MXPA97007326A - Optico nudo in a network of transfer via optinformacion - Google Patents

Abstract

The present invention relates to an optical node in an optical information transfer network. The node comprises transmitters (Tx: 1-3) and receivers (Rx: 1-3) adapted to particular wavelength channels and ordered to communicate through the information transfer network with receivers and transmitters corresponding to which of wavelength in other nodes. The knots according to the invention are characterized in that they comprise optical movement safety devices (S1-S5) in connection with the transmitters and the receivers of the node, in such a way that the transmitters and the receivers, if necessary, can be moved from a first fiber optic (1, 2) to a second fiber optic (1,

Description

OPTICAL KNOT IN A TRANSFER ROUTE NETWORK OPTICAL INFORMATION Technical Background The present invention relates to an optical node in an optical information transfer network. The node comprises transmitters and receivers that adapt to particular wavelength channels and are placed to communicate through the optical information transfer network with receivers and transmitters for the corresponding wavelength channels in other nodes.

The invention also relates to a process carried out in an optical information transfer network.

Previous Technique Within the field of telecommunications, there is often a need for high transmission capacity. Large amounts of information can be transmitted very quickly using optical transmission through modulated light signals.

Multiplexing or simultaneous transmission of wavelength (WDM) is used to transmit a plurality of light signals through a common optical means. The signals are sent via independent wavelength channels that can be present simultaneously in an optical fiber.

The optical transmission can be carried out in an optical information transfer network comprising a plurality of optically connected nodes adapted for mutual communication. In the case of an optical information transfer network having N knots connected to one another in series through two optical fibers, the communication in both directions between the knots can be carried out as a result of the first fiber. which is used for transmission in one direction and the second fiber being used for transmission in the other direction. Each node communicates with each of the nodes through a single channel of wavelength. This means that at least N-1 wavelength channels are present at the same time on each optical fiber.

Each node comprises at least N-1 receivers and N-1 transmitters that communicate through wavelength channels with the transmitters and receivers that correspond to these channels at the other nodes. Each transmitter transmits information that has input on one of the two optical fibers, each receiver receives information that < = > The optical fibers are extracted from one fiber.

Preferably, the optical information transfer network is arranged so that in the case of an interruption in the network, the communication between all the nodes can be maintained by a pair of reserve fibers placed for interruption situations. However, this type of interruption triggers the communication between the different nodes and involves one or more receivers and transmitters in each node, having to be changed in such a way that it receives or sends respectively a wavelength channel through one of these reserve fibers. In order to restrict the number of wavelength channels used, it is possible to reuse the channels. Reusing the channels means that one or more wavelength channels received at a node are used for transmission from the same node on the same fiber when this is possible. The minimum number of channels that can be used is restricted by the number of nodes to Ni / 4 if N is even or (N2-l) / 4 if odd. Since the same channel is therefore often used to transmit on the same fiber, problems can arise when the communication between the two nodes is also maintained when there is an interruption in the network.

The ps-5 159 95 has already disclosed a network comprising a number of nodes that are connected to each other in an annular configuration. Each node can communicate with the other node through the network. In the case of a conventional network configuration, each message is transmitted between two nodes via both fibers from a sending node to a destination node; in this same way, a message is received from the fibers oppositely directed in a knot. This means that communication in the case of an interruption in the information transfer network can be maintained without it being necessary to change it. A disadvantage of this system is that the network usually has a large unnecessary number of wavelength channels and therefore is too dimensioned.

Description of the invention The invention relates to an optical knot that is adapted for communication through transmitters and receivers that are connected to two optical fibers, with at least two other optical knots in an optical information transfer network. This network of optical information transfer path. it includes extra communication paths to ensure that communication between the two nodes is maintained after an interruption in the information transfer network.

A problem with this type of security of a traffic information network is that if a cable is defective, the receivers and transmitters need to be changed in such a way that they communicate through the other optical fiber and thus maintain the communication.

