WO2004084449A1

WO2004084449A1 - Synchronous network

Info

Publication number: WO2004084449A1
Application number: PCT/JP2003/003175
Authority: WO
Inventors: Takeshi Miyagawa
Original assignee: Fujitsu Limited
Priority date: 2003-03-17
Filing date: 2003-03-17
Publication date: 2004-09-30

Abstract

A synchronous network includes a first transmission device for transmitting a plurality of clocks and a synchronous state message concerning the quality of the clocks, a second transmission device for receiving a plurality of synchronous state messages and selecting one clock according to the synchronous state messages, and a first NMS. The network further includes a plurality of detection units provided in the first transmission device for detecting the quality of the clock associated with each synchronous state message, a quality information report unit provided in the first transmission device for reporting information on the quality of each clock associated with the synchronous state message to outside according to an enquiry, an enquiry unit provided in the first NMS for requesting the first transmission device to transmit clock quality information, a judgment unit provided in the first NMS for judging whether the quality of clock selected by the second transmission device according to the plurality of clock quality information from the first transmission device has been deteriorated, a clock switching instruction unit provided in the first NMS for instructing the second transmission device to switch to another clock according to the judgment of the judgment unit, and a clock switching control unit provided in the second transmission device for controlling the clock switching according to the instruction of the clock switching instruction.

Description

Description Synchronous network technology field

The present invention relates to a transmission network of SDH (Synchronous Digital Hierarchy) / SOET (Synchronous Optical NETwork), and a cross-connecting device (SDH and SONET or SDH and SDH) in the network. It relates to a synchronous network when the SS MB information that identifies the network quality cannot be transferred via the main signal. Background technology

In a synchronous network, an SSU (Synchronous Source Unit) generates a master clock source, sequentially distributes the master clock source to transmission equipment, and synchronizes dependently on the distributed clock, thereby synchronizing the entire network. Has been taken. In a synchronous network, the transmission source device determines the clock quality and sends the SS MB information that identifies the clock quality to a predetermined byte of the SOH (Section OverHead) of the synchronous frame, for example, Then, the lower 4 bits of the S1 packet are used to pass the data to the transmission destination device via the main signal, and the clock source is selected based on the SSMB information received by the transmission destination device. When connecting the latest SDH to the old SDH on the existing network, the SSMB definition may be different, so that the functions inherent in SSMB may not be used up. In general, the network is often composed of only SDH or only SONET, but recently, with the globalization of each market, SDH and SONET have become increasingly common in transmission networks. Mixed cases are coming up. In this case, since the definition of SS MB is different between SDH and SONET, the SSMB function cannot be used when passing SS MB from SDH to SONET or when passing SS MB from SQNET to SDH ₍

In SDH and SONET networks, at the beginning (from around 94 years) STM-1 and 4 networks were shifted to STM-16 (2.5 G) networks, and around 97 years Recently, STM—64 (10 G) was netted by ■ '■. At the center of the network, each operator wants to connect to the STM-64 network without throwing away the existing STM-14, 16 equipment. Clock quality may not be controllable due to mismatch between SSMB and other standards (old equipment and newest equipment) while inputting 4, 16 and 64.

FIG. 15 is a diagram showing an example of the bit pattern of the SMB. Here, the SSMB information of SONET (GR-235-CORE) and SDH (ITU-TG781.OtioneI) are compared. A 4-bit code indicating the clock quality (QL (Quality Level)) is set in SSM. The clock quality (QL) is “1” for the highest quality clock (Highest), “7 J” for the lowest quality clock (SOJ), and “5” for the SDH. .

In SONET, QL = 1 is PRS (Stratum 1 Traceable), QL = 2 force SS Τ U (Synchroni zed-Trace abi 1 itty Unknown), QL = 3 force ST 2 (Stratum 2 Traceable), QL = 4 force ST 3 (Stratum 3 Traceable), QL = 5 force SMC (Sonet Minimum Clock Traceable), QL = 6 force SST 4 (Stratum 4 Traceable), QL = 7 force SD US (Don't Use for Synchronization), each QL Is assigned a 4-bit code.

