MXPA97007480A - Optical network and ordination and method in said - Google Patents

Abstract

The present invention relates to a redóptica that is ordered to ensure communication between nodes in an order line and a higher order line when there is an interruption in the lower order line or in case of a failure in the bell. Each lower order line consists of an information transfer network (5) with bells, and a node or a plurality of nodes (A-D). Two optical fibers (1, 2) connect to the nodes in each information transfer network (5) and are used for communication in opposite directions between the nodes. Each information transfer network comprises precisely two bells (H1, H2) of which the first closes the end of the information transfer network at the first end thereof, and the second closes the information transfer network in the other extreme. The bells connect the information transfer networks (5) in a lower order line and connect this line with a higher order line. Each node in the information transfer network is ordered to communicate with each bell. The invention also relates to a channel distribution process in the aforementioned red-optic. The distribution of channels can be carried out in such a way that the channels received at one of the nodes can be reused for transmission on the same fiber from the same node.

Description

OPTIC NETWORK AND ORDINATION AND METHOD IN SUCH NETWORK Technical Field The present invention relates to an optical network that is ordered to ensure communication between nodes in a lower order line and a higher order line when there is an interruption in the lower order line.

The invention also relates to a process for ordering channels in the aforementioned optical network.

PREVIOUS TECHNIQUE In the field of telecommunications, there is often a need for high capacity transmission. The information can be transmitted very quickly by means of optical transmission through modulated light signals.

Large optical networks are often constructed as stratified or hierarchical networks comprising local or lower order lines and central or higher order routes. The lower order lines are formed by means of nodes in which a plurality of subscribers are connected to the network. The knots are preferably connected to another through two optical fibers in which the messages are sent in opposite directions. The communication between the nodes in different lower order lines is carried out in a manner in which the messages to and from the lower lines are transmitted through a line or a plurality of higher order lines. A bell placed on the lower order line concentrates traffic from the lower order line and transmits it to the higher order line. Correspondingly, the bell converts the traffic of the higher order line and transmits it to the lower order line in an appropriate manner.

A large proportion of teletraffic occurs between the lower order lines and therefore it is important that the possibilities for communication between the lower order lines and the higher order lines are good. In order to ensure this communication, it is already known that a plurality of bells can be ordered in a given line of lower order.

It is already known from US-A-5 218 604 to order two bells between a first annular network and an annular one of higher order that is structurally similar, which can be compared with a local line and a center line. Both the first and second ring networks comprise add / drop multiplexers (ADM) through means by which the channels can be fed or derived from the ring networks. These consist of two lines that transmit information to and from the ADMs mentioned above in two different directions in the direction and opposite to the clock hands in the ring networks.

Each ADM in the ring networks can communicate with both bells in which the channels are sent to both networks in direction and opposite to the hands of the clock, that is, the same message is sent in opposite directions on different lines. All channels are sent on each line to both bells, which are connected to the two lines that on a given channel received a first bell that is derived only partially from the line; this residual remnant of this channel can continue on the line of the next bell. A first bell is ordered to transmit the received channels from one network to a first line in the second ring network and a second bell is ordered to transmit the same channel to a second line in the second network.

A disadvantage with this already known solution is that it is only intended for communication between two annular networks of similar structure communicating only with one another. If the known solution is applied to an optical network, the annular structure causes an optical noise to circulate in the annular network, which damages the quality of the signal. In addition, the known solution can not be adapted to stratified networks that have a plurality of different levels and a plurality of lines in each level.

DESCRIPTION OF THE INVENTION The object of the present invention is to solve the problem to ensure communication between a lower order line and a higher order line when there is a fault in the cable in the lower order line.

This objective is achieved by an optical network that has one or a plurality of lower order lines connected to a higher order line. The lower order lines comprise at least one information transfer network with bells and a node or a plurality of nodes that connect with each other through two optical fibers, the optical fibers in the information transfer network are They use for transmission in different directions.

