ZXWM M920 Product Description

ZXWM M920 (V4. 10) Product Description

ZXWM M920 Product Description

ZTE Confidential Proprietary 2009 ZTE Corporation. All rights reserved. I


Version Date Author Approved By Remarks

R1.0 Feb.,6,2009 Fang Huanhuan Xia Yan Not open to the Third Party

2009 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosed or used without the prior written permission of ZTE.

Due to update and improvement of ZTE products and technologies, information in this document is subjected to change without notice.


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TABLE OF CONTENTS

1 Overview ................................................................................................................ 1

2 Highlight Features ................................................................................................. 2 2.1 Large Capacity and Easy Upgrade .......................................................................... 2 2.2 Single 40Gbit/s system............................................................................................ 3 2.3 Super-long-haul Transmission ................................................................................. 3 2.4 Multi-service Access Mode ...................................................................................... 3 2.5 Flexible networking modes ...................................................................................... 4 2.6 Wavelength Add/Drop Functions ............................................................................. 4 2.7 Reliable Protection Functions .................................................................................. 4 2.8 Performance Monitoring Technologies..................................................................... 4 2.9 Power Management Technology ............................................................................. 4 2.10 Powerful NM ........................................................................................................... 5 2.11 WSON .................................................................................................................... 5

3 Functionality .......................................................................................................... 5 3.1 Functions ................................................................................................................ 6 3.1.1 Large Transmission Capacity .................................................................................. 6 3.1.2 Ultra-long-haul Distance Optical Source .................................................................. 6 3.1.3 Optical Amplifier ...................................................................................................... 7 3.1.4 Power Management ................................................................................................ 8 3.1.5 Performance Detection Function.............................................................................. 9 3.1.6 OTN Description.................................................................................................... 10 3.1.7 Dispersion Management........................................................................................ 15 3.1.8 Service Functions.................................................................................................. 15 3.1.9 Wavelength Add/Drop Function............................................................................. 16 3.1.10 Communication and Monitoring Functions ............................................................. 16 3.1.11 Alarm Input/Output Function.................................................................................. 17 3.1.12 System Level Protection........................................................................................ 17 3.1.13 Network level Protection........................................................................................ 18 3.1.14 Network management channel backup.................................................................. 21 3.1.15 Supervision Subsystem ......................................................................................... 22 3.1.16 L0/L1/L2 integrated transport technologies ............................................................ 23 3.1.17 ROADM Function .................................................................................................. 24 3.1.18 Electrical Cross-Connect Function......................................................................... 25 3.1.19 Wavelength Tuning Function ................................................................................. 26 3.2 Networking............................................................................................................ 27 3.2.1 System Applications .............................................................................................. 27 3.2.2 Networking Modes................................................................................................. 32 3.3 Transmission Codes Supported............................................................................. 34

4 System Architecture ............................................................................................ 37 4.1 Description of System Functional Platform............................................................. 37 4.1.1 Optical transfer platform ........................................................................................ 38 4.1.2 Service convergent platform .................................................................................. 38 4.1.3 OM/OD platform.................................................................................................... 39 4.1.4 Add/drop platform.................................................................................................. 39 4.1.5 Optical amplifying platform .................................................................................... 39 4.1.6 Monitoring platform................................................................................................ 39 4.2 Hardware Architecture........................................................................................... 40 4.2.1 Sub-rack ............................................................................................................... 40 4.2.2 Board Description.................................................................................................. 40


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4.3 The NM Software System Structure....................................................................... 44 4.3.1 Hierarchical structure ............................................................................................ 45 4.3.2 2Interface description......................................................................................... 46 4.4 System Configuration ............................................................................................ 47 4.4.1 Optical Terminal Multiplexer (OTM) ....................................................................... 47 4.4.2 Optical Add/Drop Multiplexer (OADM) ................................................................... 47 4.4.3 Optical Line Amplifier (OLA) .................................................................................. 50

5 Technical Specifications ..................................................................................... 51 5.1 Working Wavelength Requirements....................................................................... 51 5.2 System Component Indices................................................................................... 59 5.3 OMU/ODU Performance Parameters..................................................................... 61 5.4 WSUA/WSUD & WBU Performance Parameters ................................................... 67 5.5 OADM Performance Parameters ........................................................................... 69 5.6 OA Parameters ..................................................................................................... 69 5.7 OTU Interface Indices............................................................................................ 84 5.8 Tributary overhead processing of convergence board............................................ 94 5.9 Service Convergence parameters.......................................................................... 95 5.10 OS Channel (SOSC) Performance Indices .......................................................... 108 5.11 Supervision interfaces indices ............................................................................. 108 5.12 Dispersion compensation parameters.................................................................. 109 5.13 Physical Performance.......................................................................................... 109 5.13.1 Structure Indices ................................................................................................. 109 5.13.2 Bearing Requirements of the Equipment Room ................................................... 110 5.13.3 Power Supply Indices.......................................................................................... 110 5.14 Environment Conditions ...................................................................................... 112 5.14.1 Grounding Requirements..................................................................................... 112 5.14.2 Temperature and Humidity Requirements............................................................ 113 5.14.3 Requirements for Cleanness ............................................................................... 113 5.14.4 Dustproof and Corrosion-Proof Requirements ..................................................... 114 5.14.5 Environment for Storage...................................................................................... 114 5.14.6 Environment for Transportation ........................................................................... 114 5.14.7 Electronic Static Discharge (ESD) ....................................................................... 115 5.14.8 Safety requirements ............................................................................................ 117 5.15 Introduction to Interfaces ..................................................................................... 119 5.15.1 Interface on SEIA board ...................................................................................... 119 5.15.2 Interface on SPWA board.................................................................................... 122

6 Appendix A Abbreviation .................................................................................. 124

7 Appendix B Followed Standards and Recommendations ............................... 127


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FIGURES

Figure 1 Rack Diagram of Unitrans ZXWM M920................................................................... 1 Figure 2 ZTEs New-Generation Digital Transmission Product Family...................................... 2 Figure 3 Principles of RA......................................................................................................... 7 Figure 4 Power management sub-system................................................................................ 9 Figure 5 OTN description ...................................................................................................... 10 Figure 6 OTN section............................................................................................................ 11 Figure 7 Interconnection at SDH level ................................................................................... 12 Figure 8 Explanation of SM byte............................................................................................ 12 Figure 9 Dispersion management.......................................................................................... 15 Figure 10 The Block Diagram of Optical Path 1: N Protection Function.................................... 18 Figure 11 Optical Path Layer 1+1 Protection (Chain Networking)............................................. 19 Figure 12 Ring Networking...................................................................................................... 19 Figure 13 Functional Block Diagram for MS 1+1 Protection ..................................................... 20 Figure 14 Schematic diagram of 2-fiber bidirectional path shared protection............................ 21 Figure 15 Network management through supervisory channel................................................. 22 Figure 16 Network management through backup supervisory channel..................................... 22 Figure 17 The position of supervision subsystem .................................................................... 23 Figure 18 Electrical Cross-Connect System Structural Diagram............................................... 25 Figure 19 Whole Network Application with the ZXWM M920 (the System less than 48-

Wavelength)............................................................................................................ 27 Figure 20 Whole Network Application with the ZXWM M920 (the System with 80/96-

