JP2003023407A - Node device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a node device that can reduce the time required for redundant switching, without having to interrupt part time traffic on the occurrence of a fault in the device. SOLUTION: An active system switch section 2-1 and a standby system switch section 2-2 receive traffic from all interface sections 1-1, 1-2, 1-3, 1-4, 4-1, 4-2, 4-3 respectively. When these is no fault, only the system switch section 2-1 carries out switching connection of all traffics, redundant switching is executed on the occurrence of a fault in the active system switch section 2-1, so that only the standby system switch section 2-2 makes switching connection for all the traffic.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to, for example, SDH (Sy
nchronous Digital Hierarchy) or SONET (Syn
The present invention relates to a node device used in a digital signal transmission system conforming to a standardized system such as a chronous optical network), and more particularly to a switching control technique between an active system and a standby system.

[0002]

2. Description of the Related Art For example, in a digital signal transmission system applied to a trunk network, a duplex structure having an active system and a standby system in an interface device in a node device, a transmission line, etc. is adopted to perform backup at a system level. I am trying. With this dual configuration, when a failure occurs in the active system, the communication path of the service traffic set in the active system can be diverted to the standby system, and the reliability against failure or disconnection can be improved.

Further, in the recent duplex system, a communication path is set by using a spare transmission line which is vacant when there is no failure in the working system, and this communication path accommodates traffic different from service traffic. , There is a system designed to improve the traffic accommodation efficiency of the entire network. The traffic accommodated in the communication path using this backup transmission path is the Extra Traf in the ITU-T recommendation.
There is fic etc., and it is treated as traffic with lower priority than service traffic. Hereinafter, this type of traffic is referred to as part-time traffic.

By the way, in the conventional node device capable of accommodating part-time traffic, the following problems occur. That is, in the conventional node device, the switch unit for switching and connecting signals is duplicated, and when there is no failure, service traffic passes through the working switch unit and part-time traffic passes through the standby switch unit. If a failure occurs in the active system switch section from this state, there is a problem that part-time traffic is cut off in order to bypass the service traffic to the standby system switch section.

Further, in the conventional node device, the line setting states of the active system switch unit and the standby system switch unit when there is no failure are completely different.
It is necessary to take the procedure of resetting the line setting state of the standby system switch unit to the same state as the working system switch unit before the failure. Therefore, there is a problem that the processing takes time and the time until the redundancy switching processing is completed becomes long.

[0006]

As described above, in the conventional node device capable of accommodating part-time traffic, the part-time traffic is cut off at the time of device failure, and the redundant switching process due to the device failure is performed. There was a problem that the time was long.

The present invention has been made under the above circumstances.
An object of the present invention is to provide a node device capable of shortening the time required for redundancy switching without disconnecting part-time traffic when the device fails.

[0008]

In order to achieve the above object, the present invention provides a main traffic interface unit connected to a service line for transmitting main traffic, and a sub traffic different from the main traffic. A sub-traffic interface section connected to a sub-traffic line, and a line interface section connected to a signal transmission path for transmitting a multiplexed signal in which at least one of the main traffic and the sub-traffic is multiplexed. A plurality of redundant switch units connected to the main traffic interface unit, the sub traffic interface unit, and the line interface unit, and the main traffic, the sub traffic, and the multiplexed signal are in active operation. Introduced intensively in the switch section, The switch unit in switching waiting, characterized by comprising a connection control unit to wait as the same switching state the switching state of the switch unit in the current operation.

By taking such means, all the traffic is aggregated in the switch section which is currently in operation. In other words, in the prior art, the spare resources of the switch unit in the standby state for redundancy switching (standby system) were used to accommodate sub-signals such as part-time traffic, whereas in the node device of the present invention, the switch in active operation is used. The department accommodates both service traffic and part-time traffic. When a failure occurs in the switch part that is currently in operation, the standby switch part starts operating as the active system, and the redundant switching process diverts both service traffic and sub-traffic to the new active switch part. To be

Therefore, in the event of a device failure, the secondary traffic can be accommodated in the standby system switch section, which makes it possible to avoid disconnection of part-time traffic.

