MXPA97010099A - Auto-reparad network - Google Patents

Abstract

The present invention relates to a communication network system (100), comprising at least three nodes, which are interconnected by transmission link (110), which carry traffic to and from the nodes. These transmission links (110) are divided into a working ring (112) and a protection ring (114), where the working ring (112) and the protection ring (114) can transmit the traffic in opposite directions. A node is able to detect when an error occurs in the intermediate environment, the transmission links (110) or the node. Each node can by itself divert the traffic from the work ring (112) to the protection ring (114) and / or by itself divert the traffic from the protection ring (114) to the work ring (112). A recovery action is performed when the err is repaired

Description

AUTO-REPAIR NETWORK TECHNICAL FIELD OF THE INVENTION The present invention relates to an apparatus and a method for a communications network, more particularly to a self-healing network. DESCRIPTION OF THE RELATED ART In a conventional self-healing ring architecture, the SDH synchronous digital hierarchy or SONET synchronous optical network, using a multiplexer (add-on / suppressor) (ADM), the optical fiber is only used as a link from one point to another and the optical-electric conversion is operated in each node. In such a ring, the bottleneck is constituted by the speed of the electronic parts of the process and the sharing of the bandwidth is characteristic for this architecture and leads to a limitation of the capacity of the network. In the article "Self-Repairing Ring Network Architecture, Using DM for Growth", ECOC 92, Tu P1.16, by Aly Elrefaie, a self-healing ring network is presented. It is described by a 2-fiber WDM ring network, where the local offices N-1 originate the traffic, which is served by a single hole in the connection panel. The transmission in both fiber rings is identical except in the direction of propagation; the counter that propagates the signals facilitates the survivability of the network during a cable cut. Each of the local offices N-l is assigned a single wavelength for transmission to and reception from the connection panel hole. In the PCT application WO 93/00756, by Sandesara, a bi-directional self-repairing logical ring network is described, using transverse connection nodes. The network is divided into independent segments. Each segment consists of two or more nodes, interconnected with two transmission links that work in different directions. When a fault occurs, a cross-connection maintains a previously selected pattern of interconnections between segments. In the prior PCT application WO 93/00756 a self-healing unidirectional network is described. In addition to the transmission link there is also a spare link. The transmitted signal doubles and flows on both links at the same time. The destination node then selects the best of the two signals. It also establishes that the signal structure in the prior known uni-and bi-directional networks consists of a predetermined number of multiplexed channels of the sub-regime, operating at a fixed rate.

COMPENDIUM This invention addresses the problem, which takes a long time, between detecting a fault and redirecting traffic in a communications network, in particular a self-healing ring network. This invention also addresses the problem that a tremendous amount of traffic and data may be lost when an error occurs and the traffic has to be redirected in the communication network. In accordance with this invention, a communication node in a communication network can detect the failure easily and quickly, in which the detection takes place in the node itself. Also, the node is capable of detecting a failure in the network, which occurs in the immediate vicinity of this node. Upon detecting a failure, the node is able to quickly redirect any traffic and, additionally, it will go from an active work state into a protection state. After the identification of the error, the node will auto-repair, recover and automatically go back into the working state. The purpose of the invention is to achieve a self-healing network, in which the nodes quickly self-repair.

Another purpose is that the nodes do not need network address for repair. An advantage is that the node can add / delete any of the wavelengths for local traffic and to divert others. Another advantage is that if a cable is cut or broken, all traffic can be quickly re-guided by the node itself, the restoration takes place within the node's local control system, without involving the direction of the network. Still another advantage is that this invention shortens the time necessary for the network to recover. A further advantage is that the restoration of the network is fast, in order to provide a high quality service. The invention will be presented with the aid of the best mode for carrying out the invention, characterized by the peculiar aspects indicated in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The Figure shows a network system of co-operations. Figure Ib is a communication network system with links cuts. Figure lc shows a communication network system with node failures.

Figure 2 shows a detailed node structure. Figure 3 shows a detailed head node, and a tail node. Figure 4 shows a modified node structure. Figure 5a shows a collector communications network system. Figure 5b shows a collector communication network system, with link cuts. Figure 6 shows a flow chart on a method for a node in the working state to become the leading node. Figure 7 shows a flow chart on a method for a node in the protection state to become a normal node. Figure 8 shows a flow chart on a method for a node in the working state to become a queue node. Figure 9 shows a flow chart on a method for a node in the protection state to become a normal node.

DETAILED DESCRIPTION OF THE MODALITIES The Figure shows a schematic view of a communication ring network 100, where the present invention can be carried out. This network 100 has a number of N nodes 102-108, connected to each other by transition links, for example optical links 110, N represents at least three, and means that the network 100 consists of at least three nodes. The transmission links 110 are comprised of: a first transmission link or work ring 112, and a second transmission link or protection ring 114. The work ring 112 carries traffic in a transmission direction, clockwise in the figure. The protective ring 114 carries traffic in the opposite direction of transmission, counterclockwise in the figure. The traffic can, for example, be electrical, optical or wavelength channels. If wavelength channels are used, there are M optical channels transmitted, where M can be smaller, equal or greater than N nodes. Figure la also shows communication network 100 in its normal working state, where the. M optical channels are transmitted in one direction through the working ring 112 together with the spontaneous emission of the optical amplifier (ASE). In the protection ring 114, it is only the ASE energy that propagates, in the opposite direction to the work ring 112.

