WO2019180349A1

WO2019180349A1 - Method for deregistering a terminal from an ip communication network, and corresponding control entity and computer program

Info

Publication number: WO2019180349A1
Application number: PCT/FR2019/050546
Authority: WO
Inventors: José DORÉE; Jean-Claude Le Rouzic
Original assignee: Orange
Priority date: 2018-03-20
Filing date: 2019-03-13
Publication date: 2019-09-26
Also published as: FR3079382B1; FR3079382A1

Abstract

The invention relates to a method for deregistering a terminal previously registered in an IP communication network comprising a first and a second control entity, the first entity being of the proxy type and a point of entering the terminals in the network, and the second entity being responsible for registering the terminals in the network. According to said method: - the second entity receives (21) or intercepts at least one message transmitted by the first control entity indicating a communication problem with the terminal; and - the second entity initiates (22) the deregistering of the terminal from the network.

Description

Methods of de-registering a terminal in a corresponding IP communication network, control entity and 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 "multimedia IP subsystem").

More specifically, the invention provides a solution for deregistering a previously registered terminal 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 in the network. For example, if an IMS-type network is considered, this recording can be done 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 as seen from the core network (i.e. registered or unregistered terminal), the mechanism implemented to join the terminal is different. For example, if the terminal is not registered in the communication network, the calls to the terminal can be directly sent back to an e-mail. Conversely, if the terminal is registered in the communication network, the core network seeks to join the terminal.

A problem appearing in IP telephony type networks (VoLTE, VoWiFi for example) is linked to the persistence of the registration of a terminal when it is no longer reachable (for example because its battery is discharged , because it came out of a coverage area, because its radiocommunication module is failing, 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 steps to completely destroy this radio connection in the various equipment of the access network;

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

if a customer B is trying to reach customer A, as customer A's terminal is still seen as registered in the heart of the network, the latter will try to join the terminal of the client A. Or, since there is no longer a radio connection, a call failure will occur.

This is detrimental to customers, because if the client A terminal had been unregistered, some "non-registration" services could have been triggered (forwarding to voicemail, broadcasting an announcement, forwarding to another facility, etc.). ).

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

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

A partial solution to this problem is, during the processing associated with the call to the terminal of the client A, to implement additional procedures on the application server ("Application Server") SCC-AS. These procedures allow you to monitor the call progress at 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 so-called "CS Fallback" procedure, ie presents the call to the circuit domain. The client terminal A is then joined via the circuit domain to dispose of the call.

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

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

There is therefore a need for a new technique for deregistering a previously registered terminal in an IP communication network, in case of detection of a communication problem with the terminal.

3. Presentation of the invention

The invention proposes a new solution for initiating a de-registration of a previously registered terminal in an IP communication network comprising a first and a second control entity, the first control entity being of the proxy type. and an entry point of the terminals in the IP communication network, and the second control entity being responsible for registering the terminals in the IP communication network. This method is intended to be implemented by the first control entity, and comprises: detecting a communication problem with said terminal, and

transmitting at least one message signaling said communication problem.

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

The invention also relates to a method of de-registering a previously registered terminal in an IP communication network comprising a first and a second control entity, the first control entity being of the proxy type and an entry point of the terminals in the an IP communication network, the second control entity being responsible for registering the terminals in the IP communication network, the method comprising:

the reception or interception by the second control entity of at least one message sent by the first control entity signaling a communication problem with the terminal, and

initiating the unregistering of the network terminal by the second control entity.

The proposed solution thus makes it possible to trace back to the network core a communication problem, such as a loss of radio connection, detected for example by the first control entity, and which is the point of entry of the terminals into the IP communication network. . In other words, according to the invention, it is advantageously the entity that is closest to the terminals (ie which is directly connected to the terminals) that informs the entity responsible for the records of the terminals of the malfunctions encountered, if any, with them.

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

The second control entity of the network can thus, in a very simple way to implement, be quickly informed of a problem of communication with the terminal, and take the necessary actions, without waiting for the expiry of a timer for example, which makes it possible, in particular, according to at least one embodiment, to avoid consuming unnecessarily network resources (call signaling, restart delay, etc.).

Note that the invention applies regardless of the nature of the terminal, in other words that it is a fixed terminal or a mobile terminal, and whatever the nature of the problem of communication or reachability encountered with the terminal (loss of connection with the network, loss of the signaling path, etc.).

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

In another embodiment, the invention relates to a proxy control entity of an IP communication network, said first control entity, said IP communication network comprising said first control entity, terminal point of entry. in the IP communication network, and a second control entity responsible for recording the terminals in the IP communication network, said first control entity comprising a reprogrammable calculation machine or a dedicated computing machine configured to:

detect a communication problem with a terminal previously registered in said network, and

transmitting at least one message signaling said communication problem to the second control entity.

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

In particular, such an entity may be a P-CSCF proxy of an IP communication network having an IMS architecture. Such an entity may include physical and / or software means.

