KR20000025600A - Method for designating signal label discriminating between ds-3 signal and ds3e in synchronous digital hierarchy transmission system - Google Patents

Abstract

PURPOSE: A method for designating a signal label in a synchronous digital hierarchy transmission system is to confirm a content of C2 byte and automatically discriminate between DS-3 signal and DS3E signal. CONSTITUTION: A method for designating a signal label comprises the steps of: when a multiplexing signal to be transmitted by a transmission side is DS-3 signal, allotting a first byte value to C2 byte of a high leveled POH(Path Overhead), when the multiplexing signal is DS3E signal, allotting a predetermined a second byte value to C2 byte, and transmitting the allotted signals; detecting C2 byte of the high leveled POH from synchronous multiplexing bit stream received at a received side; and determining that the multiplexing signal is DS-3 multiplexing signal when the detected C2 byte is the first byte value and that the multiplexing signal is DS3E multiplexing signal when the detected C2 byte is the second byte value.

Description

METHOD FOR SETTING SIGNAL LABEL TO DISCRIMINATE DS-3 SIGNAL AND DS-3E SIGNAL IN Synchronous Digital Hierarchy TRANSMISSION SYSTEM

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous digital hierarchy (SDH) transmission apparatus, and in particular, differs between a DS-3 (44.736 Mbps) signal and a DS-3E (34.368 Mbps) signal at a transmitter of a synchronous digital hierarchy (SDH) device. The present invention relates to a method of setting a signal label that inserts an identifier into a C2 byte of a high path overhead to automatically distinguish a DS-3 signal and a DS3E signal from a receiver of a synchronous digital hierarchy (SDH) transmission system.

In general, in the synchronous digital hierarchy (SDH) transmission system, as shown in FIG. 1, the mapping process of the existing DS-3 signal is made of the VC-3 signal, and then the AU-3 signal is converted into the management unit group (AUG) signal. It is made and transmitted as STM-n signal. In the case of DS-3E signal, it is converted into VC-3 signal and then made into AU-4 signal through TU-3 and TUG-3, and then transmitted as STM-n signal. The STM-n signal is composed of optical communication signals such as STM-1 (155 Mbps), STM-4 (622 Mbps), and STM-16 (2.5 Gbps) depending on the optical station.

On the sender side, when transmitting various pleiochronous digital hierarchy (PDH) signals, the signal is labeled with a C2 byte hexacode (Hex Code) within the VC-3's path overhead (POH), depending on the signal type. Insert it and send it.

However, in the prior art, the DS-3 signal is always multiplexed only in the AU-3 direction, and the DS-3E is multiplexed only through the TU-3 to the AU-4, so there is no problem in signal separation.

However, when the DS-3E signal is mapped through the AU-3 path and the DS-3 signal is mapped through the AU-4 path, the DS-3 signal is the DS-3E path because the C2 value is the same as '04H' at the receiver. In the event of a signal, mismatch information cannot be generated, and out of frame (LOF) or loss of frame (LOF) is lost in a Plesiochronous Digital Hierarchy (PDH) device. It is difficult to determine where the problem occurred because only a frame) is detected, and C2 mismatch information cannot be generated even when the DS-3E signal is mapped to AU-3 and follows the DS-3 path. There is a problem.

Accordingly, the present invention has been proposed to solve the above problems, and an object of the present invention is to automatically distinguish two signals in a synchronous digital hierarchy (SDH) transmission apparatus that simultaneously processes a DS-3 signal and a DS-3E signal. Even if the operator does not know the contents of the mapped signal, it provides a signal label setting method for distinguishing the DS-3 signal from the DS-3E signal by checking the contents of the C2 byte.

In order to achieve the above object, the present invention provides a Synchronous Digital Hierarchy (SDH) transmission system, wherein if the multiplexed signal to be transmitted by the transmitting side is DS3, the predetermined first byte value is C2 bytes of the high path overhead. Assigning a second byte value to C2 bytes if the DS3E is transmitted; Detecting C2 bytes of the high path overhead in the synchronous multiplexed bitstream received at the receiving side; And determining that the detected C2 byte is a DS3 multiplexed signal when the detected C2 byte is the first byte value and a DS3E multiplexed signal when the C2 byte is the second byte value.

1 is a block diagram showing a multiplexing structure of a network-node interface of a synchronous digital hierarchy (SDH) recommended in ITU-T G.707;

FIG. 2 illustrates a multiplexing process of T1 (DS1) / C-11 / TU-11 / TUG2 / VC-3 / AU-3 / AUG / STM-1 as an embodiment for explaining the synchronous multiplexing structure of FIG. Conceptual Concept,

3 shows the format of the high path overhead in synchronous digital hierarchy;

4 is a table defining C2 bytes of high path overhead according to the present invention.

* Explanation of symbols for main parts of the drawings

SDH: Synchronous Digital Hierarchy

C: Container VC: Virtual Container

TU: Tributary Unit

TUG: Tributary Unit Group

AU: Administration Unit

AUG: Administration Unit Group

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the synchronous multiplexing hierarchy to which the present invention is applied will be described.

1 is a diagram illustrating a multiplexing structure of a network node interface of a synchronous digital hierarchy (SDH) recommended in ITU-T G.707.

ITU-T recommended synchronous transport multiplex structure (C: Container), virtual container (VC: Virtual Container), Tributary Unit (TU), Tributary Unit Group (TUG) This section describes the basic concepts of an administrative unit (AU) and an administrative unit group (AUG).

The container (C: Container) receives the pseudo-synchronous frame data and changes it into a shape of standardized communication data.

