JP3950012B2 - Node device and redundant design method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a node device provided in a transmission system compliant with a standard such as SDH (Synchronous Digital Hierarchy) / SONET (Synchronous Optical Network) and a redundant design method thereof.
[0002]
[Prior art]
For example, in a digital signal transmission system applied to a trunk network, a duplex configuration including a service system and a protection system is employed for interface devices and transmission paths in node devices. According to the duplex configuration, when a failure occurs in the service system, the communication path of service traffic can be detoured from the service line to the protection line, and transmission information can be relieved from the failure or disconnection.
[0003]
When there is no failure in the service system, the protection line is empty. Thus, in recent duplex systems, there is a system in which a communication path is set in an empty resource of the protection line and traffic different from service traffic is accommodated in this communication path. In this way, the traffic accommodation efficiency in the entire network can be increased.
[0004]
The traffic accommodated in the communication path on the protection line side includes Extra Traffic described in the ITU-T recommendation. This type of traffic is treated as lower priority traffic than service traffic. Hereinafter, this type of traffic is referred to as part-time traffic.
[0005]
By the way, in a node device used in this type of system, a 1: 1 redundant configuration is usually adopted. That is, one protection device is prepared for one service device. This type of device includes TSA (Time Slot Assignment) and ADM (Add Drop Multiplexing) that perform separation / multiplexing processing between high-order group signals and low-order group signals.
[0006]
In the case of adopting a 1: 1 redundant configuration, both the service system TSA and the protection system TSA must have a scale capable of processing all of the transmission capacity of the node device. However, in recent years, there has been a demand for downsizing of devices due to footprints and the like, and there is a need to reduce the size of devices such as TSA itself and boards on which they are mounted as much as possible. .
[0007]
When the 1: 1 redundant configuration is adopted, service traffic is allocated to the service TSA when the apparatus is normal, and part-time traffic is allocated to the protection TSA. If a failure occurs in the service TSA from this state, part-time traffic is excluded from the protection TSA in order to bypass the service traffic. Therefore, although it is impossible to transmit part-time traffic in this state, it is desirable that even low-priority traffic can be saved from a failure.
[0008]
Further, when the apparatus is normal, the switching state of the service TSA and the state of the protection TSA are completely different. This is because the transmission destinations of service traffic and part-time traffic are different from each other. Therefore, in order to switch the service traffic to the protection TSA, it is necessary to copy the state of the protection TSA to the state of the service TSA before the failure in advance. Since this process is performed only after a failure occurs, there is a problem that the time required for the redundancy switching process becomes long.
[0009]
[Problems to be solved by the invention]
As described above, in the conventional node device, a 1: 1 redundant configuration is adopted in the device. For this reason, it is necessary to provide a pair of devices having the same processing capability, which hinders size reduction of the apparatus. In addition, the conventional node device cannot transmit part-time traffic in the event of an in-device failure. On the other hand, there is a need to be able to transmit part-time traffic even in the event of an in-device failure. In addition, the conventional node device requires time to reflect the service traffic restoration control data in the protection TSA in the event of a failure in the device, and the time required from the occurrence of the failure in the device to the completion of the redundancy switching process. There is a problem of being long.
[0010]
The present invention has been made in view of the above circumstances, and a first object of the invention is to provide a node device and a redundant design method thereof that are reduced in size without impairing the redundant switching function.
[0011]
A second object of the present invention is to provide a node device capable of transmitting part-time traffic even when an in-device failure occurs, and a redundancy design method thereof.
[0012]
A third object of the present invention is to provide a node device and a redundancy design method thereof in which the time required from the occurrence of an in-device failure to the completion of redundancy switching processing is shortened.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the present invention transmits a high-speed interface unit connected to a high-speed line for transmitting a multiplexed signal in which a plurality of time slots are multiplexed, and a low-order group signal having a lower multiplicity than the multiplexed signal. A plurality of low-speed side interface units connected to a plurality of low-speed lines, respectively, and set in the same switching state as each other, and having processing capability in units lower than the line setting unit in the high-speed line, N service system switch units (N is a natural number of 2 or more) for performing signal add / drop processing between the side interface unit and the plurality of low speed side interface units, and the same switching state as these service system switch units Is set and has processing capability equivalent to the service system switch unit, and the high-speed side interface unit and the plurality of low-speed interface units, respectively. M number of performing add-drop processing signals to and from the side interface unit (M is a natural number smaller than N) and the protection system switch of any of the service system switch unit failure either in the case of occurrence ; and a switching unit control means for switching operation of the protection system switch unit as an alternative, the high-speed side interface unit separates the time slot to be multiplexed into the multiplexed signal to the N service system switch unit High-speed side distribution means for distributing, and high-speed side connection means for connecting the time slots added in the N service system switch units to generate the multiplexed signal and sending the multiplexed signal to the high-speed line. Each of the plurality of low-speed side interface units is dropped from the N service system switch units. Low-order side connection means for connecting the time slots to generate the low-order group signal and sending the low-order group signal to the low-speed line; and the N services by separating the time slots of the low-order group signal And a low speed side distribution means for distributing to the system switch section.
