WO2011001062A1

WO2011001062A1 - Supervision of communication quality in telecommunication network gateway

Info

Publication number: WO2011001062A1
Application number: PCT/FR2010/051253
Authority: WO
Inventors: José DOREE; Jean-Claude Le Rouzic
Original assignee: France Telecom
Priority date: 2009-06-30
Filing date: 2010-06-21
Publication date: 2011-01-06
Also published as: EP2449746A1

Abstract

In order to supervise communication quality in a resource managed by a gateway connected to a service entity (ES) via an intermediate monitoring entity (ECI1) in a telecommunication network supporting a session initiation protocol, after detecting a quality defect in the resource, the gateway transmits (A5) a quality notification (NOTIFY_Q) to the service entity after establishing a service communication (AD) between the latter. The notification contains an identifier and a datum of the communication quality of the resource. Before or after reestablishing the communication, the service entity can subscribe to the supervision by transmitting (A1) a subscription request (SUBSCRIBE) that includes a type of resource monitored by the gateway. The gateway can be preconfigured to establish the communication for notifying the service entity of the quality defect.

Description

Supervision of communication quality in a gateway of a telecommunication network

The present invention relates to real-time monitoring of the quality of communication in a gateway of a packet-switched telecommunication network in the context of voice and multimedia data applications. It is located at the layers of control and application of the architecture of an IMS multimedia subsystem ("Internet protocol Multimedia

Subsystem "in English) network supporting a signaling protocol of the type of session initiation protocol SIP (Session Initiation Protocol) The SIP protocol is intended to control end-to-end sessions, including the establishment of a call between two user equipment or between a user equipment and an application server The quality of a communication is not constant over time and suffers sporadic or permanent degradation that may result from traffic overloads supported by packet routers, packet routing reconfigurations, or other disruptive events.

In next-generation NGN (Next Generation Generation Network) architectures, due to the decoupling between the control plane relating to signaling, commands and service applications and the media plan relating to transport, access and switching, disturbances of the media plane are not directly noticeable by the control plane. For example, if the requested service is conversational and there is a significant degradation in the quality of the audio stream, then it is not possible for the control plane to maintain network failure snapshots. tariff policy, or to order the triggering of test procedures.

The H.248 signaling protocol intended to control network media gateways allows through some extension packages (or

"packages" in English) the notification of such events to a MGC ("Media Gateway Controller" in English). These media gateways in the network are in practice large in size as gateways for access or trunk or route exchange, or gateways for processing and multiplexing MRF multimedia streams for broadcast announcements or conference bridges, and not are not small residential gateways. Only the MGC accessing the call processing is able to receive information about the quality of communications. In addition, information from quality are broadcast point-to-point from gateways to the MGC and no entity, such as a service server, not involved in call processing can benefit from this information. One of the aims of the invention is to remedy the shortcomings and disadvantages of the state of the art and to make improvements within the framework of a session initiation protocol by providing a method for supervising a quality of communication in a gateway managed resource connected to a service entity through at least one intermediate control entity in a telecommunication network supporting the session initiation protocol, which is characterized in that it comprises a transmission of a quality notification from the gateway to the service entity after establishment of a service dialogue between the service entity and the gateway and following a detection of a quality defect in the resource, the notification of quality containing an identifier of the resource and a communication quality data of the resource.

The intermediate control entity is an entity located in the control plane or control plane. For example, in a telecommunication network supporting the SIP session initiation protocol, it may be a call session control entity for service S-CSCF (Serving-Call Session Control Function). and / or a P-CSCF call session control proxy server ("Proxy-Call Session Control Function"). It is emphasized here that for a telecommunication network implementing the H.248 protocol, the MGC plays the role of this intermediate control entity and therefore it is not possible for a service entity to receive quality notification.