This communication network 100 can be a self-healing ring communication network 100, multiplexed in the wavelength division, as in Figure la. Other types of networks are, for example, wavelength division multiplexing (WDM) networks that are not shown here, and can also be used as a communications network system. Each node 102-108 in the communication network 100 may consist of an optical add / drop multiplexer 118, OADM, which is capable of adding / removing dedicated wavelength or traffic channels to the node, i.e. local traffic , and divert others. Some wavelength channels can be dedicated to a node, other wavelength channels will be passed through and will go to the next node in the work ring 112. Figure Ib shows the communication network 100 with the link error, by example, a cable cut, between the node 102 and the node 104. The protection actions have taken place within the nodes 102 and 104 by themselves, without involving the network management system 116, which is merely reported in failure events. The protection actions are achieved by the node, which uses electronic parts in a combination of the signal connected / disconnected in the node itself in the work / protection ring 112, 114. The node 102 detects itself when a link error occurs. , for example, a cable cut, occurs and by itself will automatically divert the traffic in the work ring 112 to the protection ring 114. All the traffic leaving the node 102 will then go back inside the protection ring and a tail node. The node 104 also detects itself when a link error occurs, for example a cut wire, and by itself, automatically, will divert traffic from the protection ring 114 to the work ring 112. All traffic leaving the node 104 will then go back into the work ring 112 and a leading node will emerge. The nodes, 106 and 108, will act as transit nodes, which means that the wavelength channels that are normally transmitted only in the work ring 112, are also transmitted in the protection ring 114, but will pass through the nodes 106 and 108 without any addition / deletion of any wavelength channel. When the transmitted wavelength channels return back to the node in the work ring 112, the add / drop channels work in a normal manner at each node. There are actually at least two types of link errors, for example cut cables; one is when the error, for example the cut cable, occurs only in the protection ring 114. When the error occurs in the work ring 112, the first node 104, after the traffic direction clockwise, will automatically change its operating mode to a head node automatically. The last node 102 before the error in the traffic direction clockwise, automatically by itself will change its operation mode to the queue node. In the second case, when an error, for example a cut cable, occurs in the protection ring 114, the last node 102, before the error in the traffic direction, automatically, by itself, will change its mode of operation to a tail node and traffic node 104, after the error in the traffic direction, automatically, by itself, will change its operation mode to a leading node. Figure lc shows the communications network 100 with a node failure. The same kind of reconfiguration, that is, the change in the mode of operation, will occur as in Figure Ib, so that a head node, node 104, and a tail node, node 108, will be established. Also, in this case, there is a transit node 106 between the head node 104 and the tail node 108. Figure 2 shows a block diagram of an optical add / drop multiplexer node 200, according to the invention, this node can be any of the nodes 102-108 in Figure 1. The node 200 has an input 202 of the working ring, which is connected to a first light propagation element, for example a first optical link 210 of input , which can be an optical fiber. The input 202 of the working ring is connected to a first optical input 216 of an optical switch element, for example the first optical switch 214, which can be switched for work in any bar or transverse state. A second light propagation element, for example a second optical input link 220, which can be an optical fiber, is connected to an input 208 of the protection ring of the node 200. This input 208 of the protection ring is connected to a second optical input 218 of the first optical switch 214. A first optical output 230 of the first optical switch 214, which in the bar state is coupled to the first optical input 216, is connected to a first optical input 228 of a switch selective optical channel or wavelength selective switch 226, which also works in any state of bar or cross. The first optical input 228 of the channel selective switch 226 is coupled to a first optical output 244 of the channel selective switch 226 in the bar state. This first optical output 244 is optically connected to an input 242 in a line terminal 274, which is associated with the node. An output 246 on the line terminal 274 is optically connected to a second input 248 of the channel selective switch 226. This second input 248 is in the bar state connected to a second optical output 236 of the channel selective switch 226, this second optical output 236 is optically connected to a first input 234 of an optical switch element, for example a s - ^^ undo optical switch 232. The second optical switch 232 can operate in the bar and transverse states. A second input 238 of the second optical switch 232 is connected to a second output 240 of the first optical switch 214, this second output 240 is coupled to a second input 218 in the bar state. A first output 250 of the second optical switch 232, which in the bar state is coupled to the first input 234, is connected to an optical amplifier 260, which, in turn, is connected to a first optical switch 264 of cutting . This cut-off switch 264 is connected to an output 206 of the working ring in the node 200. The output 206 of the working ring was connected to a third light propagation element 270. A second output 252 of the second optical switch 232, which in the bar state is coupled to the second input 238, is connected to a second optical amplifier 262, which, in turn, is connected to a second optical switch 266. The second switch 266 is connected to an output 204 of the protection ring in the node 200, which is connected to a fourth light propagation element 272. A first input link supervision element, for example a first fault monitor 222, is optically connected to the first input 236 of the first optical switch 214. A second input link supervision element, for example a second monitor 224 of failures, it is optically coupled to the second input 218 of the first optical switch 214. A first energy sensing monitor 254 is optically coupled to the first output 250 of the second optical switch 232, and a second energy detection monitor 256 is optically coupled to the second output 252 of the second optical switch 232. The fault monitors 222 and 224, the amplifiers 260 and 262, as well as the energy sensing monitors, 254 and 256, are electrically connected to a control element or unit 258. of local control. The unit 258 