[0014]
With this configuration, the switch unit has an M: N redundant configuration. Preferably, M = 1 and a 1: N redundant configuration is used. In this case, for example, when the switch unit is mounted on a substrate, the number of substrates in the entire apparatus can be reduced, and thus the size of the entire apparatus can be reduced.
[0015]
Also, in the present invention, the switch unit control means sets all the switching states of the service system and protection system switch units to be the same. By doing so, it is not necessary to reflect the restoration control data in the protection system switch unit at the time of redundant switching of the switch unit. Therefore, the switching time can be increased.
[0016]
Furthermore, the present invention is characterized in that at least one of the plurality of low-speed side interface units accommodates sub-traffic such as part-time traffic that is different from service traffic accommodated in the other low-speed side interface units. In this way, both service traffic and part-time traffic are processed in the service system switch unit. Therefore, service traffic can be protected without eliminating part-time traffic even when redundant switching is performed in the switch unit.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a digital signal transmission system in which a node device according to the present invention is installed. In this embodiment, a system conforming to SDH is assumed. This system includes a plurality of node devices (Node: hereinafter referred to as nodes) #A to #E, and a service line SL and a protection line PL that connect these nodes in a ring shape. The protection line PL is a backup system for the service line SL.
[0018]
For example, a client device 10 such as an exchange or a terminal device is connected to each of the nodes #A to #E. Nodes #A to #E exchange service traffic or part-time traffic with the client apparatus 10.
[0019]
Low-order group signals exchanged between the client apparatus 10 and each of the nodes #A to #E are, for example, STM (Synchronous Transport Module) -1, STM-4, STM-16, or STM-64 level in SDH. is there. This low-order group signal is multiplexed at each of the nodes #A to #E and sent to the service line SL and the protection line PL as a high-order group signal such as STM-64. Note that there are two types of high-order group signal transmission directions in each of the nodes #A to #E, a clockwise (Clockwise) direction and a counterclockwise (Counter Clockwise: CCW) direction. Here, for convenience, the CW direction in the node A is referred to as the East side, and the CCW direction is referred to as the West side.
[0020]
Each node #A to #E is connected to a monitoring control device 20 that performs monitoring processing and control processing of the entire network. The number of the monitoring control devices 20 is arbitrary according to the system design needs. For example, the entire system may be comprehensively monitored and controlled by one monitoring control device 20.
[0021]
In addition, this system has a function of relieving service traffic from a failure using a transmission resource on the protection line PL when a failure related to the transmission of service traffic occurs in the service line SL. This function is called APS (Automatic Protection Switching) in SDH, and is realized by autonomous distributed control of nodes #A to #E. APS methods include BLSR (Bi-directional Line Switched Ring).
[0022]
FIG. 2 is a block diagram showing a configuration of node #A shown in FIG. Nodes #B to #E have the same configuration. The node #A includes a high-speed interface block (HS I / F block) 1, a low-speed interface block (LS I / F block) 2, a multiplexing / demultiplexing unit 3, a main control unit 4, and a storage unit 5. .
[0023]
The high-speed interface block (HS I / F block) 1 includes active high-speed interface units (HS I / F (SRV)) 11 and 12 and standby high-speed interface units (HS I / F (PRT)) 13 and 14. Is provided. The HS I / F (SRV) 11 is connected to the East side service line SL, and the HS I / F (SRV) 12 is connected to the West side service line SL. The HS I / F (PRT) 13 is connected to the East side protection line PL, and the HS I / F (PRT) 14 is connected to the West side protection line PL.
[0024]
Both HS I / F (SRV) 11 and 12 and HS I / F (PRT) 13 and 14 terminate the remote section (R-Section) termination process and the terminal station section (M-Section) termination process. And carry out.
[0025]
On the other hand, the LS I / F block 2 includes low-speed interface units (LS I / F) 21 to 2n corresponding to the number n of channels reaching the client device 10. The LS I / Fs 21 to 2n are all connected to the multiplexing / demultiplexing unit 3.