The service entity in the control plane receiving the quality notification may be either a call processing entity that can terminate the monitored communication or attempt re-routing procedures, that an entity not a priori not involved. in call processing, such as an application server for example relating to billing and / or providing a network failure snapshot. The quality notification can be transmitted in "multipoint" mode to one or more service entities and to one or more supervisory entities, the latter being able to continuously receive quality notifications of several gateways and trigger alarms. The control plane is then able to determine the quality of a data flow depending on many parameters that are not necessarily known to the control plane, nor to know by it.

Moreover, it is also emphasized here that in a telecommunication network implementing the H.248 protocol, a resource or termination is assigned to one and only one gateway and the quality notifications for that resource can only flow between that gateway and the MGC.

The communication quality data may be independent of the nature of the faulty resource, such as the physical medium or the transport layer thereof. The quality data can be generic information of degradation or return in normal condition satisfactory for the service entity. For example, if the requested service is conversational, a significant deterioration in the quality of the audio stream is notified to the service entity so that it maintains network failures, applies a specific tariff policy, or controls the triggering a test procedure. The degradation information may be accompanied by a threshold indication to allow modulated processing policies, and compiled by the service entity according to criteria specific to the level of quality and supervision sought by the network operator. telecommunication.

According to the invention, the quality notification can be transmitted after or without a quality subscription procedure by the service entity to the gateway. Thus the method can comprise, between the establishment of the dialogue and the transmission of the quality notification, or before the establishment of the dialogue, a transmission of a subscription request including a type of resource to be monitored by the gateway since the service entity to the gateway, or include a configuration of the gateway prior to establishing the dialogue to subsequently notify the service entity of the quality defect.

In order for the service entity to effectively control the communication quality supervision, the subscription request may include a timeout parameter to activate a timer in the gateway and the quality notification may include the time remaining from the timeout since the timeout. moment when the quality defect has been detected in the resource.

The quality notification may further include an identifier of the dialogue established previously to the quality notification.

The invention also relates to a telecommunication network able to support a session initiation protocol for supervising a quality of communication in a gateway capable of managing a resource and to be connected to a service entity through at least one entity. intermediate control, characterized in that the gateway is able to transmit a quality notification to the service entity after establishment of a service dialogue between the service entity and the gateway and following detection of a quality defect in the resource, the quality notification containing an identifier of the resource and a communication quality data of the resource.

The invention also relates to a gateway and a service entity. The gateway is able to manage a resource and be connected to a service entity through at least one intermediate control entity in a telecommunication network able to support a session initiation protocol, to supervise a quality of communication, and is characterized in that it is capable of transmitting a quality notification to the service entity after establishment of a service dialogue between the service entity and the gateway and following detection of a quality defect in the resource, the quality notification containing a resource identifier and a communication quality data of the resource.

The service entity for supervising a quality of communication in a resource capable of being managed by a gateway able to be connected to the service entity through at least one intermediate control entity in a telecommunication network able to support a communication protocol session initiation, is characterized in that it is able to receive a quality notification of the gateway after the establishment of a service dialogue between the service entity and the gateway and following a detection of a lack of quality in the resource, the quality notification containing a resource identifier and a communication quality data of the resource.

The invention further relates to a signal for monitoring a communication quality in a gateway-managed resource connected to a service entity through at least one intermediate control entity in a telecommunication network supporting a session initiation protocol, characterized in that it constitutes a quality notification containing a resource identifier and a communication quality data of the resource, to be transmitted from the gateway to the service entity after restoration of a service dialogue between the entity service and the gateway and following a detection of a quality defect in the resource. Other characteristics and advantages of the present invention will emerge more clearly on reading the following description of several embodiments of the invention given by way of non-limiting examples, with reference to the corresponding appended drawings in which: FIG. 1 is a schematic block diagram of a telecommunication network implementing a communication quality supervision method according to the invention;

FIGS. 2, 3 and 4 are time diagrams of steps composing the supervision method according to three embodiments of the invention; and

FIG. 5 is a timing diagram according to a variant of the method shown in FIG.