On the other hand, in SDH, QL = 1 force SPRC (Primary Reference Cloc "G.811)) and QL = 2 are SSU-A (G.811 Type I or V slave clock), QL = 3 force SSSU—B (G. 812 Type IV slave clock), QL = 4 power SSEC (SDH Equipment Clock (G.813 option I), QL = 5 is D NU (Do Not Use for Synchronization), and each QL has a 4-bit code. Assigned.

In the transmission equipment, the reception clock set with the highest quality QL is usually used for frame synchronization and clock distribution. The corresponding code is assigned to each QL. As shown, codes assigned in SONET, such as “0000” and “001”, are unused in SDH, or conversely, “001”. , Such as “0100”, codes that are allocated in SDH and are unused in SONET, or codes of the highest quality QL are “00001” in SONET , In DH, SONET and SDH may be different even for QL with the same value, such as “0 0 1 0”. In this way, SONET and SDH Differs in the definition of SSMB. Similarly, in SDH, the definition of SSMB may differ for different transmission speeds.

Figure 16 shows the configuration of the synchronous network. The network shown in Fig. 16 shows an example composed of SSU 2, SDH 4 # 1, 4 # 2, 4 # 3, and SONET 6 #l, 6 # 2. It is assumed that the SDH 4 # 1 and SONET 6 #l are connected by a 2.5 G signal (STM-18 / OC-48) X 4 link. The names of the links are LI, L2, L3, and L4. The clock uses the synchronous clock source CLK1 of SSU2 as the master clock. The clock flow is as follows. SSU 2 generates clock CLK 1 as master clock and distributes it to SDH 4 # 1 _c Clock card 10 # 1 of SDH 4 # 1 receives master clock CK 1 The clock CLK 2 is output to the interface unit (Inf unit) 20 # 1 j (j = 1, ■,..., 4). The control unit 30 # 1 notifies each interface unit 20 # 1 j of the SSMB information according to the advance setting from the NMS (Network Management System). For example, link L1 is a primary (1st Priority), and link L2 is a secondary (2nd Priority).

When each interface unit 20 # lj (j = 1 to 4) receives a clock from the clock card 10 # 1, it detects the quality and notifies the control unit 30 # 1. . The clock quality is determined, for example, by detecting a pulse width, a rising and falling delay time, and the like. The SSMB information notified from the control unit 30 # 1 is set in the SOH, and the SMB is transmitted through the links L1 to L4 together with the main signal and the clocks CLK3 to CLK6. Send to # 1. For example, the interface unit 20 # 11 transmits S SMB = 0 10 10 to the link L 1. Also, the interface unit 20 # 12 transmits S SMB = 0 100 to the link L2.

SONET 6 # 1 interface unit 40 # 1 j (j = 1,..., 4) receives the clock from link L j and receives the clock card 50 0 # 1 Output to Also, it outputs the SSMB information and the like contained in the SOH to the control unit 60 # 1. The control unit 60 # 1 tries to instruct the clock card 50 # 1 to select a clock based on the SSMB information, but the SSMB transmitted from the link L 1 of SDH 4 # 1 = Since the message of 0 0 10 is undefined in SONET, it is ignored and controlled by NMS. Select the clock CLK 7 from the interface unit 20 # 11, for example, instructed to the unit 60 # 1, and set it to the interface unit 40 # 15, 40 # # 16 Output.

In S ONET 6 # 1, it is assumed that the interface unit 40 # 15 is preset as a protection and the interface unit 40 # 16 is preset as a work. Since the interface unit 40 # 15 is a protection, the clock CLK 8 indicates the secondary.SSMB = 0 01, and the interface unit 40 # 16 is a work. Is transmitted to SONET 6 # 2 to indicate that this is the case. S ONET 6 # 2 receives the clock from SONET 6 #l and sends it to the clock card 50 # 2. At the same time, the SSMB information and the like stored in the SOH are output to the control unit 60 # 2. The clock card 50 # 2 selects the clock output from the interface unit 1, 40 # 22 according to the instruction from the control unit 60 # 2 and selects the clock CLK 10 0 Is output. The interface cards 40 # 23, 40 # 24 set the S SMB according to the preset settings and transmit to the SDH 4 # 2, 4 # 3. As a result, the master clock force is distributed to SSU2 → SDH4 # 1 → link L1 → SONET6 # 1 → link L5 → SDH4 # 2, 4 # 3.

