JP4124711B2 - Optical network design method and optical network design apparatus - Google Patents

Description

  The present invention relates to an optical network design apparatus for an optical network system using an optical wavelength multiplexing technique, and more particularly to an optical network design apparatus for obtaining a communication device arrangement that minimizes the equipment cost of the optical network system.

  As a transmission technology that constitutes the broadband Internet, a wavelength division multiplexing transmission technology that can transmit a large amount of information at high speed with a single fiber has attracted attention. In addition, optical network technology that configures a single optical path by combining signals transmitted by this wavelength division multiplexing transmission technology into a network and an optical network node technology that constitutes an optical network are rapidly developing. is doing. Along with this, there is a need for a technology that can design an optical network that minimizes equipment costs for configuring an optical network while ensuring signal reachability.

  An optical network includes a branch station (Hub) that branches and outputs a wavelength-multiplexed optical signal received from a certain fiber in a plurality of directions, and a wavelength-multiplexed optical signal received from a certain fiber for only one fiber. And a terminal station that passes all wavelength-multiplexed optical signals received from a certain fiber to the client device. FIG. 1B shows an example of such an optical network.

  An optical path terminator, a linear repeater (optical amplifier), a regenerative repeater, and the like are arranged in the branch station, the relay station, or the termination station. The optical path terminator is used to insert a signal of the client device into the optical network or pass a signal from the optical network to the client device.

  The linear repeater is used to collectively amplify the attenuated received optical signal in a multiplexed unit. In general, noise occurs in a linear repeater and is superimposed on the signal, so if the amplification in the linear repeater is repeated several times, the optical signal-to-noise ratio deteriorates and a digital signal transmitted from the client device is received. It becomes impossible to reproduce at the end. In order to avoid this, it is necessary to decompose an optical signal wavelength-multiplexed in the middle of transmission into signals of individual wavelengths as necessary and to pass through a regenerative repeater. In the regenerative repeater, since the optical signal is converted into an electric signal and reproduced as a digital signal, the influence of accumulated noise can be removed.

  Non-Patent Document 1 below shows a conventional communication network system realization method. In this method, first, a HUB that performs signal reproduction and reproduction signal amplification on all channels is installed in all stations with traffic demand. Next, the intensity loss of the multiplexed signal is verified, and a linear repeater and a signal regenerator are placed between the stations. In such a network in which signal reachability is guaranteed between all stations, path routing with the shortest distance is performed, and efficient use of network resources such as bandwidth and the number of wavelengths is realized.

  FIG. 13 shows a flowchart of a conventional network design method for optimally arranging regenerative repeaters in a certain linear communication network system. FIG. 14 shows a device arrangement example between terminal stations according to the conventional network design method shown in FIG.

  As shown in FIG. 14, the section of the terminal stations 1 # 1 to 1 # 2 provided with the optical path terminators is divided into seven segments 3 # 1 to 3 # 7. Here, the segment is a linear repeater (1R) or regenerative repeater (3R) arranged at a predetermined position between the terminal stations 1 # 1 to 1 # 2, and 1R / 3R between the terminal station 1 # 1. Between end stations 1 # 2 and 1R, between 1R and 3R. The network design is based on the fiber loss (segment loss) of the optical fiber arranged in each segment, and each relay station installation position (node) 2 # 1-2 # 6 at the end of each segment 3 # 1-3 # 7. Means to arrange 1R / 3R. Hereinafter, the relay station installed in the node 2 # i is referred to as “relay station 2 # i”.

  Here, the fiber loss becomes a design parameter because it is necessary to amplify each segment loss by 1R / 3R of each node in order to compensate the attenuation amount of the optical signal passing through the optical fiber of each segment. This is because an optical signal-to-noise ratio (optical SNR) is deteriorated by generating or amplifying noise by this amplification. That is, the segment loss is a factor for determining whether or not the signal can be reproduced.

  Hereinafter, a conventional network design method will be described with reference to FIGS. In step (S202), a temporary regenerative repeater is arranged at node 2 # 1 of segment 3 # 1 to obtain the current node position. Here, the section in which the temporary regenerative repeater is arranged is referred to as a temporary 3R section. In step (S204). The incoming optical SNR for the provisional 3R section is calculated.

  Here, as shown in FIG. 14, it is assumed that the transmission optical power of the transmission-side terminal station is 0 dBm and the output optical SNR is 30 dB. In addition, it is assumed that all the segment losses are 26 dB, and the noise figures of the linear repeater (1R) and the regenerative repeater (3R) are all 7 dB.