With reference to FIG. 1, a telecommunication network RT comprises an RC control network at the control and application layers of the multimedia IMS subsystem of the network RT. The RC control network is connected to various RES networks through GW gateways such as access gateways and trunk bridges located at the transport layer. EQ user equipments access via access gateways to packet mode networks such as, for example, a UTRAN cellular radio access network ("UMTS Terrestrial Radio Access Network"), a GPRS network ("General"). Packet Radio Service (English), a set of xDSL lines ("x Digital Subscriber One" in English), or a Wireless Local Area Network (WLAN). Networks of different types such as a packet switching network and an RTC switched telephone network interwork via trunk bridges.

The RC control network is decoupled from the media plane through the GW gateways. The RC network controls multimedia communication sessions relating to voice-related calls, including voice over IP, and data-related calls, as well as interconnections between networks.

The invention is particularly oriented in the control network RC to exchanges of requests and responses between a GW gateway and an ES service entity communicating through at least one intermediate control entity ECI of the control network. The gateway and the entities rely on the IP internet protocol and the SIP session initiation protocol.

The gateway GW according to its type ensures for example that a user equipment EQ communicates multimedia data from one user equipment to another or to an application server through at least one network, or a network to another network. It also exchanges signage

SIP with the RC control network. The gateway can be a digital multiplexer DSLAM user lines ("Digital Subscriber An Access Multiplexer" in English) connected to the Internet, a trunking bridge ("Trunking"). Gateway "in English) to a PSTN switched telephone network, a residential gateway ADSL RGW (" Residential Gateway ") at the end of a user terminal, a bridge exchange gateway between routers BGW (" Border Gateway ") in English), or a multimedia flow multiplexer MRF In general, the gateway offers a higher or lower bit rate and is traversed by a packet stream of one or more end-to-end communications. one of the gateways in Figure 1, the gateway manages RS resources and includes an AGS communication quality monitoring agent for detecting communication quality defects in one or more RS resources monitored by the agent.

The ES entity establishes rules for the quality of communications using resources managed by the GW gateway. The ES entity may be an AS service application server. An application can be for billing, triggering a service such as messaging or conferencing, processing SIP signaling, or testing. The I / O service entity may also be a session call control entity for S-CSCF (Serving-Call Session Control Function) service for recording and controlling sessions and for interacting with application servers.

The intermediate control entity ECI may be an S-CSCF control entity or a P-CSCF call session control proxy server ("Proxy-Call Session Control Function"). The proxy server is an entry point of the RC control network for user equipment that transmits SIP signaling requests to it.

In the embodiments of the communication quality supervision method illustrated in FIGS. 2 to 5, it is assumed that the service entity ES is an application server AS connected to the gateway GW through two intermediate control entities ECU and ECI2 which are an S-CSCF entity and a P-CSCF proxy server. The supervision is based on the specific event notification according to the SIP Protocol RFC 3265 specification published in June 2002 by the Internet Engineering Task Force (IETF).

With reference to FIG. 2, the communication quality supervision according to the first embodiment comprises SIP request transmission steps S1 and S6 after the service entity ES has established a service dialogue with a step AD. the GW gateway through the entities

ECU and ECI2 for the needs of a service. During this service dialogue, the service entity ES, as a subscriber, initiates in step A1 supervision by a subscription request SUBSCRIBE transmitted by the service entity. ES and retransmitted by the ECU and ECI2 entities to the GW gateway as a "Notifier". The SUBSCRIBE subscription request according to the invention can either reuse the previously established service dialogue or create its own dialogue and in this case it carries a message body containing the references of the service dialogue. It comprises, for example, header fields with known contents and contents specific to the invention. The header fields with known contents are in particular "To" and "From" identifying by addresses the destination gateway and the service entity, "CaII-Id" identifying a sequence in this case of subscription established by the ES entity, "Cseq" identifying the request SUBSCRIBE by the request sequence number SUBSCRIBE for example equal to 1, "Contact" including an URL of the entity ES and "Content-Length" including the length of a body message possibly carried by the request in bytes. The header fields with contents specific to the invention are "Event" including the type of subscription, in this case a quality report, and "Accept" indicating the format of the body of a NOTIFY notification transmitted in. response to SUBSCRIBE subscription request. The "Accept" field includes a type of resource to be monitored, such as the reception or routing of packets or the control of a data flow or an interface, in relation to a service application implemented in the ES entity, a type a report of quality and a type of notification encoding, such as a text mode or a language such as the Extensible Markup Language (XML), related to the service application.