The invention attempts to solve the above problem by providing an optical node in a simple manner that allows the transmitters / receivers to be exchanged between the fibers of the information transfer area when there is an interruption in the network. The node according to the invention comprises a plurality of transmitters and receivers that in pairs allow communication with any other node through two optical fibers in an information transfer network. Optical fibers connect the nodes in the information transfer network and allow bidirectional communication between each of the nodes. The node comprises at least the same number of change security devices that are ordered to switch to the transmitters and receivers in a node between the two optical fibers.

The invention also relates to a node that does not necessarily comprise transmitters and receivers, but comprises a plurality of muitiplexers and demultiplexers between the two optical fibers.

By virtue of the construction of the node according to the invention, in the case of the distribution of the channel with a re-use of the channels in such a way that the minimum quantity of the wavelength channels is distributed to the transmitters and Recipients to fine-tune the wavelengths in the network of information transfer, allow these transmitters and receivers to be exchanged between the two optical fibers, so that the distribution of the transmission and reception channel can be maintained for communication between the included nodes in the communication transfer network, even when there is an interruption in it.

Due to this relatively simple design, the construction of the node according to the invention is also advantageous in the case of other types of transfer network information in which the advantageous distribution process of the aforementioned channel is not used. However, a condition for the use of the knot is that it should exist _? T? risk in the infusion transfer network that would be affected by changes in the configuration of the network; for example, an interruption somewhere in the information transfer network; These changes require that the transmitters and receivers are switched between the optical fibers.

The invention also relates to a process that is carried out at an optical node when there is an interruption in the information transfer network.

Description of the Figures FIGS. 1-E show a network of optical information transfer path with four nodes in the case of situations other than interruption in the information transfer network; Figur-: shows a first embodiment of the optical knot according to the invention; and Figure 3 shows a second embodiment of the optical node according to the invention.

Preferred Modes The invention will now be described in great detail with reference to the Figures and in particular to Figure 2 and Figure 3 showing two different embodiments of the optical node according to the invention.

Figures la-c show an optical information transfer path network having four A knots, B, C, D and is provided with an extra pair of fibers 3, 4 that can be used in case of an interruption in the regular information transfer network. Each node comprises three transmitters and three receivers. Depending on the location of the network where the node is located, a variable number of Tx transmitters will be connected: 1-4 and Rx receivers: 1-4 to the first fiber 1. For example, a first node A has three Rx receivers: -3 connected to fiber 1; all its signals will go to the left in the Figures and multiple transmitters Te: l-3 are connected to the fiber 2; all your signals will go to the right of the Figures. On the other hand, a last node D ti ne three receivers Rx: 1,2, 4 connected to the fiber 2 and the three transmitters Tx; 1,2,4 connected to the fiber 1. The intermediate nodes have both Tx transmitters and Rx receivers connected to both fibers.

Each Tx transmitter in the optical information transfer network transmits a signal at a given wavelength; a channel known as wavelength. Each Rx receiver in the network receives a given wavelength channel and allows other channels to pass over the next node. Two channels of the same wavelength will never be presented over the same common fiber section, since in that case the channels would not separate in the receivers. This means that the channel that is received by means of the receiver in a node has to be entirely separated from the optical information transfer network. A pair of transmitter / receiver in each node is reserved for communication with each other node, that is, a transmitter in a first node transmits a channel of wavelength to another specific node and a receiver in the first node receives a channel of wavelength from the other node. This transmitter and this receiver in the first node, which together allow the first node to communicate completely with the second node, form a transmitter / receiver pair in the first node. Therefore, each node comprises the same amount | of transmitter / receiver pairs as the amount of other nodes present in the network.