Each information transfer network comprises precisely two bells that close each end of the information transfer network. The bells are ordered to change and concentrate the traffic from the lower order line in a form suitable for transmission on the higher order line or the lower order line. Each node of the information transfer network is ordered for transmission to one of the two bells through one of the two optical fibers and for the transmission to the second of the two bells through the second of the two optical fibers .

The invention also relates to a process for the distribution of channels in an information exchange network in an optical network of the aforementioned type. During the distribution of the channel, at least one wavelength channel is placed in each node for the transmission to the bells and the reception from the bells, these placed at each end of the information transfer network. The distribution of the channel can be carried out in such a way that the channels received in a node can be reused for transmission on the same fiber from the same node.

DESCRIPTION OF THE FIGURES Figure 1 shows an optical network consisting of a higher order line and lower order lines; Figure 2 shows a lower order line consisting of a simple optical information transfer network for use in an optical network; Figure 3 shows a construction of a preferred knot; Figure 4 shows a lower order line comprising two optically separated information transfer networks; and; Figure 5 shows a lower order line of the grid type comprising a plurality of separate information transfer networks.

PREFERRED MODALITY In the following, the invention will be explained by reference to the Figures and in particular to Figures 2, 4 and 5 which show the preferred embodiments of a lower order line placed in an optical network.

Figure 1 schematically shows a known construction for an optical network that was constructed as a stratified network. In the example shown in the Figure, the network comprises three lower order lines, 4a-4c communicating through a higher order line 3. Each lower order line comprises a node or a plurality of nodes that are show as circles in the Figures. The optical knots are connected to each other through two optical fibers directed in an opposite way and communicate with each other through two bells that are placed on the line and shown as a diamond in the figures. The bells are also used for communication between the knots in different lower order lines; the higher order line is used to transmit information between two bells on intercom lines. The known bells are ordered to convert and consolidate the signals received in a form adapted for subsequent transmission within the line or to the next level. An even more extensive network can obviously comprise more than two levels, such that each lower order line it is ordered to communicate with a higher order line through one or a plurality of intermediate lines. The construction of the intermediate lines may be identical to that of the lower order lines that were described herein. A large part of all the teletraffic in an optical network is presented between different optical lines of lower order and therefore it is important that the possibilities for communication between a lower order line and a higher order line are good.

In order to ensure operation in the optical network shown in Figure 1, a plurality of geographically separated bells may be arranged in each of the lower order lines 4a-4c. In accordance with the invention, each line 4a-4c consists of a network or a plurality of information transfer networks; each of these closes precisely with the two bells. Through the bells, the transfer network d < = > The information can be connected to a lower order line 4a-4c comprising a plurality of information transfer networks. In the example shown in Figure 1, each lower order line 4a-4c comprises precisely two information transfer networks that are coupled in parallel, such that an O or? Line is formed. d «= * n lower.

Figure 2 shows a first mode of a lower order line in an optical network according to the invention. This line consists of an information transfer network 5 comprising four different A-D nodes that are connected to each other through two optical fibers, 1,2, which are used for transmission in opposite directions. The information transfer network 5 comprises a first and a second bell Hl, H2 which is ordered at each end of the information transfer network. Each node is ordered to communicate with each bell through a wavelength channel, such that the node sends a wavelength channel to the bell H2 along with a fiber 1 that goes to the right side in the Figure and a wavelength channel to the bell Hl along with a fiber that goes to the left of the Figure.

In the case of the modality shown in the Figure, the Hl bell sends four channels on the fiber that goes to the right side. A first channel is completely extracted from the fiber by a de-multiplexer in node A and is prevented from continuing on the line. Accordingly, this wavelength channel can be reused on the same fiber for further communication from node A to bell H2. The other channels continue unaffected through the node A. A second channel is then removed at node B and the channel can be reused for transmission on the same fiber from node B to bell H2. The last two channels are extracted and reused correspondingly at junctions C and D. The traffic that travels to the left side works from the same way. The H2 bell sends to the same four channels that were extracted in the knots A, B, C and D; new messages are supplied to the wavelength channels for transmission to the Hl bell. Naturally, the order in which they are extracted or incoporated to channels within the information transfer network may vary.