The actual synchronization itself can be synchronized on the receiving side if a good clock is sent, but since SS MB is different between SDH and S ONET, S ON ET 6 #l Clock cannot be selected according to the contents of S SMB of SDH 4 # 1. For example, in SDH 4 # 1, the clock quality of link L1 deteriorates for some reason, the SS MB is changed from PRC to DNU, and the clock of link L2 is connected to SONET 6 # 1. Even if you want to select a link, SONET 6 # 1 tries to keep synchronizing with link L1 without knowing its contents. As long as the fiber of the link L1 and the like are not physically cut, there is a ray problem unless the clock is switched.

The following were the prior literature.

Patent Document 1 discloses that a SONE TZ SDH sync message conversion circuit is provided to enable SSMB communication between S ONET and S DH by converting the SSM of its own device to the SSM of the partner transmission device. It is disclosed that. Patent Document 1

Japanese Patent Application Laid-Open No. H11-1771719

However, in Patent Document 1, it is necessary to separately provide a conversion circuit in the transmission device, which increases the cost, and it is necessary to add a conversion circuit to an existing device, or a conversion circuit is added to an existing device. There was a problem that the quality of the cook could not be managed without changing the existing equipment, because it was necessary to replace the transmission equipment.

An object of the present invention is to provide a synchronous network capable of performing clock quality management even when the SSMB standard is different, such as between SDH and SONET. Disclosure of the invention

According to an aspect of the present invention, a plurality of synchronization status messages are received by a first transmission device that transmits a plurality of clocks and a synchronization status message related to the quality of each of the clocks. A synchronous network including a second transmission device for selecting one clock based on the synchronization status message and a first NMS, and a link related to each of the synchronization status messages. A plurality of detection units provided in the first transmission device for detecting the quality of the first transmission device, and the first transmission device for notifying the quality information of each clock related to the synchronization status message to the outside based on an inquiry A quality information notification unit provided in the first NMS that requests the first transmission device to transmit the quality information of each of the clocks; Second transmission based on the quality information of the mouth A judgment unit provided in the first NMS for judging whether or not the quality of the clock selected by the device has deteriorated; and switching to another clock based on the judgment of the judgment unit. A clock switching instruction unit provided in the first NMS for instructing the second transmission device; and a clock switching instruction unit provided in the second transmission device for controlling clock switching based on the instruction of the clock switching instruction. A synchronous network characterized by comprising a click switch control unit.

According to another aspect of the present invention, a first transmission device for transmitting a plurality of clocks and transmitting a synchronization status message relating to the quality of each clock, a plurality of synchronization status messages , A second transmission device that selects one clock based on the synchronization status message, a first NMS that manages the first transmission device, and a second NMS that manages the second transmission device A synchronous network including a second NMS and a third NMS that manages the first and second transmission devices, wherein the first network detects the quality of a clock corresponding to each of the synchronous status messages. A plurality of detection units provided in the transmission device, and a plurality of detection units provided in the first transmission device for notifying the quality information of each clock related to the plurality of synchronization state messages to the outside based on a transmission request command. An inquiry section provided in the third NMS for transmitting an inquiry command including a command code indicating an inquiry of the quality information of each clock to the first NMS, Transmitting the transmission request command requesting the first transmission device to transmit the quality information of the clock to the first transmission device, and transmitting the quality information of each clock from the quality information notification unit. Quality information provided in the first NMS that receives A transmitting unit provided in the second NMS for transmitting the quality information of the plurality of cookies collected by the quality information collecting unit based on the inquiry command to the third NMS; Receiving the quality information of each clock from the first NMS, converting the quality information of the clock into a synchronization information message conforming to the standard of the second transmission device, and A conversion unit provided in the third NMS for transmitting to the NMS; and a conversion unit provided in the second NMS for receiving the synchronization information messages from the third NMS and informing the second transmission device of the synchronization information messages. The notification unit, and ignoring the plurality of synchronization information messages from the first transmission device, and controlling selection of one clock based on the plurality of synchronization information messages from the notification unit. Synchronization characterized by having a clock switching control unit provided in the second transmission device. Tsu network is provided, a brief description of the drawings