Wavelength)............................................................................................................ 28 Figure 21 Whole Network Application with the ZXWM M920 (160/176- Wavelength) ............... 29 Figure 22 Whole Network Application with the ZXWM M920 (the System with 192-Wavelength)31 Figure 23 Point-to-Point Networking (Short-Haul) .................................................................... 32 Figure 24 Point-to-Point Networking (Long-Haul)..................................................................... 32 Figure 25 Application of Chain Networking .............................................................................. 33 Figure 26 Application of Ring Networking................................................................................ 33 Figure 27 Ring-with-Chain Networking .................................................................................... 34 Figure 28 Cross Connection Networking ................................................................................. 34 Figure 29 Functional Blocks of the ZXWM M920 ..................................................................... 38 Figure 30 Board Slot Arrangement of OTU Sub-rack ............................................................... 40 Figure 31 The Hierarchical Structure of the Element Management Software............................ 45 Figure 32 Functional Blocks of the OTM.................................................................................. 47 Figure 33 Functional Blocks of the FOADM............................................................................. 48 Figure 34 Optical Connection of ROADM Equipment with WBU Boards................................... 49 Figure 35 Optical Connection of ROADM Equipment with WBM Boards .................................. 49 Figure 36 Optical Connection of ROADM Equipment with WSU Boards................................... 50 Figure 37 Functional Blocks of the OLA................................................................................... 50 Figure 38 Schematic Diagram of the DWDM System............................................................... 60 Figure 39 Common Interface Area of the OTU Sub-rack........................................................ 119 Figure 40 Interfaces on the SPWA board .............................................................................. 122


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TABLES

Table 1 Characteristics of dual/single pump source................................................................ 7 Table 2 The application modes ............................................................................................ 14 Table 3 Functions of board in supervision subsystem........................................................... 22 Table 4 ZTE Networking Scheme And Application Environment ........................................... 24 Table 5 ZTE/ ROADM Solutions........................................................................................... 24 Table 6 Boards Supporting Wavelength Tuning Function ..................................................... 27 Table 7 The Transmission Codes Supported by 40 2.5 Gbit/s System................................ 35 Table 8 The Transmission Codes Supported by 40 /48 10 Gbit/s System ........................... 35 Table 9 The Transmission Codes Supported by 80/96 10 Gbit/s System ........................... 36 Table 10 The Transmission Codes Supported by 192 10 Gbit/s System .............................. 36 Table 11 The Transmission Codes Supported by 40/48 40 Gbit/s System ........................... 36 Table 12 The Transmission Codes Supported by 80/96 40 Gbit/s System ........................... 37 Table 13 Board Description.................................................................................................... 40 Table 14 The Wavelength Allocation based on C band 40 CH/100 GHz Spacing.................... 51 Table 15 The Wavelength Allocation based on C/C+ band 192 CH/ 25 GHz Spacing ............. 52 Table 16 The Wavelength Allocation based on C/C+ band 48/96 CH/100 GHz/50 GHz

Spacing................................................................................................................... 55 Table 17 The Wavelength Allocation based on C/C+ band 80 CH/100 GHz Spacing .............. 57 Table 18 The Wavelength Allocation based on L/L+ band 80 CH/100 GHz Spacing ............... 58 Table 19 Meaning of Components and Interfaces of the DWDM System ................................ 60 Table 20 OMU Performance Parameters ............................................................................... 61 Table 21 The VMUX Performance Parameters....................................................................... 62 Table 22 ODU Performance Parameters................................................................................ 62 Table 23 50 GHz / 100 GHz Inter-leaver Performance Parameters......................................... 63 Table 24 25 GHz /50 GHz Inter-leaver Performance Parameters............................................ 64 Table 25 C/L Band OMU/ODU Performance Parameters ....................................................... 64 Table 26 ODU80 & OMU40couplerPerformance Parameters .......................................... 65 Table 27 The performance parameters of PDU-4-X are listed in following table...................... 65 Table 28 The performance parameters of PDU-5-X are listed in following table...................... 66 Table 29 The performance parameters of PDU-8-X are listed in following table...................... 66 Table 30 The performance parameters of PDU-9-X are listed in following table...................... 66 Table 31 The performance parameters of PDU-16-X are listed in following table .................... 67 Table 32 WBU Performance Parameters ............................................................................... 67 Table 33 WSUA/WSUD Performance Parameters.................................................................. 68 Table 34 WBM Performance Parameters ............................................................................... 68 Table 35 OADM Performance Parameters ............................................................................. 69 Table 36 C/L band EOBA Performance Parameters of the 40-channel ................................... 70 Table 37 C/L band EOBA Performance Parameters of the 80-channel ................................... 71 Table 38 C band EOBA Performance Parameters of the 48-channel ...................................... 72 Table 39 C band EOBA Performance Parameters of the 96-channel ...................................... 73 Table 40 EOLA Performance Parameters of the 40/80-channel System ................................. 74 Table 41 Optical Preamplifier Performance Parameters of the 40-channel System................. 76 Table 42 Optical Preamplifier Performance Parameters of the 80-channel System................. 77 Table 43 Optical Preamplifier Performance Parameters of the 48-channel System................. 78


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Table 44 Optical Preamplifier Performance Parameters of the 96-channel System................. 79 Table 45 EONA Performance Parameters of the 40/80-channel System................................. 80 Table 46 EONA Performance Parameters of the 48/96-channel System................................. 81 Table 47 Performance Parameters of EDFA+RAMAN Amplifier ............................................. 83 Table 48 Performance Parameters of RAMAN amplifier ......................................................... 83 Table 49 Performance Parameters of RPOA amplifier............................................................ 84 Table 50 The Interface Indices of 2.5 Gbit/s OTU at the Transmitting End of the ZXWM M92084 Table 51 The Interface Indices of 2.5 Gbit/s OTU for the Regenerator.................................... 85 Table 52 The Interface Indices of 2.5 Gbit/s OTU at the Receiving End of the ZXWM M920... 86 Table 53 The Interface Indices of 10 Gbit/s OTU at the Transmitting End of the ZXWM M920 86 Table 54 The Interface Indices of 10 Gbit/s OTU for the Regenerator..................................... 87 Table 55 The Interface Indices of 10 Gbit/s OTU at the Receiving End................................... 88 Table 56 The Interface Indices of 40 Gbit/s OTU(DPSK) at the Transmitting End of ZXWM

M920....................................................................................................................... 89 Table 57 The Interface Indices of 40 Gbit/s OTU(DPSK) for the Regenerator ......................... 90 Table 58 The Interface Indices of 40 Gbit/s OTU(DPSK) at the Receiving End ....................... 91 Table 59 The Interface Indices of 40 Gbit/s OUT (DQPSK) at the Transmitting End of ZXWM

M920....................................................................................................................... 92 Table 60 The Interface Indices of 40 Gbit/s OUT(DQPSK) for the Regenerator.................... 92 Table 61 The Interface Indices of 40 Gbit/s OTU (DQPSK) at the receiving End..................... 93 Table 62 Tributary overhead processing of convergence board.............................................. 94 Table 63 The parameters of SRM41 ...................................................................................... 95 Table 64 Specification of SRM42 Board................................................................................. 97 Table 65 The parameters of MQT3(DPSK) .......................................................................... 98 Table 66 The parameters of MQT3 DQPSK ............................................................... 100 Table 67 Specification of GEM2/GEMF Board...................................................................... 101 Table 68 Specification of GEM8 Board................................................................................. 102 Table 69 Specification of DSA Board ................................................................................... 103 Table 70 Specification of DSAF Board ................................................................................. 104 Table 71 Specification of DSAE Board ................................................................................. 105 Table 72 Specification of SMU Board................................................................................... 106 Table 73 Specification of FCA Board ................................................................................. 107 Table 74 Main Performance Indices of SOSC ...................................................................... 108 Table 75 Functions and parameters of supervision interface at boards................................. 108 Table 76 Parameters of dispersion compensation equipment............................................... 109 Table 77 Dimensions and Weight of ZXWM M920................................................................ 109 Table 78 Power Consumption of Commonly Used Boards/Units of ZXWM M920.................. 110 Table 79 Temperature and Humidity Requirements.............................................................. 113 Table 80 Requirements for Harmful Gases in the Equipment Room ..................................... 113 Table 81 Climate requirement .............................................................................................. 114 Table 82 Requirements for mechanical stress...................................................................... 114 Table 83 Climate requirement .............................................................................................. 115 Table 84 Static discharge anti-interference........................................................................... 115 Table 85 RF electromagnetic radiated susceptibility ............................................................. 115 Table 86 Electrical fast transient burst susceptibility at the DC power port ............................ 115 Table 87 Electrical fast transient burst susceptibilities at the signal cable and control cable

ports...................................................................................................................... 116 Table 88 Surge susceptibility of DC power ........................................................................... 116