In step A2, the gateway GW receives the request SUBSCRIBE and returns a response 200 OK taking the path opposite to that of the request to the entity ES via the entities ECU and ECI2.

The gateway analyzes the contents of the "Event" and "Accept" fields and confirms the creation of the subscription by transmitting a confirmation notification NOTIFY_C to the entity ES which acknowledges it by returning a response 200 OK in step E4. Receipt of the 200 OK response passes the AGS communication quality monitoring agent in the gateway GW to an ASU step from a neutral state to an activated state to detect quality defects in the RS resources monitored by the agent.

If the agent AGS detects a defect degrading the quality of a communication traversing one of the monitored resources, the agent establishes in step A5 a notification of quality NOTIFY_Q which is transmitted by the gateway to the ES entity via the ECU and ECI2 entities. The entity ES acknowledges the NOTIFY_Q notification by returning a response 200 OK in step A6. The notification NOTI FY_Q specific to the invention contains the known header fields "To", "From", "Contact", "CaII-Id", "Cseq" identifying the rank of the notification NOTIFY_Q in a sequence of notification, equal to 2, since this notification is the second after the confirmation notification NOTI FY_C, "Content-Type" indicating the type of the body of the notification defined by the resource, the type of quality report and the type of response which were extracted from the received request SUBSCRIBE, and "Content-Length". The notification NOTI FY_Q also contains header fields specific to the invention which are for example "Event" including a "QualityReport" event identifier but also a message body containing for example the "Resource" information containing a identifier of the resource causing the detected quality defect, and "QualityGrade" including communication quality data, such as a degraded quality rate of not more than 100%, associated with the resource.

During the dialogue, steps A5 and A6 are repeated each time a quality defect is detected by the AGS agent in the gateway GW. Depending in particular on the type of the resource that has produced the quality defect and the quality rate associated with the resource, the application implemented in the ES entity processes this information, in particular to remedy the quality defect. For example, the entity ES decides to reduce or eliminate the charge related to the communication crossing the faulty resource, to cut the communication, to modify the routing of the communication in order to route it by avoiding the faulty resource, or to trigger a test procedure or an alarm inviting an agent of the network operator to visit the site of the failed resource for testing and repair.

The end of the dialogue between the ES and the GW gateway completes the communication quality supervision according to the first realization.

The second embodiment of the communication quality supervision shown in FIG. 3 comprises steps B1 to B6 respectively similar to steps A1 to A6 completed by a delay BT. Subscription procedure B1 -B4 is executed outside the establishment of any BD service dialog. The subscription request SUBSCRIBE transmitted by the service entity ES (step B1) puts the service entity ES waiting for any quality notification NOTI FY_Q (step B5) succeeding the corresponding confirmation notification NOTI FY_C (step B3) and establishing a dialogue subsequent for the needs of a service (BD stage). The SUBSCRIBE request includes an additional "Expires" field including a timeout parameter. The gateway GW extracts the timing parameter of the request SUBSCRIBE so that a timer TP in the gateway (FIG. 1) is activated in a step BT succeeding step B4 of the acknowledgment of the confirmation notification transmission NOTIFY_C and remains activated until the expiry of a timer defined by the timeout parameter and indicating the end of the subscription. The step BT is concomitant with the step BSU of activating the AGS communication quality monitoring agent.