Figure 1 is the principle diagram of the present invention;

FIG. 2 is a configuration diagram of a synchronous network according to the first embodiment of the present invention;

Fig. 3 is a functional block diagram of the upper NMS in Fig. 2;

Figure 4 is a functional block diagram of NMS for SDH in Figure 2;

Fig. 5 is a functional block diagram of NMS for SONET in Fig. 2;

Fig. 6 is a functional block diagram of the control unit in the SDH in Fig. 2;

Fig. 7 is a functional block diagram of the interface unit in the SDH in Fig. 2; Fig. 8 is a functional block diagram of the control unit in the SONET in Fig. 2; Figure 9 shows the clock switching control;

Figure 10 shows the clock switching control;

Figure 11 shows the switching sequence chart;

FIG. 12 is a configuration diagram of a synchronous network according to a second embodiment of the present invention;

Fig. 13 is a functional block diagram of the upper NMS in Fig. 12;

Fig. 14 is a functional block diagram of NMS for SON in Fig. 12;

Fig. 15 shows S SMB specified by ITU-T and S SMB specified by GR-235; Fig. 16 shows a conventional synchronous network. BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a diagram illustrating the principle of the present invention. As shown in FIG. 1, the synchronous network includes a first transmission device 100, a second transmission device 102, and a first NMS 104. The first transmission device 100 has a detection unit 11 2 # i in the interface unit 110 # i (i = l, 2, '...) and an SSMB update unit 1 1 in the control unit 116. 8 and a clock quality notification unit 120 are provided. The second transmission device 102 includes a clock selection unit 130, a control unit 132, and an SMB monitoring unit 134 and a lock switching control unit 133. The first NMS 104 has an inquiry unit 140, a judgment unit 142, and a dock switching instruction unit 144. It is assumed that the first transmission device 100 transmits the S MB information and the second transmission device 102 receives the S SMB information, but the definition of the S SMB is different. Each inspection unit 1 1 2 # i (i = 1,...) Inspects the quality of the clock distributed to the second transmission device 102. The SSMΒ updating unit 1 18 updates each SSMB information based on the clock quality from each of the inspection units 1 1 2 # i (i = 1, 2,...).

The query unit 140 queries the first transmission device 100 about the clock quality to be distributed to the second transmission device 102. The clock quality notification unit 120 notifies the first NMS 104 of each clock quality. The determining unit 142 determines whether or not the quality of the clock selected by the second transmission device 104 has deteriorated based on each clock quality from the first transmission device 102. to decide. If the clock quality selected by the second transmission device 102 is judged to be degraded, the clock switching instructing unit 144 will determine the clock quality of another high quality clock. The switching is instructed to the second transmission device 102. Clock switching control section 1 3 6 is clock Clock switching is controlled based on the instruction of the switching instruction section 144. As a result, the clock quality can be managed even when the first transmission device 100 and the second transmission device 102 have different definitions of SSMB information.

1st form

FIG. 2 is a configuration diagram of a synchronous network according to the embodiment of the present invention. As shown in Fig. 2, the upper NMS 150, NMS for SDH 152, NMS for SONET 153, SSU 154, SDH 156 # 1 ~: 156 # 3 and It is composed of SONET 158 # l and 158 # 2.

FIG. 3 is a functional block diagram of the upper NMS 150 in FIG. As shown in FIG. 3, the upper NMS 150 has an SSMB information inquiry unit 200, an SSMB information determination unit 202, and a clock switching instruction unit 204. The SSMB information inquiry unit 2000 has the following functions. Click lock quality information link L 1 ~ L 4 to distribute the S DH 1 5 6 # 1 good Ri clock to SONET 1 5 8 # 1, for example, _c query to query the SSMB information command This is done by sending The link to be queried is set in advance by the operator, for example, and stored in a table or the like. It is assumed that the timing for issuing the inquiry command is regular.