Figure shows the optical information transfer network in the normal case, that is, without interruptions. In this Figure the extra pair of fibers is illustrated in dotted lines to show more clearly that this is not used for communication in the normal situation. In the information transfer network that was shown, the channels are reused, that is, the length wave channels that are received in a node are used for the transmission from the same node on the same fiber when it is possible. , in order to be able to use the minimum number of numbers for the communication between the different nodes. In the case of the information transfer network shown in Figure la, the wavelength channel 3 is received by the receiver Rx: ¿. A Tx transmitter: in the same node it is again used in the same channel for the transmission of the node D. When a channel is used again in a network of information transfer and has N nodes, it means that a network of Information transfer has to distribute a minimum number of wavelength channels (N2-I) if N is an odd number and channels of wavelength N, and '4 if Ms par. r knot distributes N-l channels on each fiber for communication to and from the node. In the example shown in the Figures, with an information transfer network that has four nodes, communication can be maintained between all the nodes if at least four different wavelength channels are used for this communication. Each node has distributed three wavelength channels for transmission to the other nodes. These wavelength channels are reused directly when they have been received in a node. Of course, the node according to the invention can be found in the information transfer networks in which the channels are not used again.

Figure Ib shows the new configuration obtained after a fiber cut between node A and node B in the original information transfer network. In this case, the extra fiber has to be used in order to allow communication between node A and the other nodes. The advantageous distribution of the channel allows communication between the different nodes to use the same channels as is the case in accordance with Figure 1, despite the fact that the distribution of the channel according to Figure 1 is based on the distribution of the channel. the minimum number of wavelength channels. However, in all nodes, the given transmitters and receivers have to use opposite optical fibers, as in the case shown in Figure la. After the interruption, the node A is the last one in the network so that the traffic passes to the right and in this way must have three rereptores connected to the fiber ¿and three transmitters connected to the fibr 1. In the B node, the changes are really very few, since only the transmitters and the receivers for the communication between the node A and the node B need to move between the fibers. Before the interruption occurred, the transmitters were used in node B that intended communication with node A for transmission through the fiber 1 in the direction h ^ i left n the figures. Instead of this, after the interruption, these transmitters have to communicate with the node A, through the fiber 2, in the direction that goes towards the e. In contrast, the re-emitters in node B intended for reception from node A, have to be changed to receive the information from the fiber going to the left, fiber 1. Correspondingly, a pair of transmitter / receiver what to change the node C and one in the node D, etc. An interruption between node A and node B would be reflected as a consequence in all transmitters and receivers in node A, having to change between the fibers, while only one transmitter / receiver pair needs to be changed in the other nodes. The Figure shows the corresponding case by an interruption between the node B and the node C. The figures show that in some cases it is necessary to change? transmitters and receivers between the two optical fibers that pass through a given node. It will be appreciated that the examples shown in the Figures are only some of the many cases in which the change is desired.

Figure 2 shows a first embodiment for an optical node that is configured so that the aforementioned change can be carried out. The node (shown in the Figures is intended for the information transfer network shown in Figure 1), therefore, each node comprises three Tx transmitters and three Rx receivers with fixed wavelength distribution, which is connected to two optical fibers 1. These fibers pass through the knot in such a way that both fibers 1, 2 are transmitted in the node in the same direction.The knot shown in Figure 2 corresponds to node A in Figure 1. Therefore, the transmission from the node occurs through the three transmitters Tx: l-3, destined for the wavelength channels 1, 2 and 3. As indicated in connection with the Fiaura 1, the reception of the node occurs through the same wavelength channels 1,2 and 3. The receiver Rx: 1 is placed at the farthest point upstream in the node and the transmitter Tx: 3 is placed in the most point distant -or i nf down in the knot.The knot comprises three demu1 ti pl xors 3a, h, o, for extract the wavelength channels towards the respective receivers Px: 1-3 and fres mulfiplexer s 4a, b, e, to input the wavelength channels from the corresponding transmitters Tx: l-3 within the two optical fibers 1 ' The node also comprises five 2x2 switching or switching devices of safety switching S1-S5 in order to be able to carry out the necessary change in the node when there are changes in the information transfer network. Each security change device comprises two eneradas and two outputs, of which a first input is connected to a first optical fiber 1 and a second input is connected to a second optical fiber 2; Correspondingly, a first input is connected to the first optical fiber 1 and a second output is connected to the second optical fiber. When the switching devices are in the first state, the signals are coupled through the input that is connected to the fiber 1 towards the outlet that is connected with this fiber, while the signals from the input that are connected to the fiber 2 are coupled to the output that is connected to the same fiber. When the security change devices are in the other state, a signal that is connected from the input to the fiber is additionally accommodated to the output that is connected to the fiber 2; Correspondingly, the signal at the input that is located +one -adjusted to the fiber ° is coupled to the output that is connected to the fiber 1.