Further, since no traffic is given to the switch units waiting for redundancy switching, these switch units do not participate in signal transmission. Therefore, by setting the switching states of these switch units to be the same as those of the switch units that are currently in operation, it is possible to omit the processing procedure of newly setting the switching states in the redundant switching process. Therefore, it becomes possible to shorten the processing time for redundancy switching.

In this specification, the device failure means
The node device is not in a state where it cannot transmit service traffic, but redundant switching processing is performed,
This means that service traffic can be normally transmitted regardless of some functional failures.

[0013]

BEST MODE FOR CARRYING OUT 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 system, a plurality of node devices (Node) A to D are connected in a ring shape via an active transmission line SL and a standby transmission line PL. A low-order group device 10 is connected to each of the node devices A to D. The low-order group device 10 is, for example, an exchange or a terminal device, and exchanges service traffic or part-time traffic with a node device of a connection destination.

The low-order group signals transmitted and received between the low-order group device 10 and the node devices A to D are, for example, S in SDH.
TM (Synchronous Transport Module) -1, STM-
4, STM-16 level. This low-order group signal is multiplexed in each of the node devices A to D, and sent as a high-order group signal such as STM-64 to the working transmission line SL and the protection transmission line PL. It should be noted that the high-order group signals are transmitted in the clockwise direction (Clockwise: C) in each of the node devices A to D.
W) direction and counterclockwise direction (Counter Clockwise: CC
There are two ways, W). Here, for convenience, the CW direction in the node A is called the East side and the CCW direction is called the West side.

FIG. 2 is a block diagram showing a main part configuration of the node equipment A shown in FIG. Node device B to
D has the same configuration. The node device A includes an active system switch unit 2-1 and a standby system switch unit 2 which are redundant with each other.
-2 and. The active system switch unit 2-1 and the standby system switch unit 2-2 are both active system line interface units 1-1 and 1-3 and the standby system line interface unit 1-.
2, 1-4. The active line interface 1-1 is connected to the West side active transmission line SL. The active system line interface unit 1-3 is connected to the East side active system transmission line SL. The standby system line interface unit 1-2 is connected to the West side standby system transmission line PL. The standby line interface unit 1-4 is East
It is connected to the side standby system transmission line PL.

Further, the node equipment A has a service line 2 respectively.
The active system low-speed interface unit 4-1 connected to 01 and 202 and the standby low-speed interface 4-2, and the part-time traffic interface unit 4-3 connected to the part-time line 203 are provided. Service line 2
Service traffic is transmitted to 01 and 202, and part-time traffic is transmitted to the part-time line 203. Each line is connected to the low-order group device 10 that accommodates each line.

Here, the active low speed interface section 4-
1, the standby low-speed interface 4-2, and the part-time traffic interface 4-3 are all connected to the active switch 2-1 and the standby switch 2-2.

Solid arrows in FIG. 2 indicate service traffic S input / output in the active low-speed interface section 4-1 and the active line interface section 1-1.
/ T is shown. Further, the dotted arrow indicates the part-time traffic P / T input / output at the part-time traffic interface unit 4-3 and the standby system line interface unit 1-2. Note that these traffics are examples, and for example, the active low-speed interface section 4-1 is used.
It is possible that the service traffic introduced from the active line interface unit 1-3 is sent out.

By the way, the node device A comprises a connection control means 6 which is realized by software processing of a CPU (Central Processing Unit) (not shown). The connection control means 6 intensively introduces either the service traffic S / T or the part-time traffic P / T into the switch part in the active operation.

In FIG. 2, when there is no failure in the switch unit 2-1, both the service traffic S / T and the part-time traffic P / T pass through the active system switch unit 2-1. At this time, the switch unit 2-1 is said to be in the active operation. At this time, switch unit 2-2
Is in the redundant switching standby state, and the connection control means 6 changes the switching state of the switch unit 2-2 to the switch unit 2-1.
Same as the switching state inside.