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Table 89 Surge susceptibility of the outdoor signal cable...................................................... 116 Table 90 Surge susceptibility of the indoor signal cable........................................................ 116 Table 91 Conductivity susceptibility of RF field..................................................................... 116 Table 92 Conductive emission electromagnetic interference at the direct current port........... 117 Table 93 Radio active emission electromagnetic interference............................................... 117 Table 94 Definitions and Description for the Common Interface on SEIA1............................ 120 Table 95 Definitions and Description for the Common Interface on SEIA2............................ 121 Table 96 Definitions and Description for the Common Interface on SPWA............................ 123


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1 Overview Unitrans ZXWM M920 Dense Wavelength Division Multiplexing Optical Transmission Equipment is a large-capacity ultra-long-haul transmission system. It can multiplex up to 192 wavelengths (uni-direction) in a single-core fiber, with total transmission capacity of 1920Gb/s in 10G system and 3840Gb/s in 40G system. It offers full-rate optical access capability from STM-1/OC-3 to STM-256/OC-768, as well as complete access capability for other services, such as POS, ATM, GbE and PDH. ZXWM M920 rack is illustrated in Figure 1. Figure 1 Rack Diagram of Unitrans ZXWM M920

Based on the development idea of creating free, powerful and scalable optical transmission networks, ZTE develops its new-generation of digital transmission products including Unitrans ZXWM M920 DWDM equipment which provides large bandwidth and


2 2009 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

long-haul transmission at the backbone layer, ZXMP M820 DWDM equipment, ZXMP M720 DWDM equipment, ZXMP M600 CWDM equipment.

The new-generation digital transmission products of ZTE can satisfy all applications from the backbone network to end user access, and provide users with future-oriented overall transmission solutions.Figuer2 shows the applications of ZTEs optical transmission products. Figure 2 ZTEs New-Generation Digital Transmission Product Family

Metro Core

Metro Edge

Backbone Layer

NNooddee BB

Broad

Triple PSTN

RNC GSR

GSR

CWDM

MSTP

DWDM/ROADM

DWDM/ROADM Backbone

BRAS M720

M720 M820

M820

M920

M920

M920

M920

M600 M600

M600

M600 DWDM

M720

M720

M720

M720

ZXWM M920 is mainly applied to the national backbones and provincial backbones.

2 Highlight Features This chapter introduces the salient features of ZXWM M920.

2.1 Large Capacity and Easy Upgrade ZXWM M920 can provide 1920/3840 Gbit/s transmission capacity, fully satisfying the ever-growing requirements on bandwidth. The system is designed with modular structure and multi-rack management technology. It can be smoothly upgraded to 192-wavelength. Its good scalability and expansibility can protect users investment maximally



2.2 Single 40Gbit/s system ZXWM M920 can supports single 40Gbit/s system, and has following features:

1 Support 96 wavelengths

Support 80/96*40G transmission and the capacity of at most 3.84T;

2 P-DPSK and RZ-DQPSK modulation for ULH transmission

Improved DPSK coding has good OSNR tolerance and can restrain the non-linear effect well. It can reach 1500KM without the REG with 50GHZ spacing.

RZ-DQPSK coding has good PMD tolerance and can restrain the non-linear effect well. It can reach 2000KM without the REG with 50GHZ spacing.

3 Embedded TODC and EDFA and the same dispersion tolerance & power budget as 10G system.

OTU board is embedded with TODC and EDFA, the system allows the biggest dispersion tolerance of -700ps/nm ~+700ps/nm, and the dispersion tolerance & power budget are the same as 10G system.

4 Ultra high integration

40G board only needs 2 slots, with high integration and low power consumption. Single rack supports 2140G wavelengths.

5 Smooth network upgrade

The 40G board can plug and play in the legacy equipment because the system is developed on the existing WDM platform. It supports smooth upgrade from 10G to 40G without any service interruption.

2.3 Super-long-haul Transmission With different optical transponder units (OTU), EDFA, FEC and AFEC technologies, RZ coding technology, P-DPSK coding technology, distributed Raman amplifier and dispersion management technology, ZXWM M920 can perform super long non-electric relay transmission from several kilometers up to thousands of kilometers.

2.4 Multi-service Access Mode ZXWM M920 adopts an open design. The accessed optical signals can be converted to ITU-T G.692 recommendation compliant wavelength signals for output by employing optical/electric/optical conversion technology.

It supports transparent transmission of optical signals in multiple formats, such as STM-N (N=1, 4, 16, 64,256), POS, GbE/10GE, ATM, ESCON, FICON and FC, which protect users benefit and provide an ideal means for network expansion.



ZXWM M920 also can multiplex low-rate services into 40G10G or 2.5G rates transparently to improve the availability of system wavelength.

2.5 Flexible networking modes Functionality of ZXWM M920 can be changed from OLA to OADM to OTM by choosing different combination of functional modules, making it more flexible for complicated network topologies, such as chain, star, cross, tangent-ring and mesh networks.

2.6 Wavelength Add/Drop Functions Filters in the ZXWM M920 can be configured flexibly to implement the adding/dropping of 1 to 80 wavelengths. With this kind of design, the ZXWM M920 supports both the FOADM and the ROADM functions.

FOADM: This function is to implement the adding/dropping of fixed wavelengths.

ROADM: With this function, wavelengths to be added/dropped can be reconfigured. Besides, add/drop ports can be assigned to these wavelengths flexibly, that is, the port assignment function. ZXWM M920 support ROADM function based on WB, PLC and WSS technologies.

2.7 Reliable Protection Functions ZXWM M920 can provide multiple and effective protection modes: Optical subnet connection protective switchover (OSNCP); Unidirectional optical line protective switchover (ULSR); Unidirectional optical channel protective switchover (UPSR); Bidirectional optical line share protective switchover (BLSR); Bidirectional optical channel share protective switchover (BPSR); 1: N tributary protection etc. which with the switching time shorter than 50 ms. When ZXWM M920 is configured as OADM node on a ring network, route protection of channels can be accomplished.

2.8 Performance Monitoring Technologies ZXWM M920 uses a board performance monitoring unit to capture board performance data, which can be viewed to accurately locate a fault via NMS.

2.9 Power Management Technology ZXWM M920 adopts excellent power management technology to adjust and control the power and power spectrum at each point in the system.

ZXWM M920 system supports LAC (line attenuation control), APC (automatic power control), AGC (automatic gain control) etc. technologies. The gain adjustment range of LAC card is: 2-26dB; the gain adjustment range of general optical amplifier is 5dB which can both be adjusted via NM.



APC and AGC technologies can control the launched power/gain on MS level to ensure hitless in-service insertion or removal of channels.

2.10 Powerful NM ZXONM E300, adopted by ZXWM M920, can manage CWDM, DWDM and SDH equipments. It employs three-layer C/S structure of GUI/Manager-DB/Agent. Due to flexible networking, it offers the remote NM and hierarchical NM, easily synchronizes the data of multi-NMS or active/standby NM and actualizes the automatic and manual switching.

Based on OSPF algorithm, the NMS has ECC automatic route function, that is to say the ECC route between NEs can be set up automatically without manual configuration, which could make the networking application easily and fast.

In addition, the NMS supports remote and online upgrade of NE software and board software, provides management at multiple layers, i.e. NE layer, NE management layer and network management layer, and offers the fault management, performance management, security management, configuration management, maintenance management and system management.

