02-OHCNATS02 SDH Principle ISSUE 1.00(May 7,2015)
SDH Principle www.huawei.com Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Objectives Upon completion of this course, you will be able to: Understand the basic of SDH multiplexing standard Know the features, applications and advantages of SDH based equipment Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page1 Contents 1. SDH Overview 2. Frame Structure & Multiplexing Methods 3. Overheads & Pointers Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page2 Emergence of SDH What is SDH? Synchronous Digital Hierarchy It defines a standard frame structure, a specific multiplexing method, and so on Why did SDH emerge? Need a system to process increasing amounts of information Need a new standard that allows interconnecting equipment of different suppliers Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page3 Advantages of SDH Interfaces PDH electrical interfaces Only 3 regional standards: European (2.048 Mb/s), SDH electrical interfaces SDH optical interfaces Japanese, North American (1.544 Mb/s) PDH optical interfaces Universal standards Can be connected to different vendors’ optical transmission equipments No standards, manufacturers develop at their will Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page4 Disadvantages of PDH Multiplexing methods: Level by level 140 Mb/s 140 Mb/s 34 Mb/s 34 Mb/s 8 Mb/s 8 Mb/s Multiplexers Demultiplexers 2 Mb/s Not suitable for huge-volume transmission Headache for network planners More equipment to achieve this functionality More equipment More floor space More power More costs Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page5 Advantages of SDH Multiplexing methods: byte interleaved STM-1A AA Lower rate SDH to higher rate SDH (STM-1 STM-4 STM-16 STM-64) A … STM-1B BB One Byte from STM-1 B B 4:1 STM-4 STM-1C C C --- Synchronous multiplexing method and flexible mapping structure STM-1D D D What about PDH? --- Multistage pointer to align PDH loads in SDH frame, thus, dynamic drop-and-insert capabilities Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page6 Advantages of SDH OAM function PDH SDH In the frame structure of PDH signals, there are few overhead bytes used for for OAM OAM. Weak OAM function Abundant overheads bytes Remote & Centralized Management Fast circuit provisioning from centralized point Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page7 Advantages of SDH Compatibility STM-N Transmit Receive Processing PDH SDH ATM Processing SDH Network Container Pack STM-N Ethernet Container PDH SDH Service Signal Flow Model Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page8 Unpack ATM Ethernet Comparison between SDH and PDH Low bandwidth utilization ratio In PDH, E4 signal (140Mbits/s) can contain 64 E1 signals. In SDH, STM-1 (155 Mbits/s) can only carry 63 E1 signals. Complex mechanism of pointer justification Influence of excessive use of software on system security Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page9 Contents 1. SDH Overview 2. Frame Structure & Multiplexing Methods 3. Overheads & Pointers Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page10 SDH Frame Structure From ITU-T G.707: 1. One frame lasts for 125 microseconds (8000 frames/s) 2. Rectangular block structure 9 rows and 270 columns (Basic frame: STM-1) 3. Each unit is one byte (8 bits) 4. Transmission mode: Byte by byte, row by row, from left to right, from top to bottom Frame = 125 us 1 2 3 4 5 6 7 8 9 9 rows 270 Columns Bit rate of STM-1= 9*270*8*8000 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page11 SDH Frame Structure (Cont.) Three parts: SOH AU-Pointer Information Payload Frame = 125 us 1 2 3 4 5 6 7 8 9 RSOH AU-PTR Information Payload MSOH 9 270 Columns Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page12 9 rows SDH Frame Structure (Cont.) Information Payload Also known as Virtual Container level 4 (VC-4) Used to transport low speed tributary signals Contains low rate signals and Path Overhead (POH) Location: rows #1 ~ #9, columns #10 ~ #270 LPOH, TU-PTR RSOH package HPOH 9 rows AU-PTR low rate signal Payload MSOH 9 package 1 270 Columns LPOH, TU-PTR Data package Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page13 SDH Frame Structure (Cont.) Section Overhead Functions: Fulfills the section layer OAM 1 2 3 Types of Section Overhead RSOH 1. AU-PTR 5 6 7 8 9 Information Payload MSOH 9 9 rows RSOH monitors the regenerator section 2. MSOH monitors the multiplexing section Location: 1. RSOH: rows #1 ~ #3, columns #1 ~ #9 2. MSOH: rows #5 ~ #9, columns #1 ~ #9 270 Columns Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page14 SDH Frame Structure (Cont.) AU-PTR Function: Indicates the first byte of VC4 RSOH 4 AU-PTR Information Payload Location: row #4, columns #1 ~ #9 MSOH J1 9 270 Columns Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page15 9 rows SDH Multiplexing Features SDH Multiplexing includes: Low to high rate SDH signals (STM-1 STM-N) PDH to SDH signals (2M, 34M & 140M STM-N) Other hierarchy signals to SDH Signals (IP STM-N) Some terms and definitions: Mapping Aligning Multiplexing Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page16 SDH Multiplexing Structure ×1 ×1 AU-4-64c AUG-64 ×4 ×1 AUG-16 ×1 AU-4-16c STM-16 ×4 ×1 AUG-4 ×1 AU-4-4c STM-4 STM-64 ×4 STM-1 ×1 VC-4-64c C-4-64c VC-4-16c C-4-16c VC-4-4c C-4-4c VC-4 C-4 E4 signal ×1 AUG-1 AU-4 ×3 Mapping Aligning Multiplexing Go to glossary TUG-3 ×1 TU-3 VC-3 C-3 E3 signal TU-12 VC-12 C-12 E1 signal ×7 TUG-2 ×3 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page17 From 140Mb/s to STM-N C4 VC4 1 140M Rate adaptation 1 H P O H Add HPOH Mapping 1 260 Next 9 125μs Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. 9 1 125μs Page18 261 From 140Mb/s to STM-N 10 1 AUG-1 270 STM-1 270 RSOH Add AU-PTR AU-PTR AU-4 AU-PTR Add SOH X1 Info Payload MSOH 9 Aligning Multiplexing AUG-N 1 STM-N 270N RSOH One STM-1 frame can load only one 140Mbit/s Signal AU-PTR Add SOH MSOH 9 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page19 Info Payload From 34Mb/s to STM-N C3 VC3 1 34M Rate Adaptation 1 L P O H Add LPOH Next 9 1 84 9 Mapping 125μs Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. 1 125μs Page20 85 From 34Mb/s to STM-N TUG-3 TU-3 1 H1 H2 H3 1 86 Fill gap 1st align Aligning 1 1 9 VC-4 86 H1 H2 H3 1 1 261 H P R R O H ×3 R 9 3 9 Multiplexing Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page21 Same procedure as 140M From 2Mb/s to STM-N C12 1 4 1 1 2M Rate Adaptation TU12 VC12 4 LPOH Add LPOH 1 1 4 1 LPOH Add TU-PTR Next page TU-PTR 125μs 9 9 Mapping Aligning Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page22 9 From 2Mb/s to STM-N TUG-3 TUG-2 1 86 1 12 1 1 X7 X3 R R 9 Multiplexing 9 Same procedure as 34M Multiplexing Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page23 Questions What are the main parts of SDH Frame structure? What is the transmission rate of STM-4? How to calculate it ? Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page24 Contents 1. SDH Overview 2. Frame Structure & Multiplexing Methods 3. Overheads & Pointers Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page25 Overheads Overheads Section Overhead (SOH) Regenerator Section Overhead (RSOH) Multiplex Section Overhead (MSOH) Path Overhead (POH) High Order Path Overhead (HPOH) Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page26 Low Order Path Overhead (LPOH) 1 2 3 4 5 6 7 8 9 10 1 A1 A1 A1 A2 A2 A2 J0 X X J1 2 B1 ● ● E1 ● F1 X X 3 D1 ● ● D2 ● D3 MSOH C2 AU-PTR 4 5 B2 B2 6 D4 7 B2 B3 K1 K2 D5 D6 D7 D8 D9 8 D10 D11 D12 9 S1 M1 ● Media dependent bytes (Radio-link, Satellite) X Reserved for National use Huawei propriety bytes Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. G1 F2 H4 E2 F3 V5 J2 N2 K4 K3 LPOH: VC-11/12 Page27 N1 HPOH: VC-3/4 RSOH Overheads (Cont.) A1 and A2 Bytes Framing Bytes Indicate the beginning of the STM-N frame Bytes are unscrambled A1 = f6H (11110110), A2 = 28H (00101000) STM-N: (3XN) A1 bytes, (3XN) A2 bytes STM-N STM-N STM-N STM-N STM-N Finding frame head Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page28 STM-N A1 and A2 Bytes (Cont.) Frame Find A1,A2 N Y over 625μs (5 frames) OOF over 3ms LOF Next process AIS Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page29 D1 ~ D12 Bytes Data Communications Channel (DCC) Bytes RS-DCC – D1 ~ D3 – 192 Kbit/s (3x64 Kbit/s) MS-DCC – D4 ~ D12 – 576 Kbit/s (9x64 Kbit/s) NE NE NE NE DCC channel NMT OAM Information: Operation, Administration and maintenance Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page30 E1 and E2 Bytes Orderwire Bytes E1 – RS Orderwire Byte Used between regenerators E2 – MS Orderwire Byte Used between multiplexers NE NE NE NE E1 and E2 Digital telephone channel E1-RS, E2-MS Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page31 B1 Byte Bit interleaved Parity Code (BIP-8) Byte A parity code (even parity) Used to check the transmission errors over the RS B1 BBE is represented by RS-BBE (performance event) STM-N B1 Rx Tx BIP-8 A1 A2 A3 A4 00110011 11001100 10101010 00001111 B 01011010 1#STM-N Calculate B 2#STM-N