, such an entity can include the various characteristics relating to the process for initiating a deregistration according to the invention, which can be combined or taken in isolation.

In particular, such an entity is a P-CSCF proxy. Such an entity may in particular include physical means and / or software.

In yet another embodiment, the invention relates to a control entity responsible for registering the terminals of an IP communication network, known as the second control entity, comprising a reprogrammable calculation machine or a configured dedicated calculation machine for :

receive or intercept at least one message sent by a first control entity, of the proxy type, from the network and signaling a communication problem with a terminal previously registered in the network, and initiate the deregistration of the network terminal.

Such an entity is particularly suitable for implementing the deregistration process described above. Thus, such an entity can include the various characteristics relating to the deregistration method according to the invention, which can be combined or taken in isolation.

In particular, such an entity is an S-CSCF server. Such an entity may in particular include physical means and / or software.

In another embodiment, the invention relates to one or more computer programs comprising instructions for the implementation of at least one method as described above, when this or these programs are executed by a processor.

In yet another embodiment, the invention relates to one or more non-removable or partially or completely removable information carriers, readable by a computer, and comprising instructions for one or more computer programs for execution steps of at least one method as described above.

The methods according to the invention can therefore be implemented in various ways, in particular in wired form and / or in software form.

4. List of figures

Other characteristics and advantages of the invention will appear more clearly on reading the following description of a particular embodiment, given by way of simple illustrative and nonlimiting example, and of the appended drawings, among which:

FIG. 1 illustrates the main steps implemented by a first control entity for initiating the deregistration of a terminal according to a particular embodiment of the invention;

FIG. 2 illustrates the main steps implemented by a second control entity for the deregistration of a terminal according to a particular embodiment of the invention; and FIGS. 3 and 4 respectively show the simplified structure of a first control entity and the simplified structure of a second control entity of an IP communication network.

5. Description of an embodiment of the invention

5.1 General principle

The general principle of the invention is based on the detection, by a first control entity, of the proxy type, of an IP communication network, of a communication problem with a terminal previously registered in the network, and the ascent to the heart of this communication problem. Such a first proxy-type control entity is in fact a network entity near the terminal, and is therefore capable of detecting problems of reachability of a terminal.

In this way, it is possible to quickly initiate deregistration of the terminal in the network, without waiting for the expiration of a timer for example.

Note that the terminal can be any type of terminal of an IP communication network, in particular a smartphone, a tablet, etc. The proposed solution is therefore generic and applicable to all types of terminals, and in particular makes it possible to cause deregistration on detection of permanent loss of connectivity with a terminal.

The main steps implemented by a first proxy-type control entity of an IP communication network are presented below, in relation to FIG. 1, for initiating the deregistration of a previously registered terminal. in the IP communication network, according to at least one embodiment of the invention.

For example, if we consider an IMS type IP communication network, such a first control entity is of the P-CSCF type. It is considered that the registration of the terminal in the IMS network has been carried out in a conventional manner beforehand, by the exchange of SIP requests between the terminal and an entity responsible for the registration of the terminals of the network, for example of the S-CSCF type. as described in TS 24.229, paragraph 5.4.1.2.

During a first step 11, the first network control entity detects a communication problem with the terminal. For example, the detection 11 of a communication problem, by the first control entity, implements at least one action belonging to the group comprising:

detecting the loss of at least one signaling path to the terminal; for example, if we consider an IMS type IP network:

o the reception on the RX interface of a message of type “break in the support channel” (“RELEASE OF BEARER”) concerning the default support channel (“Default Bearer”), may indicate the loss of the signaling path to the terminal;

o the reception of a message of type “rupture of the support channel” (

BEARER ") concerning the dedicated support channel (" Dedicated Bearer ") signaling the loss of the media path, and the analysis of the content of an attribute indicating the nature of the incident which caused the loss of the media path (for example l attribute "AVP RAN-NAS-Cause"), can indicate the loss of all signaling paths to the terminal;

o etc. ;

absence of response from the terminal; for example, if we consider an IP network of IMS type, the repeated absence of responses from the terminal on periodic procedures (maintenance of TCP “TCP keepalive”, periodic OPTIONS, etc.);

receiving an error message; for example, if we consider an IMS type IP network, the reception of certain ICMP responses, such as "host unreachable", etc. ;

failure to receive refresh requests from the terminal; for example, if we consider an IP network of IMS type, the absence of refresh requests from the terminal if there is a NAT between the terminal and the first proxy-type control entity (Frequent REGISTER, or “keepalive” from the terminal);

etc.