controls the first and second optical switches 214 and 232, the selective wavelength switch 226 and the first and second cut-off switches 264 and 266. The local control unit 258 is connected to a network address element, the so-called network address system 116, which is located outside the node 200. This network address system is correspondingly connected to the other nodes as well. The first light propagation element 210, connected to the input 202 of the working ring of the optical multiplexer node 200 of addition / suppression forms with the third light propagation element 270, connected to the output 206 of the working ring, a part of the work ring 112, see FIG. 1 and FIG. 2, the second light propagation element 222, connected to the input 208 of the protection ring of the optical multiplexer node 200 of addition / suppression form with the fourth element 272 of light propagation, connected to the output 204 of the protection ring, a part of the protection ring 114, see Figure Ib. When the optical multiplexer addition / deletion node 200 is in the normal working state (Figure 1), the number of M wavelength channels comes within the node 200 from the input 202 of the working ring and they arrive at the selective switch 226 of wavelength after passing through the first optical switch 214, which is in the bar state. The selective wavelength switch 226 executes the addition / suppression wavelength channels, i.e. the local traffic, and the wavelength channels that bypass the node 200. The selective wavelength switch 226 selects and the wavelength channels dedicated to the node 200 fall to the line terminal 274 at its input 242 (Rx). The line terminal 274 comprises an optical receiver connected to the input 242 by means of a filtering device, and a transmitter connected to the output 246. The line terminal 274 adeiu.13 comprises an element for demodulating the modulated light (not shown). ) and an element for converting the modulation to electrical signals (not shown) and, also, an element for transporting these electrical signals to dedicated receivers by means of the electrical outputs. The line terminal 274 also receives, by the electrical input, electrical signals containing information, these signals will be sent to a receiver through the network 100. The electrical signals are converted to the modulation of the light with the selected wavelength , which is sent to the transmitter to be added to the network 100. The network management system 116 communicates with the local control unit 258, by means of a standard interface. The local control unit 258 then controls the selective switch 226 of the wavelength to obtain the required selection. Wavelength selective switch 226 adds new local traffic, which comes from terminal 274 of line at exit 246 (Tx). The network address system 116 can order which wavelength channel will be added to the work ring 112. The selective wavelength switch 226 diverts and equalizes all wavelength channels not dedicated to the node. The aggregate wavelength channels and the deviated wavelength channels, which come from the selective wavelength switch 226, pass through the second optical switch 232 in the bar state, through the optical amplifier 260 (e.g. a fiber amplifier, with Erbium impurities, EDFA) will be amplified and through optical cut-off switch 264 will be placed at output 206 of the working ring to reach the next OADM node. As shown in Figure 2, the entrance 208 of the protection ring is connected to the output 204 of the protection ring, which is obtained by the two optical switches, 214 and 232, both being in the bar states. This also allows any optical energy that comes within the input 208 of the node protection ring, to be simply amplified by the second optical amplifier 262, and transferred to the output 204 of the protection ring. The wavelength channels that come within the optical multiplexer node 200 of addition / suppression, can have different power levels and, in order to avoid unbalanced channel power through the network 100, an equalization of power of the wavelength channels in each node 200. In order to achieve such a function, a quantity of outgoing optical power is suppressed by the power detection monitor 254, which measures the optical energy levels. The optical power levels are sent to the local control unit 258, which calculates the attenuation values for each wavelength channel, in order to obtain the equalization. The local control unit 258 sends the attenuation values to the selective wavelength switch 226, which selectively applies them to the respective channels. This invention relates to a recovery of network failure by the nodes when a link fails between two nodes, for example between nodes 102 and 104, see Figure Ib. A first failure event may be when both of the work ring 112 and the protection ring 114 fail. The communication network 110 will then be reconfigured with the help of the failure of the nodes 102 and 104, changing themselves over the mode of the head node, Figure Ib, and the mode of the queue node, respectively. In order to discover an error, for example the break, of the first transmission link or work ring 112, the node of the add / delete optical multiplexer 200 in Figure 2 is equipped with the first fault monitor 222, which diverts a small amount of the optical power that enters from the input 202 of the working ring. This can be in the wavelength and / or power ASE channels. The local control unit 258 obtains information from the first fault monitor 222 and if there is any optimum power, this first fault monitor 222 remains in its working state. If the work ring 112 has failed and there is no optical power in the first fault monitor 222, if the traffic changes over the protection state. The ASE power may still be present in the protection ring 114. Any detection of the loss of traffic by the first fault monitor 222 initiates the reconfiguration of the node 200 by the local control unit 258. The first fault monitor 222 or the local control unit 258 are placed in the protection state. After knowledge of failure by the first fault monitor 222, the local control unit 258 changes the first optical switch 214 from the bar state to the crossed state. The first optical switch 214 in the crossed state means that the second optical input 218 of the first optical switch 214 and the first optical output 230 of the first optical switch 214 are connected to each other. This means that the power of the ASE and / or the traffic on the protection ring 114 is diverted to the work ring 112. The local control unit 258 will also open the second switch 266, so that neither the traffic nor the ASE power can be supplied to the output 204 of the protection ring after the alteration. The node 200 has already entered the head node mode as in Figure Ib: The local control unit 258 communicates with the network management system 116 and reports that the node 104 has already become a leading node. A process for recovering a head node from the work state protection state is initiated by the network address system 