[0026]
The low-speed interface units LS I / Fs 21 to 2n include a main signal working system interface unit (I / F (SRV)) 61, a main signal standby system interface unit (I / F (PRT)) 62, and a part-time traffic interface unit. (I / F (P / T)) 63. The I / F (SRV) 61 is connected to the service line 201. The I / F (PRT) 62 is connected to the service line 202. The I / F (P / T) 63 is connected to the part time line 203. Service lines 201 and 202 transmit service traffic. The part-time line 203 transmits part-time traffic. Both lines are connected to the client device 10 that accommodates each line.
[0027]
The I / F (SRV) 61 and the I / F (PRT) 62 are connected to the multiplexing / demultiplexing unit 3 via the changeover switch unit (PSW (SRV)) 51. Further, the I / F (SRV) 61, the I / F (PRT) 62, and the I / F (P / T) 63 are connected to the multiplexing / demultiplexing unit 3 through the changeover switch unit (PSW (PRT)) 52. Is done.
[0028]
The node #A operates based on various control programs stored in the storage unit 5 under the control of the main control unit 4 including a CPU (Central Processing Unit) (not shown).
[0029]
Incidentally, the main control unit 4 includes a switch control unit 4a realized by, for example, software processing of the CPU. The switch control unit 4a performs control to switch the traffic transmission path in the apparatus when a failure occurs in the multiplexing / demultiplexing unit 3.
[0030]
FIG. 3 is a block diagram showing a configuration of a main part according to this embodiment of the node #A shown in FIG. The other nodes #B to #E have the same configuration. As illustrated in FIG. 3, the multiplexing / demultiplexing unit 3 of FIG. 2 includes service system switch units 31 to 33 and a protection system switch unit 34. As described above, in this embodiment, the switch unit having the traffic add / drop function has a 1: 3 redundant configuration. That is, the protection system switch unit 34 operates as an alternative when a failure occurs in any of the service system switch units 31 to 33. In FIG. 3, a plurality of LS I / Fs 21 to 2n are connected to the multiplexing / demultiplexing unit 3. Of these, only the LS I / F 21 is shown in FIG. Although not shown, the LS I / Fs 22 to 2n are also connected to the multiplexing / demultiplexing unit 3.
[0031]
FIG. 4 is a diagram showing a traffic transmission state when node #A shown in FIG. 3 is normal. In FIG. 4, the HS I / F block 1 includes a distribution unit 15 and a selection unit 16. The distribution unit 15 divides service traffic introduced from the high-speed side line (here, West SRV) into three systems in units of time slots and distributes the service traffic to the service system switch units 31 to 33. For example, if the line setting unit is AU (Administrative Unit) -4, the distribution unit 15 generates three AU-3 signals and distributes the AU-3 signals to the service switch units 31-33. In FIG. 4, this signal transmission path is indicated by a solid line arrow.
[0032]
In FIG. 4, a backup route is set in the protection switch 34. This route is a route for diverting traffic when any of the service switch units 31 to 33 fails.
[0033]
The selection unit 16 connects the time slots introduced from the service system switch units 31 to 33 to generate a high-order group signal, and sends it to the high-speed side line. When a failure occurs in any of the service system switch units 31 to 33, the protection system switch unit 34 is switched to the service system, and the selection unit 16 switches the acquisition destination of the time slot to the protection system switch unit 34.
[0034]
On the other hand, the LS I / F 21 includes a selection unit 41 and a distribution unit 42. The selection unit 41 connects the time slots introduced from the service system switch units 31 to 33, generates a low-order group signal, and sends it to the low-order group line (here, the service line 201) line. When the protection system switch unit 34 is switched to the service system, the selection unit 41 switches the acquisition destination of the time slot to the protection system switch unit 34.
[0035]
The distribution unit 42 divides service traffic introduced from the service line 202 into three systems in units of time slots, and distributes them to the service system switch units 31 to 33.
[0036]
In this state, in this embodiment, the line setting states of the service system switch units 31 to 33 and the protection system switch unit 34, that is, the switching states are all the same. That is, the protection system switch unit 34 is set in advance to the same switching state as the service system switch units 31 to 33.
[0037]
FIG. 5 is a diagram showing a traffic flow when a failure occurs in the service system switch unit 31 from the state of FIG. A processing procedure in the apparatus in this case will be described below. First, a failure of the service system switch unit 31 is detected. Then, the distribution units 15 and 42 switch the signal connected to the service system switch unit 31 to the protection system switch unit 34. Next, the selection units 16 and 41 switch the acquisition destination of the time slot from the service system switch unit 31 to the protection system switch unit 34.