B1 = B 2#STM-N Calculate B’ Compare B’ & B RS-BBE Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page32 1#STM-N B2 Byte Bit interleaved Parity Code (MS BIP-24) Byte BIP-24 is used to check the bit errors over the MS B2 BBE is represented by MS-BBE (performance event) The working mechanism of B2 is same as B1 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page33 M1 Byte Multiplexing Section Remote Error Indication Byte A return message from Rx to Tx ,when Rx find B2 bit errors Value is the same as the count of BIP-24xN (B2) bit errors Tx generate corresponding performance event MS-FEBBE Traffic Rx Tx Generate MS-FEBBE MS-REI Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Return M1 Find B2 bit errors Generate MS-BBE Page34 K1 and K2 (b1-b5) Bytes Automatic Protection Switching (APS) bytes I I I I S S P P WTR WTR Used for network multiplexing protection switch function Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. P P Transmitting APS protocol Page35 K2 (b6 ~ b8) Byte Rx detects K2 (b6-b8) = "111“ Generate MS-AIS alarm Tx detects K2 (b6-b8) = "110" Start Generate MS-RDI alarm Detect K2 (b6-b8) 110 111 Generate MS-AIS Return MS-RDI Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page36 Generate MS-RDI S1 Byte Synchronization Status Message Byte (SSB): S1 b1 ~ b4 Value indicates the external clock ID (Extended SSM) b5 ~ b8 Value indicates the sync. Level (Standard SSM) bits 5 ~ 8 Description 0000 Quality unknown (existing sync. Network) 0010 G.811 PRC 0100 SSU-A (G.812 transit) 1000 SSU-B (G.812 local) 1011 G.813 (Sync. Equipment Timing Clock) 1111 Do not use for sync (DNU). Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page37 Path Overheads 1 2 1 2 3 4 5 6 7 8 9 3 4 5 6 7 8 9 R S O H A U–P T R M S O Higher Order Path Overhead H 10 J1 VC-n Path Trace Byte B3 Path BIP-8 C2 Path Signal Label G1 Path Status F2 Path User Channel H4 TU Multiframe Indication F3 Path User Channel K3 AP Switching N1 Network Operator Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page38 J1 Byte Path trace byte The first byte of VC-4 User-programmable (HUAWEI SBS) Detect J1 N Y Match The received J1 should match the expected J1 Next process HP-TIM Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page39 B3 Byte Path bit parity Even parity code Used to detect bit errors Mechanism is same as B1 Verify B3 N Correct Y and B2 HP-BBE Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Next process Page40 C2 Byte Detect C2 Signal label byte The received C2 should match with the expected C2 N 00H Y Specifies the mapping type in the VC-n 00 H Unequipped 02 H TUG structure 13 H ATM mapping Y Next process Match N HP-UNEQ HP-SLM Insert AIS downward Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page41 Path Overheads V5 Low Order Path Overhead Indicated by TU-PTR Error checking, Signal Label 1 4 1 V5 J2 N2 K4 and Path Status of VC-12 b1 - b2 Error Performance VC-12 VC-12 VC-12 Monitoring (BIP-2) b3 Return Error detected in VC-12 (LP-REI) b8 Return alarm detected 9 in VC-12 (LP-RDI) Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. 500μs VC-12 multi-frame Page42 VC-12 Pointers Pointers Bytes indicated Administrative Tributary Unit Pointer (AU-PTR) Unit Pointer (TU-PTR) Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. AU-PTR VC-4 J1 TU-PTR VC-3 J1 VC-12 V5 Page43 AU-PTR 1 Positive justification justification RSOH Negative 4 H1YYH2FF H3H3H3 0 --- 1--- --- --- --- --- --- --- --- --- --- 86 87 --- 88 --- --- --- --- --- --- --- --- --- 173 MSOH 9 435 --- 436 --- --- --- --- --- --- --- --- 521 1 522 --- 523 --- --- --- --- --- --- --- --- 608 RSOH 4 H1YYH2FFH3H3H3 125μs 696 --- 697 --- --- --- --- --- --- --- --- 782 0 --- 1 --- --- --- --- --- --- --- --- --- --- 86 87 --- 88 --- --- --- --- --- --- --- --- --- 173 MSOH 9 1 435 --- 436 --- --- --- --- --- --- --- --- 521 250μs 9 270 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page44 TU-PTR TU Multi-frame 500μs 4 1 1 H1 TU POINTERS H2 H3 VC3 VC- VC- VC- VC- 12 12 12 12 TU POINTERS 9 V1 Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. V2 Page45 V3 V4 Questions Which byte is used to report the MS-AIS and MS-RDI? What is the mechanism for R-LOF generation? Which byte implements the RS (MS/HP) error monitoring? Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page46 Summary SDH Overview Frame Structure & Multiplexing Methods Overheads & Pointers Copyright © 2012 Huawei Technologies Co., Ltd. All rights reserved. Page47 Thank you www.huawei.com
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