116, which communicates with the local control unit 258. With the end of the recovery procedure from the head node, the local control unit 258 then closes the second switch 266 and activates the second optical amplifier, so that the optical power can reach the preceding node in the fun of the traffic (the queue mode) if the link is fault-free, for example the optical fiber does not rotate. The local control unit 258 checks whether the first fault monitor 222 detects any optical power from the input 202 of the working ring. This power can be the wavelength channels and / or the ASE power. If the first fault monitor 222 detects optical power the node will go to the working state. The first fault monitor 222 or the local control unit 258 is placed in the working state. The local control unit 258 changes the first optical switch 214 of the transverse state to the bar state, so that the traffic can be received from the input 202 of the working ring. This traffic can now go through the entry of the work ring to output 206 of the work ring, which means that the traffic in the work ring is later. The ASE power goes from the input 204 of the protection ring to the output 208 of the protection ring. The local control unit 258 informs the network management system 116 that the node 104 has gone back to the working state. If the first fault monitor 222 does not detect any optical power, it will remain in its protection state. After a certain time, for example 500 msec, the local control unit 258 disconnects the second optical amplifier 262, opens the second switch 266 and cancels the recovery procedure. The local control unit 258 informs the network management system 116 that the recovery of the node 104 has been canceled. In order to discover an error, for example a break of the second transmission link or the protection ring 112, the node 200 of the optical add / delete multiplexer, in Figure 2, is equipped with the second fault monitor 224, which diverts a small amount of the optical power that enters from the entrance 208 of the protection ring. This may be the ASE power and / or the wavelength channels. The local control unit 258 obtains information from the second fault monitor 224 and, if there is any optical power, this second fault monitor 224 remains in its working state. If the protection ring 114 has failed and there is no optical power in the second fault monitor 224, if the traffic changes over the protection state. The ASE power may still be present in the work ring 112. Any detection of loss of the ASE power or traffic by the second fault monitor 224, initiates the reconfiguration of the node 200 by the local control unit 258. The second monitor of failures 224 or the local control unit 258 is placed in the protection state. After knowledge of the failure detection by the second fault monitor 224, the local control unit 258 changes the second optical switch 232 from the bar state to the transverse state. The second optical switch 232 in the transverse state means that the first optical input 234 of the second optical switch 232 and the second optical output 252 of the second optical switch 232 are connected to each other. This means that the traffic on the work ring 112 is diverted to the protection ring 114. The local control unit 258 will also open the first cut-off switch 264, so that neither the traffic nor the ASE power can be supplied to the output 202 of the working ring after the alteration. The node 200 has now entered the queue node mode, as in Figure Ib. The local control unit 258 communicates with the network management system and informs the network management system 116 that the node 102 has become a queue node. A process for recovering a queue node from the protection state to the work state is initiated by the network management system 116, which communicates with the local control unit 258. In order to recover the procedure from the network node. tail. The local control unit 258 then closes the first cut-off switch 264 and activates the first optical amplifier 260, so that the optical power can reach the node that follows after the traffic deviation (the overhead node), if the link It is free of faults, for example the fiber optic is not broken. The local control unit 258 checks whether the second fault monitor 224 detects any optical power from the input 208 of the protection ring. This power can be the wavelength channels and / or the ASE power. If the second fault monitor 224 detects the optical power the node will go into the working state, the second fault monitor 224 or the local control unit 258 is placed in the working state. The local control unit 258 changes the second optical switch 232 from the transverse state to the bar state, so that the traffic can return to the output 206 of the working ring. The traffic can now go through the input 202 of the work ring to the output 206 of the work ring, which means that the traffic on the work ring 112 is later. The potpr. <; -: ASE goes from the entrance 204 of the protection ring to the exit 208 of the protection ring. The local control unit 258 informs the network management system 116 that the node 102 has returned to the working state. If the second fault monitor 224 does not detect any optical power, it will remain in its protection state. After a certain time, for example 500 msec, the local control unit 258 disconnects the first optical amplifier 260, opens the first cutting switch 264 and the recovery procedure is canceled. The local control unit 258 informs the network management system 116 that the recovery of the node 102 has been canceled. Despite the link error between node 102 and node 104, no traffic will be lost. The traffic will go between the head node 104 and the tail node 102 in the communication network 100, they will still detect the optical energy, ie the signals on both fault monitors 222, 224, Figure 2, which maintains its normal configuration . This allows network 100 to retain the normal functions for work ring 112. Tail node 108 deviates briefly from all wavelength channels from input 202 of the work ring to output 204 of the protection ring. The leading node 104 deviates briefly from all the wavelength channels from the input 208 of the protection ring to the output 206 of the working ring. The deviation of the traffic by the queue node to the protection ring 114 reaches the head node, which bypasses the work ring 112 again and a cycle is formed. There can be at least one node between the head and tail nodes, in this case working as the transit nodes 106, 108. The transit nodes 106, 108 are just nodes that are not head or tail nodes. They can add / delete wavelength channels, deflect wavelength channels in the work ring 112 and / or the protection ring 114. In Figure 3a, a second fault event can be when only the ring fails. work 112. If the work ring 112 is defective, for example broken, the first fault monitor 222 detects the loss of signal and the node 104 starts the reconfiguration in the head node, see the first failure event, which opens the second switch 266.

