FR2849729A1 - Optical fiber cross connecting arrangement for use in communication network, has control unit associated with diagnostic unit to answer particular diagnostic to automatically control adapted commutation of distributor - Google Patents

Abstract

The arrangement has an optical distributor with a diagnosing unit to diagnose a connection set in work by the optical distributor. A control unit associated with the diagnostic unit answers to the particular diagnostic to automatically control an adapted commutation of the optical distributor. The control unit includes a prememorized plan for the control of commutation of the distributors in a communication network. Independent claims are also included for the following: (a) a process of arranging optical fibers in a communication network (b) a communication network.

Description

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  The invention relates to switches in fiber optic communication networks, and more specifically to such switches when implemented within multiple adjacent fibers, these switches were then called "patching".

  To perform this function, we mainly know about photonic brewers. Photonic brewers have the defect of being expensive, not always sufficiently reliable, and of generating strong insertion losses.

  All the equipment manufacturers have backtracked, for the moment, on the development of this solution.

  There are also known optical distributors which are completely passive network elements. On the one hand, they are controlled in a purely manual manner (the installation of optical jumpers is done by hand) and on the other hand no information or alarm comes from such equipment. The object of the invention is to propose an arrangement of optical mixing which is less expensive, more reliable and of satisfactory technical efficiency in comparison with photonic mixers.

  This object is achieved according to the invention thanks to an arrangement for patching between optical fibers within a communication network, the arrangement comprising an optical distributor, the arrangement being characterized in that it further comprises means for diagnose at least one connection implemented by the optical distributor as well as a control member associated with this diagnostic means, in order to respond to a particular diagnosis by automatically controlling a suitable switching of the optical distributor.

  There is also proposed according to the invention a method of patching 30 between optical fibers within a communication network, the method using an optical distributor, the method being characterized in that it comprises a step consisting in using a means intended to diagnose at least one connection implemented by the optical distributor as well as a step carried out by a control member associated with this diagnostic means, step consisting in responding to a particular diagnosis by automatically controlling a suitable switching of the optical distributor.

  A communication network is also proposed according to the invention comprising an arrangement for patching between optical fibers, the arrangement comprising an optical distributor, the network being characterized in that it further comprises means for diagnosing at least one connection set up. works by the optical distributor 10 as well as a control member associated with this diagnostic means, to respond to a particular diagnosis by automatically controlling a suitable switching of the optical distributor.

  The automation of the control of this dispatcher and the addition of a coupling function, an example of an even more advantageous implementation of the invention, will make it possible to supervise the state of the traffic and to propose here functions of protection, comparable to that of photonic brewers on the market.

  Other objects, characteristics and advantages of the invention will appear on reading the detailed description which follows, made with reference to the appended figures in which: - Figure 1 is a descriptive diagram of the implementation of a distributor optics as part of a transport network; FIG. 2 is a diagram illustrating a possible commissioning of a device according to the invention in a data transport management system.

  In FIG. 1, automatic optical distributors 11 to 16 (ROA) appear which are controlled by managers grouped under the reference 20. From information concerning the state of the links which are reassembled by couplers 31 to 36, the manager will implement an appropriate command of the dispatcher considered. The couplers 31 to 36 take a part of the signal here and send it to a detector, not shown. The state of the links we are talking about here and which will be thus diagnosed by the device (connection state) can be a measure of the quality of the link, or an identification of the link, ie an identification of the elements connected by the dispatcher .

  The information coming from the couplers 31 to 36 can be simply an optical power level: in the event of passing under a certain pre-programmed threshold, an alarm is emitted. On the example chosen, the distributors 1 1 to 16 will indicate a lack of power to the managers 20, concerning in particular the link at 2.5 Gb / s between 10 Aubervilliers and Montsouris.

  This alarm then triggers a re-routing process on all of the distributors concerned, on a pre-established end-to-end protection route or else on the section or sections concerned (mesh type protection / restoration, established in real time according to the 15 network availabilities).

  The protection route can also be a route calculated at the time of the network incident, ie a route calculated in real time. The backup route chosen will have a route attenuation 20 compatible with the optical cards of the routers concerned. The restoration can be done in one direction, or in two directions (transmission and reception directions at the same time).

  In the example presented, a control plan pre-stored by the managers will send a certain number of connection orders to the 25 distributors 11, 12, 13 and 14 to establish the backup path and switch the routers to this new path .

  Current control plans have very short reaction times, the longest time coming from the execution of connections by automatic distributors. . The distributors are here called automatic, as in the prior art, to qualify the fact that they are robotized in the mechanical execution of the connection.

