FR2785117A1 - Client server communications network link validation/qualification/fault detection having fault detection discriminating anomalies and analysis finding anomaly/fault origin/nature. - Google Patents

Abstract

The information qualification technique and fault location operates between client sites exchanging frame and non frame digital words in a network. The technique detects the anomalous information and/or faults in the network section between client sites (30,34), and discriminates anomalies (36).

Description

METHOD FOR QUALIFYING INFORMATION AND

  ASSISTING THE LOCATION OF DEFECTS ON DIGITAL NETWORK

TELECOMMUNICATION

  The present invention relates to a system and method for qualifying information and assisting the location of faults in a digital telecommunication network comprising a plurality of equipment

  transmission arranged between at least one first site

  client and at least a second client site exchanging, via at least one operator site, digital data in raster mode or in untrammed mode, each client site being connected to the network via a network-client interface equipment able to discriminate anomalies and / or

  defects from the customer site or the operator site.

  The invention relates particularly but not exclusively to a method intended to be implemented in a digital network, such as for example leased links El / T1, E2 / T2, E3 / T3, E4 (1.5 Mbit / s to Mbit / s) to provide telecommunications operators with reliable information on the

  locating any defects.

  The liberalization of telecommunications at national and international level has generated strong competition between operators which has led them to establish contracts in which they undertake to provide users of national and international digital networks a guarantee on their

  quality and the recovery time of any defects.

  The criteria used for quality calculation (QoS) and localization of faults generally used are based on international standards (ITU-T, ETSI). On the basis of these standards, operators commit themselves to their customers on two main parameters: - the maximum annual (or monthly) period of unavailability of services sold, also called

  "Guaranteed Maximum Downtime in English" GMD.

  - The Time Lapse Guarantee, GTR also called "Guaranteed Time to Repair in English", which represents the maximum time that the operator has to repair a defect before paying penalties. The GTR expresses itself most often in hours (s). The quality criteria (QoS) generally used are based on international standards (ITU-T G. 826, NMF 701) that define availability, and the "Service Level Agreement" (SLA in English). According to these standards, availability is defined by a typical value parameter of 99.9%, which translates into nine hours of service unavailability per year, the backup time guarantee (GTR) has a typical value of two hours or four hours and is the minimum time allowed for the operator to restore the service as soon as a problem is notified by the customer.The SLA is a weighted combination of G.826 and GTR parameters. qualification of the relevant information to calculate quality of service (QoS) and SLA, and any false detection of this information results in an artificial degradation of QoS and SLA. telecommunications operators to move staff

  intervention and to pay penalties wrongly.

  In addition, these standards do not provide for the ability to locate faults on all duct sections of digital networks. The object of the invention is to solve the above problem by means of a method making it possible on the one hand to guarantee the operator information and quality parameters, and on the other hand, to locate in real time possible defects in digital telecommunication networks such as leased lines. The method according to the invention is characterized in that abnormality and / or defect information is detected in the portions of the network located between the client sites, the anomalies and / or defects originating from the site are discriminated against. client or the operator-site, at least one signal representative of the type and origin of the anomaly and / or of the detected defect is generated, then the generated signal is analyzed in order to deduce the origin and the nature of this anomaly. and / or this defect. The method according to the invention thus enables the operator to achieve: - pro-active supervision of their end-to-end services (client site to customer site); - the provision of instant and reliable means of locating defects without moving personnel

  and without intervention at the customer.

  Preferably, the method according to the invention further comprises the following steps: a- an acquisition step of collecting, dating and synchronizing anomaly and fault information in at least one point of the network, then sorting and isolate incoming information, outgoing information and end-to-end information, then record this information in a buffer, b- a test step of checking whether incoming information generates end-to-end information and / or outgoing information; c- a correlation step of repositioning the incoming information in one direction and their consequent action on the end-to-end information flowing in the opposite direction and then calculating at least one parameter representative of the quality and / or performance of the network or part of it; d- a step of validating the relevance of the information at each of the preceding steps; e- a step of processing the information validated in the previous step; Through this process, operators can optimize the quality of service they provide to

their clients.