This causes the loss of signal in the second fault monitor 224 of the previous node 102, which then begins the reconfiguration of the node 102 in the queue node, see the first failure event, which opens the first breaker 264. In Figure 3b, a third failure event may be when only the protection ring 114. fails. If the protection ring 114 is defective, eg broken, the individual actions of recovery of the node will be the same, but with an order inverted sequence, compared to the second fault event. This means that first the tail node and then the head node arise, obtaining the same node states and communication paths as the first failure event. This invention also relates to a failure recovery when a node, for example 102, fails, Figure 1c, with the same procedure as in the first failure event. The difference is that the different nodes will become head and tail nodes. In this failure event, the node 104 will become the head node 104, see the first failure event, and the node 108 will be the tail node 108, see the first failure event. The defective node 102 will be isolated from the others in Figure lc. The process to recover any failure event, described above, is done in the same way as to recover the head node from the protection state, and recover the failure node from the protection state. Figure 4 shows a block diagram of an alternative node 400, which can act as a head node and / or tail node. The alternative node 400 can be any of the nodes 102-108 in Figure 1, according to the invention. The alternative node 400 has the input 202 of the working ring, which is connected to the first element 210 that propagates the light, for example an optical fiber. The input 202 of the working ring is connected to a first optical input 404 of the optical switch or the optical switch element 402, which can be changed by the working input, for example, the status bar, to the first transverse state and / or second transverse state. The second light propagation element 220, which can also be an optical fiber, is connected to the input 208 of the protection ring of the node 400. This input 208 of the protection ring is connected to a second optical input 406 of the optical switch 402 A first optical output 408 of the optical switch 402, which in the bar state is coupled to the first optical input 404, is connected to the first optical cut-off switch 264. The third element 270 that propagates the light is connected to the output 206 of the working ring, which is connected to the first optical cut-off switch 264. A second optical output 410 of the optical switch 402, which in the bar state is coupled to the second optical input 406, is connected to the second optical switch 266. The fourth light propagation element 272 is connected to the output 204 of the protection ring, which is connected to the second optical switch 266. The first fault monitor 222 is optically connected to the first input 404 of the optical switch 402. The second fault monitor 224 is optically coupled to the second input 406 of the optical switch 402. Fault monitors 222, 224 and optical switch 402 are electrically connected to the control element or local control unit 258, which controls the first and second cut-off switches 264 and 266. The local control unit 258 is connected to the network management element or the network management system 116, which is located outside the node. This network management system 116 is connected correspondingly to the other nodes as well. When the alternative node 400 is in the working state, as shown in Figure la, the number of M wavelength channels come within the node 400 from the input 202 of the working ring and they pass through the optical switch 402 that is in the state of bar, the local control unit 258 controls the optical switch 402, and communicates with the network management system 116, via the standard interface. As shown in Figure 4, the first light propagation element 210 and the entrance 202 of the working ring are connected to the third light propagation element 270 by means of the optical switch 402 in the bar state, the first switch 264 cutting, the output 206 of the working ring and forms part of the working ring 112, Figure la. As is also shown in Figure 4, the second light propagation element 220 and connected to the entrance of the protection ring 208, connected to the second light propagation element 220, by means of the optical switch 402 in the bar state, the second switch 266, the output of the protection ring, which forms part of the protection ring 114, as shown in Figure la. Alternative node 400 can operate as a work node, described above, as the head node, as the tail node or as a transit node. In order to discover an error, for example a break, in the first transmission link or work ring, the node 400, in Figure 4, is equipped with the first fault monitor 222. This monitor 222 diverts a small amount of optical power from input 202 of the working ring. This can be channels of wavelength and / or power SE. The local control unit 258 obtains information from the first fault monitor 222 and if there is any optical power, the fault monitor 222 remains in its working state. If the work ring 112 has failed, the fault monitor 222 changes to the protection state. The ASE power may still be present in the protection ring 114. Any detection of loss of traffic by the first fault monitor 222 initiates the reconfiguration of the node 400 by the local control unit 258. The first fault monitor 222 or the unit Local control 258 are placed in the protection state. After the detection of faults, the local control unit 258 switches the optical switch 402 to the first transverse state. The first transverse state means that the second input 406 of the optical switch 402 and the first output 408 of the optical switch 402 are connected to each other. This means that the ASE power and / or the traffic on the protection ring 114 is bent to the work ring 112. The local control unit 258 will also open the second switch 266, so that neither the traffic nor the ASE power can go at exit 204 of the protection ring after alteration. The node 400 has now entered a head node. The local control unit 258 communicates with the work management system 116 and reports that the node 104 has become the overhead node. The process of recovering the head node is done in the same way as described above. The difference is that the optical switch 402 will return to the bar state, which means that the first optical input 404 of the optical switch 402 is coupled to the first optical output 408 of the optical switch 402. In order to detect an error, example the break of the second transmission link or protection ring, the node 400, in Figure 4, is equipped with the second fault monitor 224. This monitor 224 diverts a small amount of optical power from the entrance 208 of the protection ring. This can be an ASE power and / or the wavelength channels. The local control unit 258 gets information from the second fault monitor 224 and if there is any optical power, the fault monitor 224 remains in its working state. If the protection ring 114 has failed, the fault monitor 224 changes to the protection state. The ASE power may still be present in the work ring 112. Any detection of the loss of traffic by the second fault monitor 224 initiates the reconfiguration of the node 400 by the local control unit 258. The second fault monitor 224 or the local control unit 258 is placed in the protection state. After failure detection, the local control unit 258 switches the optical switch 402 to the second transverse state. This second transverse state means that the first input 404 of the optical switch 402 and the second output 410 of the optical switch 402 are connected to each other. This means that the traffic on the work ring 112 is bent to the protection ring 114. The local control unit 