JPH0723045A - Alarm display signal generating circuit - Google Patents

Abstract

PURPOSE:To constitute a VP-AIS cell generating circuit of a small hardware by rewriting an alarm cell generated with regard to all virtual paths which become an object to an identifier of a connecting destination, and rejecting an unregistered cell. CONSTITUTION:When an interface alarm S1 arrives, a virtual path alarm (VP-AIS) cell generating part 1 is actuated, and all virtual path numbers which can become objects to be informed with regard to an interface which becomes an object are generated successively, and joined with a main signal passage S5. In a virtual path identifier extracting part 2, a receiving side virtual path identifier is detected from a header of a cell of this main signal passage S5, and it is supplied as an address to a virtual path identifier conversion table 3. When a connecting destination is registered in advance in the address concerned of the conversion table 3, a virtual path identifier of its connecting destination is read out, and its header information is rewritten by a virtual path identifier converting part 4. Also, as for the identifier whose connecting destination is not registered, its cell is rejected by a cell rejecting part 5.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is used in digital communications. The present invention is applicable to asynchronous networks (ATM, Asyncrono).
It is used for us Transfer Mode) communication.
The present invention is used in an ATM exchange. The present invention relates to a virtual path / alarm cell (VP-AIS cell, Virtual Path-) generated in response to an interface alarm.
The present invention relates to a generation circuit of Alarm Indication Signal).

[0002]

2. Description of the Related Art In an ATM switch, when an interface alarm is generated due to loss of synchronization or other causes, a virtual path identifier (VPI) number for the connection destination
An alarm cell is sent out to notify that the alarm is in the faulted condition.

Conventionally, there is known a technique for notifying with an alarm signal in a synchronous network, but in a newly developed asynchronous network, a cell (virtual path / alarm cell,
VP-AIS) must be generated and notified,
The conventional technology of the synchronous network cannot be directly adopted.

In the asynchronous network, the virtual path / alarm cell is required to be generated only for the VPI number of the connection destination registered for the virtual path of the receiving side accommodated in the interface. The information of the VPI number is stored in the VP cross connect unit, and the interface unit does not have the information. Therefore, in order to generate a virtual path / alarm cell destined for only the registered VPI number of the connection destination, either the information of the VPI number accommodated in the interface part or the virtual path /
It is necessary to generate an alarm cell in the cross connect section.

[0005]

When the virtual path / alarm cell is generated in the cross-connect section, the virtual path / alarm cell generating circuits provided for each interface for a large number of interfaces are intensively provided in the cross-connect section. However, there is a drawback in that the hardware of the cross-connect part increases due to the arrangement.

On the other hand, when the information of the VPI number accommodated in the interface is provided in the interface section, the information becomes duplicated, and the operation for managing the duplicated information so that it always agrees is necessary. Become.

The present invention has been made in view of such a background, and provides a virtual path / alarm cell generation circuit which can be constructed with a small hardware and substantially without adding hardware. The purpose is to do.

[0008]

The present invention is characterized in that the information of the VPI number accommodated in the interface in the cross-connect section is used as it is. That is, the virtual path / alarm cell generation unit that sequentially generates virtual path / alarm cells for all virtual path numbers that can be notified by the interface alarm, and the reception-side virtual path identifier from the cell header generated by this generation unit. A virtual path identifier extraction unit to be extracted, a virtual path identifier conversion table in which the virtual path identifier of the connection destination registered at the address is recorded using the reception side virtual path identifier extracted by this extraction unit as a search address, and this conversion table A virtual path identifier conversion unit for rewriting the header information of the cell transmitted from the virtual path / alarm cell generation unit according to the information read from the connection destination on the conversion table generated from the virtual path / alarm cell generation unit. For cells that have unregistered virtual paths as the virtual path identifier on the receiving side, those cells are discarded. Characterized by comprising a cell discard unit for.

Further, this virtual path identifier conversion table uses a conversion table for cross-connect control, and the output cells of the virtual path / alarm cell generator are merged into the cross-connect input side main signal path.

[0010]

When the interface alarm is sent out, in principle, the main signal flowing into the cross connect disappears. At this time, virtual path / alarm cells are sequentially generated for all virtual path numbers that can be notified of the interface alarm, and these are sent to the cross-connect input side main signal path. This virtual path identifier is converted into the virtual path identifier of the connection destination by the virtual path identifier conversion table. The alarm cell of the virtual path number on the receiving side which is not registered in this conversion table may be discarded. As the virtual path identifier conversion table, a conversion table for cross-connect control can be used.

