This standard specifies the frame structure of synchronous digital hierarchy (SDH) signals at the network node interface (NNI). This standard applies to public telecommunication networks and private networks of SDH, including optical fiber digital line systems, digital wireless systems, digital cross-connection equipment, etc. with SDH optical (or electrical) interfaces. GB/T 15409-1994 Frame structure of synchronous digital hierarchy signals GB/T15409-1994 Standard download decompression password: www.bzxz.net

UDC621.391
National Standard of the People's Republic of China
GB/T15409—94
Frame structure for synchronous digital hierarchy signal
Frame structure for synchronous digital hierarchy signalPublished on 1994-12-28
State Administration of Technical Supervision
Implementation on 1995-08-01
National Standard of the People's Republic of China
Frame structure for synchronous digital hierarchy signal
Frame structure for synchronous digital hierarchy signalGB/T15409—94
This standard is formulated with reference to the relevant contents of the International Telegraph and Telephone Consultative Committee (CCITT) Recommendation G.708. 1 Subject content and scope of application
This standard specifies the frame structure of synchronous digital hierarchy (SDH) signals at the network node interface (NNI). This standard applies to public telecommunication networks and private networks of SDH, including optical cable digital line systems, digital wireless systems, digital cross-connection equipment, etc. with SDH optical (or electrical) interfaces. 2 Terminology
2.1 Pointer (PTR: Pointer)
Used to specify the frame offset of the virtual container relative to the frame reference point of the transmission entity that supports it. 2.2 Section Overhead (SOH: Section Overhead) refers to the part of the network node interface data stream after deducting the information payload and management unit pointer, including frame positioning and operation, management and maintenance information.
2.3 Administrative Unit (AU: Administrative Unit) The administrative unit is an information structure that provides adaptation between the high-order path layer and the multiplex section layer. It consists of information payload (high-order virtual container) and management unit pointer.
2.4 SDH Multiplexer Section (SDH Multiplexer Section) The SDH multiplex section consists of two adjacent multiplex terminals and the transmission media and related equipment (including regenerators) between them. 3 Frame structure of synchronous digital system signal
Synchronous digital system signals are divided into synchronous transport module (STM-N) signals of different orders, where N is a positive integer. Currently, N can only be 1, 4, and 16. The bit rate of the basic module STM-1 signal is 155520 kbit/s, and the bit rate of the STM-N signal is N times the bit rate of the basic module STM-1 signal.
3.1STM-N frame structure
The STM-N frame structure is shown in Figure 1. The STM-N frame consists of three main areas, which are the segment overhead (SOH);
Administrative unit pointer (AUPTR):
Payload.
3.2 STM-1, STM-4, STM-16 frame section overhead (SOH) arrangement State Technical Supervision Bureau 1994-12-28 approved 1995-08-01 implementation
9N to (school section)
Segment opening error
Management unit pointer
(AUPTR)
Segment unlocking
GB/T15409-94
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STM-N net load
(Paykd)
STM-N frame structure
The arrangement of various SOH in STM-1, STM-4, STM-16 frames is shown in Figure 2, Figure 3, and Figure 4 respectively. Baobu bzxz.net
Yingyi unit pointer
\ RSOH
Legend: × is a byte reserved for domestic use
*Unscrambled byte
is a byte related to the transmission medium
All unmarked bytes are to be determined by future international standards (media-related applications, additional domestic use and other purposes)
Figure 2STM-1SOH
GB/T15409—94
56 bytes
Mangli single-heart fingerprint
2222222221222222222.222225
Figure Note: × is reserved for domestic use
* Unscrambled byte
All unmarked bytes are to be determined by future international standards (media-related applications, additional domestic use and other purposes)Z. To be determined by future international standards
Figure 3STM-4SOH
144
Legend: × is reserved for domestic use
* Unscrambled byte
All unmarked bytes are to be determined by future international standards (media-related applications, additional domestic use and other purposes)Z. To be determined by future international standards
Figure 4STM-16SOH
3.3SOH byte description
Determine the byte: A1, A2
At:11110110;
A2:00101000.
b. Regeneration section trace byte: Jo
GB/T15409—94
In STM-N, J is located at S(1,7,1). The byte is used for the regeneration section trace, and its content is subject to future international standard determination. When used to cross the network boundary, its content must be agreed upon by both parties. The definition and use of the bytes located from S(1,7,2) to S(1,7,N) are subject to future international standard determination.
c. Data communication channel (DCC) bytes: Di~D12DCC is used to form the transmission channel of the SDH management network. Among them: Di, Dz and D, the 192kbit/s channel is used as the DCC of the regeneration section; the 576kbit/s channel of DD12 bytes is used as the DCC of the multiplexing section. d Public liaison bytes: E1, E2
E1 is used as the public liaison of the regeneration section.
E2 is used as the public liaison of the multiplexing section.
User channel byte: F1
This byte is reserved for the user (usually the network provider) to provide a temporary data/voice channel connection for special maintenance purposes. f.BIP-8 byte: B
Used for error monitoring of the regeneration section, this is an 8-bit code (BIP-8) with even parity. The BIP-8 code is obtained by calculating all bits after the scrambling of the previous STM frame and placed in the B position before the scrambling.
BIP-NX24 byte B2
B, byte is used for error monitoring of a multiplex section (for N-1, that is, STM-1, Bz has three bytes, a total of 24 bits). It is a NX24 code with even parity. The generation method is similar to the BIP-8 code. This code calculates all bits of the previous STM-N except the regeneration section overhead (RSOH) and is placed in the B2 byte position before the scrambling. h. Automatic Protection Switching (APS) Channel Bytes: Ki, K2 These two bytes are used as automatic protection switching instructions. i. Synchronization Status Byte S, (bs~ba)
Bits 5 to 8 of the S1 byte are used to transmit synchronization status information. Table 1 shows its bit arrangement. j. Segment Far-End Error Block (FEBE) Byte: M This byte is used as multiplex section FEBE. For STM-1 to STM-16, this byte is used to transmit the number of error blocks detected by BIP-NX24 (B2 byte).
k. Spare Bytes: Z, Z2
The functions arranged by these bytes are yet to be defined. Table 1
SOHSi byte bit 5 to bit 8
SDH synchronization quality level type
Quality unknown (existing synchronization network)
Reference clock
Transfer station slave clock
Local station slave clock
SOHSi byte bit 5 to bit 8
Additional instructions:
GB/T15409—94
Continued Table 1
This standard is proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard is drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Yinghao and Wei Leping. SDH synchronization quality level type
Synchronous equipment timing source
Not used for clock synchronization
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