JPH11346225A - Atm alarm processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply transfer fault display signal cell of a VP segment by setting simply whether or not a fault is in the inside or at the outside of a virtual path VP segment corresponding to each VP with respect to the ATM alarm processing system that uses a segment VP-AIS cell in compliance with the ITU-T recommendations I.610 so as to manage a fault in VP segments of an ATM network. SOLUTION: A network management device 1 gives a specific cell 4 that includes a VPI value being an object of a VPI and whose information area stores setting information as to whether or not a segment VP-AIS cell is to be transferred with respect to transmitters 2-0-2-n in a network each configuring the VP segment. When each transmitter configuring the VP segment detects the specific cell 4, each transmitter stores the setting information in the information area and transfers sequentially the specific cell 4 to post-stages of the transmitters till the specific cell 4 reaches the end of the segment sequentially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ITU-T Recommendation I. The present invention relates to an ATM alarm processing method for managing a transmission line failure in a segment of an ATM network using a segment VP-AIS cell conforming to 610.

In an ATM network, there are devices for managing the entire network, and various settings are made directly from the management device to all devices in the network. For example, each connection point is connected to a virtual path VP (or virtual channel VC). In the segment of the throat or at the beginning,
Although the setting such as whether or not the terminal is performed has been performed, it takes time and effort to perform such a setting for all the devices in the network.

[0003]

2. Description of the Related Art ITU-T recommendation I. 610 is "B-IS
DN OPERATION AND MAINTANANCE PRINCEPLES AND FUNCTI
ONS ”, according to which OAM (0perat
FIG. 8 shows the relationship between the physical layer and the ATM layer with respect to the hierarchy level of “ion and maintenance”. That is, the physical layer is F1 (regenerator section level), F2 (digital section section).
Level), F3 (transmission path level)
The ATM layer is divided into two levels, F4 (virtual path level: VP) and F5 (virtual channel level: VC), and has an end point corresponding to each level. Level of connection points.

FIG. 9 shows an example of a segment configuration. Are two VC (virtual channel) switches 1,
2 (VCswitch1, VCswitch2) is provided with a VP cross-connect (referred to as VPC). In this example, a VCC (VC Connection) is connected between the internal terminations of the two VC switches 1 and 2.
A segment is provided, and a VPC (VP Connection) segment is provided between both ends of the VP cross-connect VPC.

[0005] FIG. Are two VP cross-connects 1 and 2 (VPcross-connect 1, VPcross-connect
2) A VPC segment A is provided between the external ends, and the right end of VP cross-connect 2 and VP cross-connect 3 are connected.
A VPC segment B is provided between the left terminals of t3), and a VPC segment C is set between the left end of the VP cross-connect 3 and the VC switch.

[0006] At the F4 level (VP), the "user cell" used for OAM is determined so that the value of the VCI takes a specific value, and FIG. 10 shows the value. Also,
At the F5 level (VC), the "user cell"
The cell has the same VCI / VPI value as the user cell, and as shown in FIG. 11, indicates that the cell is an OAM cell by a specific value of PTI (Payload Type Identifier).

FIG. 12 shows an example of the configuration of the OAM flow.
For the arrangement for transmission shown at the top, the physical layer (F
1, an F2 level section and an F3 level transmission path) and an ATM layer. In this example, the FPC level VPC-OAM
V flows to PI1, VPI2, and VPI3, and indicates that it is at F5 level by PTI (payload type identifier).
CC-OAM cells VCI1 and VCI2 flow.

The OAM cell format of the ATM layer has a field common to all OAM cells, and the principle of coding of the unused common and specific fields is that the octed of the unused OAM cell information field is "01101".
010 ”(6AH), and bits (incomplete octets) of the unused OAM cell information field are coded to all“ 0 ”.

One of the OAM functions in the ATM layer is generation of a VP-Alarm Indicating Signal (VP-AIS) cell. This signal is sent to the VP connection point (for example, A
(TM cross-connect) and sent downstream to the transmission termination of all associated driven VP connections. The VP-AIS cell is generated immediately after the failure is detected and transmitted to the subsequent stage to notify the failure of the VP, and is periodically transmitted during the failure to indicate that the cell transfer capability at the VP level has been interrupted. You. The generation cycle of the VP-AIS cell is usually one cell per second.

In a conventional ATM transmission device, there is a management device for managing the entire network, and various settings are made directly from the management device to all devices in the network. Therefore, like the transfer of a segment VP-AIS cell that transfers within a VP segment, an alarm cell is generated only within a certain segment section of the transmission path, and the alarm cell is generated outside that section (outside the segment section). If the transfer is not performed, the setting of whether it is within the segment or outside the segment (or whether it is the generation point of the segment VP-AIS cell) must be performed for each VP of all devices in the network. Did not. The VP segment can be set by a network administrator, and may be separated from a user, further separated by an optical fiber, or separated by a certain transmission device (a device including a cross-connect or a switching unit). is there. Within such a segment, segment OAM cells are generated and processed within the segment, and at the end of the segment such cells are discarded.

[0011]

As described above, the VP
The management of the setting (registration) of the start point, the end point, and whether the segment is inside the VP segment or outside the VP segment is managed by each VP (virtual, virtual) of each device in the network.
Pass) had to be done every time. That is, a large number of VPs (up to 4096 VPIs can be set) can be provided for each transmission device, and there is a problem that when the network becomes large-scale, it becomes burdensome to manage the network.

Further, when a VP segment is set for a certain VP path (or when a VP segment is released), the setting as to whether the VP segment is inside or outside the VP segment is made from one end of the network to the other end of the network. Since the information must be set as management information, if the number of devices through which a certain VP path passes increases, the setting must be performed on all the devices that pass through. Therefore, there has been a problem that the setting itself is a large amount of work and the burden is large.

[0013] The above-mentioned problem relating to the segment of the VP path has also occurred in the segment (VC segment) of the VC (virtual channel).

According to the present invention, whether the inside or the outside of the VP segment is set for each VP of each transmission device can be easily set, and the setting for transferring the fault indication signal (segment VP-AIS) of the VP segment can be simplified. It is an object of the present invention to provide an ATM alarm processing method that can be implemented. In addition, the present invention
Another object is to make it possible to easily set the P path management information.

[0015]

FIG. 1 is a diagram showing the principle configuration of the present invention. 1 is a network management device, 1a is a segment end setting unit, 1b is a specific cell generation unit for setting in a segment, 2-0 to 2- (n-1) are n ATM transmission devices, 2a is a start end setting unit, 2b is a termination setting unit, 2c is a specific cell detection segment setting unit, 3 is a transmission line, and 4 is a specific cell.

First, the network management device 1 sends a transmission device 2-0 at the beginning of a segment and a transmission device 2-0 at the end of the segment.
Information for setting the start and end of the VP segment is supplied to (n-1). This gives
A segment start end and a segment end are set in the segment end setting units 2a and 2b of the transmission devices 2-0 and 2- (n-1), respectively, corresponding to the VP. When the specific cell for setting within the segment is input from the network management device 1 to the transmission device 2-0 at the start of the segment from the specific cell for setting for intra-segment lb, the transmission device 2 through the transmission device 2-0. -1 and sequentially transmitted within the segment, and the transmission device 2- (n-1) at the end of the segment
, Where the specific cell is discarded.

When this specific cell passes, each transmission device 2
In -1, 2-2,..., 2- (n-1), each VPI stored in the information field of the specific cell is set as being within the segment. After a segment with a VP is set in this way, if a failure occurs in a VP in the segment, a segment VP-AIS cell for notifying that the VP has failed is generated. in this case,
The segment VP-AIS cell is sequentially transmitted to each downstream transmission device, notified that the VP set in each transmission device is faulty, and transmitted at the end of the segment.
This segment VP-AIS cell is sent to (n-1) and discarded at the end.

In this description, the VP segment is used as an example. However, the VC segment can be set at the start and end of the VC segment, and can be set within the segment according to the same principle.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is an explanatory diagram of setting a start point and an end point of a VP segment. In the figure, 1 is a network management device, 2 is an ATM transmission device, and is represented by devices A to E.

In the example of the configuration shown in FIG.
Constitutes one VP segment, the network management apparatus 1 sends setting information of a VP segment start point to the apparatus A, and sends setting information of a VP segment end point to the apparatus E. In this case, it is transmitted to the start and end devices corresponding to the value of VP. As a result, the device A sets the information indicating the beginning of the segment in the memory corresponding to the VP, and the device E
Similarly, information indicating the end of the segment is set in the memory corresponding to the VP.

At this time, the network management device 1 does not make any settings for the devices B to D. After setting the start point and end point of the VP segment, an OAM cell of the VP segment (shown in FIG. 4 described later) in which the alarm transfer setting information of the segment VP-AIS cell is described is a device which is the start point of the VP segment. From A, insert in the direction inside the VP segment. The OAM cell is transferred from the device A to the device B to the device E while being VPI-converted. When the OAM cell reaches the device E in which the VP segment end point is set, it is discarded. The function of discarding the OAM cells of the VP segment at the end point of the VP segment is described in ITU-T Recommendation I.T. 610.

In the present invention, the cell in which the alarm transfer setting information of the segment VP-AIS cell is described is used by using the OAM cell of the VP segment as the cell in which the alarm transfer setting information of the segment VP-AIS cell is described. It is possible to prevent the data from being transferred outside the VP segment in the network. In addition, when a transmission line failure occurs in the devices A and E at the ends of the VP segment, the problem of whether or not to transfer the segment VP-AIS cell depends on the configuration and design of the network.
Either may be used.

In a normal network, VPs are set in both the upstream and downstream directions. Therefore, similar processing is performed in the reverse direction with the device E as the start point of the VP segment and the device A as the end point of the VP segment. Will be.

Furthermore, when releasing a VP segment that has already been defined in the network, a setting to stop the alarm transfer of the segment VP-AIS cell before releasing the VP segment has been described. A
A cell for alarm transfer setting of an IS cell is inserted from the start point of the VP segment. In the configuration of FIG.
Are transferred from the VP-AI to the device E, when a transmission line failure occurs, the segment VP-AI
It is set not to perform the alarm transfer of the S cell. Also in this case, since the cell is an OAM cell of the VP segment, this cell is discarded by the device E which is the terminal point of the VP segment.
In the same manner as described above, the stop setting of the alarm transfer of the segment VP-AIS cell is performed for the VP path in the reverse direction. A cell in which the setting for stopping the alarm transfer of the segment VP-AIS cell is described is flown, and the setting for stopping the alarm transfer of the segment VP-AIS cell is performed. By setting the release of the VP segment of the VP, it is possible to prevent the segment VP-AIS cell from being alarm-transferred from a device that is not in the VP segment.

FIG. 3 is a block diagram of the transmission of the OAM cell of the VP segment, and FIG. 4 shows the full format of the OAM cell of the VP segment. 3, 1 and 2 are the same as those in FIG. 2, 1 is a network management device, 2 is an ATM transmission device, and is represented by devices A to D. In the devices A to D, which are a plurality of ATM transmission devices shown in FIG. 3, the device A is set in advance as the start end of the VP segment by the configuration of FIG. 2, and the device E not shown in FIG. It is assumed that

An OAM cell for VP segment setting is transmitted from the network management device 1 to the device A. FIG. 4 shows the format of the OAM cell of the VP segment. The format of the OAM cell of this VP segment is such that the VPI value of the target VP (“00
1h "(h is a hexadecimal notation), and the VCI has a value (" 0003 ") indicating that it is a VP segment OAM cell.
h "), PTI is" 000b "(b represents a bit),
The CLP is “0b”. However, the VPI value is transferred through the network while being converted according to the setting of each device. The OAM cell of the VP segment is
Set for PI (from 0 to 4096).

The O for setting the VC segment is
An AM cell is displayed by setting a PTI (Payload Type Identifier) to a specific value. In the example of FIG.
When a P-segment OAM cell is input to the device A of FIG. 3, the VPI value of the input cell changes from “001h” to “0”.
The device B converts the input cell VPI value from “002h” to “003h” and transfers it.The device C converts the input cell VPI value to “003h”. The device D converts the input VPI value of the cell from "004h" to "005h" and transfers it. At the time of this transfer, the contents described in the information area of this cell are transferred. Is set for each device.
This setting information can be information for setting the inside (or outside) of the segment corresponding to the VP.

Further, as this setting information, when a transmission line failure occurs, a setting is made in the information area (ATM cell) of whether or not to perform the alarm transfer of the segment VP-AIS cell in the VP accommodated in the transmission line. The cell described in the (payload portion after the header) is inserted from the network management device 1 into the device A. In this case, the cell in which the alarm transfer setting information of the segment VP-AIS cell inserted into the device A is set flows from the device A to the device D while being VP-converted by each transmission device. Each transmission device has a function of detecting the cell, and when the cell is detected by a certain VP,
The segment VP-A described in the information area of the cell
According to the information on the alarm cell transfer setting of the IS cell, when a transmission line failure occurs, the segment V goes downstream of the transmission line.
Processing for transferring or not transferring the P-AIS cell is performed.

FIG. 5 shows the configuration of an embodiment of the transmission apparatus. In FIG. 5, 30 is a header detection circuit, 31 is an information area match comparison circuit, 32 is a RAM control circuit, 33 is a segment VP-AIS cell alarm transfer setting memory (configured with RAM).
It is. Each transmission device has a cell detection block in which alarm transfer setting information of a segment VP-AIS cell is described in an information area, and a management block for managing the information for each VPI.

First, when the header detection circuit 30 detects a match by comparing the VCI value of the arriving cell with "0003h" which is a value representing the OAM cell of the VP segment, the cell is identified as the OAM cell of the VP segment. . Also, a part or all of the information area (payload part) of the OAM cell is defined so that the cell can be distinguished from the segment VP-AIS cell for alarm transfer setting, and the arrival cell matches the pattern. Whether to perform the comparison is performed in the information area match comparison circuit 31.

When the arriving cell is a VP segment type OAM
If the cell is identified as a cell for alarm transfer setting of a segment VP-AIS cell, the RAM control circuit 32
Stores alarm setting information in each segment VP-AIS cell alarm transfer setting memory 3 for each VPI value of an arrival cell.
3 and the segment VP-AIS for each VPI
Manages cell alarm forwarding settings.

For example, if the information of the alarm transfer setting of the segment VP-AIS cell is defined as "1", alarm transfer is performed (in the segment), and if "0", alarm transfer is not performed (out of the segment), VPI of the arrival cell is "0"
02h "and a cell for alarm transfer setting of the segment VP-AIS cell, and if the alarm transfer setting of the segment VP-AIS cell is" alarm transfer ", VPI =" 00 "
"1" is written to the RAM data of the segment VP-AIS cell alarm transfer setting memory 33 corresponding to "2h".

FIG. 6 shows a segment V in the transmission apparatus.
This is a configuration for generating a P-AIS cell. 6, reference numeral 33 denotes a segment VP-AIS cell alarm transfer setting memory, similarly to FIG.
Denotes a segment VP-AIS cell generator, 36 denotes an idle cell detector, and 37 denotes a selector (denoted by SEL).

In the transmission line of this transmission device, a transmission line failure (LOS: Loss Of Signal or LOF: Loss Of Fr)
ame, etc.), the transmission path failure detection unit 34 sends a segment VP-
The AIS cell generator 35 is notified that a transmission line failure has occurred. The segment VP-AIS generator 35 uses the notification of the occurrence of the transmission line failure as a trigger to
Start generating one segment VP-AIS cell per second for P. At this time, the segment VP-AIS cell generator 35 generates the segment VP-AIS of the corresponding VPI.
The information in the cell alarm transfer memory is read out, and if the alarm transfer setting is “generate”, the segment VP−
When an idle cell (empty cell) is detected by the idle cell detector 36 from the main signal, an output for controlling the insertion of the selector 37 to generate the AIS cell at that timing is generated. If the alarm transfer setting is “Not generated”,
Without inserting a segment VP-AIS cell, the next VPI
Move on to processing. This processing is performed from VPI = 0 to 40 per second.
By performing the processing up to 95, the alarm transfer processing of the segment VP-AIS cell is performed.

FIG. 7 shows an example of the format of a VP segment type OAM cell which carries setting information for alarm transfer of a VP-AIS cell. This configuration conforms to ITU-T Recommendation I. Activation / Deactivation according to 610
ivation) using cells.

As shown in FIG. 7, in the header area from the first byte to the fifth byte, the VPI is the VPI value of the target VP (“001h” in the example of FIG. 3), as in FIG.
In the VCI, a value indicating that the cell is an OAM cell of a VP segment (“0003h”), the PTI is “000b”, and the CLP
Is “0b”.

The information area from the 6th byte to the 53rd byte of the cell in FIG. 7 is as follows. The first half of the sixth byte is a code value indicating the type of the OAM cell. The OAM type is set to “1000b” indicating a start / stop cell. 6
The 4-bit Function Type in the second half of the byte is an undefined value, for example, "1000
b ”. Message ID of the 7th byte
Is "000001b" (activate) in the case of "alarm transfer" in the alarm transfer setting of the segment VP-AIS. The two bits next to the message ID are set to “00b” because they are not used. Since the 9th byte is not used, "00"
Since the 10th to 51st bytes are unused, the upper 6 bits of the 52nd byte are “000000b”, the lower 2 bits and the 8th of the 53rd byte.
The bits are combined with an error detection code (EDC: Error Detect
ion Code). An error is detected by performing an operation using the error detection code. A 4-bit Function
The Code value of Type is currently in ITU-T Recommendation I. 610
It is sufficient to define a value other than that defined in
000b ".

[0038]

According to the present invention, for a given VP path, V
When a P segment is set, the segment VP- is shifted from the generation point of the VP segment to the inside of the VP segment.
By flowing the cell in which the alarm transfer setting information of the AIS cell is described, the information of the alarm transfer of the segment VP-AIS cell can be transferred to each device in the VP segment. Simplifies the configuration of generating.

In the VP of each device, the segment V
Since it is not necessary for the network administrator to directly manage the setting information of the alarm transfer of the P-AIS cell, the load of the network management can be reduced.

Further, as a cell for setting the alarm transfer of the segment VP-AIS cell, the ITU-T Recommendation I.T. 6
10 is defined. VP segment type OAM
By using the cell, the cell inserted from the generation point of a certain VP segment is discarded at the end point of the VP segment, so that the setting of the alarm transfer of the segment VP-AIS cell is performed only within the VP segment. It can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a principle configuration of the present invention.

FIG. 2 is an explanatory diagram of setting of a start point and an end point of a VP segment.

FIG. 3 is a configuration diagram of transmission of an OAM cell of a VP segment.

FIG. 4 is a diagram showing a full format of an OAM cell of a VP segment.

FIG. 5 is a diagram illustrating a configuration of an embodiment of a transmission device.

FIG. 6 is a diagram showing a configuration for generating a segment VP-AIS in a transmission device.

FIG. 7 is a diagram showing an example of a format of a VP segment type OAM cell in which setting information of alarm transfer of a VP-AIS cell is mounted.

FIG. 8 shows physical layer and AT for hierarchical levels of OAM.
FIG. 4 is a diagram illustrating a relationship between M layers.

FIG. 9 is a diagram illustrating an example of a segment configuration.

FIG. 10 is a diagram showing VCI values used for user cells at the F4 level (VP).

FIG. 11 is a diagram showing a PTI value used for a user cell at an F5 level (VC).

FIG. 12 is a diagram illustrating an example of a configuration of an OAM flow.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Network management apparatus 1a Segment end setting part 1b In-segment specific cell generation part 2-0-0-n ATM transmission device 2a Start end setting part 2b Termination setting part 2c Specific cell detection segment setting part 3 Transmission line 4 Specific cell

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshiaki Watanabe 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yuji Takizawa 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Co., Ltd. (72) Inventor Masami Yokoyama 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Inside Fujitsu Co., Ltd. No. 1 Inside Fujitsu Limited (72) Hiroshi Ota 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (72) Ryoichi Iwase 3-2-1 Nishi Shinjuku, Shinjuku-ku, Tokyo No. Nippon Telegraph and Telephone Co., Ltd. (72) Inventor Yoshihiko Uematsu Nippon Telegraph and Telephone Co., Ltd.

Claims (7)

[Claims] 1. ITU-T Recommendation I. In an ATM alarm processing system that uses a segment VP-AIS cell conforming to 610 to manage failures in a VP segment of an ATM network, a network management device sends a VPI target to a transmission device in the network. A specific cell containing a value and setting information on whether or not to transfer the segment VP-AIS cell in the information area is input to the transmission device constituting the VP segment, and each transmission device constituting the VP segment is The ATM alarm processing method, wherein when the specific cell is detected, the setting information in the information area is stored, and the specific cell is sequentially transferred to a subsequent transmission device until reaching the end of the segment. 2. The method according to claim 1, wherein the segment VP
-The specific cell in which the setting information for AIS cell transfer is stored is:
An ATM alarm processing method, which is a VP segment type OAM cell in which a specific value is set in a VCI of a header. 3. The network management device according to claim 1, wherein the network management device sets each transmission device corresponding to a start point and an end point of the VP segment when setting the VP segment in the network. The above-mentioned VP segment type OAM cell is supplied to a transmission device at a start point of the VP segment, sequentially transferred, and discarded by a transmission device at an end point of the VP segment.
M alarm processing method. 4. An OAM cell of the VP segment according to claim 2, wherein defined specific information indicating that the OAM cell is a cell for setting information of segment VP-AIS cell transfer is set in a part of an information area, Each of the transmission devices has the V
A header detection circuit for detecting a P-segment type OAM cell; and an information area match comparison circuit for detecting the specific information. An ATM alarm processing method, wherein a set value corresponding to a VP is stored in an alarm transfer setting memory provided in the transmission device. 5. The transmission device according to claim 4, wherein:
Segment V activated by notification signal of transmission line failure state
A P-AIS cell generator, wherein the segment VP-A
The IS cell generation unit reads the setting information from the alarm transfer setting memory corresponding to each VP, and generates an segment VP-AIS cell when an instruction for alarm transfer is set, and generates an idle in the main signal on the transmission path. An ATM alarm processing method wherein a cell is inserted into a detected slot and transferred. 6. The segment VP according to claim 2, wherein
-As a VP segment type OAM cell that stores setting information for AIS cell transfer, the ITU-T Recommendation I.T. 61
An ATM alarm processing method characterized in that setting of forwarding and non-forwarding of an alarm is performed using an activation (activation) / deactivation (deactivation) cell conforming to 0. 7. The ATM alarm processing method according to claim 1, wherein the VP (virtual path) is replaced with a VC (virtual channel) and an alarm transfer is performed for a segment of the VC.