  A method of calculating the incoming optical SNR will be described with reference to FIG. Now, an optical signal is transmitted in the direction between the terminal stations 1 # 1 and 1 # 2. The incoming optical SNR at the relay station 2 # N is given by the following equation (1).

  Here, the value of the output optical SNR of the terminal station 1 # 1, which is the transmission optical SNR, is a given parameter depending on the optical transmission device arranged in the terminal station 1. The section optical SNR can be obtained from the signal loss in each segment and the amount of noise generated by the equipment installed in each relay station. In the example of FIG. 15, the section optical SNR from the terminal station 1 # 1 to the relay station 2 # 1 is obtained from the segment loss of the segment 3 # 1 and the amount of noise generated by the equipment arranged in the relay station 2 # 1. Can do. The signal loss (segment loss) of each segment is given in advance as input information for network design together with other information related to the optical fiber used in the network. Further, the amount of noise generated by the equipment arranged at each relay station is determined by the type of optical fiber and the type of equipment arranged at the relay station.

  For example, the incoming optical SNR at the relay station 2 # 1 is calculated according to the equation (1) under the conditions shown in FIG. Under this condition, the segment optical SNR is about 24.991 dB for all segments, so the incoming optical SNR is

  It becomes. By performing the same calculation, the incoming optical SNRs at the relay station 2 # 2, the relay station 2 # 3,... Can be obtained as 21.4 dB, 19.8 dB,.

  Accordingly, in step (S204), when the transmitting terminal station 1 # 1 transmits an optical signal with an optical SNR of 30.0 dB, the incoming optical SNR of the relay station 2 # 1 is 23.8 dB. In step (S206), it is determined whether or not the incoming optical SNR exceeds the transmission permission determination value.

  If the incoming optical SNR exceeds the transmission enable / disable determination value, the process proceeds to step (S208). If it is equal to or less than the transmission permission / inhibition judgment value, the process proceeds to step (S216). In relay station 2 # 1, the incoming optical SNR is 23.8 dB, which exceeds the transmission permission / inhibition determination value of 17.5 dB, so the process proceeds to step (S208). In step (S208), if the previous node is a provisional linear repeater installation station, it is formally determined to arrange a linear repeater (S210), and if the previous node is a transmission-side terminal station or a regenerative repeater installation station do nothing. Here, nothing is done because the previous node is the transmitting end station (1 # 1). In step (S212), it is determined whether or not the current node position is the receiving terminal station. If the current node position is the receiving end station, the process ends.

  If the current node position is not the receiving terminal station, the process proceeds to step (S214). In step (S214), the temporary linear repeater is arranged at the current node position, and the current node position is moved to the next node. Here, relay station 2 # 1 is a temporary linear repeater, the node position is moved to relay station 2 # 2, which is the next node, and the process returns to step (S202). Hereinafter, it is assumed that the current node position reaches the relay station 2 # 6 by repeating this.

  In relay station 2 # 6, in step (S202, S204, S206), a temporary regenerative repeater is arranged in relay station 2 # 6 which is the current node, and the incoming optical SNR in the temporary 3R section is calculated. Then, the incoming optical SNR of the relay station 2 # 6 is 17.0 dB, which is below the transmission permission / inhibition judgment value, and the process proceeds to step (S216). In step (S216), it is determined whether or not the previous node is a provisional linear repeater installation station. If the previous node is a provisional linear repeater installation station, the process proceeds to step (S218), and if not, the process proceeds to step (S220). Relay station 2 # 6 proceeds to step (S218) because relay station 2 # 5, which is the previous node, is a provisional linear repeater installation station. In step (S218), the provisional linear repeater of relay station 2 # 5 is determined as a regenerative repeater, but the node position is not changed and the process returns to step (S202).

  Since the node 2 # 5 is provided with a regenerative repeater and performs signal regeneration / amplification and plays a role similar to that of the transmission-side terminal station 1 # 1, the relay station 2 # 6 has the following steps (S202 to S214): The same processing as in the case of the relay station 2 # 1 is performed, and the current node position is moved to the receiving end station 1 # 2 with the relay station 2 # 6 as a temporary linear repeater. Then, the relay station 2 # 6 is formally determined as a linear repeater in steps (S202 to S212), and the network design is finished.