In the embodiments shown, the safety or time change devices of -Onmufa ~ uLón are so arranged that there is never more than precisely one receiver and precisely one lian-Jini _3or between the two switching time devices S1 -S5. A pair of transmitter / receiver Tx: 1 / Rx: 2, Tx: 2 / Rx: 3, the mial communicates with another given node, never uses the same fiber and this pair can then be ordered together with the safety devices of switching time S1-S5 on each side. However, the transmitter in this pair must be ordered so that the receiver, i.e. the demoditor 3a, 3b, 3c to extract a receiver, is never found downstream of the node in relationship to the transmitter and its mul + 'iplexor 4a, 4b, 4c. In the case of the advantageous distribution of the channel when the minimum amount of wavelength is used, the node has to comprise five switching safety devices, that is, N + l ii safety positions of "onmutarion", since A transmitter with a given length of time should never be placed upstream in a node compared to a receiver for the same wavelength, This means that when monkeys a safety change device has to be placed between the multiplexer 4z and the demol Iple 3 for one of the transmitter / receiver pairs, in the mode shown in Figure 2., the tiplexor de_.mul is placed at the furthest point upstream in the node and the multiplexer 4a is placed at the furthest point downstream in the node, with the security change devices Sl, S2 on each side of the node. _smul tiplexer 3a and the security change devices S4, S5 on each side of the multiplexer 4a. This split demodiplexer / multiplexer pair 3a, 4a can also be placed in elite positions in the node, since the demultiplexer 3a is never placed downstream in the information transfer network relative to the multiplexer 4a.

If additional wavelengths are introduced into the information transfer network in accordance with Figure 1, a node with only four switching security devices, ie II switching security devices sufficient to carry out the change in each interruption situation on the information interf rrence rod. an example of these is a situation shown in Figure 3, in which a situation is shown in which two channels of additional wavelengths 5 and 6 allow the construction of a node with N exchange security devices. In the normal case shown in Figure 1 for communication in an information transfer network with four nodes and reuse channels, all Tx transmitters: 3 in one A are transmitted over fiber 2 and all Rx receivers: 1-3 in a node A are heard on the fiber 1. As for node A, this means that the exchange security devices S1-S5 in the node in accordance with Figure 2, has to be held in a Primor status or in a normal state, that is, without moving between the fibers. However, when an interruption occurs between two nodes, the motion safety devices have to change to another state of change.

Fiqura shows you, for example, a cable twist between the node B and the node C. In this case, the transmitters for channel 1 wavelength and channel 3 wavelength in node A have to be coupled to the fiber 1; At the same time, the receivers for the wavelength channels 1 and 2 have to be changed to fiber 2. This can be carried out as a result of the activation of the change values, so that they can be changed to a On the other hand, the change occurs between fiber 1 and fiber 2. Table 1 below shows that fiber ^ 1 or 2 ¡¿> it uses for the respective transmitters and receivers in node A for each type of interruption situation in the network of transfer of error. The tabia below illustrates the first state of the exchange rate devices with two parallel lines. The second state of the security devices is shown by means of a cross X. The rage shows the status for each of the positive security changes in node A, in the different situations of incorruption and the knot is designed in accordance with Figure? . Tx: 1 Tx: Tx: í Rx: 1 Normal Cd: 2 1 Interruption A-B: 1 1 Interruption B-p: 1 2 Interruption C-D: 1 2 Rx: 2 Rx: 3 SI S2 S3 S4 S5 Normal case: 1 1 TI II TI II II Interruption AB 2 2 X II II II X Interruption BC X II Interruption CD II II II TABLE 1 If an interruption occurs in the network, between the node B and the node C, it causes the Channels of wavelength 1 and 3 have to be transmitted through fiber 1 from e] node A, instead of through fiber 2, with in the case standard. Therefore, the muitiplexers 4a, 4b for coupling in these wavelength channels have to be moved so that the channels are coupled through the fiber 1. Correspondingly, the Figure shows that the receivers for Channels 1 and 2 must be routed to fiber 2 after an interruption. Table 1 shows that a node adapted to the interruption is obtained if the change safety devices SI, Si, S4 and S5 are operated to change the state.