The SMB information determining unit 202 has the following functions. (L) The clock quality information of each link to be collected is received by the NMS 152 for SDH. (2) Based on the received clock quality information, is the clock of the link selected as the primary by SONET 158 # 1 on the clock receiving side degraded in quality? No, for example, it is determined whether the SSMB information of the link has been changed from PRC to DNU. (3) Clock If it is judged that the quality has deteriorated, another good quality clock or a predetermined clock, for example, a secondary clock, is used. select. The clock switching instructing unit 2 ◦ 4 determines that the primary clock quality has been degraded by the SSMB information determining unit 202 and switches to the other selected clock. Instruct NM S153 for SONET to switch.

FIG. 4 is a functional block diagram of the NMS 152 for SDH in FIG. The NMS 15 2 for SDH is a function block (not shown) related to the advance setting such as line setting to SDH 15 6 # i (i = l to 3) and the S SMB information of SDH 1 5 6 # 1. Figure related to acquisition It has an SS MB information acquisition unit 210 and an SS MB information transmission unit 212 shown in FIG. The SS MB information acquisition unit 210 has the following functions. (1) When the SS MB information acquisition unit 210 receives an inquiry about clock quality information from the upper NMS 150, the SS MB information acquisition unit 210 sends the clock of each link to be collected to SDH 156 # 1. Instructing the user to provide check quality information. (2) Receive clock quality information of each link from SDH 156 # 1. The SSMB information transmitting unit 212 transmits the clock quality information of each link to be collected to the upper NMS 150.

FIG. 5 is a functional block diagram of NMS 153 for SONET in FIG. The SONET NMS 153 is a functional part (not shown) related to pre-setting such as line setting for SONET 158 # i (i = l to 3) and a click switch finger for SONET 158 # i. And a clock switching instruction unit 220 shown in FIG. The clock switching instruction section 220 receives the clock switching instruction from the upper NMS 150 and issues a clock switching instruction to the SONET 158 # 1. SSU154 generates a master clock CLK1 and distributes it to SDH156 # 1. The SDH 156 # i includes the control section 160 # i, the clock card 16 2 # i, the interface unit 16 4 # ij (j = 1, 4) and a cross connector (not shown). Have.

FIG. 6 is a functional block diagram of the control unit 160 # i in FIG. As shown in FIG. 6, the control unit 160 #i is composed of the SOH control unit 250 #i, the clock switching control unit 25 2 # i. SS MB monitoring unit 25 4 # i and SS MB information transmission section 2 5 6 # i. The SOH control unit 250 # i controls section overhead transmitted and received by each interface unit 1664 # ij, for example, sets SMB information. When there are multiple clocks to be distributed, the clock switching control unit 25 2 # i uses the clock card 16 2 based on the SSMB information from each link of the distribution source. # Control the clock selected by i. The SS MB information monitoring unit 25 4 #i receives clock quality from each interface unit that distributes the clock periodically, and if the clock quality is degraded, Update the SS MB information. The SSMB information transmitter 2 5 6 # i receives the instruction of the notification of the cook quality information from the NMS 15 2 for SDH and sends the latest SSMB information of each link to the NMS 15 2 for SDH. Send to

Fig. 7 is a functional block diagram of the interface unit 16 4 #ij in Fig. 2. As shown in FIG. 7, the interface unit 164 # ij includes a clock transmitting / receiving unit 260 # ij, a clock quality detecting unit 262 # ij, a SOH transmitting / receiving unit 264 # ij, It has a main signal transmitting / receiving section 2 6 6 # ij. The clock transmission / reception unit 260 #ij transmits and receives the clock. The clock quality detector 26 2 # ij detects the clock quality to be distributed and outputs it to the controller 160 # i. The SOH transmitting / receiving section 264 # ij outputs the received SOH to the control section 160 # i, and inputs and transmits the SOH from the control section 160 # i. SONET 158 # i has control unit 170 # i, clock card 172 # i, interface unit 174 # ij (j = 1, ..., 4) and not shown Has cross-connects.