[0038]
At this time, since the service system switch units 31 to 33 and the protection system switch unit 34 are all in the same switching state, it is not necessary to reflect the restoration data in the protection system switch unit 34 at the time of switching. Therefore, the traffic can be restored to the protection system only by switching the states of the distribution units 15 and 42 and the selection units 16 and 41. Therefore, the switching time can be shortened.
[0039]
Further, in the present embodiment, the switch units 31 to 34 having the processing capability in units of AU-3 have a 3: 1 redundant configuration. Conventionally, a switch unit having a processing capacity in units of AU-4 is set to 1: 1 redundancy, and the scale of the switch unit tends to increase due to the signal processing capacity. On the other hand, since the scale of the switch unit can be reduced in this embodiment, the size of the apparatus can be reduced.
[0040]
FIG. 6 is a diagram illustrating a traffic flow when a failure occurs in the service system switch unit 33 from the state of FIG. Even in this case, the traffic can be restored to the protection system only by switching the states of the distribution units 15 and 42 and the selection units 16 and 41.
[0041]
FIG. 7 is a diagram showing a traffic transmission state when part-time traffic is accommodated when node #A shown in FIG. 3 is normal. The transmission path for part-time traffic is indicated by a bold line. The thin line indicates the transmission path of the service traffic as in FIGS.
[0042]
Part-time traffic is exchanged inside and outside the apparatus via an I / F (P / T) 63 (here P / T) and an HS I / F (PRT) 14 (here West PRT). Similar to FIGS. 4 to 6, the part-time traffic is subjected to conversion processing between AU-4 and 3 × AU-3 by the distribution units 15 and 42 and the selection units 16 and 41, and then to the switch units 31 to 34. A transmission route is set. The same applies when the protection route is set in the protection switch 34. In this way, transmission paths for service traffic and part-time traffic are set in the service switch units 31-33. Thereby, even if a failure occurs in any of the service system switch units 31 to 33, the service traffic is relieved only by switching the transmission route to the protection system switch unit 34. Moreover, since the part-time traffic transmission route is also switched to the protection system switch unit 34 at the same time, the part-time traffic can also be relieved.
[0043]
FIG. 8 is a diagram showing the flow of traffic when a failure occurs in the service system switch unit 32 from the state of FIG. A processing procedure in the apparatus in this case will be described below. First, a failure of the service system switch unit 32 is detected. Then, the distribution units 15 and 42 switch the service traffic and part-time traffic connected to the service system switch unit 31 to the protection system switch unit 34. Next, the selection units 16 and 41 switch the acquisition destination of the time slot from the service system switch unit 31 to the protection system switch unit 34. In this way, both service traffic and part-time traffic can be relieved only by switching the states of the distribution units 15 and 42 and the selection units 16 and 41.
[0044]
As described above, in the present embodiment, the multiplexing / demultiplexing unit 3 that performs multiplexing / demultiplexing of signals in units of AU-4, the service system switching units 31 to 33 each having processing capability in units of AU-3, and protection system switches Part 34 and having a 1: 3 redundant configuration. Then, the distribution units 15 and 42 and the selection units 16 and 41 perform a process of distributing the AU-4 signal to the three AU-3 signals, and the AU-3 signal of each system is sent to the service system switch units 31 to 33. Distribute each. The switching states of the switch units 31 to 34 are all the same, and when a failure occurs in any of the service system switch units 31 to 33, the signal path is retracted to the protection system switch unit 34.
[0045]
In the present embodiment, as with service traffic, part-time traffic is distributed to the service system switch units 31 to 33 as three AU-3 signals, and the restoration route is formed in the protection system switch unit 34. I have to.
[0046]
From these facts, according to the present embodiment, it is possible to provide a node device and a redundancy design method thereof that are reduced in size without impairing the redundancy switching function. Further, according to the present embodiment, it is possible to provide a node device capable of transmitting part-time traffic even when an in-device failure occurs and a redundant design method thereof. Furthermore, according to the present embodiment, it is possible to provide a node device and a redundancy design method thereof that reduce the time taken from the occurrence of an in-device failure to the completion of the redundancy switching process.
[0047]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to provide a node device and a redundancy design method thereof that are reduced in size without impairing the redundancy switching function. Further, according to the present invention, it is possible to provide a node device capable of transmitting part-time traffic even when an in-device failure occurs and a redundant design method thereof. Furthermore, according to the present invention, it is possible to provide a node device and a redundancy design method thereof in which the time required from the occurrence of an in-device failure to the completion of redundancy switching processing is shortened.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a digital signal transmission system in which a node device according to the present invention is installed.