  In addition, in order to equalize the chromatic dispersion of the fibers that make up the optical network while reducing the number of regenerative repeaters installed, and to make the regenerative repeater section longer, optical transmission that performs dispersion equalization for each linear repeater section A system is proposed by the following Patent Document 1.

P. P. Arijs, B. B. Van Caenegem, P.A. P. Demeester, P.M. P. Lagasse, W. W. Van Parys and P.C. P.Achten, “Design of ring and mesh based WDM transport networks”, Optical Networks Magazine, July 2000, Vol. 1, No. 3, p. 25-40 JP 2000-115077 A

  In the system disclosed in Non-Patent Document 1, since a signal reproduction device is always provided in each station, the signal performance is high, but the communication network system is redundant and inefficient in terms of equipment cost. . On the other hand, in order to obtain an economical communication network system by installing equipment with reduced signal regeneration equipment while maintaining high reliability, not only the intensity loss of multiplexed signals but also the optical SNR and chromatic dispersion are considered. Detailed design is required. However, when the facility arrangement with the minimum cost is made in the entire network, the number of arrangement combinations becomes enormous, and the number of steps required for the design becomes large, which is not practical.

  In the conventional design method described above, the signal performance is guaranteed between the linear end stations. However, in an actual communication network, paths having different start points and end points intersect in a complicated manner, and signal reproduction is performed for each channel. Therefore, even if the linear amplifier and the regenerative amplifier are efficiently arranged in the linear section, the signal regenerator is redundantly arranged when viewed as the entire communication network. In particular, in a mesh communication network, there is a possibility that a redundant playback device is arranged at a branch point.

  Thus, in the conventional communication network design method, an efficient communication network system (for example, low facility cost) is not realized for a non-linear communication network. The present invention has been made in view of the above, and an object of the present invention is to provide a communication network system design apparatus having an economical facility introduction cost by applying an efficient design method to a transmission system network. .

  In order to achieve the above object, a network design apparatus according to the present invention first divides a communication network at any one or more nodes to derive a plurality of linear design sections, and performs regenerative relay to nodes at both ends of each design section. Assign the unit deletion priority.

  Then, based on the signal performance of each optical fiber connecting between the nodes, transmission is possible in each design section when regenerative repeaters are arranged at the nodes at both ends of each design section, and the regeneration among the both ends of the design section is possible. A linear repeater or a regenerative repeater is arranged in each node so that a node having a higher repeater deletion priority has a margin of received signal quality.

  After that, the design sections can be combined in the form of a communication network, and transmission can be performed in the two adjacent design sections without arranging a regenerative repeater at the node that is the boundary between the two adjacent design sections on the communication network. At this time, this regenerative repeater will be deleted.

  1A to 1B are principle diagrams of the present invention. FIG. 1A is a configuration diagram of an optical network design apparatus, and FIG. 1B is a model diagram showing an optical network to be designed.

  As shown in FIG. 1A, the optical network design device 10 includes a section dividing unit 12, a regenerative repeater deletion priority list 14, a section designing unit 16, and a regenerative repeater deleting unit 18. As shown in FIG. 1B, the optical network model 20 to be designed includes a terminal station 1 # 1 to 1 # 3, a branch station 4, a relay station 2 # 1 to 2 # 3, It consists of optical fibers 3 # 1-3 # 6 provided in the segment connecting them.

  The section dividing unit 12 divides the optical network model 20 at the branch station 4, and includes the terminal station 1 # 1 to the branch station 4, the branch station 4 to the terminal station 1 # 2, and the branch station 4 to the terminal station 1 # 3. Three design sections are derived. Then, regenerative repeaters are arranged at both ends of each design section. In the regenerative repeater deletion priority list 14, the regenerative repeater deletion priority for each of the relay stations 2 # 1 to 2 # 3, the terminal stations 1 # 1 to 1 # 3, and the branch station 4 is set and held by some method. (Memorized). The section design unit 16 determines the linear repeater and the regenerative repeater necessary for guaranteeing the reachability of the signal in the design section according to the division result of the section division unit 12 and the regenerative repeater deletion priority list 14. It arrange | positions to relay station 2 # 1-2 # 3. At this time, the section design unit 16 performs a design such that the quality of the received signal with respect to the station having a high regenerative repeater deletion priority has a margin with respect to the transmission availability determination value.