  According to an important characteristic of the invention, when the digital data is transmitted in non-raster mode, the signal generated is either a first S1 signal (SIA signal) scrambled, or a second signal S2 type IAD (Distinct Alarm Indication Signal) scrambled, a third S3 signal of scrambled IAD type. By way of non-limiting example, the first signal S1 is obtained by scrambling a first sequence M1 encoded on a first number or bits, the signal S2 is obtained by scrambling a second sequence M2 encoded on a second number n2. of bits, the signal S3 is obtained by scrambling a third sequence M3

  coded on a third number n3 of bits.

  When the digital data is transmitted in raster mode, the generated signal is either a fourth partially modified SIA signal S4, a fifth IAD type signal S5 carrying a first code, or a sixth IAD type signal S6 carrying a

second code.

  Other features and benefits of

  the invention will emerge from the description which will

  follow, taken by way of non-limiting example, made by reference to the model of a leased link (LL) in a multi-operator or client-operator application with the services using the non-raster mode or the raster mode on the digital networks telecommunication and with reference to the appended figures in which: - Figure 1 shows schematically a leased link in a digital multi-operator communication network in which is installed a system according to the invention; FIG. 2 represents a schematic block illustrating a method according to the invention; FIG. 3 represents a block diagram illustrating an acquisition step according to the invention; FIG. 4 represents a schematic block illustrating a test step according to the invention; FIG. 5 represents an exemplary implementation of the method in a network over which digital data is transmitted in non-raster mode; FIG. 6 represents a flow chart illustrating an example of data processing at the site-operator according to a method according to the invention in a network on which non-rasterized digital data is transiting; FIG. 7 represents an exemplary implementation of the method in a network over which digital data is transmitted in raster mode; FIGS. 8 and 9 represent a flowchart illustrating an example of data processing according to a method according to the invention in a network on which digital data is transmitted in

raster mode.

  FIG. 1 illustrates a system for qualifying information and assisting the location of faults in a digital telecommunication network comprising a plurality of transmission equipment arranged between at least a first client site and at least one

  second customer-site exchanging via at least one site-

  operator, digital data in raster mode or in non-raster mode, each client site being connected to the network

  via a network-client interface equipment.

  According to a first important characteristic of this system, each network-client interface equipment comprises means capable of discriminating anomalies.

  and / or defects from the customer-site or site-

  operator, means for generating at least one signal representative of the type and origin of said defect, means for analyzing the generated signal so as to deduce the origin and the nature of the anomaly and / or the defect. As illustrated in FIG. 1, two remote devices A and B integrating said network-client interface equipment are connected in

  a digital network 20, through a leased line LL.

  In order to detect anomalies that may affect communications in the networks 20, one or a plurality of probes (not shown) are placed between the remote devices A and B in order to capture and analyze the relevant information to calculate at least a criterion of quality and / or performance of the

network 20.

  A central device 21 is installed at O in one of the premises of the operator. The remote devices A, B and the central device O are inserted in break

  on the leased line and exchange via the site-

  operator, digital data in raster mode or in non-raster mode. The remote devices A and B acquire and process the anomaly and / or fault information, while the central device 21 acquires the anomaly and / or fault information, the processing of this information. and possibly the steps of testing and validating the relevance. The line between the customer sites A and B and the central site 0 is divided into portions numbered from 1 to 16. The anomaly and / or defect information is detected in A, B, and O

  (and possibly at other intermediate points).

  In the event of anomaly and / or defect detected in A and / or B, at least one signal representative of the type and origin of said defect is generated. In O, we analyze the (s) different signal (s) generated to deduce

  the origin and nature of the anomaly and / or defect.

  In a preferred embodiment of the invention, when the digital data is transmitted in non-raster mode, the generated signal is either a first signal SIA (Alarm indication signal) scrambled, or a second signal S2 type IAD (Distinct Alarm Indication Signal) scrambled,

  a third signal S3 of scrambled IAD type.