A node in an information transfer network according to Figure 2 has four nodes, consequently it should comprise five change security devices S1-S5 in order that the transmitters and the rereptores can be changed to each fiber situation desired in the case of the channel distribution shown in Figure 1 with the reuse channel. This usually means that a node in an information transfer network that has a total of N nodes should comprise N + l exchange security devices if the minimum number of channels has been distributed in the information transfer network. , ie (N2-l) / 4 channels if N is an odd and 112/4 channels if N is even, so that the transmitters and receivers can be changed, so that it is possible to adapt to any interruption situation In the net.

Since the distribution of the channel for the information transfer network is not carried out with a complete network of channels, an operating node can be produced in an information transfer network that has N nodes with N devices. Change security, that is, a change security device less than that shown in Figure 2. Figure 3 shows this knot construction by node A. The knot comprises only knots and does not work satisfactorily for the node. situation shown in Figures la-c in which the full re-use of the channel is used. In the embodiment shown in Figure 3, two additional channels, wave length channels 5 and 6, were added. These extra channels mean that the four exchange security devices S1-S4 are sufficient in the node. If the channels are distributed so that only the N-2 or less wavelengths of transmitters and receivers in a node are the same, that is, at least one receiver and at least one transmitter does not operate at the corresponding wavelengths, It is possible to use a node that has M 2x2 change security devices in accordance with Figure 3. Alternatively, the same configuration of the node can be used if the communication that comes and goes from the other nodes is carried out in pairs over the same wavelengths, that is, the node A had the node B over the same wavelength, as it does with the node P which speaks to the node A., etc. Then a transmitter is placed together with a receiver on the same wavelength between two 2x2 exchange security devices.

The invention is not restricted to the modalities described above with reference to the Figures, but can be modified within the scope of the following r i v i n i ations.

Claims (8)

CLAIMEDICATION

1. The optical node comprises at least Nl transmitters (Tx: 1-31 and at least Nl receivers (Rx: 1-3 that adapt in such a way that they communicate with receivers i Rx: l-3j and transmitters (Tx: 1-3 , 1 at these additional nodes through an information transfer network having two optical fibers (1,2) which are arranged to be transmitted in different directions towards other Nl optical nodes, characterized in that the node comprises at least N devices. exchange security SI-S51, which are placed to move the receivers (Rx: l-3í and the transmitters (Tx: l-3) between the optical fibers [1, 1) when there is an interruption in the information transfer network.

2. The optical node comprising at least Nl mult pl xores [4a, b, r) placed to output a corresponding number of wavelength channels for the 'Tx: 1-3 transmitters within one of the two optical fibers ( 1,2) in an information transfer network and when less than the number of selective wavelengths (3a, 3b, 3c) that are placed to extract a corresponding number of wavelength channels from one of the two optical fibers (1,2) in a network of information transfer to the IRx receivers: 1-3); these wavelength channels are ordered to transmit in different directions through two optical fibers (l, i) of the information transfer network to the receivers (Rx: l-3) and the transmitters (Tx: l-3) ) respectively, corresponding to the wavelength channels in connection with Nl of other optical nodes in the information transfer network, characterized in that the node comprises at least N optical change security devices (S1-S5) that are placed to move to the multipoles (4a, 4b, 4c) and / or demulsors (3a, 3b, 3c) between the optical fibers (1,2) of the optical transfer network when there is an interruption in the same .

3. The optical node according to any one of the preceding claims, characterized in that both optical fibers (1,2) are arranged to pass through the exchange security devices in the same direction of transmission from a current position upwards of a first shift safety device (SI) co-located at the node to a downstream position of a last shift safety device (S5) positioned at the node.