  After this, the network designed for each section is combined to return to the form of the network to be designed. Finally, it is verified whether or not the regenerative repeater can be deleted at the branch station 4 which is the boundary of the design section. If it can be deleted, the regenerative repeater is deleted.

  By dividing the optical network into linear design sections as described above, it is possible to reduce unnecessary regenerative repeaters in each divided design section using the above-described linear network design method. Is possible.

  Furthermore, regenerative repeater deletion priorities are assigned to the stations at both ends of each design section, and a margin for transmission quality judgment value of received signal quality is assigned to the stations with high priorities in the design within each design section. In many cases, the arrangement of the regenerative repeater in the station at the boundary of each design section can be omitted.

  As a result, it is possible to prevent redundant regenerative repeaters from being arranged at the branching points or the like that are the boundaries of each design section, and it is possible to design to reduce the number of regenerative repeaters in the entire network.

  FIG. 2 is a configuration diagram of the optical network design apparatus of the present invention. As shown in the drawing, the optical network design apparatus 10 is realized by a computer (computer) such as a personal computer or a workstation having the arithmetic processing unit 42. The user 52 inputs various input information necessary for designing an optical network from the input unit 44 such as a keyboard. The input information is processed by the arithmetic processing unit 42 and accumulated in the storage unit 46. The storage unit 46 stores an optical network design method according to the present invention and stores a program 61 for realizing the optical network design apparatus according to the present invention. The arithmetic processing unit 42 is described in the program 61. Process according to the rules. The calculation result is output to the user 52 through the output unit 48 such as a display unit.

  The storage unit 46 stores topology information 62, signal performance information 63, traffic demand information 64, a regenerative repeater deletion priority list 65, and optical path route information 66, which are various information necessary for designing an optical network. The

  FIG. 3 shows an example of the data structure of the topology information. The topology information can be divided into two types of information: fiber information and station information. The station information includes a station identifier and a station position provided in each node. The station identifier is information for uniquely identifying the station in the network, and the station position information is information indicating geographical coordinates such as latitude and longitude of the station as shown in the figure. The fiber information includes a fiber identifier for uniquely identifying an optical fiber provided in a segment connecting the stations in the network, a station identifier on the fiber start point side, and a station identifier on the fiber end point side. The length of the fiber and the type of the fiber (for example, SMF (Single Mode Fiber) or NZ-DSF (Non-Zero Dispersion Shifted Fiber)).

  FIG. 4 shows an example of the data structure of signal performance information. The signal performance information is used to determine the optical fiber loss (segment loss) in each segment. The segment loss in each segment can be obtained by various methods. However, in the example of the data structure shown in FIG. 4, from the fiber type and the fiber length of the optical fiber of the segment acquired from the fiber information in the topology information. Find segment loss. For this reason, the signal performance information stores the fiber loss per unit length of the corresponding fiber type from the fiber type of the optical fiber connecting the stations.

  FIG. 5 shows an example of the data structure of traffic demand information. The traffic demand information includes information on demand identifiers, identifiers of start and end stations, signal types, and the number of channels. The demand identifier is used to uniquely identify each demand, that is, traffic demand. The identifiers of the start station and the end station respectively indicate stations at both ends having a traffic demand (demand), and the signal type indicates a required band, a framing format, and the like. The number of channels indicates the number of requested paths.

  FIG. 6 shows an example of the data structure of the path route information. The path route information includes an identifier for uniquely identifying the path and a list of stations through which the path passes.

  FIG. 7 shows an example of the structure of the regenerative repeater deletion priority list. The regenerative repeater deletion priority list is a list in which priority levels for deleting regenerative repeaters are assigned to the stations indicated by the station identifier.

  Hereinafter, an optical network design method according to the first embodiment of the present invention will be described. FIG. 8 shows a flowchart of the design method according to the first embodiment of the present invention. First, the user inputs topology information, traffic demand information, optical path route information, and regenerative repeater deletion priority information (S102). Here, the example of the topology information to be input has a form as shown in FIG. In the example of the priority of the regenerative repeater input, the branch station 4 is set to the highest, the relay stations 2 # 1 to 2 # 9 are set to the lowest, and the end stations 1 # 1 to 1 # 3 are values between them. Is set.

  The input traffic demand is assumed to be one channel each between the terminal station 1 # 1 and the terminal station 1 # 2 and between the terminal station 1 # 1 and the terminal station 1 # 3. Assume that optical paths 5 # 1 and 5 # 2 shown in FIG. 9 are input as the optical path paths of the path route information. Note that the optical path route information may be automatically calculated from the topology information and the traffic demand information using an existing route search method such as the shortest route search without depending on the user input.