  In addition, the first signal Si is obtained by scrambling a first sequence Mi coded on a first number or bits, the second signal S2 is obtained by scrambling a second sequence M2 encoded on a second number n2 bits, and the signal S3 is obtained by scrambling a third sequence M3

  coded on a third number n3 of bits.

  In raster mode, the signal generated is either a fourth partially modified SIA signal S4, a fifth IAD type signal S5 carrying a first code, or a sixth IAD type signal S6 carrying a second code. As an example of implementation, the signal S4 is obtained by forcing a part of the bits of an SIA signal to a logic level 1 during at least one determined time interval, the signal S5 is obtained by a first coding of a particular bit of an IAD signal, the signal S6 is obtained by a second coding of a particular bit of a

IAD signal.

  The signal S4 is, for example, a signal all at 1 over the last thirty-one time intervals IT1 to IT32 of the 2 Mbit / s frame which comprises thirty two, the signal S5 can be obtained by a first coding of a national reserve bit associated with bit 4 of the time interval IT0 of the 2 Mbit / s frame, and the signal S6 can be obtained by a second coding, different from the first coding, of a national reserve bit associated with the bit 4 of the IT0 time interval

O10 of the frame 2 Mbit / s.

  In operation in non-raster mode, as illustrated in FIG. 5, when a fault of the MQS or SIA type is detected at the client interface on the client site (A or B), a transmission is transmitted. signal If at the operator site, when a MQS fault is detected at the network interface on the client site (A or B), a signal S2 is transmitted to the operator site and a signal of the type SIA on the client side, when an SIA fault is detected at the network interface on the client site (A or B), a S3 signal is transmitted to the operator site and an SIA signal is forced on the client side, when a signal of type Si is detected at the level of the network interface on the client site (A or B) a signal of

SIA type on the client side.

  Furthermore, as shown in FIG. 6, in the non-raster mode, the anomaly and / or fault information collected on each side of the point O is detected (see FIG. 1). This point O is for example a central point of control at the operator. Thus, when one of the defects of the type Si, S2 or S3 is detected on one of the sides of the point O, the other side (towards the operator-client demarcation point A or B) is transmitted an Si-type signal; and when an MQS defect, SIA, is detected is detected on one of the sides of the point O, on the other side (towards the operator-client demarcation point A or B) a signal of the SIA type is transmitted. In raster mode, as shown in FIG. 7, when a fault of the MQS or SIA type, or of the Loss of Frame Lock (PVT) type is detected on the client interface side at the client site (A or B)

  an alarm signal S4 is generated on the site side

  operator, when a fault of the type IAD is detected on the side of the client interface on the customer site (A or B) and in the absence of MQS or SIA or PVT type fault on the side of the network interface on the client site propagates this Remote Anomaly Indication (IAD) signal on the operator site side, when a SIA or PVT type fault is detected on the network interface side at the client site a S5-type signal on the operator-site side while inhibiting the IAD-type signal on the operator-site side and forcing a client-side SIA-type signal when a MQS-like fault is detected on the the network interface on the site-client generates a signal of type S6 on the side of the operator-site

  while inhibiting the IAD type signal on the site side

  operator and forcing an SIA signal on the client side and inhibiting client-side S5 or S6 signals when they are detected at the client-site network interface. In addition, as shown in FIGS. 8 and 9, in raster mode, anomalous and / or defect information collected from 1I is detected each side of the point O (see FIG. 1). This point O is for example a central point of control at the operator. Thus, when a S4-type fault is detected on one of the sides of the point O, an SIA-type signal is transmitted on the other side (towards the operator-client demarcation point (A or B), and when MQS, SIA or PVT fault is detected on one of the sides of the point O, a signal is transmitted on the other side (towards the operator-client demarcation point A or B)

o SIA type.