FIG. 8 is a functional block diagram of the control unit 170 # i in FIG. As shown in FIG. 8, the control unit 170 #i includes an S〇H control unit 280 #i, a clock switching control unit 282 #i, and an SSMB monitoring unit 284 #i. Have. The SOH control unit 280 # i is basically the same as the S〇H control unit 250 # i, although there is a difference between SDH and SONET. The clock switching control unit 282 # i has the same functions as the clock control unit 158 # i, and in addition to the clock switching instruction from the NMS 153 for SONET, Clock 1 7 2 # Control i to switch clocks. S S MB information monitoring unit 2 8 4

#i has the same function as the SMB information monitoring unit 25 4 #i. Clock card 1 7 2 # i and interface unit 1 7 4 # i j are clock cards 1 6 2

It has the same function as #i and interface unit 16 4 #i j. It is assumed that SDH156 # 1 and S SNET158 # 1 are connected by a 2.5 G signal (STM- 18 ZOC-48) X 4 link.

The upper NMS 150, the NMS 152 for SDH, and the NMS 153 for SONET are configured by a computer. The control sections 160 # i and 170 # i are composed of a processor and a program running on the processor. Communication between them is performed by LAN or WAN. The format of the communication message is a message in which necessary information is added to the command code indicating the communication content. The NMS 152 for SDH and the NMS 153 for SONET use commands to configure the line for SDH 156 # i and SONET 158 # i. Therefore, for the communication between the upper NMS 150, the NMS 152 for SDH and the NMS 153 for S NET, the conventional command code was inquired. This can be realized by adding command codes such as commands, and installing a program having a function to support these commands in the upper NMS 150 or the like. For SDH 15 6 # i and SONET 15 8 # i, download a program with the corresponding function to the control section 16 0 # i or 17 0 # i from NMS 15 2, 15 3 This can be achieved by: In other words, when SDH 156 # 1 is an existing transmission device and SONET 158 #i is an additional transmission device, SDH 156 #i and SONET 15 8 # i This can be achieved simply by adding a program.

Hereinafter, the operation of FIG. 2 will be described.

(1) Advance setting

The operator can access the SDH 156 # i (i = l, 2, 3) or SONET 158 # i (i = l, .-- ), Set the line and SSMB information. For example, as shown in FIG. 9, in SDH156 # 1, it is assumed that the SSMB of the link L1 is PRC (primary) and the link L2 is a secondary (SSMB-PRC). With the above setting, the master clock CLK1 generated by SSU154 is distributed through the following route. Clock force — clock 1 6 2 # 1 → interface unit 1 6 4 # 1 2 —> Link L l → clock card 1 7 2 # 1 → interface unit 1 7 4 # 16 → Clock card 1 7 2 # 2—Interface unit 1 7 4 # 2 3, 1 7 4 # 2 4 — SDH 1 5 6 # 2, 1 5 6 # 3 The operator sets the link for which clock quality information needs to be collected in the upper NMS 150.

(2) S SMB collection and clock switching

9 and 10 are diagrams showing clock switching control. Figure 11 is a switching sequence chart. As shown in (2) in Fig. 10 and (2) in (11) in Fig. 11, the upper NMS 150 is an interface unit that needs to periodically collect the SS MB according to the settings. Issue an SS MB information inquiry command to the SDH NMS 152 that manages the SDH 15 6 # 1 in which 1 1 to 16 4 # 14 is accommodated. As shown in (10) in FIG. 10 and (4) in FIG. 11, the NMS 155 for SDH has the SS for the links L1 to L4 added to the SDH156 # 1. Inquire about MB information. control As shown at (20) in Fig. 10, the unit 16 0 # 1 has the interface units 16 6 # 11 to 16 6 # 14 for the links L 1 to L 4 Update SSMB information from clock quality information // Maintain (SSMB monitoring). As shown in (22) in FIG. 10 and (6) in (11) in FIG. 11, the control unit 1660 # 1 transmits the S SMB information on the links L1 to L4 to the NMS 1520 for SDH. Send to Here, as shown in FIG. 9, it is assumed that the SSMB information has been changed to DNU as shown in FIG. 9 due to the clock deterioration of the link L1, which is the primary and is currently synchronized.

The NMS 15 2 for SDH receives the S SMB information of the links L 1 to L 4 from the SDH 15 6 # 1 and receives (12) in FIG. 10 and (12) in FIG. 11. As shown in (8), send it to the upper NMS 150. When the upper NMS 150 receives the SS MB information of the links L1 to L4, the interface for the used clock source is used as shown in (4) in FIG. Check whether the SSMB information of unit 1 6 4 # 11 is normal, for example, check whether the SSMB information has changed from PRC to DNU. Here, it is determined that the clock quality of the currently synchronized link L1 is degraded.