258 also opens the first cut-off switch 264 so that neither the traffic nor the ASE power can go to the output 202 of the working ring, after the alteration. The node 400 will become the queue node. The local control unit 258 communicates with the network management system 116 and informs this network management system 116 that the node 102 has become the queue node. The process of recovering the head node is done in the same way as described above. The only difference is that the optical switch 402 will return to the bar state, which means that the second optical input 406 of the optical switch 402 is coupled to the second optical output 410 of the optical switch 402. The node 400 can work as head nodes and tail at the same time. The difference of the above description is that the first and second cutting switches 264 and 266 are not open when the node 400 becomes the head and tail nodes. The traffic from the overhead node does not conflict with the traffic from the queue node, because the optical switch 402 separates the different traffic directions from each other. Figure 5a shows a schematic view of an alternative communication network, a collector communication network 500 embodying the present invention. The collector communication network 500 has the number of N nodes 502-508, connected to each other by the collector transmission links, for example the optical links 510. At one end there is a first node or start node 502, which it can be designed as nodes 200 or 400, and at the opposite end there is the node of order N or an end node 508, which can be designed as node 200 or 400. The collector transmission links 510 comprise a first collector or work link transmission link 512 and a second collector transmission link or protection link 514. At the start node 502 the work link 512 is in contact with the protection link 514, and the node 502 acts As the queue node, see a first failure event. At the end node 508, the protection link 514 is in contact with the work link 512 and the node 508 acts as the head node, see the first failure event. The collector communication network 500 is formed by the first node 502, the end node 508, the work link 512 and the protection link 514 together. The collector network 500 is transmitting the wavelength channels in one direction through the work link 512 and in the opposite direction through the protection link 514. FIG. 5a also shows the collector communication network 500 in its working state, which means those N wavelength channels together with an ASE power traveling in one direction through the work link 512 in the 514 protection link. This collector communication network 500 can also be a self-healing, multiplexed, wavelength division, collector communication network. Other types of collector communication networks, not shown here, can be used as the collector communication network. Each node in the collector communication network 500 may consist of an optical add / drop multiplexer, which is capable of adding / deleting traffic wavelength channels, dedicated to the node, ie the local traffic, and diverting other . Other nodes, such as in Figure 4, can be used as the head node, tail node or transit nodes. The collector communication network 500 is working as previously described.

Figure 5b shows examples of two places A and B where link failures may occur, for example cable cuts. The cut wire can be any in the collector communication network. Each node, after a cut wire, will act as a head node and each node, before the cut wire, will act as a tail node, as previously described in relation to Figur? 2 and Figure 4. Figure 6 shows the method for a node to become head node 104, Figure Ib, which was described earlier in this section. The main stages are as follows:. work status, block 600. 222 fault monitor, diverts the optical power, block 502. information diverted to control unit 258, block 604 any optical power in the fault monitor 222 ?, block 606 If it is not the answer to the question in block 606, the following main stages are taken: node to the protection state, block 608 optical switch 214 to the transverse state, block 610 open cut switch 266, block 612. information management system 116 whose node is the head node, block 634. protective state (not head), block 616. If the answer is yes to the question in block 606, the following main stage is taken: • working status, block 620. Figure 7 shows the method for a node in the protection status of how the normal node becomes. This was described earlier in this section. The main stages are as follows: • protection status (head node), block 700 • initiation of recovery of the head node, block 702 closure of cut-off switch 266, block 704 • drive amplifier 262, block 706 • any optical power in fault monitor 222, block 708 If the answer is yes to the question in block 708, the following main steps are taken: • node to the working state, block 710. optical switch 214 to the bar state, block 712 report to the operating system 116 that the node is normal, block 714. working status, block 716 If the answer to the question is no in block 708, the following main steps are taken: • disconnect amplifier 262, block 720 • open cut-off switch 266, block 722 • inform the operating system 116 that the node is the head node, block 724. protection status (head node), block 726 Figure 8 shows the method for a node to become the tail node, Figure Ib. This was already described in this section. The main stages are as follows:. work state, block 800 • fault monitor 224 diverts optical power, block 802 information diverted to control unit 258, block 804 • any optical power in fault monitor 224?, block 806 If the answer to the question in block 806 is no, the following main stages are taken: node to the protection state, block 808 optical switch 232 to the transverse state, block 810 to open cut-off switch 264, block 812 to inform the management system 116 that the node is the node queue, block 814 protection status (queue node), block 816 If the answer is yes to the question in block 806, the next main stage is taken:. working state, block 820. Figure 9 shows a method for the protection state to become the normal node. This was already described earlier in this section. The main stages are as follows: protection state (queue node), block 900 recovery initiation of the queue node, block 902 • closure of cut-off switch 264, block 904 connection of amplifier 260, block 906 any optical power in the fault monitor 224?, block 908 If the answer to the question is no in block 908, the following main stages are taken: • node to the working state, block 910 • optical switch 932 to the bar state, block 912 • report to the management system 116 that the node is normal, block 914 • working status, block 916 If the answer is yes to the question in block 908, the following main steps are taken: • disconnect amplifier 260, block 920 • open cut-off switch 264, block 922 • inform management system 116 that the node is the queue node, block 924. Protection status (queue node), block 926. The advantage is that the channel selective switch is not involved in the node reconfiguration process. This means that it is not affected by any transient state, where by the traffic path and addition / suppression functions are stable during the node configuration routine. - The invention, described above, was exposed in an optical solution, but this is not a necessary requirement. The invention, described above, can be incorporated into yet other specific forms, without departing from its spirit or essential characteristics. Thus, the present embodiments are considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims, rather than by the foregoing descriptions, and all changes that fall within the meaning and range of equivalence of the claims, therefore, are intended to be included within this invention.