  In non-raster mode, the fault locating step illustrated in FIG. 6 consists in: inhibiting the S2 or S3 type signals on the side of one of the client sites when a defect of another type is detected on the side of the other client site; - locate the defect in the portion 1

  (respectively in part 9) of the line, ie

  say the first (respectively second) site-client when a fault of type S1 is detected at O of side A (respectively B); - locate the fault in the portion 2 or 3 (respectively in the portion 10 or 11) of the line, that is to say upstream of the last transmission equipment before the central site when an SIA-type fault is detected at O on the A side (B respectively); - locate the defect in portion 4

  (in part 12) of the line, that is,

  that is, downstream of the last transmission equipment before the central site when an MQS or HDB3 error is detected at O on the A side (respectively B); locating the fault in the portion 5 or 6 (respectively in the portion 13 or 14) of the line, that is to say upstream of the last transmission equipment after the central site when a defect of the type S2 is detected at O on the B side (A respectively); - locate the defect in the portion 7

  (in part 15) of the line, that is,

  downstream of the last transmission equipment after the central site when a S3-type defect is

  detected in O on the B side (A respectively).

  Furthermore, in raster mode, as illustrated by FIG. 8 (respectively by FIG. 9), the fault location on the first (respectively second) site-client side consists of: inhibiting the IAD, S5 type signals or S6 on one of the sides of the client sites when a fault of another type is detected on the side of the other client site; - locate the defect in the portion 1

  (respectively in part 9) of the line, ie

  say upstream of the first client site (respectively of the second), when a S4 type fault is detected at O on the A side (respectively B); - locate the fault in the portion 2 or 3 (respectively in the portion 10 or 11) of the line, that is to say upstream of the last transmission equipment before the central site when an SIA-type fault is detected at O on the A side (B respectively); - locate the defect in portion 4

  (in part 12) of the line, that is,

  that is, downstream of the last transmission equipment before the central site when an MQS or HDB3 error is detected at O on the A side (respectively B); - locate the fault in the portion 2, 3, 4 (respectively in the portion 10, 11, or 12) of the line, that is to say between the first client site

  (respectively the second customer site) and the site-

  central when a fault type PVT or possibly PVT CRC or EB is detected in O on the side A (respectively B); - locate the fault in the portion 1, 2, 3 or 4 (respectively in the portion 9, 10, 11 or 12) of the line, that is to say either upstream of the first customer site (respectively on the side second client site), either between the first client site (respectively the second client site); and the central site when a VT error is detected at O on the A side (respectively B); - locate the fault in the portion 13 or 14 (respectively in the portion 5 or 6) of the line, that is to say upstream or downstream of the first transmission equipment after the central site when a defect of type S5 is detected in O on the A side (respectively

B);

  - locate the defect in the portion 15

  (respectively in section 7) of the line, that is,

  say downstream of the last transmission equipment after the central site when a S6-type fault is detected at O on the side of the second A (respectively B); - locate the fault in the portion 16, (respectively in portion 8) of the line, when an IAD type of fault is detected at O side A (respectively B); - locate the defect in the portion 9, 10, 11, 12, 13, 14, 15, 16, (respectively in the portion 1,

  2, 3, 4, 5, 6, 7, 8) of the line, that is to say

  end-to-end between the second client-site and the first client-site and the second client-site when a bit-e-type defect is detected at O on the A side (respectively B. As has been said previously, the method according to the invention also makes it possible to qualify relevant information to calculate at least one

  criterion of quality and / or performance for that purpose.

  (see Figure 2): a- an acquisition step of collecting, dating and synchronizing fault and fault information at the probes, then sorting and isolating the incoming information, the outgoing information and the information information; at the end, then to save this information in a memory

buffer 32.

  b- a test step 34 consisting of checking whether incoming information generates end-to-end information and / or outgoing information; c- a correlation step 36 of repositioning the incoming information in one direction over time and their consequent actions on end-to-end information traveling in the opposite direction and then calculating at least one parameter representative of the quality and / or performance of the network or part of it; d- a validation step 40 of the relevance of the information at each of the preceding steps; e- a processing step 42 of the information. Note that in each of the preceding steps, synchronization 44 of the calendar clocks of the probes and a resynchronization are carried out.

  events during the communication.