The NMS also provides the northbound interfaces, e.g. CORBA, Q3, SNMP and MML, so as to access the higher-lever NM easily.

2.11 WSON ZXWM M920 supports GMPLS/WSON control plane load, and has following features:

1 Rapid automatic route discovery

2 Strong ability for automatic resource discovery

3 Versatile resource management functions

4 Fast end-to-end service provisioning

5 Multi-level SLA

6 Standard technology and open platform

7 Flexible equipment upgradeability

8 Highly operable and maintainable

3 Functionality This chapter introduces the functions of ZXWM M920 in detail, including transmission, ultra-long-haul distance transmission, power management, performance test, dispersion management, service capability, communication monitoring, alarm input/output and protection.



3.1 Functions

3.1.1 Large Transmission Capacity

Transmission system less than 48-wavelength employs on the C band with 100 GHz channel spacing.

80/96-wavelength transmission system employs on the C band via inter-leaver technology with 50 GHz channel spacing.

192- wavelength transmission system employs on the C band via inter-leaver technology with 25 GHz channel spacing.

3.1.2 Ultra-long-haul Distance Optical Source

ZXWM M920 employs the ultra-long-haul distance optical source technologies including forward error correction (FEC) coding, advanced out band FEC coding, RZ code pattern and self-adaptive receiving.

1 FEC technique

i Description

FEC is a signal data processing technique. At the transmitting end, it sends the data with the redundant code generated by the specific algorithm, while, at the receiving end, according to the relevant algorithm, it checks and corrects the bit errors occurring during transmission with the redundant codes, and restores the original signals.

ii Features

Improve the error tolerance capability of the transmission signals to reduce signal/noise ratio required by the system, and extend the transmission distance.

The conventional FEC based on G.709 can increase the OSNR tolerance about 5~6 dB, and the advanced FEC technique adopting more effective coding algorithm can increase the OSNR tolerance about 7~9dB.

2 Return to zero (RZ) technique

RZ code allows higher peak value of power than NRZ code, and the mean transmitting optical power of RZ and NRZ code are on the same level, so it improves the signal/noise ratio for receiving signals of the system.

And RZ code reduces signal power spectral density to effectively suppress non-linear impact during transmission, so RZ code is more suitable for ultra-long-haul transmission.

3 Self-adaptive receiving technology

The receiver adjusts the judgment point level and phase automatically according to the signal receiving conditions, in order to obtain a higher Q value and lower bit error rate.



3.1.3 Optical Amplifier

Optical fiber amplifier of ZXWM M920 system is based on single-stage mode or double-stage mode. Enhanced Optical Booster Amplifier (EOBA)Enhanced Optical Line Amplifier (EOLA) and Enhanced Optical Preamplifier (EOPA) is based on single-stage mode , and Enhanced Optical Node Amplifier(EONA) is based on double-stage mode. EOBAEOLA and EONA use dual pumps, and EOPA use single pump or dual pumps. The wavelength of single pump source is 980nm, and the wavelengths of dual pump sources are 980nm and 1480nm. Gain flatness is 1dB. Extra metal ion and Gain Flattening Filter (GFF) can be added to ensure OA gain flatness.

Characteristics of dual/single pump source of EDFA are shown as below:

Table 1 Characteristics of dual/single pump source

Quantity of pump source

Wavelength

Output power

Power stability

Power stableness technique

980nm 100-150mW 0.02dB Automatic gain control Dual pumps 1480nm 200-350mw 0.02dB Automatic gain control

Single pump 980nm 100-150mW 0.02dB Automatic gain control

ZXWM M920 employs ultra-long-haul distance technologies, such as RAMAN amplifier and large power EDFA. Working principles of Raman amplifier (RA) are shown as following: Figure 3 Principles of RA

Compared with EDFA, the RAMAN fiber amplifier enjoys low noise merit. The equivalent noise factor of the distributed RAMAN amplifier board (DRA) of ZXWM M920 is 0 dB, and switching gain is 10 dB.

ZXWM M920 also provides large power EDFA, which directly improves OSNR to extend the transmission distance.



3.1.4 Power Management

To guarantee the network performance, ZXWM M920 adopts power management technology to adjust and control the power and power spectrum at each point in the system.

1 Intelligent Power Management

The intelligent power management is implemented by the line attenuation card (LAC), optical amplifier board and EMS. It can detect the changing state of the optical line power and make relevant adjustments accordingly, so as to maintain the receiving power and OSNR ratio at the normal value during ZXWM M920s operation.

Attenuation of LAC can be adjusted form 2dB to 26dB. And attenuation of LAC with attenuation slope compensation can be adjusted form 5dB to 26dB. The gain of optical amplifier in ZXWM M920 system can be adjusted via NM, and the typical range is 5dB.

ZXWM M920 can provide APR or APSD protection process, that is, the EDFA automatically reduces the power or switches off the power in case of no input light, so as to make operator safety.

Protection process is fulfilled as follows:

Optical power supervision device detects signal loss at active optical channel.

Reversing pump of RA shuts down.

Codirectional EDFA output at downstream node of breakpoint remains (APR) or shuts down (APSD).

Inverse EDFA at downstream node of breakpoint shuts down and automatically checks system recovery in intervals specified.

Inverse EDFA output at upstream node of breakpoint remains (APR) or shuts down (APSD).

Codirectional EDFA at upstream node of breakpoint shuts down and automatically checks system recovery in intervals specified.

After bidirectional fibers of the system recover, the output of EDFA and RA at the transmission section of breakpoint returns to normal.

In ZXWM M920 system, RA can automatically shut down and manually restart.

2 Auto Performance Optimization

When APO (Auto Performance Optimization) is adopted, the power management subsystem plane can intelligently adjust LAC and EDFA gain to automatically optimize and manage DWDM system parameters such as optical power and OSNR.



The power management subsystem is composed of controller, executor, monitor, communication (within a NE or between NEs) interface and protocols, as shown in the following figure: Figure 4 Power management sub-system

SNCP SOSC

EMS SNMS

Optical board Optical board

Monitor Executor

Monitor Executor

Backplane Interface

Backplane Interface

Backplane Interface

Backplane Interface

Board control/ management backplane interface (across

subracks and racks)

Communication control interface within a NE

Communication control

interface between NEs

Power management functions are at SNMS level. The controller is embedded in

Manager.

It takes the data from EMS database and analyzes it according to system service and network topology.

It makes the management scheme (comprising the setting states of the power adjustment executors of the NEs) in accordance with the power management algorithm.

It supplies the scheme to the operator to view, and then sends it to the NEs to optimize the power.

The network power optimization starts under the command of auto performance optimization. After the automatic optimization completion, it can be executed with the operators approval.

The automatic power management starts after operation, and monitors the system performances. It can handle a fault automatically, store and display the result.

3.1.5 Performance Detection Function

1 ZXWM M920 systems can provide OPM to supervise optical parameters at each optical channel, e.g., optical channel power, central wavelength and OSNR. It can supervise active optical channel in real time without disconnecting services, send



related data to NMS and check the associated physical quantity at NM in two view modes: illustration and data. Measurement precision of central wavelength is 0.1nm, power 1.0dB and OSNR 1.5dB.

OPM functions are shown as following:

Supervise path wavelength, optical power and OSNR of WDM signals in real-time.

Automatic self-calibration.

Supervise four channels of input optical signals (with optical switch);

Process data on boards, and find out power, wavelength and OSNR at peak points.

If OPM is not configured, NMS can supervise OA and OTU input and output power. Precision of optical power is 1dB.

2 The OTU part has performance monitoring and overhead processing functions, which can accurately locate faulty point and type by layer.

OTN layer: Monitor loss of frame alarm (OTUk-LOF) and bit interleaver parity check (OTUk-BIP8), and process overhead SM-TTI.

SDH signal: Monitor and check B1, B2 and J0 bytes.

GbE signal: Monitor and collect error packets and error packet rate statistics.