Optionally, the detection 11 by the first control entity of a communication problem triggers the storage 12, by the first control entity, in a context associated with the terminal, of information representative of the communication problem with the terminal. Such information makes it possible in particular to indicate a loss (temporary or permanent) of connectivity with the terminal. For example, the context associated with the terminal on the first control entity (P-CSCF) can be marked "Temporarily Lost", or "Permanently Lost".

During a next step 13, the first control entity sends at least one message signaling the communication problem, intended for a second network control entity, responsible for registering the terminals, or passing through the second network control entity.

In particular, if information representative of the communication problem with the terminal has been stored in a context associated with the terminal, the message signaling the communication problem can be sent taking this context into account. For example, the message reporting the communication problem may indicate whether the loss of connectivity to the terminal is temporary (“Temporarily Lost”) or permanent (“Permanently Lost”).

If we consider an IMS network, initiating the deregistration of a terminal previously registered in the network therefore implies new functionalities of the P-CSCF.

We now present, in relation to FIG. 2, the main steps implemented by a second control entity of the IP communication network, responsible for registering the terminals, for the deregistration of a previously registered terminal, according to at least an embodiment of the invention.

For example, if we consider an IMS type IP communication network, such a second control entity is of the S-CSCF type.

During a first step 21, the second network control entity receives, or intercepts, at least one message sent by the first control entity, of proxy type, and signaling a communication problem with the terminal. Such a message can be intended for the second control entity, or else intended for another entity of the network, or for another terminal, but passes through the second control entity.

The second control entity is thus informed by the first control entity of a communication problem with the terminal.

During a second step 22, the second control entity initiates the deregistration of the network terminal, in particular the contact address of the terminal.

According to a first example, the reception or the interception, by the second control entity, of a message signaling a communication problem triggers the immediate deregistration of the network terminal.

In a second example, the deregistration of the network terminal is implemented when at least one of the following conditions is met:

verification, by the second control entity, of the communication problem with the terminal; for example, the second control entity implements a terminal survey procedure;

predefined time elapsed from receipt or interception of the message signaling a communication problem with the terminal;

number of messages received or intercepted signaling a communication problem with the terminal greater than a predetermined threshold;

etc.

If we consider an IMS network, the deregistration of a terminal previously registered in the network therefore implies new functionalities of the S-CSCF.

Two examples of implementation of the invention are presented below.

5.2 First embodiment

We consider, according to a first embodiment, an IP communication network comprising a first proxy-type control entity implementing the steps of detecting 11 a communication problem with a terminal previously registered in the IP network, storage 12 , in a context associated with the terminal, of information representative of the communication problem with the terminal, and emission 13 of at least one message signaling the communication problem.

According to this first embodiment, the detection 11 by the first entity of a communication problem with the terminal triggers the signaling of the communication problem in the context associated with the terminal, for example by marking the context associated with the terminal with the indicator "Temporarily Lost", or the "Permanently Lost" indicator, or any other indicator indicating a communication problem.

Following the reception on the first control entity of a request intended for the unreachable terminal, the first control entity analyzes the context associated with the terminal and finds that it carries an indicator signaling a communication problem (for example "Permanently Lost" ). The first control entity then sends to the calling terminal, or to another entity of the network, a response carrying the message signaling the communication problem.

For example, the message reporting a communication problem has an error code. Such an error code can in particular be a dedicated code, for example of the 419 type. By way of example, the response carries the error code "419 Permanently Lost".

The message signaling the communication problem is therefore sent by the first control entity (for example P-CSCF) in response to a request intended for the terminal (for example a SIP request), taking into account the context associated with the terminal. Such a response passes in particular through the second control entity (S-CSCF) of the network, responsible for registering the terminals. This then initiates the deregistration of the unreachable terminal, according to terms which depend on the policy of the network operator.