  Thus, in order to carry out the acquisition step 30, the probes are synchronized on the frame of the data exchanged between the remote devices A and B. The collected information is then processed according to the standard in force before being recorded in the buffer 32. Said buffer 32 is then managed so as to compensate the response time of the remote devices A and B and the propagation time

data in the LL loop.

  As illustrated by FIG. 4, the test step 34 consists of checking whether an incoming information from A to O (from B to O) from

  default type is correlated with end-to-end information

  end of B to A (respectively A to B) and / or outgoing information. Following this test, incoming information of the default type will be qualified if it is correlable with end-to-end information.

  and will not be qualified otherwise.

  The parameters used to represent the quality and performance of the network depend on the transmitted bit error rate and / or the propagation delay

  and / or the efficiency of the telecommunication network.

  For example, the ITU-T G.826 standard defines the parameter K (CD) representative of the availability of the link between the two points C and D by the difference between the parameter K <c), representing the availability at point C and parameter K (D), representing the availability at point D:

K (CD) = K (C) K (D)

  The calculation of K (CD) makes it possible to highlight the inconsistencies that affect the communication to

through the network 2.

  According to an important feature of the method according to the invention, these inconsistencies are classified into four categories IA, IB, IC and ID. The inconsistency will be of the type IA if the information is not qualified in the test step 30, of the type IB if the difference of QoS KóCD) is negative between two points of the same LL, of the type IC if simultaneous information circulate in both directions of transmission, and of the ID type in case of desynchronization. In the case of an inconsistency of the type IA, by hypothesis, the terminal loops the information. The probable causes of such an inconsistency are either a simultaneity defect in the two directions of transmission of the link which has the effect of concealing the looped information, or the fact that "m" seconds disturbed in a direction of transmission correspond to "m +/- l" seconds disturbed in the other direction or the fact that the probes provide false information. The method according to the invention makes it possible to determine that the probe provides false information if, on the one hand, there is no presence of a simultaneous fault in the two directions of transmission of the link, and on the other hand On the other hand, if "m" seconds disturbed in one direction are not correlable with "m +/- l" seconds disturbed in the other direction. In the case of an IB type inconsistency,

  hypothesis the probe does not supervise the physical layer.

  The probable causes of such an inconsistency are verified by the probes and can be either a non respect of the engineering rules, or the fact that m "seconds disturbed in a direction of transmission correspond to" m +/- l "seconds disturbed in the other meaning or the fact that the probes

provide false information.

  In this case, the method according to the invention makes it possible to deduce that the engineering rules are not respected or that the probes provide "false information." The probable causes of an IC type inconsistency are either a break in the link which is detected by the probes, that the link is faulty in both directions.This is also detected by the probes.In this case, the information is not

classifiable.

  Inconsistencies of the ID type may be due to sensor detection failure or

failure in server access.

  In this case, the server detects its anomalies and

  the information is not qualifiable.

  The information processing step 42 makes it possible to manage the alarms at the level of the equipment, network and services layers. The result of these treatments is then presented in the form of a dashboard for example made available to the operators.

Claims (18)