Claims (20)

1. CLAIMS 1. A communication node, for communication with other nodes, by the reception of energy over incoming optical links and the transmission of power over outgoing optical links, this node comprises: a first element of supervision of the incoming link, to direct the incoming energy from an incoming optical first link; a second incoming link supervision element, for detecting the incoming energy from a second incoming optical link; optical switching elements, which switch the incoming energy, from the first or the second optical incoming link to the first or second optical output link; and a control element, connected to the monitoring element and the switching element, for controlling the node in a transit mode or a head mode or an operation queue mode, in response to the detection of incoming power in one or both incoming optical links.
2. 2. A communication node, according to claim 1, wherein the control element controls the node in the transit mode, when the link monitoring element detects the energy coming from both the first and the second links, so which node sends forward the energy from the first incoming link to the first outgoing link and the energy from the second incoming link to the second outgoing link.
3. 3. A communication node, according to claim 1, wherein the control element controls the node in a queue mode, when the link monitoring element detects incoming energy from the first, but not the second, incoming links, whereby the node sends forward the energy from the first incoming link to the second outgoing link, but not to the first outgoing link.
4. 4. A communication node, according to claim 1, wherein the control element controls the node in a head mode, when the link monitoring element detects incoming power from the second, but not the first, incoming link, whereby the node sends forward the energy from the second incoming link to the first outgoing link, but not to the second outgoing link.
5. 5. A node, according to any of claims 1 to 4, wherein: the first links, incoming and outgoing, are connected to separate other nodes and form part of a first transmission link of a communication ring network; and the second links, incoming and outgoing, are connected to separate nodes to constitute part of a second transmission link of the communication ring network.
6. 6. A communication network system, comprising at least three nodes, which are interconnected by transmission lines carrying wavelength channels to and from the nodes, these transmission links are divided into a first transmission link and a transmission link. second transmission link, the nodes have a working ring input and a working ring output for the first transmission link, and also have a protection ring input and a protection ring output for the second transmission link , where the first and second transmission links can transmit the wavelength channels in opposite directions, each of the nodes comprises: fault monitor elements, connected to the inputs of the working ring and of the protection ring; elements for switching over the wavelength channels from the first transmission link to the second transmission link; a local control unit, which is connected to the elements to inspect faults and also to the elements for switching in the wavelength channels.
7. 7. A communication network system, comprising at least three nodes, which are interconnected by transmission links carrying wavelength channels to and from the nodes, these transmission links are divided into a first transmission link and a transmission link. second transmission link, the nodes have a working ring input and a working ring output for the first transmission link, and also have a protection ring input and a protection ring output, for the second transmission link, where the First and second transmission links can transmit the wavelength channels in opposite directions, each of the nodes comprises: an element for inspecting faults, connected to the work ring entries of the protection ring; an element for switching in the wavelength channels from the second transmission link to the first transmission link; a local control unit, which is connected to the element to inspect faults and is also connected to the element for switching in the wavelength channels.
8. 8. A node communication network system, according to claims 6 and 7, in which the nodes comprise: a first fault monitor, which is connected to the input of the working ring; and a second fault monitor, which is connected to the entrance of the protection ring.
9. 9. A node in a communication network, this node is interconnected with other nodes by transmission links, which carry wavelength channels to and from the nodes, these transmission links are divided into a first transmission link and a second transmission link. transmission, the nodes have a working ring input and a working ring output for the first transmission link, and they also have a protection ring input and an output of the protection ring for the second transmission link, where the First and second transmission links can transmit the wavelength channels in opposite directions, each of the nodes comprises: elements for inspecting faults, connected to the inputs of the working ring of the protection ring; elements for switching over the wavelength channels, from the first transmission link to the second transmission link; a local control unit, which is connected to the elements to inspect faults and also to the elements to switch over the wavelength channels.
10. 10. A node in a communication network, this node is interconnected to other nodes by transmission links carrying wavelength channels to and from the nodes, the transmission links are divided into a first transmission link and a second transmission link , the nodes have a working ring input and a working ring output for the first transmission link, and also have a protection ring input and an output of the protection ring for the second transmission link, where the first and second transmission links can transmit the wavelength channels in opposite directions, each of the nodes comprising: fault monitor elements, connected to the inputs of the working ring and of the protection ring; elements for switching in the wavelength channels from the second transmission link to the first transmission link; a local control unit, which is connected to the elements to inspect faults and also to the elements for switching in the wavelength channels.
11. 11. A node, according to claims 9 and 10, comprising: a first fault monitor, connected to the input of the working ring; and a second fault monitor, connected to the protection ring input.
12. 12. An optical node of the addition / suppression multiplexer (multichannel), for communication with other optical nodes, for receiving and transmitting wavelength channels by means of the light propagation element, this node comprises: a first propagation element of light an entrance of the working ring, which is connected to the first light propagation element; a second propagation element gives light; an input of the protection ring, which is connected to the second light propagation element; an optical switch, switchable between two states, bar and transverse state; a first optical input of the optical switch, which is connected to the input of the working ring; a second optical input of the optical switch, which is connected to the protection ring input; a first cut-off switch; an output of the working ring, which is connected to the first optical cut-off switch; a third element of light propagation, which is connected to the output of the working ring; a second optical cut-off switch; a first optical output of the optical switch, which is connected to the second optical cut-off switch; an output of the protection ring, which is connected to the second optical cut-off switch; a fourth light propagation element, which is connected to the output of the protection ring; a second optical output of the optical switch, connected to the second optical cut-off switch; a first fault monitor, which is optically coupled to the first input of the optical switch; a second fault monitor is optically coupled to the second input of the optical switch; a local control unit is connected to the fault monitors, this local control unit controls the optical switch, the first and second cut-off switches; and a network management system, which is connected to the local control unit.