In yet another embodiment, the invention relates to a control entity responsible for recording the terminals of an IP communication network, said 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, of the proxy type, of the IP communication network, said first control entity being an entry point of the terminals in the IP communication network, said message indicating a communication problem with a terminal previously registered in the network, and

initiate the unregistering of the network terminal.

Such an entity is particularly suitable for implementing the deregistration method described above. Thus, such an entity may comprise 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 of an IP communication network having an IMS architecture. Such an entity may include physical and / or software means.

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 the program or these programs are executed by a processor.

In yet another embodiment, the invention relates to one or more information carriers, irremovable, or partially or totally removable, readable by a computer, and including instructions of 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 hard-wired form and / or in software form.

The invention also relates to an IP communication network comprising:

a first proxy-type control entity, the point of entry of the terminals into the IP communication network; and

a second control entity according to the invention responsible for registering the terminals in the IP communication network;

the first control entity comprising a reprogrammable calculation machine or a dedicated calculation machine configured to:

transmitting at least one message signaling said communication problem to the second control entity. In a particular embodiment, the IP communication network has an IMS architecture, and the first control entity is a P-CSCF type entity and the second control entity is an S-CSCF type entity.

4. List of figures

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

FIG. 1 illustrates the main steps implemented by a first control entity for the initiation of 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

Figures 3 and 4 show respectively 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 recovery towards the network core of this communication problem. Such a first proxy-type control entity is indeed an entity of the network near the terminal, and is therefore able to detect the problems of reachability of a terminal. This is the point of entry of the terminal on the IP communication network, that is, it is the entity of the IP communication network that is directly connected (via the access network) to the terminal.

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

Note that the terminal can be any type of terminal of an IP communication network, including a smartphone, a tablet, etc. The solution proposed is therefore generic and applicable to all types of terminals, and allows in particular to cause a deregistration on detection of permanent loss of connectivity with a terminal. In the following, with reference to FIG. 1, the main steps implemented by a first control entity, of the proxy type, of an IP communication network, for the initiation of the deregistration of a previously registered terminal are presented below. 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 a P-CSCF type entity. It is considered that the registration of the terminal in the IMS network has previously been carried out in a conventional manner, by the exchange of SIP requests between the terminal and an entity responsible for recording the terminals of the network, for example an entity of type S -CSCF as described in TS 24.229, paragraph 5.4.1.2.

During a first step 11, the first control entity of the network 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 a loss of at least one signaling path to the terminal; for example, if we consider an IP network of IMS type:

o the reception on the RX interface of a "RELEASE OF BEARER" message concerning the default bearer channel, may indicate the loss of the signaling path to the terminal; o the receipt of a "RELEASE OF BEARER" message concerning the Dedicated Bearer channel indicating the loss of the media path, and the analysis of the content of an attribute indicating the nature of the incident that caused the loss of the media path (for example, the "AVP RAN-NAS-Cause" attribute), may indicate the loss of all signaling paths to the terminal;

o etc. ;

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

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

the absence of receiving refresh requests from the terminal; by example, if we consider an IP network type IMS, the absence of refresh requests from the terminal if there is a NAT between the terminal and the first control entity of the proxy type (Frequent REGISTER, or message maintenance 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 problem of communication with the terminal. Such information notably makes it possible 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) may be marked "Temporarily Lost" or "Permanently Lost".

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

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

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

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 type S-CSCF.

During a first step 21, the second control entity of the network receives, or intercepts, at least one message sent by the first control entity, of the proxy type, and signaling a communication problem with the terminal. Such a message may be intended for the second control entity, or 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 unregistering of the terminal of the network, in particular of the contact address of the terminal.

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

According to 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 polling procedure of the terminal;

predefined delay elapsed from the receipt or interception of the message indicating a communication problem with the terminal;

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

etc.

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

Two examples of implementation of the invention are presented below.

5.2 First embodiment

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

According to this first embodiment, the detection 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 signaling a communication problem. Following reception on the first control entity of a request destined 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 the calling terminal, or another network entity, a response carrying the message indicating the communication problem.

For example, the message signaling a communication problem carries an error code. Such an error code can in particular be a dedicated code, for example of type 419. 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 a P-CSCF entity for an IP communication network having an IMS architecture) in response to a request to the terminal (for example a SIP request). , taking into account the context associated with the terminal. Such a response is transmitted in particular by the second control entity (for example an S-CSCF entity for an IP communication network having an IMS architecture) of the network responsible for registering the terminals. This then initiates the unregistering of the unreachable terminal, in ways that depend on the policy of the network operator.