3 ZXWM M920 equipment provides monitoring port in each board for the carrier to test and monitor the signal quality by accessing the apparatus.

3.1.6 OTN Description

1 The functions supporting OTN

i ZTE DWDM product provides the FEC function for STM-16, STM-64, GbE, 10GbE LAN, STM-256, and the FEC satisfies the coding/decoding mode of G.709 standard.

ii Provides overhead test and process functions, which can test and manage optical channel in optical domain flexibly.

iii By adopting the standard RS (255,239) coding/decoding specified in G.709, it can relax OSNR by 5~6dB depending upon requirement.

iv It is very convenient for testing various services on optical layer, and clarifying network structure.

v In traditional mode, it can access and test SDH services, which are shown as following:

vi Figure 5 OTN description



WDM

OTU

WDM

OTUWDM

SDH/SONETPerformance

monitor

WDM NETWROK

SDH/SONETEquipment

SDH/SONETEquipment

SDH/SONETPerformance

monitor

Note: For brief explanation, it is only required to illustrate the unidirectional network application in above figure.

Such modes are only applied to SDH services tests, and both SDH equipments and WDM equipments carry out the tests on SDH services.

With G.709 standard OTN, the network hierarchy may be very clear. It applies the rich overhead sources in OTN to test and manage network, and performs corresponding test for customer services if necessary. Figure 6 OTN section

WDM

OTN

WDM

OTN

OTN SECTION

SDH/SONETETHERNETSAN...

WDM NETWORK

CLIENTEquipment

CLIENTEquipment

OTNPerformance

monitor

Client servicePerformance

monitor

OTNPerformance

monitor

Client servicePerformance

monitor

Provides services inter-working and interconnection on OTN conveniently and cuts the cost down.

With standard G.709 interface, it may actualize the network inter-working and interconnection of different equipment manufacturers on OTN, and avoid the unnecessary investment.

The figure below shows that Site A, B and C adopt the transmission equipments from two different manufacturers, and the inter-working and interconnection are at SDH level.



Figure 7 Interconnection at SDH level

SITE A

Provider_1'sSTM64 FECTransmitter

STM64+FEC STM64 STM64+FEC

SITE B SITE C

Provider_1'sSTM64 FECReceiver

Provider_2'sSTM64 FECTransmitter

Provider_2'sSTM64 FECReceiver

In above figure, Site B requires the equipments of two manufacturers to stand in the back-to-back mode, which increases the cost.

However, as the equipments on OTN have uniform interfaces, it will save much money.

vii Allowable network test on OTN

Judges LOF via FAS.

Offers the loss of multi-frame (LOM) signal for the overhead signals of some OTU and ODU spanning over multiple frames.

Tests the SM (section monitor) overhead in OTUk

Following figure is the explanation of SM byte. Figure 8 Explanation of SM byte

Reserved for network operator

DAPI

SAPI

TTI

1 2 3

BIP-8

SM

BEI RESIAEBDI

0

1516

3132

63

The TTI is used to transfer a 64-byte message (similar to the J0 byte function in SDH/SONET domain), the message contains a source address and a destination



address flag, which OTU signal applies to select route via network; in addition, other bytes are applied for the special purposes of operator.

In SM, it defines one BIP-8 byte, similar to the B1 of SDH/SONET.

2 Introduction to corresponding supported bytes

i rocess of frame alignment

OTUk frame alignment

OTUk frame alignment should be established by searching the OA1, OA2 FAS bytes in OTUk frame (please refer to G.709 recommendation).

An OTUk LOF alarm works via monitoring the FAS bytes of OTUk frame. On reset, the frame aliagner goes into out of frame state. In out of frame state, the frame aligner goes into in-frame state when there are 24 consecutive valid frame patterns. In in-frame state, the frame aligner goes into out of frame state when there are 24 consecutive invalid frame patterns. The OTUk LOF alarm arises in in-frame state and disappears in out of frame state.

OTUk multi-frame alignment

OTUk multi-frame alignment should be established on the basis of MFAS byte contained in OTUk frame (please refer to G.709 recommendation).

When the received MFAS does not match the expected number of multi-frame during 5 continuous OTUk frames, it should be regarded as out of multi-frame.

When a MFAS error is not found in 2 continuous OTUk frames, it should be regarded as multi-frame alignment recovery and turned into multi-frame synchronous state.

For the new frame alignment requirement, it needs to add two relevant alarms:

OTUk out of frame alignment OTUk-LOF (k=1,2)

OTUk out of multi-frame alignment (LOM)

ii Functions of TTI

All OTS, OTUk and ODUk layers have their own TTI. Currently, only the TTI test function of OTUk is considered, and the test items make use of the TTI in SM byte.

The TTI mismatching is based on the comparison between the expected value and the input one of APIs (i.e. SAPI and DAPI). The APIs is a part of 64-bit TTI signal defined by G.709 recommendation.

Both SAPI and DAPI must be under consideration. In order to enhance the flexibility, the test items can be set via NM (only SAPI, only DAPI, both, both not, 4 test modes). The following are the application modes:



Table 2 The application modes

Test item SAPI comparison result DAPI comparison result Alarm state

Both not test Not considered Not considered No alarm Both test Both matched No alarm Both test One not matched at least TIM alarm Only test SAPI Matched Not considered No alarm Only test SAPI Not matched Not considered TIM alarm Only test DAPI Not considered Matched No alarm Only test DAPI Not considered Not matched TIM alarm

The following functions are available:

Alarm:

OTU1 and OTU2 have the OTUk TTI mismatching (TIM). The alarm only exists at the receiving side of the line.

Setting command:

The test configuration of the received OTUk TTI has four modes: SAPI, DAPI, SAPI&DAPI, or no SAPI&DAPI. The configuration is rate independent, and only exists at the receiving side of the line.

The TTI of OTUk can be configured. SAPI and DAPI can be set at the transmitting end of the line, and the expected values of SAPI and DAPI can be set at the receiving end of the line.

BIP-8 test

Both OTUk and ODUk layers have their own BIP-8. Currently, only BIP-8 test function of OTUk is considered, and the test items make use of the BIP-8 in SM byte.

The following functions are available:

Performance:

OTUk BIP-8 bit error statistics is required by both OTU1 and OTU2.

Alarm:

The threshold-crossing alarm of 15-minute OTUk BIP-8 bit error is provided.



3.1.7 Dispersion Management

Dispersion restrictions must be taken into consideration in long-haul transmission. Certain amounts of the dispersion compensation modules are configured in the dispersion compensation plug-in box (DCM) of ZXWM M920 on actual demands.

By configuring the values of line compensation, precompensation and post-compensation reasonably, the system could actualize the balance compensation, as shown in Figure 9. Figure 9 Dispersion management

3.1.8 Service Functions

1 Service Access Function

ZXWM M920 can access the following services:

SDH services including STM-1/4/16/64/256

SONET services including OC-3/12/48/192/768

ATM or POS services including VC4, VC4-4c and VC4-16c

Ethernet services including FE, GbE, 10GbE

Enterprise intranet services such as ESCON, FICON, and FC.

Any rate services between 34 Mbit/s ~ 2.7 Gbit/s

2 Service Convergence Function

ZXWM M920 can converge and de-multiplex the low rate signals.

Each SRM42 board converge 4 STM-1/4 SDH signals or ATM signals to STM-16 signal.

Each SRM41 board converge 4 STM-16 SDH signals or ATM signals to STM-64 signal.



Each MQT3 board converge 4 STM-64/OC-192/10GbE/OTU2 signals to OTU3 signal.

Each GEM2/GEMF board converge 2 GbE signals to 2.5 Gbit/s rate.

Each GEM8 board converge 8 GbE signals to 10 Gbit/s rate.

DSA board implements the multiplexing/demultiplexing between eight data service signals at tributary side and two STM-16 signals at aggregate side.