As long as the timer TP is active, one or more service dialogs that may each generate one or more NOTI FY_Q quality notification transmissions may be established between the ES and the GW gateway, as shown in steps BD, B5. and B6. A NOTIFY_Q quality notification includes, in addition to the fields defined above, a subscription status field "Subscription-State: active; expires = [TX]" containing an active value corresponding to the timer state for the accepted subscription by the gateway and a TX value indicating the remaining time of the delay since the moment a fault has been detected in a faulty resource monitored by the AGS agent and identified in the "Resource" field of the quality notification, fields in the header of the invention which are for example "Event" including a "QualityReport" event identifier and also a message body containing "Local Tag", "Remote Tag" and "CaII-ID" fields identifying a service dialog and also the "Resource" information containing an identifier of the resource causing the detected quality defect, and "QualityGrade" including communication quality data, such as degraded quality of up to 100%, associated with the resource.

In this second embodiment, the service entity ES proposes the duration of the quality supervision and can establish statistics on the frequency of quality defects as a function of the instant of activation of the timer and the associated delay values TX detected quality defects.

The subscription according to the second embodiment is terminated when the timer expires when the value TX in the timer TP is zero. This is signaled by a notification with a "Subscription-State" field containing a terminated subscription value, or by the transmission of a another SUBCRIBE subscription request containing a null TX value, which disables the TP timer.

The third embodiment of the communication quality supervision shown in FIG. 4 does not contain any A1-A4 or B1-B4 communication quality subscription and therefore no subscription request. The gateway GW is configured at a step CONF to notify quality defects to the ES entity prior to any CD dialogue established therebetween for the purposes of a service. The RC network transmission paths between the ES and the GW gateway via the ECU and ECI2 entities are not congested by subscription requests and confirmation notifications. Quality supervision only includes sets of steps CD, C5 and C6 similar to steps BD, B5 and B6. The gateway GW may be configured to multicast NOTIFY_Q quality notifications to one or more destination I / O service entities whose identifiers have been previously stored in the gateway. The AGS agent of the gateway may further be configured to notify quality defects only with respect to a subset of resources managed by the gateway.

Each of the three implementations comprising an AD, BD, CD dialog facility may be combined with a configuration of the GW gateway to also transmit NOTIFY_Q quality notifications to one or more supervisory entities other than the ES service entity, whose identifiers are pre-stored in the gateway.

According to the example illustrated in FIG. 5, the communication quality supervision comprises steps A1 to A6, ASU and AD according to the first embodiment and in addition to the steps D5 and D6 in relation with a local or remote SUP supervision entity. After subscription A1-A4 and during the dialogue established in step AD, if a quality defect is detected by the AGS agent, the gateway GW establishes in steps A5 and D5 quality notifications NOTI FY_Q which are similar to the recipient fields and dialogue identifiers and transmitted respectively to the ES service entity and the SUP supervision entity. Then the ES and SUP entities acknowledge the quality notifications by independently returning the 200 OK responses to steps A6 and D6. The implicit subscription in the SUP entity is terminated by a configuration action intervening in the gateway. Steps similar to steps D5 and D6 may occur before setting AD dialog or before A1-A4 subscription. The ES service entity receives only high quality notifications following the restoration of an AD, BD, CD dialog. On the other hand, the supervision entity SUP receives, at stages D5, the quality notifications associated with all the quality defects detected by the AGS agent, independently of any subscription and of any dialogue establishment, and can thus be responsible for centralizing all incidents occurring in the RT network gateways. The invention relates to a communication quality monitoring method, a telecommunication network, a gateway and a service entity. It also relates to computer programs that can be implemented respectively in the gateway and the service entity.

A computer program adapted to be implemented in the service entity is characterized by instructions which when the program is executed in a processor of the control entity, whose operation is then controlled by the execution of the program , implement steps of the method according to the invention.

A computer program adapted to be implemented in the gateway is characterized by instructions which when the program is executed in a gateway processor, whose operation is then controlled by the execution of the program, implement steps of the process according to the invention.

Accordingly, the invention also applies to computer programs, in particular recorded on or in a computer-readable recording medium or media and any data processing device, adapted to implement the invention. These programs may use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code such as in a partially compiled form, or in any other form desirable for implementing the method according to the invention.