When the clock quality is determined to be degraded as shown in (4) in FIG. 10, the upper NMS 150 determines whether the interface MBMS information of the interface socket is correct. Check if it is normal. If the clock of link L1 is not normal, as shown in (6) in Figure 10 and (10) in Figure 11, another normal clock source or Then, the NMS 153 for SONET is instructed to switch the clock to the determined spare clock source, for example, the link L2 as the secondary clock source. As shown in (30) in Fig. 10 and (12) in Fig. 11, the NMS for SONET 153 connects SONET 158 # 1 from link L1 to link L2. Indicates switching of the receive clock. As shown in (32) in Fig. 10, the control unit 172 # 1 switches the receive clock from link L1 to link L2 to the clock card 172 # 1. Instruct. The clock card 170 # 1 switches from link L1 to the receive clock of link L2, and synchronizes dependently on link L2. As a result, in SONET 158 # 1, the clock of the link L2 of good quality is synchronized with the clock of the link L2 of good quality, not the clock of the link L1 whose quality has deteriorated. No, can control clock quality. In this embodiment, as a transmission device having a different SSMB standard, the clock distribution source is SDH according to the SSMB information standard that conforms to ITU-T, and the clock distribution destination is S ON. The case of ET has been described as an example, but the clock distribution source and the clock distribution destination may be opposite. The SDH without the S SMB conforming to the ITU-T and the SDH having the SS MB conforming to the ITU-T may be used. Click-locking the distribution source have SS MB, good _c second embodiment even when the transmission device click-locking the distribution destination is not at all have the SS MB information

FIG. 12 is a configuration diagram of a synchronous network according to the second embodiment of the present invention. Components that are substantially the same as the components in FIG. 2 are given the same reference numerals.

FIG. 13 is a functional block diagram of the upper NMS 200 in FIG. 12, and substantially the same components as those in FIG. 3 are denoted by the same reference numerals. . The SS MB information conversion table 350 is a table that defines the relationship between each SSMB information used by SDH 156 # 1 and the corresponding S SMB information used by SONET 304 # 1. The conversion unit 352 refers to the SSMB information conversion table 350 from the SSMB information of each interface unit 16 4 # 1 j (j = 1,) from the NMS 152 for SDH. To convert it to SS MB information used by S ONET 158 # 1. The S SMB information transmission unit 354 transmits the converted S SMB information of each interface unit 16 4 # 1 j (j = 1,...) To the NMS 302 for the SONET.

FIG. 14 is a functional block diagram of the NMS 302 for SONET in FIG. The SS MB information receiving section 360 receives the SS MB information of each link from the upper NMS 300. The SS MB information notifying unit 36 2 notifies the SS MB information to SONET 158 #l. The control unit 310 # i receives the converted SSMB information of each link from the SONET NMS 302 and controls the clock switching based on the SSMB information. In this way, the upper NMS 300 converts the clock distribution source SSMB information to the clock distribution destination SSMB information, and converts the converted SSMB information to the SONET NMS 3 Clock quality control may be performed by passing to SONET 304 #i through 02. At this time, since the conversion table is provided not in the SDH but in the upper NMS, clock quality management can be performed without changing the existing SDH. Industrial applicability

According to the present invention described above, even if the existing SDH network has a different definition between the newly established SDH or the newly established SONET and S SMB, the clock quality of the synchronous network can be synchronized with the correct one. . The higher-level NMS issues a command to check the clock quality of each link, and based on the result of the command, if the quality is poor, the link that is forcibly synchronized receives the correct link. The response can be achieved simply by having the upper NMS have a sequence to switch to the link, so there is no need to modify the existing SDH network equipment, and the response is possible. It is possible to cope with it without having to have a change table or the like in the SONET, SDH transmission device itself, the development cost is low, and the service of the customer's line is not interrupted.