  The arithmetic processing unit 42 calculates the fiber loss of the optical fiber connecting each station from the fiber information, the optical path route information, and the signal performance information in the topology information. Specifically, the arithmetic processing unit 42 extracts the “fiber type” and “length” of the optical fiber from the topology information, and further calculates the fiber loss from the optical fiber length. The signal performance information may be input at the same time as the above-described topology information input by the user, or may be stored in the storage unit 46 in advance. The fiber loss of the optical fiber may be input / stored in the fiber information in the topology information as shown in FIG.

  In the next step (S104), the network shown in FIG. 9 is divided into design sections that are linear communication networks. As an example of a method of dividing into linear design sections, there is a method of dividing at a station having a linearity of 3 or more (branch station 4 in the example of FIG. 9) in the network shown in FIG. 9 and dividing into linear design sections. Conceivable. By dividing in this way, the network is terminated by terminal station 1 # 1 to branch station 4 (design section 6 # 1), branch station 4 to terminal station 1 # 2 (design section 6 # 2), and branch station 4 to terminal station. It is divided into three linear design sections of station 1 # 3 (design section 6 # 3). Then, regenerative repeaters are arranged at both ends of each design section (S106).

  Next, the design in each design section 6 # 1-6 # 3 is performed. In the design section design, the design is such that the quality of the received signal of the station with the higher regenerative repeater deletion priority among the stations at both ends of the design section has a margin with respect to the transmission feasibility determination value (S108). . An example of a method for realizing this is to use a design method similar to the conventional network design method (FIG. 13) in the linear communication network system shown in FIG. It is conceivable to design from the side.

  That is, in each design section 6 # 1 to 6 # 3, linear repeaters or regenerative repeaters are arranged in order from the stations with the lowest regenerative repeater deletion priority among the stations at both ends. At this time, the regenerative repeater is arranged at the station immediately before the incoming optical SNR from the regenerative repeater / terminal station arranged immediately before exceeds the allowable range (that is, below the transmission feasibility determination value), and is transmitted to other stations. Will be provided with a linear repeater. By designing each of the design sections 6 # 1 to 6 # 3 in this way, the quality of the received signal of the station having the higher regenerative repeater deletion priority order has a margin.

  As an example, the design in the design section 6 # 1 will be described below with reference to FIGS. 9 and 14. First, in step (S202) shown in FIG. 13, the temporary regenerative repeater is arranged with the relay station 2 # 1 in the design section 6 # 1 as the current node position. A section in which the temporary regenerative repeater is arranged is referred to as a temporary 3R section. In step (S204), the incoming light SNR of the temporary 3R section is calculated. At this time, the arithmetic processing unit 42 receives the incoming optical SNR from the fiber loss between the terminal station 1 # 1 and the relay station 2 # 1 calculated as described above and the amount of noise generated by the repeater arranged in the relay station 2 # 1. Is calculated. At this time, the arithmetic processing unit 42 determines the amount of noise generated by the repeater arranged in the relay station 2 # 1, the fiber type between the terminal station 1 # 1 and the relay station 2 # 1, and the relay arranged in the relay station 2 # 1. Calculate according to the type of vessel.

  In step (S206), it is determined whether the incoming optical SNR is larger than the SNR of the transmission permission / inhibition determination value described above. Here, relay station 2 # 1 assumes that the incoming optical SNR is larger than the transmission permission / inhibition judgment value, and proceeds to step (S208). In step (S208), since the previous node is the transmitting end station 1 # 1, nothing is done and the process proceeds to step (S212). In step (S212), since the current node position is not the receiving end station, the process proceeds to step (S214). .

  In step (S214), relay station 2 # 1 is a temporary linear repeater, the node position is moved to relay station 2 # 2, which is the next node, and the process returns to step (S202). Hereinafter, this is repeated, and it is assumed that the current node position reaches the branch station 4 which is the receiving terminal station of the design section 6 # 1.