The construction node shown in Figure 3 is especially suitable for the optical network according to the invention. By virtue of the knot construction, the same transmitter Tx can be used for transmission over the two separate optical fibers 1,2, since the same channels in a node are used for transmission to the respective bell. Correspondingly, the same receiver Rx is used for reception on the respective fiber, since each bell sends the same wavelength channel towards an optical node through the respective fiber. A multiplexer 6a, 6b placed on each optical fiber 1, 2 is ordered to input channels p wavelength from a given transmitter Tx to both optical fibers. Due to the fact that the same Tx transmitter can be used for transmission over two separate optical fibers 1, 2, the cost of the equipment is reduced. The same message is sent from one of the knots A-D on both fibers 1,2, in different directions towards the two bells Hl, H2. From the mode, the message is received in one of the A-D nodes from both channels H1, H2, through the two optical fibers 1,2. Each node A-D comprises two demultiplexers 7a, 7b, of which s a 7a is connected to the fiber 1 traveling to the right side and the other 7b is connected to the fiber traveling to the left side. These demultiplexers 7a, 7b, are ordered to extract a channel of wavelength given c jri ld am <; = > nt ^ from the respective fiber to a receiver kx at the respective node. In the case of reception, an optical coupler 8 is used with the modality shown in the Figure, to determine which of the signals e allows it to pass through the receiver R. This coupler 8 is ordered to change between the two different states. In < = > In the first state, a signal from the demultiplexer 7a on the fiber 1 traveling to the right side is coupled to the receiver Rx, while the signal from the demodulator ipl exor 7b on the fiber 2 traveling to the left side is not taken into account; in contrast, in the other state, the demultiplexer signal 7b on the vibra 2 traveling to the left side is coupled to the receiver Rx, and in this case the signal of the demultiplexer 7a on the fiber going to the right side does not it is taken into account. An alternative solution that is shown in the Figure is also the use of two receivers. The choice of the signal is then made in an electrical change device before the message is processed.

Figure 4 shows a lower order line with two bidirectional parallel information transfer networks 5a, 5b, of the type shown in Figure 2, which are connected to the first and second bells Hl, H. Each node in the lower order line with two information transfer 5a, 5b, can communicate with each of the two bells Hl, H2 in the manner indicated in conjunction with Figure 2. Considered optically, the two information transfer networks 5a, 5b, in the lower order line 4, are not connected and all the communication between them is presented through the bells Hl, H2. The traffic between the two nodes in the same information transfer network was also presented through one of the bells. The communication within the line of the lower order or with a higher order line (not shown) by means of this can be maintained even if a cable failure occurs in one of the information transfer networks 5a, 5b, in the lower order line or in case the bell stops working.

In the configuration of the node shown in Figure 4, the traffic, for example from node A to node B, passes through fiber 2 to the bell Hl and from there continues to node B through the fiber through the fiber 1 towards the bell H2 and from there it continues towards the node B through the fiber 2. Correspondingly, the traffic from the node B towards the node A passes through the fiber 1 towards the bell H2 and from there it continues towards node A through fiber 2 or through fiber 2 towards hood H1 and from there it continues towards node A through fiber 1.

In the case of traffic between two separate information transfer networks, for example from node B to node E, the traffic passes in a corresponding manner through the bell Hl and the bell H2. Traffic d < = > From the node B it passes to the bell H2 through the fiber 1 and continues towards the node E, through the fiber 2 from the bell H2 or through the fiber 2 towards the bell Hl and continues until the node E through of fiber 1.

If a cable failure occurs, for example between node A and node B, in the example shown in Figure 4, a wavelength channel on each fiber 1.2 is used for communication between the knot A and the bell Hl. For communication with node B, a wavelength channel would be used instead on the sections of the fiber that are connected to the bell H2. The two Hl, H2 bells are connected to a higher order line (not shown). This means that the communication between the higher order line and all the nodes in the two separate information transfer networks 5a, 5b, are also ensured after a cable failure.