FIG. 2 is a block diagram showing a configuration of a node #A shown in FIG.
3 is a block diagram showing a configuration of a main part according to the present embodiment of a node #A shown in FIG.
FIG. 4 is a diagram showing a traffic transmission state when node #A shown in FIG. 3 is normal.
FIG. 5 is a diagram showing the flow of traffic when a failure occurs in the service system switch unit 31 from the state of FIG. 4;
6 is a diagram showing a traffic flow when a failure occurs in the service system switch unit 33 from the state of FIG. 4;
7 is a diagram showing a traffic transmission state when part-time traffic is accommodated when node #A shown in FIG. 3 is normal. FIG.
8 is a diagram showing the flow of traffic when a failure occurs in the service system switch unit 32 from the state of FIG.
[Explanation of symbols]
SL ... service line PL ... protection line #A to #F ... node device 1 ... high speed interface block 2 ... low speed interface block 3 ... separation unit 4 ... main control unit 4a ... switch control unit 5 ... storage unit 10 ... client device 11, DESCRIPTION OF SYMBOLS 12 ... Active system high speed interface part 13, 14 ... Backup system high speed interface part 15, 42 ... Distribution part 16, 41 ... Selection part 20 ... Monitoring control apparatus 21-2n ... Low speed interface part 31-33 ... Service system switch part 31- 33 ... Service system switch unit 34 ... Protection system switch unit 41 ... Selection unit 42 ... Distribution unit 51, 52 ... Changeover switch unit 61 ... Main signal active system interface unit 62 ... Main signal backup system interface unit 63 ... Part time traffic interface unit 201, 202 ... service line 203 ... part Im line

Claims (4)

A high-speed side interface unit connected to a high-speed line for transmitting a multiplexed signal in which a plurality of time slots are multiplexed;
A plurality of low-speed side interface units respectively connected to a plurality of low-speed lines for transmitting a low-order group signal having a lower multiplicity than the multiplexed signal;
They are set to the same switching state, have processing capability in units lower than the line setting unit in the high-speed line , and add signals between the high-speed side interface unit and the plurality of low-speed side interface units , respectively. N (N is a natural number of 2 or more) service system switch units that perform drop processing ;
These service system switch units are set to the same switching state, have the same processing capability as the service system switch unit, and add / drop signals between the high speed side interface unit and the plurality of low speed side interface units, respectively. M number of protection system switches (M is a natural number smaller than N) for processing,
If a failure to the service system switch of any occurred; and a switching unit control means for switching operation of the protection system switch of any one as an alternative,
The high-speed interface unit is
High-speed side distribution means for separating time slots multiplexed in the multiplexed signal and distributing them to the N service system switch units;
High-speed side connection means for connecting the time slots added in the N service system switch units to generate the multiplexed signal and sending the multiplexed signal to the high-speed line;
Each of the plurality of low-speed side interface units is
Low-speed side connection means for connecting the time slots dropped from the N service system switch units to generate the low-order group signal and sending the low-order group signal to the low-speed line;
A node apparatus comprising: a low-speed side distribution unit that separates time slots of the low-order group signal and distributes them to the N service system switch units. The node device according to claim 1, wherein at least one of the plurality of low-speed side interface units accommodates sub-traffic different from service traffic accommodated in another low-speed side interface unit. A high-speed interface unit connected to a high-speed line that transmits a multiplexed signal in which a plurality of time slots are multiplexed, and a plurality connected to a plurality of low-speed lines that transmit a low-order group signal having a lower multiplicity than the multiplexed signal. A redundant design method for a node device comprising a low-speed interface unit of
Each of the switch units has a processing capability in a unit lower than the line setting unit in the high-speed line, and performs signal add / drop processing between the high-speed side interface unit and the plurality of low-speed side interface units , respectively. N + M (N is a natural number of 2 or more, M is a natural number smaller than N) to form a redundant configuration,
N of these switches are operated as service systems,
The remaining M switch units are made to stand by as the protection system of the service system switch unit,
The service system switch unit and the protection system switch unit are set to the same switching state,
A redundant design method characterized by separately distributing and supplying time slots of signals accommodated in the high-speed side and low-speed side interface units to the service system switch unit. 4. The redundancy design method according to claim 3 , wherein sub-traffic different from service traffic accommodated in another low-speed interface unit is accommodated in at least one of the plurality of low-speed interface units.

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