  A method for qualifying information and assisting the location of faults in a digital telecommunication network comprising a plurality of transmission equipment arranged between at least one first client site and at least one second client site exchanging, via at least one operator site, digital data in raster mode or non-raster mode, each client site being connected to the network via a network-client interface equipment capable of discriminating anomalies and / or defects originating from the site; client or the operator-site, characterized in that one detects information of anomaly and / or defect in the portions of the network located between the sites-customers, one discriminates the anomalies and / or the defects coming from the site-client or of the operator-site, then at least one signal representative of the type and origin of said defect is generated, then the generated signal is analyzed to deduce the origin and the nature of the anomaly and / or u default. 2. Method according to claim 1, characterized in that, in non-raster mode, the signal generated is either a first signal Si of type SIA (Alarm indication signal) scrambled, or a second signal S2 type IAD ( Disturbed Alarm indication signal),   a third signal S3 of scrambled IAD type.   3. Method according to claim 2, characterized in that the first signal S1 is obtained by scrambling a first sequence M1 coded on a first number n1 of bits, the second signal S2 is obtained by scrambling a second sequence M2 coded on a second number n2 of bits, and the signal S3 is obtained by scrambling a third sequence M3   coded on a third number n3 of bits.   4. Method according to claim 1, characterized in that, in raster mode, the generated signal is either a fourth partially modified SIA signal S4, or a fifth IAD type signal S5 carrying a first code, or a sixth signal S6. IAD type carrying a second code.   5. Method according to claim 4, characterized in that the signal S4 is obtained by forcing a part of the bits of a signal SIA to a logic level 1 for at least a determined time interval, the signal S5 is obtained by a first coding of a particular bit of an IAD signal, the signal S6 is obtained by   a second coding of a particular bit of an IAD signal.   6. Method according to one of claims 1 to 3,   characterized in that a signal Si is transmitted to the operator site when a fault of the MQS or SIA type is detected at the customer interface on the customer site, the S2 signal is transmitted to the operator site. when an MQS-type fault is detected at the network interface on the client-site, and a S3 signal is transmitted to the operator-site and when an SIA-type fault is detected at the network interface on the the client site. 7. Method according to claim 6, characterized in that the anomaly and / or defect information collected on each side of the operator-client demarcation point is detected, said information is synchronized and a client-side SIA signal is transmitted when at least one of the Missing Signal (MQS) type defects SIA or Sl, is detected on the network interface on the client site.   8. The method as claimed in claim 3, characterized in that the step of locating the fault consists in: inhibiting the S2 or S3 type signals on the side of one of the client sites when a defect of another type is detected on the side of the other client site; - locate the fault in the first (respectively second) site-client when a Si type fault is detected on the side of the first (respectively second) site-client; locate the fault upstream of the last transmission equipment before the central site when an SIA-type fault is detected on the first (respectively second) client-site side; - locate the fault downstream of the last transmission equipment before the central site when an MQS or HDB3 error is detected   on the side of the first (respectively second) site-   customer; locating the fault upstream of the last transmission equipment after the central site when a S2 type fault is detected on the side of the second (respectively first) client site; - locate the downstream fault of the last transmission equipment after the central site when a S3 fault is detected on the side   the second (respectively first) site-client.   9. Method according to claim 4, characterized in that an alarm signal S4 is generated on the operator-site side when one of the faults of the MQS, SIA type, or of the Loss of Frame Lock type (PVT). ) is detected on the client-site client interface, a Remote Anomaly Indication (IAD) signal is transmitted on the operator-site side only when no MQS, SIA or PVT faults are detected on the network interface of the customer-site, we force to zero the   type S5 or S5 signals on the customer interface of the   client, an SIA signal is forced on the client interface of the siteclient when one of the defects of the MQS, SIA, or Loss of Frame Lock (PVT) type is detected on the siteclient's network interface,   an S5 type alarm signal is generated on the site side   when an SIA or PVT type fault is detected on the network interface of the customer site, an S6 type alarm signal is generated on the operator site side when an MQS type fault is detected on the interface network of the client site, and a possible IAD type signal is inhibited on the operator-site side when an MQS, SIA or PVT type fault is detected on the interface client-site client.   