Distributing an extra channel to the two information transfer networks 5a, 5b for the commonality between the Hl, H2 bells has proven to be advantageous. Without access to this extra channel, all communication between the bells would have to pass through a higher order line 3 in the case of an interruption. This loads the lines of the higher order and therefore a disadvantage can arise. If an extra wavelength is used to handle the traffic between the two bells Hl, H2, a wavelength channel can first be sent from node A to node B in situ; ion r] aforementioned interruption, towards the bell Hl through fiber 2, where it is converted for transmission through bell-to-bell wavelength transmitters, where traffic is transmitted to the H2 bell . This bell converts the traffic it receives and sends it later to a node B through the effective wavelength channel on fiber 2.

In case of an interruption, traffic is also passed between two information transfer networks in the lower order line. Traffic from node E to node B, for example, passes through fiber 1 to hood H2 and from fiber line 1 to the hood H2 and from there continues to the node E through fiber 2.

The concept of conformity with the invention can also be extended to connect a plurality of information transfer networks 5c, 5k, in a line of the lower order of grid type as shown in Figure 5. Each of the transfer networks of information 5c-5k, is closed at each end towards a bell H, which is common to one or more pluralities of the other information transfer networks, such that closed grids are formed and the line is closed.

Claims (12)

1. ! The optical network comprising lower order lines (4a-4c) that are connected to each other through at least one higher order line (3), which consists of lower-order lines of at least one transmission network. of information (5) with bells (Hl, H2) and a knot or a plurality of knots (AD) that are connected to each other through two optical fibers (1,2) transmit in opposite directions; the bells (Hl, H2) are ordered to convert and concentrate the received signals in a suitable form for the transmission in the upper order line (3) or in one of the lower order lines (4a-4c) characterized by: - each information transfer network comprises precisely two bells (Hl, H2), of which one bell is placed at the first end of the information transfer network and the other is placed at the other end of the transmission network. information; - each node (A-D) is ordered to transmit to one of the two bells (hl, H2) through one of the two optical fibers (1, 2), and; - each node (A-D) is placed to transmit to another of the two bells (hl, H2) through the other of the two optical fibers (1, 2).
2. 2. The optical network according to claim 1, characterized in that: - each information transfer network (5a; 5b; 5c; ... 5k) in a lower order line is connected to a network or to a plurality of other information transfer networks (5b; 5a; 5d; 5e, 5f, '5g, Sk; ... 5c, 5d, 5g, 5j) by means of the two bells (H, H2; H) that are placed at the ends of the respective information transfer network, in such a way that closed grids are formed by the information transfer networks in the lower order line.
3. 3. The optical network according to any of the preceding claims, characterized in that; - each node in the transfer network (5) is positioned to receive the wavelength channels from the two bells (H1, H2) at each end of the information transfer network; the reception from the first of the two bells (Hl, H2) occurs through the first of the two optical fibers (1, 2) and the reception from the second of the two bells (III, 112) occurs through the second of the two optical fibers (1, 2), and; - each node in the information transfer network (5) is ordered to send wavelength channels to the two bells (H1, 112) at each end of the information transfer network; the transmission to the first of the two bells (Hl, H2) occurs through the second of the two optical fibers (1, 2) and the transmission to the second of the two bells (III, 112) occurs through the first of the two optical fibers (1, 2).
4. 4. The optical network according to claim 3, characterized in that: - each node is ordered to send the same wavelength channel to the bells at each end of the information transfer network, and; - each node is ordered to receive the same wavelength channel from the bells at each end of the information transfer network.
5. 5. The optical network according to claim 3, characterized in that: - each node is ordered to use wavelength channels that are received from the first bell (Hl) through the first fiber / l) for a subsequent transmission , through the same fiber (1) towards the second bell (H2), and; - a knot is ordered to use wavelength channels that are received from the second bell (H2) through the second fiber (2) for a subsequent transmission from the same node, through the same fiber (2) towards the first bell (Hl).
6. 6. The optical network according to claim 4, characterized in that: - each node is ordered to use the wavelength channels that are received from J to the first cartilage (Hl) through the first fiber (1), for a subsequent transmission through the same fiber (1) towards the second bell (112), and; - each node is ordered to use wavelength channels that are received from the second bell (H2) through the second fiber (2) for a subsequent transmission from the same node, through the same fiber (2) towards the first bell (Hl).