FIG. 3 is a diagram showing the flow of traffic when a failure occurs in the active system switch section 2-1 from the state of FIG. When the active system switch section 2-1 becomes abnormal, the service traffic S / T and the part-time traffic P / T are switched by the connection control means 6 so as to pass through the standby system switch section 2-2.

That is, in the present embodiment, the scales of the active system switch unit 2-1 and the standby system switch unit 2-2 are individually set to all the interface units 1-1, 1-2, 1-.
The scale is set to accommodate the traffic from 3, 1-4, 4-1, 4-2, 4-3. Then, when there is no failure, all the traffic is switched and connected only by the active system switch section 2-1. When a failure occurs in the active system switch section 2-1, all traffic is exchanged only by the standby system switch section 2-2. Make the connection.

Therefore, when there is no failure, the standby system switch unit 2
-2 is not related to traffic transmission, it is possible to keep the switching state of the standby system switch unit 2-2 exactly the same as the state of the active system switch unit 2-1. That is, the active system switch unit 2 that changes from moment to moment
Backup system switch unit 2 while copying the line setting status of 1
-2 can be kept waiting. Such processing is realized by the connection control means 6.

By doing so, it is not necessary to take the procedure of resetting the line setting state of the standby system switch unit 2-2 to the same state as the working system switch unit 2-1 before the fault when a fault occurs. Therefore, the processing speed can be improved.

The same can be said at the time of redundant switching between the active low-speed interface section 4-1 and the standby low-speed interface section 4-2. That is, each switch unit 2-
When a failure occurs in the low speed interface section 4-1 from the state in which the 1 and 2-2 are connected to the low speed interface section 4-1, the switch system 2-1 and 2-2 are blindly used as the standby low speed interface. It may be connected to the section 4-2.

At this time, the settings of the switch units 2-1 and 2-2 relating to the part-time traffic interface unit 4-3 accommodating the part-time line 203 are not changed. This will have no impact on part-time traffic.

FIG. 4 shows the configuration of a conventional node device for comparison. The node device of FIG.
1 and a standby system switch section 5-2, an active system redundancy switching section 3-1 and a standby system redundancy switching section 3-2.

The active system switch section 5-1 is connected to the active system redundancy switching section 3-1 and the standby system switch section 5-2 is connected to the standby system redundancy switching section 3-2. Of these, the active system redundant switching unit 3-1 is connected to the active system low speed interface unit 4-1 and the standby system low speed interface 4-2. The standby system redundancy switching section 3-2 includes an active system low speed interface section 4-1 and a standby system low speed interface 4-2.
In addition to the above, it is connected to the part-time traffic interface unit 4-3.

FIG. 5 is a diagram showing the structure of the standby redundancy switching section 3-2. The standby system redundancy switching unit 3-2 includes a selector 33 and a distributor 34, and either the service traffic S / T or the part-time traffic P / T is exclusively output.

In FIG. 4, when there is no failure in the switch unit 5-1, the service traffic S / T passes through the active system switch unit 5-1 and the active system redundancy switching unit 3-1. The part-time traffic P / T is supplied to the standby system switch unit 5-2 and the standby system redundancy switching unit 3-2.
Via.

As shown in FIG. 6, when a failure occurs in the active system switch section 5-1 from the state shown in FIG. 4, the service traffic S / T causes the standby system redundancy switching section 3-2 and the standby system switch section 5-. It can be switched to via 2. At this time, the part-time traffic P / T is cut off because the service traffic passes through the protection system redundancy switching unit 3-2. This means that part-time traffic cannot be transmitted when a device fails.

In the spare system redundancy switching unit 3-2, the spare system is switched by switching between the service traffic accommodated in the spare system low speed interface unit 4-2 and the part time traffic accommodated in the part time traffic interface unit 4-3. Since the connection is made to the switch system spare system 5-2, it is necessary to set the line setup states of the standby system switch unit 5-2 and the active system switch unit 5-1 to different settings even when there is no failure. Therefore, at the time of redundant switching, there is a problem that the line setting state of the standby system switch section 5-2 must be reset.