  In the branch station 4, in step (S 202, S 204, S 206), a temporary regenerative repeater is arranged in the branch station 4 that is the current node, and the incoming optical SNR in the temporary 3R section is calculated. Here, it is assumed that the incoming optical SNR of the branch station 4 is equal to or less than the transmission permission / inhibition determination value. Therefore, in step (S216), it is determined whether or not the previous node is a provisional linear repeater installation station. Since relay station 2 # 3, which is the previous node, is a provisional linear repeater installation station, the process proceeds to step (S218). Then, the provisional linear repeater of relay station 2 # 3 is determined as a regenerative repeater, and the process returns to step (S202).

  Thereafter, the same processing (S202 to S208) as that of the relay station 2 # 1 is performed in the branch station 4, and the process ends in step (S212).

  When the design is completed for all the design sections 6 # 1 to 6 # 3 (S110), each of the stations 2 # 1 to 9 # 9 becomes a boundary between two adjacent design sections of the design sections 6 # 1 to 6 # 3. If the station is at the boundary between two adjacent design sections, it is assumed that the regenerative repeater has been deleted, and transmission permission is determined in the two adjacent design sections. If it is determined that transmission is possible, the regenerative repeater at the boundary station is deleted (S112). This determination as to whether or not transmission is possible may be performed between the regenerative repeater installation stations that are closest to the boundary station in two adjacent design sections.

  In FIG. 9, the branch station 3 is a station at the boundary between the design section 6 # 1 and the design section 6 # 2, the design section 6 # 2 and the design section 6 # 3, and the design section 6 # 3 and the design section 6 # 1. Yes. Therefore, first, transmission permission / inhibition is determined when the regenerative repeater between the design section 6 # 1 and the design section 6 # 2 is deleted. At this time, regenerative repeaters are arranged in the design section 6 # 1 and the design section 6 # 2, and the stations closest to the branch station 4 serving as a boundary between these design sections are the relay station 2 # 3 and the relay station 2 #, respectively. 4. Therefore, the transmission permission / inhibition determination is performed between the relay station 2 # 3 and the relay station 2 # 4 on the assumption that the branch station 4 has no regenerative repeater.

  The determination as to whether or not transmission is possible may be performed by comparing the received optical SNR at the relay station 2 # 4 of the optical signal transmitted by the relay station 2 # 3 with the transmission permission / inhibition determination value, for example, as in the conventional design method described above. .

  As a result, if it is determined that transmission is possible, the regenerative repeater that relays the signal of the path 5 # 1 between the design section 6 # 1 and the design section 6 # 2 is deleted. The same processing is performed between the design section 6 # 2 and the design section 6 # 3 and between the design section 6 # 3 and the design section 6 # 1.

  Here, each of the design sections 6 # 1 to 6 # 3 is designed so that the margin for the transmission feasibility determination value of the received signal quality in the branch station 4 having high regenerative repeater deletion priority information as described above is increased. In other words, by collecting the margin of the received signal quality on the branch station 4 side where the regenerative repeater deletion priority information is high, as compared with the method of designing each design section without considering the regenerative repeater deletion priority It is possible to delete many regenerative repeaters at the branch station 4 which is the boundary of the design section. By such a procedure, the number of regenerative repeaters arranged at a node that becomes a boundary of each design section can be reduced.

  The apparatus to be arranged for each station is determined as described above (S114), and the output unit 48 presents this result to the user 52 to complete the design (S116).

  The regeneration repeater deletion priority order can be set according to various criteria. In the optical network design method according to the second embodiment of the present invention shown in FIG. 11, the regenerative repeater deletion priority assigned to each station in the network is automatically calculated based on the number of optical fibers connected to each station. It will be assigned. Specifically, in the first step (S142), only topology information, traffic demand information, and optical path route information are input. Next, regenerative repeater deletion priority proportional to the number of connected optical fibers (or linearity) is calculated for each station, and regenerative repeater deletion priority is assigned from the one with the highest priority (S144). ). At this time, if the regenerative repeater deletion priority has the same value in a plurality of stations, the priority order is determined by an arbitrary method. The subsequent processing is the same as that after step (S104) in the first embodiment.

  The number of regenerative repeaters in each station increases according to the number of optical fibers connected to the station, and thus the regenerative repeater deletion priority is set higher in proportion to the number of optical fibers connected. Therefore, since the regenerative repeater can be deleted in the step (S112) of FIG. 11 as the number of optical fibers increases, more regenerative repeater savings can be expected by the design method according to this embodiment.