It is applicable to different networking conditions by selecting tributary modules and aggregation module type.

3.1.9 Wavelength Add/Drop Function

The ZXWM M920 supports the adding/dropping of wavelengths in the granularity of 1 wavelength, 4 wavelengths or 8 wavelengths. The quantity of wavelengths to be added/dropped can be expanded from 1 to 80.

An optical add/drop multiplexer subsystem can be configured as a fixed one (FOADM) or a reconfigurable one (ROADM).

FOADM: In such subsystem, OAD board is needed to add/drop fixed wavelengths in the system.

ROADM: In such subsystem, additional WBU or WSU board is needed. Configure the system in the EMS to implement the adding/dropping and direct transmission of any specified wavelengths in the same direction. Moreover, the ROADM subsystem provides the port assignment function, with which wavelengths can be added/dropped through assigned ports.

In ROADM subsystems, it is unnecessary to adjust fibers manually when the quantity of wavelength to be added/dropped changes or some other wavelengths need to be added/dropped.

3.1.10 Communication and Monitoring Functions

Communication and monitoring functions are implemented jointly by the main control board (SNP) and optical supervision channel board (SOSC). The functions are:

1 Main control board (SNP)

Sample and process the alarms and performance of all boards in the equipment and report them to the NMS.

Receive various configurations and maintenance commands issued by the NMS, and forward them to corresponding boards.

Transfer the data from other NE SNPs.



As the traffic increases, ZXWM M920 is applicable to the multi-rack configuration at one NE. One SNP board can manage 16 racks at most. Users can flexibly configure according to the actual number of racks at the node equipment.

The fan unit monitors the fan speed and temperature, and feeds back the information to NMS, so that the user can view the relevant information at the NMS. Meanwhile, NMS sends the commands to the fan unit to manually adjust the fan speed.

Optical supervision channel card (SOSC)

The SOSC uses the 1510 nm channel to transmit the NE monitoring information in the bidirectional transceiving mode at the monitoring channel rate of 100 Mbit/s. It multiplexes and demultiplexes overhead, order wire and clock synchronization.

3.1.11 Alarm Input/Output Function

1 Alarm input function

ZXWM M920 uses the optical coupler isolation signal to access the alarm inputted by the external monitoring equipment, and displays it on the NMS through the ALARM_IN interface on the SEIA board.

The system can access 10 external alarms at most. The alarm type can be set through the NMS for detection of external environment alarms, such as fan, doors and temperature.

2 Alarm output function

The equipment alarm is outputted to the WARN interface in the SEIA board and then outputted to the monitoring display cabinet or other monitoring units in the equipment room via the ALARM_OUT interface of the SEIA board. Signals are isolated by relays.

3.1.12 System Level Protection

1 OTU board 1:N protection

The WDM networks generally require spare OTU boards and elements. When configured in protective mode, spare part can realize real-time protection, which is much quicker, safer and saves maintenance cost.

1:N protection only need to configure OTU and OMCP units at both ends of OTM, and may utilize the spare OTU board also, which has a low cost.

The processes are shown in Figure 10.



Figure 10 The Block Diagram of Optical Path 1: N Protection Function

2 21 32

4

OTU 12 2

1 3

24

OTU 72 2

1 3

24

OTU 8

OTU 0

Traffic

8

0

1

7

2 2

31

24

OTU 12 2

31

24

OTU 72 2

31

24

OTU 8

OTU 0

8

0

1

7

OMCP OMCP

OA OAOptical Switch

Optical Switch

Optical Switch

Optical Switch

Optical Switch

Optical Switch

Traffic

Traffic

Traffic

Traffic

Traffic

Traffic

Traffic

When several paths of services are faulty simultaneously, it is required to protect the services with higher priority set in the NMS. One OMCP board can perform 1: 8 protections.

2 Power Supply Protection

It has 1+1 power protection on the sub-rack with two power inputs. The sub-rack power module PBX fulfills reverse connection prevention, soft start, balance and supervision of two power inputs. The information is sent to PWSB on the top of rack for processing and reporting to NM via alarm cable.

3.1.13 Network level Protection

1 Optical Path 1+1 Protection

i Protection principles

The optical path 1+1 protection is implemented with the OP board, by sending concurrently and receiving selectively in both working path and protection path.

ii Applications

One OP board is used to protect a pair of bidirectional services with the same wavelength. Under the 1+1 protection case, the number of OP boards configured is the same as that of protected channels.

iii Chain networking



The protection path and the protected path are transmitted in the same fiber. On the chain networking, 1+1 protection can only perform equipment protection instead of route protection, as shown in Figure 11.

Figure 11 Optical Path Layer 1+1 Protection (Chain Networking)

iv Ring networking

On the ring networking, the protection path and the protected path reach the receiving end through different paths. 1+1 path protection can protect both route and the equipment. The ring networking is shown in Figure 12.

Figure 12 Ring Networking

A

B

C

D

Protectionpath

Workpath



2 MS 1+1 Protection

The MS 1+1 protection of ZXWM M920 adopts 1+1 protection mode section by section, as shown in Figure 13. Figure 13 Functional Block Diagram for MS 1+1 Protection

OMD

SOP

SOP

A fiber 1l1

ODD

ODU

OMU

OTU

OTU

OTU

OTU

l2

l3

ln

l1 OTU

OTU

OTU

OTU

l2

l3

ln

OTU

OTU

OTU

OTU

OTU

OTU

OTU

OTU

l1

l2

l3

ln

l1

l2

l3

ln

A fiber 2

B fiber 1

B fiber 2

EOBA EOPA

Fiber 1 is the work path and fiber 2 is the protection path

EOBAEOPA

2-fiber bidirectional path shared protection

In the 2-fiber bidirectional path shared protection ring, 1 of the external ring forms the working path, and 1 of the internal ring forms the protection path. The working path allows wavelength multiplexing of multiple unidirectional services, and the protection path shares protection of all services on the working path. Meanwhile, the optical switch can be connected via OPCS (path shared protection board) to control the adding status of adding protection wavelengths, so as to avoid conflict, on the protection ring, of multiple services that use the same working wavelength.

In Figure 14, for example, as optical fibers on a certain span failed (indicated by the symbol of ), services passing this span are broken, thus the access switch starts operation at the transmitting end, and services are transmitted along the protection route. When the two switching switches at the receiving end start operation, services are received from the protection route, and the service protection is actualized.



Figure 14 Schematic diagram of 2-fiber bidirectional path shared protection

Sharedprotection path

Working path

Switching

switch

Accessswitch ofthe sharedprotection

path

Service routebefore switching

Service routeafter switching

3.1.14 Network management channel backup

In DWDM transmission networks, network management information is transmitted through an optical supervisory channel, which is generally transmitted through the same optical fiber with main channel. In case of any failure in main channel, it will also affect the supervisory channel, i.e. loss of control on NE. In the condition of high traffic and backbone network, it is not affordable to lose control. To solve such problems, ZXWM M920 provides abundant measurements and protection to the supervisory channel.

In ring network, when certain section fails (e.g. optical fiber damage) in a certain direction, network management information automatically switch to the optical supervisory channel in the other direction of the ring without affecting the management of the whole network.

In chain network, the situation is more critical, because breakage in optical fiber means breakage of supervisory channel. Consequently, network management administrators are unable to get the supervisory information of failed station. To avoid this accident, network management information should use the backup channel. By using data communication network (DCN) and routers, ZXWM M920 can provide backup network management channel.

When the network is normal, network management information is transmitted over the main supervisory channel, as shown in Figure 15.