On the other hand, in the node device of this embodiment,
In the active system switch unit 2-1 and the standby system switch unit 2-2,
All interface parts 1-1, 1-2, 1-
The traffic from 3, 1-4, 4-1, 4-2, 4-3 is connected, and when there is no failure, all the traffic is switched and connected only by the active system switch unit 2-1.
When a failure occurs in the active system switch section 2-1, all the traffics are switched and connected only by the standby system switch section 2-2.

Since this is done, the active system switch unit 2
Even if -1 fails, the spare system switch unit 2-2 can accommodate the part-time traffic. Further, since the standby system switch unit 2-2 can be made to stand by while copying the line setting state of the active system switch unit 2-1, it is possible to simplify the processing procedure at the time of redundancy switching. From these things, part-time traffic is not cut off in case of equipment failure,
It is possible to provide a node device that can reduce the time required for redundancy switching.

The present invention is not limited to the above embodiment. For example, in the present embodiment, the part-time traffic interface unit 4-3 has a non-redundant structure, but it can be made redundant.
The active low-speed interface unit 4-1, the standby low-speed interface 4-2, and the part-time traffic interface unit 4-3 each correspond to one channel, and in FIG. Although only shown, it is of course possible to provide a plurality of channels. In addition, various modifications can be made without departing from the scope of the present invention.

[0036]

As described above in detail, according to the present invention, the service traffic and the part-time traffic are introduced into the active switch section, and no traffic is introduced into the switch section waiting for redundancy switching. did. Then, the switching state of the switch section in the standby state is set to be the same as the switching state of the switch section in the active operation. Since this is done, part-time traffic is not interrupted in the event of equipment failure,
It is possible to provide a node device that can reduce the time required for redundancy switching.

[Brief description of drawings]

FIG. 1 is a system 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 main part configuration of a node device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a traffic flow when a failure occurs in the active system switch unit 2-1 from the state of FIG.

FIG. 4 is a block diagram showing a configuration of a conventional node device.

5 is a spare system redundancy switching unit 3-2 shown in FIG.
FIG.

FIG. 6 is a diagram showing a traffic flow when a failure occurs in the active switching unit 5-1 from the state shown in FIG. 4;

[Explanation of symbols]

A to D ... Node device SL: Working transmission line PL: Transmission line for backup system S / T ... Service traffic P / T ... part-time traffic 1-1, 1-3 ... Working line interface section 1-2, 1-4 ... Standby line interface section 2-1 ... Working system switch 2-2 ... Spare system switch 4-1 ... Working low-speed interface section 4-2 ... Standby low-speed interface unit 4-3 ... Part-time traffic interface unit 5-1 ... Working system switch 5-2 ... Standby system switch 6 ... Connection control means 10 ... Low-order group device 201, 202 ... Service line 203 ... Part-time line

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K021 AA06 BB10 CC11 DD02 FF01                       FF11                 5K028 AA11 AA14 CC02 CC05 DD04                       KK01 KK03 KK12 MM05 MM14                       PP02 PP05 QQ01 RR03                 5K031 AA08 CA08 CB12 DA12 DB14                       EA01 EB05

Claims (3)

[Claims] 1. A main traffic interface section connected to a service line for transmitting main traffic, and a sub traffic interface section connected to a sub traffic line for transmitting sub traffic different from the main traffic. A line interface unit connected to a signal transmission path for transmitting a multiplexed signal in which at least one of the main traffic and the sub traffic is multiplexed, the main traffic interface unit, the sub traffic interface unit, and A plurality of redundant switch units connected to the line interface unit, and a switch in which the main traffic, the sub-traffic, and the multiplexed signal are intensively introduced to a switch unit in active operation, and a switch is in a standby state for redundancy switching. Part is in the active operation Node device characterized by comprising a connection control unit to wait as the same switching state the switching state of the switch unit. 2. The main traffic interface unit includes a working system and a standby system for redundancy, and each system is connected to each of the plurality of switch units. Node device. 3. The sub-traffic interface unit is provided with a working system and a standby system for redundancy, and each system is connected to each of the plurality of switch units. Node device.