4. An optical node according to any of the previous claims, characterized in that each transmitter (Tx: l-3) and the receiver (Rx: l-3) have a fi xed wavelength distribution.

5. The optical node according to claim 2 or 3, characterized in that the multiplexers (4a, 4b, 4c) and the demulting elements (3a, 3b, 3c) are ordered in pair sn the node so that each pair of multiplexer / demultiplexer (3a, 4a; 3b, 4b; 3c, 4) comprises a multiplexer and demultiplier that is positioned to input or extract the wavelength channels that together maintain the connection to and from another node; and wherein at least one exchange security device (S1-S5) is arranged on each side of the multiplexer / demultiplexer pair (3a, 4a; 3b, 4b; 3c, 4c); This change security device is so arranged that, if necessary, it couples the multiplexer / demultiplexer pair placed upstream of the change security device towards the opposite fiber.

6. The optical node according to any of the preceding claims, characterized in that the knot of the optical information transfer network with N knots and advantageous distribution of the channel, the communication between the knots occurs through N2 / 4 wavelength channels if N is equal and (NJ-1) 4 channels if N is odd; comprises N- + 1 exchange security devices (S1-S5) of which at least one exchange security device (S2; S3; S4) is placed between the demultiplexer (3a) and the desmulfipiexor (4a) in a pair of mulfiplexer / demultiplexer (3a, 4a).

7. The optical node comprises monitors Nl transmitters with fixed channel distribution, each of the transmitters are connected to an ordered multiplexer to output a wavelength channel from the transmitter to an optical fiber in an information transfer network that it has two optical fibers, and Nl receivers with fixed channel distribution; each of the receivers is connected to a selective wavelength demultiplexer ordered to extract a wavelength channel from an optical fiber in a network of information transfer to the receiver; The wavelength channels are placed to transmit in different directions through two optical fibers in an information transfer network; the receptors and transmitters correspond to the wavelength channels in connection with other Nl of nodes in the information transfer network that is characterized because: the node comprises Nl of pairs of multipexers / demultiplexers that adapt to communicate with each other knots and each of them comprises a multiplexer and a demuxer, which are arranged to input and extract, respectively, the wavelength channels, which s hold together the connection to and from a second node; - the node comprises at least N optical movement security devices; - the movement safety devices are placed on each side of each pair of mulfiplexer / demulfiplexer, so that the multiplixer / demultiplexer pairs are arranged so as to be coupled with the optical fibers, and; - both optical fibers are arranged to pass through the motion safety devices in the same direction of transmission from an upstream position of a first movement safety device placed in the node to a downstream position of a Additional safety device for movement in the knot.

8. The optical knot ^ undertakes: two optical fibers to transmit in different directions towards other N-l knots in the information transfer network; these optical fibers transmit in the same direction through the node from a position upstream of the node to a position downstream of the node; - N-l transmitters with fixed channel distribution; each of them is connected to an ordered multiplexer for inputting a wavelength channel from the transmitter into an optical fiber in an information transfer network; - N-l receivers with channel distribution fi; each of these is connected to a selective wavelength demultiplexer arranged to extract a wavelength channel from an optical fiber in a network of information transfer to the receiver; the wavelength channels are ordered to transmit in different directions, through the two optical fibers to the receivers and transmitters corresponding to the wavelength channels in connection with the other N-l nodes in the information transfer network; N-l pairs of multiplexers / dcsmultiplexers to communicate with other nodes; These pairs of multipoles and polarizers are arranged to respectively input and extract the wavelength channels, which hold together the connection to and from another node; and arranged between the upstream position in the node and the downstream position in the node; -N + l optical motion security devices that are arranged to couple the muitiplexers / demultiplexers between the two fibers and which are arranged on each side of each multiplexer / splicer pair and, in the case of a pair of rt ul tiplexer / demultiplexer, both are ordered on each side of them and between the multiplexer and demultiplier in the pair, in such a way that the multiplexers are ordered downstream of the desmuitiplexer is in the information transfer network.