[0011]

1 is a block diagram of an apparatus according to an embodiment of the present invention. This device is an alarm display signal generating circuit that generates a virtual path alarm cell (VP-AIS cell) in response to an interface alarm, and is provided in the cross-connect section. This device includes a virtual path / alarm cell generation unit 1 for sequentially generating virtual path / alarm cells for all virtual path numbers that can be notified by an interface alarm, regardless of the presence or absence of a connection destination, and a virtual path / alarm cell generation unit 1 The virtual path identifier extraction unit 2 that extracts the reception-side virtual path identifier from the header of the cell and the reception-side virtual path identifier extracted by this extraction unit as the search address, and the virtual path identifier of the connection destination registered at that address is recorded. Virtual path identifier conversion table 3, a virtual path identifier conversion unit 4 for rewriting the header information of the cell sent from the virtual path / alarm cell generation unit 1 according to the information read from the conversion table, and the virtual path -A virtual path that is generated from the alarm cell generation unit and whose connection destination is not registered on the conversion table is set on the receiving side virtual path. The cell identifier includes a cell discard unit 5 discards the cell. The virtual path identifier conversion table 3 is a conversion table for cross-connect control, and the output cells of the virtual path / alarm cell generation unit 1 are sent out so as to be merged with the cross-connect input side main signal path (S5). .

In the device configured as described above, when the interface alarm S1 arrives, the virtual path / alarm cell generation unit 1 is activated, and all the virtual path numbers that can be notified of the interface targeted by the alarm. Are sequentially generated. This has, for example, a maximum of 256 virtual path numbers per interface, and all virtual path numbers are generated in that number order. The generation period is set separately according to the regulation of the interface, but is 1 cell per second, for example.

The main of the virtual path / alarm cell generation unit 1 merges into the main signal path S5, but when an interface alarm is generated, no cell arrives from the upstream of this path S5 in principle, so there is no problem. Absent. The virtual path identifier extraction unit 2 detects the reception side virtual path identifier from the header of the cell of the main signal path S5, and supplies this to the virtual path identifier conversion table 3 as an address. When the connection destination is registered in the address of the conversion table 3, the virtual path identifier of the connection destination is written. Therefore, the virtual path identifier is read out to the passage S3 and the virtual path identifier conversion unit 4 receives the header information. Rewrite. For an identifier whose connection destination is not registered in the address of the conversion table 3, unregistered information is sent to the passage S4, and the cell is discarded by the cell discard unit 5.

In an actual ATM switch, the conversion table for cross-connect control is used as the virtual path identifier conversion table 3 to configure the device shown in FIG. 1 in the cross-connect section. It is possible to do so without using any additional hardware by utilizing the free space of.

The device shown in FIG. 1 can be provided in the interface section. In that case, the virtual path identifier conversion table 3 can be realized by preparing a copy of the control conversion table of the cross-connect unit.

[0016]

As described above, according to the present invention, a virtual path alarm cell generation circuit can be realized with a small amount of hardware, without substantially adding hardware.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an apparatus according to an embodiment of the present invention.

[Explanation of symbols]

 1 virtual path / alarm cell generation unit 2 virtual path identifier extraction unit 3 virtual path identifier conversion table 4 virtual path identifier conversion unit 5 cell discard unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location H04L 12/26 H04Q 11/04 9076-5K H04Q 11/04 L (72) Inventor Hiromi Ueda Tokyo 1-1-6 Uchisaiwaicho, Chiyoda-ku Nihon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. An alarm display signal generating circuit for generating a virtual path / alarm cell (VP-AIS cell) in response to an interface alarm, wherein virtual path / alarms for all virtual path numbers that can be notified by the interface alarm. A virtual path / alarm cell generation unit that sequentially generates cells, a virtual path identifier extraction unit that extracts the reception side virtual path identifier from the cell header generated by this generation unit, and a reception side virtual path that is extracted by this extraction unit A virtual path identifier conversion table in which an identifier is used as a search address and a virtual path identifier of a connection destination registered in the address is recorded, and the virtual path / alarm cell generation unit transmits the virtual path / alarm cell generation unit according to the information read from the conversion table. A virtual path identifier conversion unit that rewrites cell header information, and the virtual path identifier Alarm display signal, which is provided with a cell discarding unit that discards the cell generated from the memory cell generating unit and whose connection destination on the conversion table is not registered as a virtual path identifier on the receiving side. Generator circuit. 2. The virtual path identifier conversion table is a conversion table for cross-connect control, and the output cells of the virtual path / alarm cell generation unit are merged with the main signal path on the cross-connect input side. Alarm display signal generation circuit.