13. 13. An optical multiplexer node Addition / suppression (multichannel) for communication with other optical nodes, to receive and transmit wavelength channels by means of the light propagation element, this node comprises: a first light propagation element; an entrance of the working ring, which is connected to the first light propagation element; a second element of light propagation; an input of the protection ring, which is connected to the second light propagation element; a first optical switch, switchable between two states, bar and transverse state; a first optical input of the first optical switch, which is connected to the input of the working ring; a second optical input of the first optical switch, which is connected to the input of the protection ring; a selective switch of wavelength, which works in the states of bar and transversal; a first optical input of the wavelength selective switch; a first optical output of the first optical switch, which is connected to the first optical input; a line terminal; a first optical output of the wavelength selective switch, which is optically connected to an input in the line terminal; a second input of the wavelength selective switch; a second optical output of the wavelength selective switch; an output on the line terminal, which is optically connected to the second input of the wavelength selective switch, which is in the bar state connected to the second optical output; a second optical switch, switchable between two states, bar and transverse state; a first input of the second optical switch, which is connected to the second optical output of the wavelength selective switch; a second optical output of the first optical switch; a second optical input of the second optical switch, which is connected to the second optical output of the first optical switch; a first optical amplifier; a first optical cut-off switch; a first output of the second optical switch, which, in the bar state, is coupled to the first input of the second optical switch and is connected to the optical amplifier, which, in turn, is connected to the first optical cut-off switch; an output of the working ring, which is connected to the first optical cut-off switch; a third element of light propagation, which is connected to the output of the working ring; a second output of the second optical switch, which, in the bar state, is coupled to the second input; an output of the protection ring, which is connected to the fourth light propagation element; a second optical cut-off switch, which is connected to the output of the protection ring; a second optical amplifier, which is connected to the second optical cut-off switch; a first fault monitor, which is optically coupled to the first input of the first optical switch; a second fault monitor, which is optically coupled to the second input of the first optical switch; a first energy detection monitor, which is optically coupled to the first output of the second optical switch; a second energy detection monitor, which is optically coupled to the second output of the second optical switch; a local control unit, which is electrically connected to the fault monitors, as well as the energy detection monitors, this local control unit controls the first and second optical switches, the selective wavelength switch and the first and second cut-off switches; and a network management system, which is connected to the local control unit.
14. 14. A method for restoring a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node having a first transmission link, a working ring input and a working ring output, each node has a second transmission link, a protection ring input and a protection ring output, where the first and second transmission links transmit signals in opposite directions, this method comprises: detecting a fault in one of the links of transmission, by fault monitor elements; switching on the signals transmitted from the second transmission link to the first transmission link, independent of the fault directed from the fault monitor element.
15. 15. A method to restore a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node has a first transmission link, a working ring input and a working ring output, each node has a second transmission link, a protection ring input and a protection ring output, where the first and second transmission links transmit signals in opposite directions, this method comprises: detecting a fault in one of the links of transmission by the fault monitor elements; switching on the signals received from the first transmission link to the second transmission link, independent of the faults directed from the fault monitor element.
16. 16. A method to restore a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node has a first transmission link, a working ring input and an output of the working ring, each node has a second transmission link, an input of the protection ring and an output of the protection ring, where the first and second transmission links transmit signals in opposite directions, this method comprises: detecting a recovery in one of the links of transmission by fault monitors elements; switching on the signals transmitted from the second transmission link to the first transmission link.
17. 17. A method for restoring a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node having a first transmission link, a working ring input and a working ring output, each node has a second transmission link, a protection ring input and a protection ring output, where the first and second transmission links transmit signals in opposite directions, this method comprises: detecting a recovery in one of the links of transmission by fault monitors elements; switch on the signals received from the first transmission link to the second transmission link.
18. 18. A method for restoring a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node having a first transmission link, a work ring input and an output of the work ring, each node has a second transmission link, an input of the protection ring and an output of the protection ring, where the first and second transmission links transmit signals in opposite directions, this method comprises: placing the node in the working state; detect that there is no optical energy in the link monitoring element; change the state of the optical switching element; change state if the optical switch informs the management system that the node is protected; place the node in the protection state; start the recovery; change the state of the cut-off switch; connect the amplifier; detecting energy in the link supervision element; change the state of the optical switch element; inform the management system that the node is working; and place the node in the working state.
19. 19. A method for restoring a communication network system of at least three nodes, the nodes are interconnected by transmission links, each node has a first transmission link, one node of the working ring and one output of the working ring, each node has a second transmission link, an input of the protection ring and an output of the protection ring, where the first and second transmission links transmit signals in opposite directions, this method comprises: placing the node in the working state; detect the optical energy in the link monitoring element; and place the node in the working state.
20. 20. A method for restoring a communication network system of at least three nodes, these nodes are interconnected by transmission links, each node having a first transmission link, a work ring input and an output of the work ring, each node has a second transmission link, an input of the protection ring and an output of the protection ring, where the first and second transmission links transmit signals in opposite directions, this method comprises: placing the node in the working state; detecting that there is no optical energy in the link monitoring element; change the state of the optical switching element; change the state if the optical switch informs the management system that the node is protected; place the node in the protection state; start the recovery; change the state of the cut-off switch: connect the amplifier; detect that there is no power in the monitoring element; disconnect the amplifier; change the state of the cut-off switch; inform the management system that the node is protected; and place the node in the protection state.