Figure 15 Network management through supervisory channel

On the failure of main supervisory channel, network elements automatically switch the management information to the backup channel to guarantee that the network management system can supervise and operate the entire network, as illustrated in the Figure 16. Figure 16 Network management through backup supervisory channel

3.1.15 Supervision Subsystem

Supervision subsystem consists of SNP board, SOSC board and SEI board. It provides a variety of functions, such as communication bus, EMS management interface and supervision channel transmission. The functions of different boards are described in the below Table 3 :

Table 3 Functions of board in supervision subsystem

Board/Fu nctional Module Code

Board Name Function Description

SNP Node Processor Board

Implements various functions, such as

SOSC Optical Supervision Channel Board

Establishes and maintains optical supervision channel between the NEs, which provides route for communication between the NEs. It also implements the



Board/Fu nctional Module Code

Board Name Function Description

transmission of ECC information, order wire information, user information (transparent user channel) and control information between the NEs.

SEI Extension Interface Board

Leads sub-rack interface to the panel so that the master rack and the slave rack can connect with each other.

The position of supervision subsystem is shown in Figure 17. Figure 17 The position of supervision subsystem

3.1.16 L0/L1/L2 integrated transport technologies

ZXWM M920 WDM platform integrates L0/L1/L2 transport technologies and enables the flexible accessing and dispatching of service, especially the prevailing Ethernet service.

ZXWM M920 offers three kinds of ROADM technology aiming at different scenarios to provide the most cost-effective solution for the customer. ZXWM M920s multi-degree ROADM based on WSS technology enables the wavelength routing and accelerates the deployment of new services.

To better transport the Ethernet service, ZXWM M920 offers both transparent transmission and statistic multiplexing of Ethernet service, the former is based on TDM technology without affecting the Ethernet service, the latter is based on L2 switch technology to enhance the transport efficiency of Ethernet service and reduce the CAPEX and OPEX of the network. ZXWM M920s L2 switch supports E-Line(EPL & EVPL) and E-LAN.



3.1.17 ROADM Function

ROADM supports dynamic wavelengths add/drop through remote control from NMS. In directionless configuration, the wavelength can be retrieved or assigned from/to any direction. In colorless configuration, any port can add/drop any wavelength. ZTE ROADM solutions are based on the WB (wavelength blocker), PLC (Planar Lightwave Circuit) and WSS (Wavelength Selective Switch) technology, which can support 2~9 directions ROADM solution.

ROADM provides node reconfiguration, implements connection between any two nodes, wavelength-level add/drop and pass-through configuration without manual intervention, thus addressing service demands and cutting operation & maintenance cost. In addition, the adoption of ULH WDM techniques greatly reduces full-band service terminations and undesirable O-E regeneration, enabling a highly scalable network, and saving equipment investment. With ROADM, multi-ring, mesh and star can be formed flexibly, adapting to dynamic characteristics and networking requirements for future service networks.

ZXWM M920 supports colorless and directionless ROADM solutions which are the most flexible. Colorless means any wavelength can be assigned to any port. Directionless means any direction can be assigned to any port.

ZXWM M920 ROADM supports multiple networking modes, meets networking requirements at different levels. The Comparison of ROADM networking schemes is shown as below table.

Table 4 ZTE Networking Scheme And Application Environment

Scheme Linear ROADM Ring ROADM Mesh ROADM Main application environment Long-haul trunk line Metro network Metro network

Technology WB ROADM PLC ROADM

WB ROADM PLC ROADM WSS ROADM

WSS ROADM

Available functions Spectrum balancing, wavelength add/drop

Wavelength add/drop, wavelength scheduling, wavelength grooming

Wavelength add/drop, wavelength scheduling, wavelength grooming

ZTE ROADM system provides multiple solutions, complete networking modes, meeting requirements of the customers with different network status and at various levels. The below table lists the recommended ROADM configuration targeting customers different requirements:

Table 5 ZTE/ ROADM Solutions

Solution Characteristics Target customer

WSS ROADM with tunable port in add channel

Add/drop wavelengths can be provisioned randomly, wavelength grooming flexibly.

Uncertainty in service growth, large traffic of future services, or requiring extremely high network



flexibility and wavelength route.

WSS ROADM with fixed port in add channel

Add/drop wavelengths are fixed, supports complex network architecture in the future.

Services are relatively fixed, future networks may evolve towards Mesh.

PLC ROADM with fixed port in add/drop channels

Add/drop wavelengths are fixed, the cost is low.

Services are relatively fixed, future services are predictable.

WB ROADM with fixed port in add/drop channels

Add/drop wavelengths are fixed, the cost is low.

Services are relatively fixed, future services are predictable.

3.1.18 Electrical Cross-Connect Function

Electrical Cross-Connect system can access data services including GE, FC, FICON, ESCON, SDH and DVB. The services can be aggregated into multiple ODUk services on the tributary convergence board and be cross connected at a granularity of ODU0/ODU1/ODU2. Then the cross connected signals are aggregated into OTU2 on the group convergence board and are eventually output from the line-side interface.

Electrical Cross-Connect system is categorized as centralized or distributed switching platform in .

Figure 18 Electrical Cross-Connect System Structural Diagram

As the figure shown, Electrical Cross-Connect system is composed of customer-side aggregation, line-side aggregation, and switching units. So it can achieve sub-wavelength dispatching. The Electrical Cross-Connect system can access multi-service such as, Ethernet, SDH, Fiber Channel (1G/2G), ESCON, FICON, etc. And it adopts a powerful electrical-layer cross-connect capability and enables trunk and wavelength conversion. Adding/dropping services and pass-through services can occupy different sub-



wavelengths in a single wavelength for transmission, minimizing pass-through wavelengths and resulting in wavelength saving and lowered CAPEX.

There are many kinds of tributary convergence boards, which multiplex the customer-side services and transmit them to the cross-connect unit via the backplane interface.

The cross-connect unit, which named CSUB, has clock processing and backplane signal cross-connect functions. The CSUB choose an advanced clock from line clocks and external clocks as system clock.

The tributary convergence units include DSAC, SAUC and SMUBC boards. DSAC board has 8 ports and can access multi-data service respectively. SAUC board can assess 4 STM-16 signals. SMUBC board can assess 10G signals

Per group convergence board, the 10G line board (OTU2 Line card 1*10G) receives the signals from the backplane, and aggregates them into OTU2 to output at the line side. And the name of group convergence board is SMUBL.

The centralized Electrical Cross-Connect system can achieve the sub-wavelength switch. The switching capacity is 360G. It also can cooperate with the ROADM to achieve wavelength and sub-wavelength switch.

The distributed service switching platform (DSS) consists of four data service access cards (DSAB), and each card is composed of line side unit, client unit and switching matrix. Client unit can access multi-service such as Ethernet, SDH, Fiber Channel (1G/2G), ESCON, FICON, etc. The non-blocking service switching between these four cards can realize sub-wavelength service dispatching or multicasting between multiple directions. The switching granularity can be ODU0/ODU1/ODU2. Total switching capacity of each DSS is 80G and single subrack can support multiple DSS. The cross connected signals are aggregated into OTU2 on the group convergence board and are eventually output from the line-side unit.

In DSS subsystem, switching matrix is distributed on service card and doesnt occupy other service slots. Such highly integrated cards can reduce power consumption effectively.

3.1.19 Wavelength Tuning Function

Traditional DWDM systems use fixed wavelength lasers as light sources, which only output fixed wavelengths complying with the specifications of ITU-T G.692. Fixed wavelength lasers can not be fully utilized when they are used as standby light sources, which results in the increase of cost. With the continuous development of light source technology, a kind of tunable wavelength laser that can meet the requirement for multi-wavelength tuning appears.

The tunable wavelength laser refers to a laser module that can be controlled to output different wavelengths in a certain bandwidth. The channel quantity and channel spacing of the output wavelengths meet the specifications of ITU-T G.692. With the application of tunable wavelength lasers, wavelengths can be selected dynamically for signals in a DWDM system according to the actual application of wavelengths. Especially when the system uses standby light sources, using tunable wavelength lasers can improve the utilization ratio of wavelengths.