  FIG. 12 shows an optical network design method according to the third embodiment of the present invention. In the design method according to this embodiment, the regenerative repeater deletion priority assigned to each station in the network is automatically calculated and assigned based on the number of optical paths passing through each station. Specifically, in the first step (S152), only topology information, traffic demand information, and optical path route information are input. Next, regenerative repeater deletion priorities proportional to the number of optical paths that pass through are calculated for each station, and regenerative repeater deletion priorities are assigned in descending order of priority. At this time, if the regenerative repeater deletion priority has the same value in a plurality of stations, the priority order is determined by an arbitrary method. The subsequent processing is the same as that after step (S104) in the first embodiment.

  The number of regenerative repeaters in each station increases according to the number of optical paths (multiplexing number) passing through the station, and thus the regenerative repeater deletion priority is set higher in proportion to the number of connected optical paths. As a result, the regenerative repeater can be deleted in the step (S112) of FIG. 11 as the number of optical fibers increases. Therefore, the design method according to this embodiment can be expected to save more regenerative repeaters. .

(Supplementary Note 1) In a network design apparatus for designing a communication network in which linear repeaters or regenerative repeaters are arranged at a plurality of nodes in a network and the nodes are connected by optical fibers, the network design apparatus includes:
A section dividing unit that divides the communication network in one or more nodes and derives a plurality of linear design sections;
Regenerative repeater deletion priority list for storing regenerative repeater deletion priority of nodes at both ends of each design section;
Based on the signal performance of each optical fiber connecting between the nodes, a linear repeater or a linear repeater or the like so that signal transmission is possible in each design section when regenerative repeaters are arranged at nodes at both ends of each design section A section design unit that places regenerative repeaters at each node in each design section,
Regenerative relay for deleting a regenerative repeater when signal transmission is possible in the two adjacent design sections without arranging a regenerative repeater at a node between the two adjacent design sections on the communication network With a vessel deletion section,
The section design unit arranges the linear repeater or the regenerative repeater so as to have a margin of received signal quality at a node having a higher priority of the regenerative repeater deletion among both ends of each design section. A network design apparatus characterized by that. (1)

(Supplementary Note 2) The section design unit arranges the linear repeater or the regenerative repeater in order from the node having the lowest regenerative repeater deletion priority among both ends of each design section,
The network design apparatus according to appendix 1, wherein the regenerative repeater is disposed at a farthest node where an optical fiber loss between the regenerative repeater disposed immediately before is within an allowable range. (2)

(Additional remark 3) The said regenerative repeater deletion priority list | wrist is characterized by determining regenerative repeater deletion priority high in proportion to the number of optical fibers connected to the said node. The network design device described. (3)

(Supplementary note 4) The regenerative repeater deletion priority order is determined so that the regenerative repeater deletion priority order is higher in proportion to the number of optical paths passing through the node. Network design method. (4)

(Supplementary Note 5) In a network design method for designing a communication network in which linear repeaters or regenerative repeaters are arranged at a plurality of nodes in a network and the nodes are connected by an optical fiber, the network design method includes:
A section dividing step of dividing the communication network at one or more of the nodes to derive a plurality of linear design sections;
A regenerative repeater deletion priority determining step for determining a regenerative repeater deletion priority for the nodes at both ends of each design section;
Based on the signal performance of each optical fiber connecting between the nodes, a linear repeater or a linear repeater so that signal transmission is possible in each design section when regenerative repeaters are arranged at nodes at both ends of each design section A section design step of arranging a regenerative repeater at each node in each design section,
Regenerative relay for deleting a regenerative repeater when signal transmission is possible in the two adjacent design sections without arranging a regenerative repeater at a node between the two adjacent design sections on the communication network A container removal step,
In the section design step, the linear repeater or the regenerative repeater is arranged so as to have a margin of received signal quality at a node having a higher regenerative repeater deletion priority among both ends of each design section. A network design method characterized by the above. (5)

(Additional remark 6) The section design step arranges the linear repeater or the regenerative repeater in order from the node having the lowest regenerative repeater deletion priority among both ends of each design section,
6. The network design method according to appendix 5, wherein the regenerative repeater is disposed at a farthest node in which an optical fiber loss between the regenerative repeater disposed immediately before is within an allowable range.

(Additional remark 7) The said regenerative repeater deletion priority determination step determines the regenerative repeater deletion priority higher in proportion to the number of optical fibers connected to the node. The network design method described.

(Supplementary note 8) The regenerative repeater deletion priority order determining step determines the regenerative repeater deletion priority order higher in proportion to the number of optical paths passing through the node. Network design method.