Claims

The scope of the claims

1. Receives a plurality of synchronization status messages with a first transmission device that transmits a plurality of clocks and a synchronization status message related to the quality of each of the clocks, and receives the synchronization status messages. A synchronous network including a second transmission device for selecting one clock based on a message and a first NMS,

A plurality of detection units provided in the first transmission device for detecting the quality of a clock related to each of the synchronization status messages;

A quality information notifying unit provided in the first transmission device for notifying outside of quality information of each clock related to the synchronization status message based on the inquiry;

An inquiry unit provided in the first NMS for requesting the first transmission device to transmit the quality information of each clock,

Provided in the first NMS for determining whether or not the quality of a clock selected by the second transmission device has deteriorated based on quality information of a plurality of clocks from the first transmission device. A judgment unit,

A switchover instruction unit provided in the first NMS that instructs the second transmission device to switch to another port based on the determination of the determination unit;

A clock switching control unit provided in the second transmission device for controlling clock switching based on the clock switching instruction;

A synchronous network comprising:

2. It further comprises a second NMS for managing the first transmission device and a third NMS for managing the second transmission device, wherein the first NMS communicates with the second NMS and the third NMS. 2. The synchronous network according to claim 1, wherein the communication network communicates with the first and second transmission devices.

3. The first transmission device transmits a synchronization status message not conforming to the ITU-T standard, and the second transmission device transmits a synchronization status message conforming to the ITU-T standard. Synchronous network according to clause 1.

4. The first transmission device is an SDH device that transmits a synchronization status message conforming to the ITU-T standard, and the second transmission device is a SONET-based synchronization status message. 2. The synchronous network according to claim 1, wherein the synchronous network is a SONET device that transmits a message.

5. The first transmission device is a SONET device that transmits a SONET-based synchronization status message, and the second transmission device is an SDH device that transmits a synchronization status message that conforms to ITU-T. 2. The synchronous network according to claim 1, wherein:

6. The first transmission device, which transmits a plurality of clocks and transmits a synchronization status message related to the quality of each clock, receives a plurality of synchronization status messages, and takes one based on the synchronization status messages. A second transmission device for selecting one clock, a first NMS for managing the first transmission device, a second NMS for managing the second transmission device, and managing the first and second transmission devices. A plurality of detection units provided in the first transmission device for detecting the quality of a clock corresponding to each of the synchronization status messages.

Based on a transmission request command, a quality information notification unit provided in the first transmission device for notifying quality information of each clock related to the plurality of synchronization state messages to the outside;

An inquiry section provided in the third NMS for transmitting an inquiry command including a command code indicating an inquiry of quality information of each cup to the first NMS;

Transmitting the transmission request command requesting the first transmission device to transmit the quality information of the clock to the first transmission device; and transmitting the quality information of each clock from the quality information notification unit. A quality information collection unit provided in the first NMS for receiving;

A transmitting unit provided in the first NMS for transmitting quality information of a plurality of clocks collected by the quality information collecting unit to the third NMS based on the inquiry command; and the first NMS. Thus, the quality information of each clock is received, and the quality information of each clock is converted into a synchronization information message that conforms to the standard of the second transmission device, and is converted to the second NMS. A converter provided in the third NMS to be transmitted;

A notification unit provided in the second NMS for receiving each of the synchronization information messages from the third NMS and notifying the second transmission device of the synchronization information message;

A plurality of synchronization information messages from the first transmission device are ignored, and A clock switching control unit provided in the second transmission device for controlling selection of one clock based on the plurality of synchronization information messages;

A synchronous network comprising:

7. Transmission of multiple clocks and selection of one clock from the first transmission device that transmits the synchronization status message related to the quality of each clock and the multiple clocks A synchronous network including a second transmission device and a first NMS,

A clock quality notifying unit provided in the first transmission device for notifying externally quality information of each clock related to the synchronization status message based on the inquiry; and An inquiry unit provided in the first NMS that requests the first transmission device for transmission,

A judgment provided in the first NMS for judging whether or not the quality of a clock selected by the second transmission device has deteriorated based on quality information of a plurality of clocks from the first transmission device. Department and

A clock switching instruction unit provided in the first NMS that instructs the second transmission device to switch to another terminal based on the determination of the determination unit;

A clock switching control unit provided in the second transmission device that controls clock switching based on the instruction of the click switching instruction;

A synchronous network comprising: