JP3493139B2 - ATM alarm processing method - Google Patents

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 by using a segment VP-AIS cell conforming to 610.

In an ATM network, there is a device that manages the entire network, and the management device directly makes various settings to all devices in the network, for example, each connection point is a virtual path VP (or virtual channel VC) connection. Within the segment of the throat segment, or at the beginning,
Although it has been set whether or not it is the termination, it is required to improve it because it takes time and time to make such a setting for all devices of the network.

[0003]

2. Description of the Related Art I.T. 610 is "B-IS
DN OPERATION AND MAINTANANCE PRINCEPLES AND FUNCTI
ONS ”, which states that OAM (0perat
The relationship between the physical layer and the ATM layer with respect to the hierarchical level of (ion And Maintenance: operation / maintenance) is as shown in FIG. That is, the physical layer is F1 (regenerator section level), F2 (digital section level).
Level), F3 (Transmission pass level)
The ATM layer is divided into two levels of F4 (virtual path level: VP) and F5 (virtual channel level: VC), and the terminal layer (end point) corresponding to each level is provided and supported. It has a connection point of a level.

FIG. 9 shows an example of the segment structure. Are two VC (Virtual Channel) switches 1,
This is a configuration in which a VP cross-connect (called a VPC) is provided between two (VCswitch1, VCswitch2). In this example, a VCC (VC Connection) is provided between the inner ends of the two VC switches 1 and 2.
Segments are provided, and VPC (VP Connection) segments are provided between both ends of the VP cross connect VPC.

FIG. 9B. Are two VP cross-connects 1, 2 (VPcross-connect 1, VPcross-connect
2) A VPC segment A is provided between the ends on the outer side, and the right end of the VP cross connect 2 (VP cross-connect 2) and the VP cross connect 3 (VP cross-connec).
The VPC segment B is provided between the terminals on the left side of t 3), and the VPC segment C is set between the left end of the VP cross connect 3 (VP cross-connect 3) and the VC switch (VCswitch).

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

FIG. 12 shows an example of the flow configuration of OAM.
For the arrangement for transmission shown at the top, the physical layer (F
1, each section of F2 level and transmission path of F3 level are configured) and ATM layer is configured. In this example, the F4 level VPC-OAM is
Flows to PI1, VPI2, VPI3, and V indicating P5 level by PTI (payload type identifier)
CC-OAM cells VCI1 and VCI2 flow.

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

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

A conventional ATM transmission device has a management device for managing the entire network, and various settings are directly made 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). In case of not performing transfer or transfer, it must be set for each VP of all devices in the network whether it is inside the segment or outside the segment (or whether it is the generation point of the segment VP-AIS cell). There wasn't. Note that the VP segment can be set by the network administrator, and may be divided with the user, further divided into optical fiber units, or divided into certain transmission devices (devices including cross-connects, switching units, etc.). is there. Within such a segment, segment OAM cells are generated and processed within the segment, and such cells are discarded at the end of the segment.

[0011]

As mentioned above, the VP
The management of the start point, the end point, and setting (registration) of whether the segment is within the VP segment or outside the VP segment is performed by each VP (virtual
I had to do it every pass). 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 managing the network becomes a burden when the network becomes large in scale.

Further, when a VP segment is set for a certain VP path (or when the VP segment is released), the setting of whether inside the VP segment or outside the VP segment is performed from the end of the network to the end of the VP path of each device. Since it has to be set as management information, when the number of devices through which a certain VP path passes increases, it is necessary to set it for all the devices through which it passes. Therefore, there is a problem that the setting itself becomes a great deal of work and a heavy burden.

Incidentally, the above-mentioned problem regarding the segment of the VP path similarly occurs in the segment of the channel of the VC (virtual channel) (VC segment).

According to the present invention, the inside or outside of the VP segment can be easily set corresponding to each VP of each transmission device, and the setting for transferring the failure 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 realized. In addition, the present invention is V
Another object is to be able 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 an intra-segment setting specific cell generation unit, 2-0 to 2- (n-1) are n ATM transmission devices, 2a is a start end setting unit, Reference numeral 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, from the network management device 1, the transmission device 2-0 at the beginning of the segment and the transmission device 2 at the end of the segment
Information for setting the start and end of the VP segment is supplied to (n-1). By this,
Start end setting portion 2a of the transmission device 2-0 and 2- (n-1), final
A segment start end and a segment end are set in the end setting unit 2b corresponding to the VP. Further, when the intra-segment setting specific cell 4 is input from the network management device 1 to the intra-segment setting specific cell generation unit lb to the transmission device 2-0 which is the beginning of the segment, the transmission device 2-0
Is transmitted to the transmission device 2-1 via the transmission line, is sequentially transmitted in the segment, and the transmission device 2- (n-
1), where specific cells are discarded.

When this specific cell passes, each transmission device 2
-1, 2-2, ... 2- (n-1) is set as being in the segment for each VPI stored in the information field of the specific cell. After the segment attached to the VP is set in this way, when a fault occurs in the VP in the segment, a segment VP-AIS cell for notifying that the VP has a fault is generated. in this case,
The segment VP-AIS cell is sequentially transmitted to each transmission device at the rear side, and it is notified that the VP set in each transmission device is a failure, and the transmission device at the end of the segment 2-
(N-1) are sent, and this segment VP-AIS cell is discarded at the end.

In this description, an example of a VP segment is shown, but for a VC segment, the start and end of a VC segment can be set and the inside of the segment can be set according to the same principle.

[0019]

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 configuration example shown in FIG. 2, devices A to E are used.
Configure one VP segment, and the network management device 1 sends the setting information of the VP segment start point to the device A and the setting information of the VP segment end point to the device E. In this case, it is transmitted to the start and end devices corresponding to the VP value. As a result, the device A sets the information indicating the start end 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, no setting is made from the network management device 1 to the devices B to D. After setting the start point and the end point of the VP segment, an OAM cell (shown in FIG. 4 to be described later) of the VP segment in which alarm transfer setting information of the segment VP-AIS cell is described is a device which is the start point of the VP segment. Insert from A toward the inside of the VP segment. This OAM cell is transferred from the device A to the devices B to E while being VPI converted, and when it reaches the device E in which the end point of the VP segment is set, it is discarded. At the termination point of this VP segment, the function of discarding the OAM cell of the VP segment has the function of Recommendation I. This is a function defined in 610.

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

In addition, since the VP is normally set to the up and down directions in the network, the same 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. It will be.

Further, when releasing the VP segment which has already been defined in the network, the setting for stopping the alarm transfer of the segment VP-AIS cell is described before releasing the VP segment. A
A cell for setting the alarm transfer of the IS cell is inserted from the start point of the VP segment. In the configuration of FIG. 2, this cell is device A
When a transmission line failure occurs, the segment VP-AI is transferred to the segment VP of each device by the transfer from the device to the device E.
It is set not to perform the alarm transfer of the S cell. Also in this case, since this is an OAM cell of the VP segment, this cell is discarded by the device E which is the termination point of the VP segment.
Further, similarly to the above, the stop setting of the alarm transfer of the segment VP-AIS cell is also set for the reverse VP path. After setting the alarm transfer stop setting of the segment VP-AIS cell by flowing a cell in which the alarm transfer stop setting of the segment VP-AIS cell is described, the network management device instructs the device A and the device B to 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. In FIG. 3, reference numerals 1 and 2 are the same as those in FIG. 2, 1 is a network management device, 2 is an ATM transmission device, and are represented by devices A to D. In the devices A to D, which are the plurality of ATM transmission devices in FIG. 3, the device A is set in advance as the start end of the VP segment and the device E not shown in FIG. 3 is set as the end according to the configuration of FIG. It is assumed that

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

It should be noted that O for setting the VC segment
AM cells are displayed by setting PTI (Payload Type Identifier) to a specific value. In the example of FIG. 4, V
When the OAM cell of the P segment 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 VPI value of the input cell from “002h” to “003h” and transfers the device. The device C transfers the VPI value of the input cell to “003h”. To “004h” and then transferred.Device D converts the VPI value of the input cell from “004h” to “005h” and transfers the contents described in the information area of this cell. Is set for each device.
This setting information can be information for setting the inside (or outside) of the segment corresponding to the VP.

As the setting information, when a transmission line failure occurs, the VP accommodated in the transmission line sets whether the alarm transfer of the segment VP-AIS cell is performed or not. The cell described in the payload portion after the header of is inserted into the device A from the network management device 1. In that case, the cell having the alarm transfer setting information of the segment VP-AIS cell inserted in the device A 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,
Segment VP-A described in the information area of the cell
According to the information of the alarm transfer setting of the IS cell, when a transmission line failure occurs, the segment V is directed 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 device. In FIG. 5, 30 is a header detection circuit, 31 is an information area coincidence comparison circuit, 32 is a RAM control circuit, and 33 is a segment VP-AIS cell alarm transfer setting memory (composed of RAM).
Is. Each transmission device has a cell detection block in which the alarm transfer setting information of the segment VP-AIS cell is described in the information area, and a management block for managing the information for each VPI.

First, in the header detection circuit 30, when the VCI value of the arriving cell is compared with "0003h" which is a value representing the OAM cell of the VP segment and a match is detected, the cell is identified as the OAM cell of the VP segment. . Further, a part or all of the information area (payload section) of the OAM cell is defined in advance so that it can be distinguished from the cell for alarm transfer setting of the segment VP-AIS cell, and the arrival cell matches the pattern. The information area coincidence comparison circuit 31 compares whether or not to perform.

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

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

Next, FIG. 6 shows a segment V in the transmission device.
This is a configuration for generating a P-AIS cell. 6, 33 is a segment VP-AIS cell alarm transfer setting memory, 34 is a transmission line failure detection unit, and 35 is the same as in FIG.
Is a segment VP-AIS cell generation unit, 36 is an idle cell detection unit, and 37 is 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.) occurs, the transmission line failure state notification signal causes the transmission line failure detection unit 34 to send the segment VP-
The AIS cell generation unit 35 is notified that a transmission line failure has occurred. The segment VP-AIS generation unit 35 uses the notification of the occurrence of the transmission line failure as a trigger for each V
Start generating one segment VP-AIS cell per second for P. At this time, the segment VP-AIS cell generation unit 35 determines that the segment VP-AIS of the corresponding VPI.
When the information in the cell alarm transfer memory is read and the alarm transfer setting is "create", the segment VP- of that VPI is read.
When the idle cell detector 36 detects an idle cell (empty cell) from the main signal of the AIS cell, an output for inserting and controlling the selector 37 to generate the AIS cell is generated at that timing. If the alarm transfer setting is "not generated",
The next VPI without inserting the segment VP-AIS cell
Move to processing. This processing is performed from VPI = 0 to 40 in 1 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 equipped with setting information for alarm transfer of a VP-AIS cell. This configuration is based on Recommendation ITU-T I. 610-based activation / stopping (Deact)
ivation) cell.

As shown in FIG. 7, the header area from the 1st byte to the 5th byte has the VPI value of the target VP (“001h” in the example of FIG. 3) as the VPI, as in the case of FIG.
VCI has a value (“0003h”) indicating that it is an OAM cell of the VP segment, PTI is “000b”, CLP
Is "0b".

The information area from the 6th byte to the 53rd byte of the cell of FIG. 7 is as follows. The first half of the 6th byte is a code value indicating the type of OAM cell. The OAM type is “1000b”, which represents a start / stop cell. 6
The 4-bit Function Type in the latter half of the byte is a value that is not currently defined, for example, "1000".
b ”. Message ID of the 7th byte
Is "000001b" (activate) when "Alarm transfer" is set in the alarm transfer setting of the segment VP-AIS. The two bits next to the message ID are unused and are set to "00b". Since the 9th byte is unused, "00"
Since the 10th byte to the 51st byte are unused, they are set to “6Ah.” 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 to form an error detection code (EDC).
ion code). An error is detected by performing an operation with this error detection code. A 4-bit Function
The code value of Type is currently ITU-T Recommendation I. 610
You can define a value other than the one defined in
It is not limited to 000b ″.

[0038]

According to the present invention, V for a certain VP path
When the P segment is set, the segment VP- is moved from the generation point of the VP segment toward the inside of the VP segment.
By passing 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. Therefore, the segment VP-AIS cell can be transferred. Simplifies the configuration of the generation of.

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

Further, as a cell for setting the alarm transfer of the segment VP-AIS cell, ITU-T recommendation I. 6
It is defined in 10. VP segment type OAM
By using a 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 alarm transfer setting of the segment VP-AIS cell is set only within the VP segment. It can be performed.

[Brief description of drawings]

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

FIG. 2 is an explanatory diagram of setting 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 showing a configuration of an embodiment of a transmission device.

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

FIG. 7 is a diagram showing an example of a format of a VP segment type OAM cell equipped with setting information for alarm transfer of a VP-AIS cell.

FIG. 8: Physical layer and AT for hierarchical levels of OAM
It is a figure which shows the relationship of M layer.

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

FIG. 10 is a diagram showing a value of VCI used for a user cell at an F4 level (VP).

FIG. 11 is a diagram showing PTI values used for user cells at the F5 level (VC).

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

[Explanation of symbols]

1 Network management device 1a Segment end setting part 1b Intra-segment setting specific cell generator 2-0 to 2-n ATM transmission device 2a Start point setting section 2b Termination setting section 2c Specific cell detection segment setting section 3 transmission lines 4 specific cells

Front page continuation (72) Inventor Yuji Takizawa 4-1-1 Kamitadanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (72) Inventor Masami Yokoyama 4-1-1 Kamitadanaka, Nakahara-ku, Kawasaki, Kanagawa Within Fujitsu Limited (72) Hidetoshi Ishikawa 4-1-1 Kamiotanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Within Fujitsu Limited (72) Inventor Hiroshi Ota 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Ryoichi Iwase 3-19-3 Nishishinjuku, Shinjuku-ku, Tokyo Japan Telegraph and Telephone Corporation (72) Inventor Yoshihiko Uematsu 3-192-3, Nishishinjuku, Shinjuku-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) Reference JP 10-84362 (JP, A) JP 6-69946 (JP, A) JP 10-70557 (JP, A) JP 9- 116542 (JP, A) IEICE technical report CS95-69 IEICE technical report CS91-92 (58) The field (Int.Cl. ^7, DB name) H04L 12/56 H04L 12/24 - 12/26 H04L 29/14

Claims (4)

(57) [Claims] 1. A recommendation of I T U-T I. In the ATM alarm processing method for managing the failure in the VP segment of the ATM network by using the segment VP-AIS cell conforming to 610, it is composed of a plurality of transmission devices sequentially connected by a transmission line.
Outside the transmission device for managing the ATM network
A network management device provided in the network, and the network management device includes a plurality of network management devices in the network.
To set the VP segment formed by the transmitter
Therefore, each transmission corresponding to the start and end points of the VP segment
Information about the beginning and end of each segment for the device
Setting means and transmission device at start of VP segment
Within the VP segment by sequentially transmitting from the
Specific segment for setting in the segment to set the information indicating that
And a means for generating a connection between the transmission device at the start and the end of the VP segment.
Each transmission device that has been set the specific cell for setting in the segment
When detected, it is specified by the information area of each cell
Information that indicates that it is in a segment
An ATM alarm processing method characterized by comprising means . 2. The transmission path in the information area of the specific cell for setting in the segment according to claim 1.
The segment of the VP that is accommodated in the transmission line when a failure occurs
Set whether to perform alarm transfer of the VP-AIS cell
The information to be performed is stored, and the transmission device detects the cell.
And the alarm transfer setting of the information described in the information area of the cell.
ATM alarm processing method characterized by storing in a fixed memory . 3. The transmission device according to claim 2, wherein each transmission device is activated by a notification signal of a transmission line failure state.
A moving segment VP-AIS cell generation unit, and the segment VP-AIS cell generation unit corresponds to each VP.
Read the setting information from the corresponding alarm transfer setting memory
If an alarm transfer instruction is set, the segment V
P-AIS cells are generated and empty cells are added to the main signal on the transmission line.
ATM alarm processing method characterized by inserting in the detected slot and transferring . 4. The VP (virtual path) according to any one of claims 1 to 3,
Alarm) for the VC segment.
ATM alarm processing method characterized by sending.