As indicated in connection with 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 de-registering the terminal . As a variant, the operator's policy on the second control entity, when receiving / interception of a message signaling a communication problem, may consist of an 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. It is only in response to a request for the unreachable terminal 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 problem of communication with the terminal. 5.3 Second embodiment

According to a second embodiment, an IP communication network comprising a first proxy-type control entity implementing the steps of detecting a communication problem with a terminal previously registered in the IP network is considered, and transmission 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 a P-CSCF entity for an IP communication network having an IMS architecture) has detected (11) the loss of connectivity with the terminal (for example in case of no reception refreshing requests from the terminal if there is a NAT between the terminal and the first proxy-type control entity, upon receipt of the signaling path loss-type events, etc.), it transmits (13) a message signaling the communication problem to the second control entity (for example an S-CSCF entity for an IP communication network having an IMS architecture) to prevent it from the communication problem 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 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 "Temporarily Lost" indicator. , or any other indicator that indicates a communication problem. Following a predetermined number of such detections, the first control entity marks the context associated with the terminal with the "Permanently Lost" indicator, and then sends the second control entity the message signaling the communication problem.

In either of these variants, the message signaling 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 header "Reason" carries information associated with an error code. As an example, such a message is a SIP request whose "Reason" header is valued at 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 (body xml).

As indicated in connection with 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 an immediate deregistration. As a variant, the operator's policy on the second control entity, when receiving a message signaling a communication problem, may consist in the triggering of one or more prior actions such as in particular: a polling procedure the terminal, a probationary period, a threshold on the number of messages signaling a communication problem with the received terminal, etc., or a combination of these criteria, before de-registering the terminal. These actions are intended in particular to verify and confirm the existence of the communication problem before de-registering the terminal (as opposed to the immediate deregistration of the terminal which does not include such prior actions of verification or confirmation).

According to this second embodiment, the first control entity is pro-active 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, the simplified structures of a first control entity, of the proxy type, of an IP communication network and of a second control entity, responsible for the registration of 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 computer, for example a processor P, and driven by the computer program 33, implementing the method of initiation of a deregistration according to one embodiment of the invention.

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

The processor of the processing unit 32 implements the steps of the method of initiation of a deregistration described above, according to the instructions of the computer program 33, to detect a communication problem with a terminal, and transmit at least a message signaling the communication problem (to 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 computing machine, for example a processor P, and driven by the computer program 43, implementing the deregistration method according to one embodiment of the invention.

At initialization, the code instructions of the computer program 43 are for example loaded into a RAM 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 receiving at least one message sent by the first entity control signaling a communication problem with the terminal.

Claims

A method of de-registering a previously registered terminal in an IP communication network comprising a first and a second control entity, said first control entity being of the proxy type and an entry point of the terminals in the IP communication network said second control entity being responsible for registering the terminals in the IP communication network, said method comprising:

the reception or interception (21) by the second control entity of at least one message sent by the first control entity signaling a communication problem with the terminal, and

initiating (22) the unregistering of the terminal of said network by the second control entity.

2. Deregistration method according to claim 1, wherein the reception or interception of said message triggers the immediate deregistration of the terminal of said network.

3. A method of de-registration according to claim 1, wherein 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 delay elapsed from the receipt or interception of the message signaling a communication problem with said terminal;

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

4. Method according to any one of claims 1 to 3, wherein said message carries an error code.

5. Method according to any one of claims 1 to 4, wherein the message is a SIP request whose header "Reason" carries information associated with an error code.

The method of any one of claims 1 to 5 further comprising detecting the communication problem with the terminal by said first control entity.

7. Method according to claim 5, wherein said detection of the communication problem with the terminal by said first control entity triggers the storage (12) by said first control entity, in a context associated with said terminal, of information representative of the communication problem with the terminal, and the message indicating the communication problem is issued taking into account said context associated with the terminal.

The method according to any one of claims 1 to 7 wherein said message signaling the communication problem is sent by the first control entity in response to a request to the terminal and received by the first control entity.

9. The method of claim 6, wherein said detection of a communication problem with the terminal by the first control entity implements at least one of:

detecting a loss of at least one signaling path to said terminal;

the absence of a response from said terminal;

receiving an error message;

the absence of reception of refresh requests from said terminal.

The method according to any one of claims 1 to 9, wherein said IP communication network is an IMS network, the first control entity is a P-CSCF entity, and the second control entity is a communication entity. type S-CSCF.

11. Computer program comprising instructions for implementing a method according to any one of claims 1 to 10 when the program is executed by a processor.

12. Control entity responsible for registering the terminals of an IP communication network, said second control entity, comprising a reprogrammable calculation machine or a dedicated calculation machine configured to:

receiving or intercepting at least one message transmitted by a first proxy-type control entity of said IP communication network, said first control entity being an entry point of the terminals in the IP communication network, said message signaling a problem of communication with a terminal previously registered in said network, and

initiating the deregistration of said terminal of said network.

An IP communication network comprising:

a second control entity according to claim 12 responsible for registering the terminals in the IP communication network;

An IP communication network according to claim 13 having an IMS architecture, and wherein the first control entity is a P-CSCF entity and the second control entity is an S-CSCF entity.