As indicated in relation to FIG. 2, the operator's policy on the second control entity, when receiving / intercepting one or more messages signaling a communication problem, may for example consist of: a polling procedure of the terminal, a probationary period, a threshold on the number of messages signaling a communication problem with the terminal received or intercepted (for example of type "419"), etc., or a combination of these criteria, before deregistering the terminal . As a variant, the operator's policy on the second control entity, when receiving / intercepting a message signaling a communication problem, may consist of immediate deregistration.

In particular, if one places oneself within the framework of an IMS network, the deregistration is initiated by the network and carried out in a conventional manner, as described in the standard TS 24.229, paragraph 5.4.1.5 for example.

According to this first embodiment, the first control entity is therefore aware of a communication problem with the terminal, but does not directly inform the second control entity thereof. It is only in response to a request for the terminal that cannot be reached that the first control entity sends a message signaling a communication problem with the terminal, intended for or passing through the second control entity and informing it of the communication problem with the terminal.

5.3 Second embodiment

We consider, according to a second embodiment, an IP communication network comprising a first proxy-type control entity implementing the steps of detecting 11 a communication problem with a terminal previously registered in the IP network, and d 'emission 13 of at least one message signaling the communication problem. Optionally, the first control entity also implements the storage 12, in a context associated with the terminal, of information representative of the communication problem with the terminal.

According to this second embodiment, the message signaling the communication problem is sent by the first control entity to a second network control entity, responsible for registering the terminals.

Thus, after the first control entity (for example P-CSCF) has detected (11) the loss of connectivity with the terminal (for example in the event of absence of reception of requests for refreshment originating from the terminal if it exists a NAT between the terminal and the first proxy-type control entity, on receipt of events such as loss of the signaling path, etc.), it sends (13) a message signaling the communication problem with the second control entity ( for example S-CSCF) in order to prevent it from the problem of communication with the terminal.

For example, the detection 11 by the first control entity of a communication problem with the terminal immediately triggers the transmission 13, to the second control entity, of a message signaling the communication problem.

As a variant, the detection 11 by the first entity of a communication problem with the terminal triggers the signaling of the communication problem in the context associated with the terminal, for example by marking the context associated with the terminal with the indicator "Temporarily Lost" , or any other indicator of a communication problem. Following a predetermined number of such detections, the first control entity marks the context associated with the terminal with the indicator “Permanently Lost”, and then sends the message to the second control entity signaling the communication problem.

In either of these variants, the message reporting a communication problem may carry an error code. If we consider an IMS network, such a message can be a SIP request (for example INFO or MESSAGE) whose “Reason” header carries information associated with an error code. As an example, such a message is a SIP request whose “Reason” header is valued with the code “419”. As a variant, information associated with an error code (for example “419”) can be inserted in a dedicated header, or in the message body (bodyxml).

As indicated in relation to FIG. 2, the operator's policy on the second control entity, when receiving one or more messages signaling a communication problem, may for example consist of immediate deregistration. As a variant, the operator's policy on the second control entity, when receiving a message signaling a communication problem, may consist of: a terminal survey procedure, a probationary period, a threshold on the number messages indicating a communication problem with the terminal received, etc., or a combination of these criteria, before deregistering the terminal.

In particular, if one places oneself within the framework of an IMS network, the deregistration is initiated by the network and carried out in a conventional manner, as described in the standard TS 24.229, paragraph 5.4.1.5 for example.

According to this second embodiment, the first control entity is proactive and directly informs the second control entity of a communication problem with the terminal.

It is noted that the first and second embodiments presented above can be combined.

5.4 Structures

Finally, in relation to FIGS. 3 and 4, we present the simplified structures of a first control entity, of proxy type, of an IP communication network and of a second control entity, responsible for recording the terminals, of this IP network, according to one of the embodiments described above.

As illustrated in FIG. 3, the first control entity, for example of the P-CSCF type, comprises a memory 31 comprising a buffer memory, a processing unit 32, equipped for example with a reprogrammable calculation machine or a machine dedicated computation, for example a processor P, and controlled by the computer program 33, implementing the method of initiating a deregistration according to an embodiment of the invention.