  Such devices have been proposed in documents FR 2 764 995, FR 2 825 477 and FR 2 825 476.

  In the prior art, an optical distributor is a device which essentially provides flexible and revisable optical continuity between the ends of first optical fibers, for example optical fibers coming from cables of underground networks, and / or coming from equipment of user of a telephone exchange. The optical connection is typically made by introducing optical connection plugs into a corresponding housing, plug and housing extending respective fibers 10 to be connected.

  In an optical distributor with matrix architecture, connection modules, also called connectors, are distributed in a plane matrix. The ends of the first optical fibers are introduced into one of the faces of the distributor in a fixed manner. The ends of the second optical fibers can be moved to the other side of the matrix distributor during the brewing operations.

  In a known embodiment where the distributor is qualified as automatic, the distributor also incorporates robotic arms. A robotic arm placed below a patch panel connects or disconnects the fibers and a second robotic arm, placed above the patch panel, manages excess fiber lengths in order to release the evolution space of the first robotic arm.

  Thus, the principle of automation referred to in the prior art for "automatic" distributors is the principle of using a robot to mechanically connect or disconnect an end chosen from a batch of fibers.

  It is therefore an automation in the execution of switching and not an automation in the initiation of switching, that is to say in the decision-making thereof.

  Indeed, although robotic, known automatic distributors require the intervention of a specialized operator to control the robot in adaptation to the situation.

  This is why the distributors are proposed until now in the implementation of commutations which have a rather rare occurrence, that is to say within the framework of commutations exceptional enough to devote to it the mobilization of a person.

  In other words, these distributors, automatic or not, and whose operation is based mainly on the physical movement of optical connectors with mutual contact, are today considered heavy of use.

  By way of illustration, these distributors (automatic or not) have been proposed for the creation, transfer or termination of a subscriber line, or even for the implementation of a remote monitoring line, and not in the context of automatic control switching.

  In the present implementation of the invention, where it is the control which is automated, it turns out that, despite the heaviness considered of the optical distributors, the delay in re-establishing the traffic of an application is reduced a few tens of seconds, even a few minutes. This is particularly the case if, we return to the traffic cut, the connections are controlled in parallel on all of the distributors concerned.

  This delay is compatible with the quality levels generally required, in particular this leads to a significant shortening of the fault recovery time, or even with an adequate time for the protection of certain data type links.

  The control plane can be either centralized (FIG. 2), or distributed in each node, according to the models already existing for pnotonic or optical mixers. More elaborate information can also be transmitted by the couplers, from the reading of certain bytes of the conveyed frames.

  As will be explained, the functions provided by a distributor 30 to which a control / monitoring system has been integrated, are for example the functions of a photonic stirrer.

  The information from it is sent to and taken into account by the management and control systems.

  In this configuration, automatic optical distributors (ROA) offer a certain number of advantages.

  In the present configuration, the following functions are in fact advantageously fulfilled: an optical distribution function, that is to say the establishment of abutments from one fiber to another fiber controlled from a remote center; - a description function in a database of established connections, ie equipment management; a function for describing in this same base the optical paths allocated to transport services, that is to say the network management; - a possible backup route calculation function based on different parameters: availability of the backup route, attenuation of the backup route, etc.

  - a traffic monitoring function, by means of a fiber coupler, of type in x% of the transmitted signal, y% sampled and by controlling an optical power level. As a variant, the ROA performs a reading and supervision of certain bytes of an SDH, OTN frame, - a measurement function on fiber (by reflectometry for example) in order to help the commissioning of new links or else the assistance in defect recovery. The measurements are then advantageously made from a remote center, and therefore do not require travel to the different sites.

  Thus, the automatic optical distributor is considered here as an active element of the network, and means are put in place to supervise it and integrate its management into a manager, for example of the SDH or WDM type.

  It therefore turns out that an active distributor of this type advantageously provides protection or automatic rerouting functions 30 which have hitherto been the sole responsibility of "photonic" mixers.

  It turns out that, since the protection times are certainly longer than the times observed in SDH for example (typically 50 milliseconds, to avoid a breakdown in telephone communication), they are however comparable to those observed for certain other transport protocols. data (one minute for example for Spanning Tree Protection of Ethernet, a few tens of seconds for centralized restoration). It even turns out to be possible to aim for a few tens of seconds to establish a connection in this new configuration.

  In the implementation of the invention, the main gains are drawn from the nature of this connection involved.