  By using the present invention, it is possible to design a network with a small number of regenerative repeaters and therefore low equipment costs while diverting an existing linear network design method to a mesh type network. Therefore, it is extremely useful practically. In addition, since the number of man-hours for designing an optical network can be reduced by the present invention, the design cost can be greatly reduced.

It is a principle diagram of the present invention. It is a block diagram of the optical network design apparatus of this invention. It is a figure which shows the example of the data structure of topology information. It is a figure which shows the example of the data structure of signal performance information. It is a figure which shows the example of the data structure of traffic demand information. It is a figure which shows the example of the data structure of path route information. It is a figure which shows the example of the structure of a reproduction | regeneration repeater deletion priority list. 3 is a flowchart of an optical network design method according to the first embodiment of the present invention. It is a figure which shows the network shape used for description of the optical network design method of this invention. It is a figure which shows the example of the fiber information in topology information. 5 is a flowchart of an optical network design method according to a second embodiment of the present invention. 7 is a flowchart of an optical network design method according to a third embodiment of the present invention. It is a flowchart of the conventional network design method which performs optimal arrangement | positioning of a regenerative repeater. It is a figure which shows the example of apparatus arrangement | positioning between the terminal stations by the conventional network design method shown in FIG. It is a figure explaining the calculation method of incoming optical SNR.

Explanation of symbols

1 # 1 to 1 # 3 ... Terminal stations 2 # 1 to 2 # 3 ... Relay stations 3 # 1 to 3 # 6 ... Optical fiber 4 ... Branch station 10 ... Optical network design device 12 ... Section divider 14 ... Regenerative repeater Deletion priority list 16 ... Section design unit 18 ... Regenerative repeater deletion unit

Claims (4)

In a network design apparatus for designing a communication network in which linear repeaters or regenerative repeaters are arranged at a plurality of nodes in a network and the nodes are connected by optical fibers, the network design apparatus includes:
A section dividing unit that divides the communication network in one or more nodes and derives a plurality of linear design sections;
Regenerative repeater deletion priority list for storing regenerative repeater deletion priority of nodes at both ends of each design section;
Based on the signal performance of each optical fiber connecting between the nodes, a linear repeater or a linear repeater so that signal transmission is possible in each design section when regenerative repeaters are arranged at nodes at both ends of each design section A section design unit that places regenerative repeaters at each node in each design section,
Regenerative relay that deletes a regenerative repeater when signal transmission is possible in the two adjacent design sections without arranging a regenerative repeater at a node between the two adjacent design sections on the communication network With a vessel deletion section,
The section design unit arranges the linear repeater or the regenerative repeater in order from the node having the lowest regenerative repeater deletion priority among both ends of each design section,
Here, the regenerative repeater is arranged at the farthest node where the loss of the optical fiber with the regenerative repeater arranged immediately before is within an allowable range . 2. The network design according to claim 1 , wherein the regenerative repeater deletion priority list is determined such that a regenerative repeater deletion priority is higher in proportion to the number of optical fibers connected to each of the nodes. apparatus. 2. The network design apparatus according to claim 1 , wherein the regenerative repeater deletion priority list is determined such that a regenerative repeater deletion priority is higher in proportion to the number of optical paths that pass through each of the nodes. . In a network design method for designing a communication network in which linear repeaters or regenerative repeaters are arranged at a plurality of nodes in a network and the nodes are connected by optical fibers, the network design method includes:
A section dividing step of dividing the communication network at one or more of the nodes to derive a plurality of linear design sections;
A regenerative repeater deletion priority determining step for determining a regenerative repeater deletion priority for the nodes at both ends of each design section;
Based on the signal performance of each optical fiber connecting between the nodes, a linear repeater or a linear repeater is used so that signal transmission is possible in each design section when regenerative repeaters are arranged at nodes at both ends of each design section. A section design step of arranging a regenerative repeater at each node in each design section,
Regenerative repeater deletion that deletes a regenerative repeater when transmission is possible in the two adjacent design sections without arranging a regenerative repeater at a boundary node between the two adjacent design sections on the communication network With steps,
The section design step arranges the linear repeater or the regenerative repeater in order from the node having the lowest regenerative repeater deletion priority among both ends of each design section,
Here, the regenerative repeater is disposed at the farthest node where the loss of the optical fiber with the regenerative repeater disposed immediately before is within an allowable range .

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