The method according to claim 9, characterized in that the fault and fault information is dated and synchronized at a centralized point at the operator site, and an SIA type alarm signal is generated on the operator side. first client site when one of the MQS, SIA, PVT or S4 type faults is detected on the side of the second client site, one generates a   SIA alarm signal on the side of the second site-   customer when one of the defects of type MQS, SIA, PVT or   S4 is detected on the side of the first client site.   11. A method according to claim 10, characterized in that the fault location on the side of the first (respectively second) site-client consists in: inhibiting the signals of type IAD, S5 or S6 on one of the sides of the sites; client when a fault of another type is detected on the side of the other client site;   - locate the fault upstream of the first site-   customer (respectively of the second), where a defect   type S4 is detected on the side of the first site-   customer (respectively the second customer site); - locate the fault upstream of the last transmission equipment before the central site when an SIA-type fault is detected on the side of the first client site (respectively on the side of the second client site); - locate the defect downstream of the last transmission equipment before the central site when a fault type MQS or HDB3 error is detected on the side of the first client site (respectively side of the second client site);   - locate the fault between the first site-   client (respectively the second client site) and the central site when a PVT type or possibly PVT CRC or EB fault is detected on the side of the first client site (respectively on the second client site side); - locate the fault either upstream of the first   site-client (respectively on the side of the second site-   client), or between the first client site   (respectively the second customer site) and the site-   central when a VT error is detected on the side of the first client site (respectively on the side of the second client site); locating the fault upstream or downstream of the first transmission equipment after the central site when a fault of the S5 type is detected on the side of the second client site (respectively on the side of the first client site); locate the defect downstream of the last transmission equipment after the central site when a S6-type fault is detected on the side of the second client site (respectively on the side of the first client site); - locate the "end-to-end" fault between the second client site and the first client site (respectively between the first client site and the second client site) when a bit-e type defect is detected on the side of the second customer site (respectively on the side of the first client site).   A method of qualifying relevant information for computing at least one quality and / or performance criterion in a digital telecommunication network (2), characterized in that it comprises: a- an acquisition step (30) consisting of collect, date and synchronize fault and fault information in at least one point of the network, then sort and isolate the incoming information, the outgoing information and the end-to-end information, and then record this information in a buffer (32); b- a test step (34) of checking whether incoming information generates end-to-end information and / or outgoing information; c- a correlation step (36) of repositioning in time incoming information in one direction and their consequent action on the end-to-end information flowing in the opposite direction and then calculating at least one parameter representative of the quality and / or performance of the network or part of it; d- a validation step (40) of the relevance of the information to each of the preceding steps; e- a processing step (42) of the information validated in the previous step.   13. The method as claimed in claim 12, characterized in that the test step (34) consists in verifying whether an incoming information of A to C (or B to C) of the default type is correlatable with an end-to-end information. -bout from B to A (respectively from A to B) and / or outgoing information. The method according to claim 13, characterized in that incoming information of the default type will be qualified if it is correlable with end-to-end information and will not be qualified. on the other hand.   15. Method according to claim 11, characterized in that the repositioning in time of the incoming information in one direction and their consequent action on the end-to-end information flowing in the opposite direction consists in managing the buffer memory (32). in order to compensate for the response time of the remote devices and the time of   data propagation in the LL loop.   16. Method according to one of claims 11 to   characterized in that the parameters representative of the quality and / or performance of the network (2) depend on the transmitted bit error rate and / or the   propagation time and / or performance of said network.   17. Process according to any one of   Claims 1 to 11, characterized in that it comprises   in addition: a- an acquisition step (30) of collecting, dating, and synchronizing fault and fault information at at least one point of the network, and then sorting and isolating the incoming information, the outgoing information, and the end-to-end information, then storing this information in a buffer (32); b- a test step (34) of checking whether incoming information generates end-to-end information and / or outgoing information; c- a correlation step (36) of repositioning in time incoming information in one direction and their consequent action on the end-to-end information flowing in the opposite direction and then calculating at least one parameter representative of the quality and / or performance of the network or part of it; d- a validation step (40) of the relevance of the information to each of the preceding steps; e- a processing step (42) of the information validated in the previous step.   18. A system for qualifying information and assisting the localization of faults in a digital telecommunication network comprising a plurality of transmission equipment arranged between at least a first client site and at least a second client site exchanging, via at least one operator site, digital data in raster mode or in non-raster mode, each client site being connected to the network via a network-client interface equipment, said system being characterized in that each interface equipment client network comprises means capable of discriminating anomalies and / or defects from the client site or the operator site, means for generating at least one signal representative of the type and origin of said defect, means for analyzing the signal generated so as to deduce the origin and the nature of the anomaly and / or the defect.