7. 7. The optical network according to claim 4, characterized in that each node comprises: - two multiplexers (ßa, ßb) of which one (6a) is ordered to be coupled to a wavelength channel for a transmitter (Tx) to a first optical fiber (1) transmitting to a first address in a transfer network of information (5) and the second (6b) is ordered to be coupled to the same wavelength channel from the same transmitter to a second optical fiber (2) transmitting in the opposite direction in the information transfer network (5) , Y; - two demultiplexers (7a, 7b) of which one is ordered to extract a wavelength channel from the first optical fiber (1) and the second (7b) is ordered to extract the same wavelength channel from the second fiber optic (2).
8. 8. The optical network according to claim 7, characterized in that the node comprises a switching device (8) that alternately connects the demultiplexers (7a, 7b) to a receiver (Rx), such that a first demultiplexer ( 7a) is connected to a receiver (Rx) in the first state of the changeover device (8) and a second demultiplexer (/ b) is connected to the receiver (Rx) in the second state of the changeover device (0).
9. 9. The optical network according to claim 7, characterized in that the node comprises two receivers; a first receiver is commanded to receive a signal from the first demultiplexer (7a) and a second receiver is ordered to receive a signal from a second demultiplexer (7b).
10. 10. The optical network comprises: . - at least one lower order line consisting of a network or a plurality of information transfer networks that have precisely two bells; these are placed at each end of the information transfer network and are arranged to convert and concentrate the received signals in a suitable form for a subsequent transmission; and a knot or plurality of knots connected to each other through two optical fibers that are transmitted from opposite directions; each node is ordered to communicate with the first of the two bells through a channel of specific wavelength towards the node and with the second of the two bells through the same wavelength channel; and a higher order line that is ordered to transmit traffic between the lines of the lower order.
11. 11. The process for distributing channels in an optical network comprises lower order lines (4a-4c) connected to each other through at least one higher order line; wherein the lower order lines consist of a network or a plurality of information exchange networks that are closed by bells (III, H2, II) and a node or a plurality of nodes connected to each other through two optical fibers (1, 2) transmitting in opposite directions; the bells are arranged to convert and concentrate the received signals into a form suitable for the transmission in the upper line (3) or in one of the lower order lines (4a-4c), characterized in that: - each node is distributed in at least one wavelength channel for reception from the bell placed at each end of the information transfer network; reception from a first bell (III) occurs through the first optical fiber (1) and reception from a second bell (H2) occurs through the second optical fiber (2), and; - each node is distributed in at least one wavelength channel to the bells placed at each end of the information transfer network; the transmission of the first bell (Hl) occurs through the second optical fiber (2) and the transmission towards the second bell (H2) occurs through the first optical fiber (1), and; - the wavelength channels that are received on an optical fiber '(1; 2) in a node, are ordered for transmission from the same node on the same optical fiber (1, 2).
12. 12. The process according to claim 11, characterized in that each node is arranged in the same channels for communication with the first bell (Hl) as well as for co-communication with the second bell (H2). SUMMARY OF THE INVENTION The present invention relates to an optical network that is ordered to ensure communication between nodes in a lower order line and a higher order line when there is an interruption in the lower order line or in case of a failure in the bell. Each lower ordinate line consists of an information transfer network (5) with bells; and a knot or a plurality of knots (A-D). Two optical fibers (1, 2) connect to the nodes in each information transfer network (5) and are used for communication in opposite directions between the nodes. Each information transfer network comprises precisely two bells (H1, H2) of which the first closes the end of the network of information transfer at the first end thereof; and the second closes the information transfer network at the other end. The bells connect the information transfer networks (5) in a lower order line and join this line with a higher order line. Each node in the information transfer network is ordered to communicate with each bell. The invention also relates to a process of distribution of channels in the aforementioned optical network. The distribution of channels can be carried out in such a way that the channels received at one of the nodes can be reused for transmission on the same fiber from the same node.