The virtual container (VC) adds path overhead (POH: Path OverHead) for maintenance and monitoring control to standardized communication data, that is, a container.

The tributary unit (TU) includes a function of notifying the virtual container VC of a start position of data and a function of compensating for data loss due to a clock difference between communication devices.

The Tributary Unit Group (TUG) represents a bundle of the Subordinate Signal Units (TUs), which are simply groups of Subordinate Signal Units.

The management unit (AU) has a function of notifying the virtual container VC of a start position of data and a function of compensating for data loss due to a clock difference between communication devices.

The Management Unit Group (AUG) represents a bundle of management units that simply group the management units (AU).

The selection of the synchronous multi-structure path is chosen on a case by country basis, and as a first step in the synchronous multiplexing structure, each digital level signal is mapped to a corresponding container (C).

The container C serves as a boundary between the sync frame and the pseudo sync frame, and receives the pseudo sync frame data and fills it into a standard sync frame. Adding a path overhead POH to the container C results in a virtual container VC and adding a pointer to it results in the dependent signal unit TU or the management unit AU. In this case, when directly mapped to STM-N without going through another virtual container (VC) as in the case of VC-4 or VC-3, it becomes the management unit (AU) and passes through another virtual container (VC). The dependent signal unit (TU).

In the TU-11 and the TU-12, several subordinate signal units (TUs) are grouped into multiplexed VC-3 and VC-4 in the form of a tributary unit group. TU-2 is considered equivalent to TUG-2 and TU-3 is considered equivalent to TUG-3. In the AU-3, three of the management units (AU) are grouped and multiplexed into the management unit group (AUG). Multiplexing the n (n = 1, 4, 16, ..) management unit groups (AUGs) and attaching a section overhead (SOH: Section Overhead) results in an STM-n signal.

For example, the process of synchronous multiplexing as shown in FIG. 2 shows the multiplexing process of T1 (DS1) / C-11 / TU-11 / TUG2 / VC-3 / AU-3 / AUG / STM-1. Can be.

Referring to FIG. 2, a path overhead (POH) is divided into a lower path overhead added at the VC1 level and a higher path overhead added at the VC3 level. The higher path overhead is shown in FIG. Path overhead attached to the virtual box, VC-3 and VC-4, located in the first column of VC-3 or VC-4, consisting of J1, B3, C2, G1, F2, H4, F3, K3, N1 do. Here, 'J1' is a channel for continuously tracking the connection status of the path, 'B3' is a bit shift even check byte for path error monitoring, and 'C2' is the configuration of VC-3 / VC-4. Signal sign to indicate. 'F2' and 'F3' are used for communication between path devices, and 'G1' is a channel for informing the VC-3 / VC-4 sender of the path status and performance at the VC-3 / VC-4 receiver. , 'H4' is used for multi-frame display of the configuration payloads. 'K3' is a reserved byte for future use, and 'N1' is a byte for monitoring the tandem connection. The low path overhead is a path overhead (POH) attached to the low virtual box, VC-1 and VC-2, and is denoted as 'V5' as the first byte of VC-11, VC-12 and VC-2. It consists of BIP-2, REI, RFI, Signal Level, and RDI.

FIG. 4 is a table showing definitions of C2 bytes of high path overhead (POH) in ITU-T G.707 SDH according to the present invention, wherein "24H" for DS3E signal and "34H" for DS3 signal. Use hex code.

In a conventional transmission system, when mapping a signal of 34.736 Mbps (DS3E) to a synchronous digital hierarchy (SDH) signal, referring to FIG. 1, C-3-> VC-3-> TU-3-> TUG-3-> AU4 path only, no device through AU-3 path.

In addition, no devices are mapped along the 44.736 Mbps (DS3) C-3-> VC-3-> AU-3 path and along the AU-4 path.

However, in a device that processes AU-3 and AU-4 signals at the same time, when the DS3E and DS-3 signals are mixed and processed, both signals have a C2 value of '04H'. Signal level mismatch information cannot be generated.

Accordingly, the present invention defines and uses C2 bytes not used to be applied to the new transmission apparatus without affecting the existing transmission signal processing scheme as shown in FIG. 4 in order to compensate for the signal level mismatch. That is, in case of DS3E (34.768 Mbps) signal, C2 byte value is assigned as '24H', and in case of DS3 (44.736 Mbps), it is assigned as '34H' and transmitted, the receiving side detects C2 byte of high path overhead. The values are classified into DS3E and DS3.

As described above, in the synchronous digital hierarchy (SDH) transmission system according to the present invention, since the signal label is differently displayed to distinguish the DS-3 signal and the DS3E signal, the receiving unit can automatically distinguish the signal from the mapping path. Regardless of whether the signal is mapped by the operator, the signal can be automatically distinguished by reading C2 bytes. In addition, DS-3 and DS-3E signals can be mixed and transmitted without distinguishing between AU-3 and AU-4, thereby improving network configuration efficiency.

Claims (1)

In a Synchronous Digital Hierarchy (SDH) transmission system, if the multiplexed signal to be transmitted by the transmitting side is DS3, a predetermined first byte value is allocated to C2 bytes of high path overhead, and if it is DS3E, a predetermined second byte value. Assigning to C2 bytes and then transmitting; Detecting C2 bytes of the high path overhead in the synchronous multiplexed bitstream received at the receiving side; And And determining the DS3 multiplexed signal if the detected C2 byte is the first byte value and the DS3E multiplexed signal if the C2 byte is the second byte value. Signal label setting method to distinguish 3 signals from DS3E signal.