A recording medium can be any entity, memory, circuit or device that can store the programs. The recording medium may be transmissible such as a signal routed via an electrical or optical cable, by radio or by other means. Programs can be downloaded via a network, such as the internet.

Claims

A method for monitoring communication quality in a gateway (GW) -managed (RS) resource connected to a service entity (ES) through at least one intermediate control entity (ECU) in a telecommunication network (RT) ) supporting a session initiation protocol, characterized in that it comprises a transmission (A5; B5; C5) of a quality notification (NOTIPZ-Q) from the gateway to the service entity after the establishment a service dialog (AD; BD; CD) between the service entity and the gateway and following a detection of a quality defect in the resource (RS), the quality notification containing an identifier of the resource and a communication quality data of the resource.

2 - Process according to claim 1, characterized in that it comprises, between the establishment of the dialogue (AD) and the transmission (A5) of the quality notification, a transmission (A1) of a subscription request (SUBSCRIBE ) including a type of resource to be monitored by the gateway from the service entity to the gateway.

3 - Process according to claim 1, characterized in that it comprises, before establishing the dialogue (BD), a transmission (B1) of a subscription request (SUBSCRIBE) including a type of resource to be monitored by the gateway from the service entity (ES) to the gateway.

4 - Process according to claim 3, characterized in that the subscription request (SUBSCRIBE) includes a timing parameter for activating a timer (TP) in the gateway and the quality notification (NOTI FY_Q) includes the remaining time of the timer since the moment the quality defect has been detected in the resource.

5 - Process according to claim 1, characterized in that it comprises a configuration (CONF) of the gateway prior to the establishment of the dialogue (CD) for notifying the quality defect to the service entity.

6 - Process according to claim 1, characterized in that it comprises a transmission (D5) of a quality notification (NOTI FY_Q) to at least one supervision entity (SUP).

7 - Telecommunications network (RT) capable of supporting a session initiation protocol for supervising a quality of communication in a gateway (GW) able to manage a resource (RS) and to be connected to a service entity (ES) to through at least one intermediate control entity

(ECU), characterized in that the gateway is able to transmit a notification of quality (NOTI FY_Q) to the service entity after establishment of a service dialogue (AD; BD; CD) between the service entity and the gateway and following detection of a quality defect in the resource (RS), the quality notification containing a resource identifier and a communication quality data of the resource.

8 - Gateway (GW) capable of managing a resource (RS) and being connected to a service entity (ES) through at least one intermediate control entity (ECU) in a telecommunication network (RT) able to support a protocol session initiation device, for supervising a communication quality, characterized in that it is able to transmit a quality notification (NOTI FY_Q) to the service entity after the establishment of a service dialogue (AD; BD; CD) between the service entity and the gateway and following a detection of a quality defect in the resource (RS), the quality notification containing a resource identifier and a communication quality data item of the resource resource.

9 - Service entity (ES) for supervising communication quality in a gateway (GW) -manageable resource able to be connected to the service entity through at least one intermediate control entity (ECU) in a facility. telecommunication network (RT) adapted to support a session initiation protocol, characterized in that it is able to receive a quality notification (NOTI FY_Q) of the gateway after restoration of a service dialogue (AD; BD ; CD) between the service entity and the gateway and following a detection of a quality defect in the resource (RS), the quality notification containing a resource identifier and a communication quality data of the resource .

Signal for supervising communication quality in a gateway (GW) -managed (RS) resource connected to a service entity (ES) through at least one intermediate control entity (ECU) in a telecommunication network (RT) ) supporting a session initiation protocol, characterized in that it constitutes a quality notification (NOTIFY_Q) containing a resource identifier (RS) and a communication quality data of the resource, to be transmitted from the gateway to the service entity after establishment of a service dialog (AD; BD; CD) between the service entity and the gateway and following a detection of a quality defect in the resource. 11 - Computer program comprising instructions for implementing the method according to claim 1, when the program is executed by one of a means comprising the gateway (GW) and other means comprising the entity Service (ES).