  There is a low insertion loss (a few fractions of dB, to be compared with the few dB, if not the ten dB of photonic crossovers 10), which reduces the amplification or regeneration costs of optical signals .

  We also benefit from a low cost per port (one, or even two orders of magnitude lower compared to MEMS).

  There is also a very high operational reliability, thanks to total independence from a power supply and thanks to a high impact resistance (compared to MEMS).

  High operational reliability is also observed because the connections operate in a protected environment (the enclosure of the distributor is generally closed) and are therefore protected from accidental handling.

  The drop in operational costs is significant because many garter operations can now be carried out without moving people.

  Furthermore, integration with an information system makes it possible to make the data concerning the distributors more reliable and makes it possible to couple the visions of the infrastructure network and the transport network (SDH, etc.) and better correlate the transmission alarms to by means of the alarms emitted by the dispatcher itself.

  We also take advantage of this equipment to promote the establishment of so-called transparent or translucent networks, thanks to this function comparable to photonic mixing, but obtained at a low cost.

  The traffic supervision function can be either summary (monitoring of an optical power level), or more complex (non-intrusive supervision of SDH or OTN type on specific bytes of the frame). As previously expressed, it is advantageously provided by an optical coupler but can be provided by any other method of sampling part of the optical signal carried by the fiber.

Claims (13)

  1. Arrangement for patching between optical fibers within a communication network, the arrangement comprising an optical distributor (11, ..., 16), characterized in that it further comprises a means for diagnosing at least a connection (20, 31, ..., 36) implemented by the optical distributor as well as a control member (20) associated with this diagnostic means (20, 31, ..., 36), to respond to a particular diagnosis 10 by automatically controlling a suitable switching of the optical distributor (11, ..., 16).   2. Patching arrangement according to claim 1, characterized in that the automatic control means (20) includes a pre-stored plane for controlling the switching of a series of distributors 15 (11, ..., 16) of the network.   3. Patching arrangement according to claim 1, characterized in that the automatic control means (20) includes means for calculating in real time a plane for controlling the switching of a series of distributors (11, .. ., 16) of the network.   4. Patching arrangement according to claim 2 or claim 3, characterized in that the control plane is a re-routing plane for re-connecting or preserving a connection between two points initially connected.   5. Patching arrangement according to any one of the preceding claims, characterized in that the means (20, 31, ..., 36) provided for diagnosing at least one connection of the optical distributor includes an optical coupler (31,. ... 36) provided for taking part of the light conveyed by this optical distributor (1 1, ..., 16).   6. Patching arrangement according to any one of the preceding claims, characterized in that the diagnostic means (20, 31, ..., 36) for connecting the optical distributor (11, ..., 16) are formed by a detection system (20, 31, ..., 36) of a low light intensity.   7. Brewing arrangement according to the preceding claim, characterized in that the diagnostic means (20, 31, ..., 36) are provided for comparing a detected light intensity with a minimum intensity threshold. 8. Patching arrangement according to any one of the preceding claims, characterized in that the connection state diagnostic means (20, 31, ..., 36) are provided for reading part of a data stream conveyed by the dispatcher.   9. Patching arrangement according to any one of the preceding claims, characterized in that it includes equipment management means (20) capable of indicating to a user the connections established at a time considered by the optical distributor.   10. Patching arrangement according to claim 9, characterized in that the equipment management means are associated with the connection diagnostic means (20, 31, ..., 36) of the optical distributor (11, 16), the connection state diagnostic means communicating with the management means for updating the indications given to the user. 11. Patching arrangement according to any one of the preceding claims, characterized in that the optical distributor (11, ..., 16) is a distributor with physical displacement of optical connectors with mutual contact.   12. A method of patching between optical fibers within a communication network, the method using an optical distributor (11, 25 ..., 16), the method being characterized in that it comprises a step consisting in: use a means provided for diagnosing at least one connection (20, 31, ..., 36) implemented by the optical distributor as well as a step carried out by a control member (20) associated with this diagnostic means (20 , 31, ..., 36), step consisting in responding to a particular diagnosis by automatically controlling a suitable switching of the optical distributor (11, ..., 16).   13. Communications network comprising an arrangement for patching between optical fibers, the arrangement comprising an optical distributor (11, ..., 16), the network being characterized in that it further comprises means for diagnosing at least one connection (20, 31, ..., 36) implemented by the optical distributor as well as a control member (20) associated with this diagnostic means (20, 31, ..., 36), to respond to a specific diagnosis by automatically controlling a suitable switching of the optical distributor (11, ..., 16).