On initialization, the code instructions of the computer program 33 are for example loaded into a RAM memory before being executed by the processor of the processing unit 32.

The processor of the processing unit 32 implements the steps of the deregistration initiation method described above, according to the instructions of the computer program 33, to detect a communication problem with a terminal, and to transmit at least a message signaling the communication problem (intended for the second control entity or passing through the second control entity).

As illustrated in FIG. 4, the second network control entity, for example of the S-CSCF type, comprises a memory 41 comprising a buffer memory, a processing unit 42, equipped for example with a reprogrammable calculation machine or a dedicated calculation machine, for example a processor P, and controlled by the computer program 43, implementing the deregistration method according to an embodiment of the invention.

On initialization, the code instructions of the computer program 43 are for example loaded into a RAM memory before being executed by the processor of the processing unit 42. The processing unit 42 receives / intercepts at least a message sent by the first control entity signaling a communication problem with a terminal.

The processor of the processing unit 42 implements the steps of the deregistration method described above, according to the instructions of the computer program 43, to initiate the deregistration of the terminal after receipt of at least one message sent by the first entity. control signaling a communication problem with the terminal.

Claims (14)

1. Method for initiating a deregistration of a terminal previously registered in an IP communication network, implemented by a first control entity, of proxy type, of said network, comprising: detecting (11) a communication problem with said terminal, and sending (13) at least one message signaling said communication problem. 2. Method for initiating a deregistration according to claim 1, characterized in that said detection of a communication problem triggers the storage (12) by said first control entity, in a context associated with said terminal, of a information representative of the communication problem with said terminal, and in that said message signaling the communication problem is transmitted taking into account said context associated with the terminal. 3. A method of initiating a deregistration according to any one of claims 1 and 2, characterized in that said message signaling the communication problem is sent by the first control entity in response to a request for the terminal and transits by a second control entity of said network, responsible for registering the terminals. 4. Method for initiating a deregistration according to any one of claims 1 and 2, characterized in that said message signaling the communication problem is sent by said first control entity to a second control entity of said network, responsible registration of terminals. 5. A method for initiating a deregistration according to any one of claims 1 to 4, characterized in that said detection of a communication problem implements at least one action belonging to the group comprising: detecting the loss of at least one signaling path to said terminal; the lack of response from said terminal; receiving an error message; the absence of reception of requests for refreshment originating from said terminal. 6. Method for deregistering a terminal previously registered in an IP communication network, implemented by a second control entity of said network, responsible for registering the terminals, comprising: reception or interception (21) of at least one message sent by a first control entity, of proxy type, of said network, and signaling a communication problem with said terminal, and initiation (22) of the deregistration of the terminal of said network. 7. Deregistration method according to claim 6, characterized in that the reception or the interception of said message triggers the immediate deregistration of the terminal of said network. 8. Deregistration method according to claim 6, characterized in that the deregistration of the terminal of said network is implemented when at least one of the following conditions is met: verification, by said second control entity, of the communication problem with said terminal; predefined time elapsed from receipt or interception of the message signaling a communication problem with said terminal; number of messages received or intercepted signaling a communication problem with said terminal greater than a predetermined threshold. 9. Method according to any one of claims 1 to 8, characterized in that said message carries an error code. 10. Method according to any one of claims 1 to 9, characterized in that said IP communication network is an IMS network, the first control entity is a P-CSCF type control entity, and the second control entity is an S-CSCF type entity. 11. Method according to claim 9 and claim 10, characterized in that said message is a SIP request whose "Reason" header carries information associated with an error code. 12. Proxy-type control entity of an IP communication network, known as the first control entity, comprising a reprogrammable computing machine or a dedicated computing machine configured for: detect a communication problem with a terminal previously registered in said network, and send at least one message signaling said communication problem. 13. Control entity responsible for registering the terminals of an IP communication network, known as the second control entity, comprising a reprogrammable calculation machine or a dedicated calculation machine configured for: receive or intercept at least one message sent by a first control entity, proxy type, of said network and signaling a communication problem with a terminal previously registered in said network, and initiate the deregistration of said terminal of said network. 14. Computer program comprising instructions for implementing a method according to any one of claims 1 to 11 when this program is executed by a processor.