Some service boards of the ZXWM M920 support both fixed wavelength output and tunable wavelength output. The below table lists the boards supporting tunable



wavelengths and their tuning ranges (relationship among operating band, channel quantity and channel spacing).

Table 6 Boards Supporting Wavelength Tuning Function

Board Operating Band Channel Quantity @ Channel Spacing

40G boards (with FEC or AFEC)

TST3 C band 40 CH@100 GHz 80 CH@50 GHz

MQT3

10 G boards (with FEC or AFEC) EOTU10G SRM41 FCA SMUBL

C band 40 CH@100 GHz 80 CH@50 GHz 96 CH@50 GHz (CE band)

SOTU10G C band 40 CH@100 GHz 80 CH@50 GHz

2.5 G boards (with FEC)

OTUF C band

4 CH@100 GHz (continuous wavelengths) 16 CH@50 GHz (continuous wavelengths)

GEMF C band

DSAF C band 16 CH@100 GHz (continuous wavelengths)

2.5 G boards (without FEC)

OTU C band 4 CH@100 GHz (continuous wavelengths)

16 CH@50 GHz (continuous wavelengths)

3.2 Networking

3.2.1 System Applications

1 8/16/32/40/48-Wavelength System Applications

For less than 48-wavelength system, ZXWM M920 whole network application is illustrated in Figure 19. Figure 19 Whole Network Application with the ZXWM M920 (the System less than 48-Wavelength)



EOBA

EDFA PA

OMU

EDFA Pre-

amplifier

OSC

OTU n-1

Sn-1ln-1

OTU 2l2

OTU n

S1l1

OTU 1

Snln

S2

OSC

F

EOPA

RM1

RM2

RMn-1

RMn

OLA

OSC

EDFA PA

EOLA

EDFA LA

EOLA

OSCF

MPI-SR'

MPI-R S'

OSC

OSCF

OADM

MPI-SR'

OAD

OAD

OTMOTM

S'

MPI-REOBA

EDFAPA

OMU

EDFA PA

OSC

OTU 2

S2l2

OTU n-1 ln-1

OTU 1

S1l1

OTU n

Snln

Sn-1

OSC

F

EOPA

RM1

RM2

RMn-1

RMn

OTU

OTU

OTU

OTU

SDn

SD2

SD1

SDn-1

ODU

OTU 1

OTU 2

OTU n-1

OTU n

R1

R2

Rn-1

Rn

SDn

SD2

SD1

SDn-1

ODU

OTU 1

OTU 2

OTU n-1

OTU n

R1

R2

Rn-1

Rn

OTU

OTU

OTU

OTU

The module shown in the diagram is board in ZXWM M920.

i Working wavelength range and channel spacing

C band (191.3 THz ~ 196.0 THz) at 100 GHz channel spacing

ii System composition

OTM: Optical terminal equipment. As shown in Figure 32. OTU belongs to the optical transfer platform, OMU and ODU belong to the OM and OD platform, EOBA and EOPA belong to the optical amplifying platform, SOSC belongs to the monitoring platform. At the receiving end of the OTM, modules should be added for dispersion compensation after long distance transmission. The wavelength spacing transferred by OTU is 100 GHz.

OLA: Optical line amplifier, including EOLA and SOSC. As shown in Figure 32., EOLA belongs to the optical amplifying platform; SOSC belongs to the monitoring platform.

OADM: Optical add/drop multiplexer. As shown in Figure 33, OAD belongs to the add/drop platform, OTU belongs to the optical transfer platform, and SOSC belongs to the monitoring platform.

2 80/96-Wavelength System Applications

Take a unidirectional 2-segment transmission for example, and the whole network application of the 80/96-wavelength ZXWM M920 is illustrated in Figure 20. Figure 20 Whole Network Application with the ZXWM M920 (the System with 80/96-Wavelength)



OMUC100_1

OTU..

OTU..

OCIC50_1

OSC

OSC

DCM LAC

OPM

100kmG.652

DRA

100kmG.652

DRA

OCIC50_1

ODUC100_1

OTU..

OTU..

OTM1 OLA OTM2

EOBA

OSC

DCM LAC

OPM

EOBA

EOBA EOPA EOPA

OMUC100_2

ODUC100_2



C band at 50 GHz spacing


OTM: Optical terminal equipment

OTU: belongs to the optical transfer platform in Figure 32.

OMU, ODU and OCI: The OM and OD platforms in Figure 33.

OMU/ODU: Multiplex/de-multiplex C band (191.3 THz ~ 196.0 THz), C+ band (191.35 THz ~ 196.05 THz), with the channel spacing of 100 GHz.

OCI: By adopting the inter-leaver technology, it multiplexes/de-multiplexes C band and C+ band, and integrates them into the C band multiplexing signals with 50 GHz channel spacing.

EOBA, EOPA: Belong to the optical amplifying platform in Figure 32. In an 80/96-wavelength system, they amplify the C band signals. At the receiving end of the OTM, modules should be added for dispersion compensation and power balance after long distance transmission.

SOSC: Monitoring platform in Figure 32.

OLA: Optical line amplifier

EOBA and EOPA: Belong to the optical amplifying platform in Figure 32.. In 96/176-wavelength systems, they amplify the C band and L band signals.

SOSC and OPM: Belong to the monitoring platform in Figure 32.. SOSC transmits and receives monitoring information, while OPM tests the optical performance of the optical interfaces.

3 160/176-Wavelength System Applications

Take a unidirectional 2-segment transmission for example, and the whole network application of the 160/176-wavelength ZXWM M920 is illustrated in Figure 21. Figure 21 Whole Network Application with the ZXWM M920 (160/176- Wavelength)



OMUC100_1

OTU..

OTU..

OTU..

OTU..

OCIC50_1

OCIL50_1

OBMC/L

EOBA

EOBA

OSC

OBMC/L

OBMC/L

OSC

EOPA EOBA

DCM LAC

EOPA EOBA

DCM LAC

OPM

OPM

100kmG.652

DRA

OBMC/L

OSC

EOPA EOBA

DCM LAC

EOPA EOBA

DCM LAC

OPM

OPM

100kmG.652

DRA

OCIC50_1

OCIL50_1

ODUC100_1

OTU..

OTU..

OTU..

OTU..

OTM1 OLA OTM2

OMUC100_2

OMUL100_1

OMUL100_2

ODUC100_2

ODUL100_1

ODUL100_2



C+L band at 50 GHz spacing




OMU, ODU, OCI and OBM: The OM and OD platform in Figure 33.

OMU/ODU: Multiplex/de-multiplex C band (191.3 THz ~ 196.0 THz), C+ band (191.35 THz ~ 196.05 THz), L band (187.0 THz ~ 190.9 THz) and L+ band (186.95 THz ~ 190.85 THz) with the channel spacing of100 GHz.

OCI: By adopting the inter-leaver technology, it multiplexes/de-multiplexes C band and C+ band, L band and L+ band, and integrates them into the C band and L band multiplexing signals with 50 GHz channel spacing.

OBM: At the transmitting end, the OBM feeds the amplified C/L band signals via the C/L pass band OM into the fiber. At the receiving end, it de-multiplexes the received signals into the C/L band multiplexing signals and sends them to the relevant amplifiers.

EOBA and EOPA: Optical amplifying platform in Figure 32. In 160/176-wavelength system, they amplify the C band and L band signals. At the receiving end of the OTM, modules should be added for dispersion compensation and power balance after long distance transmission.


OLA: Optical line amplifier. Compared with the 40/48-wavelength system, an OM part is added for C/L band signals.

OBM: Multiplexes/de-multiplexes signals of C/L band to the C band and L band.

EOBA, DCM and EOPA: Optical amplifying platform in Figure 32. In 160/176-wavelength system, they amplify the C band and L band signals. Among them, DCM compensates dispersion for long distance transmission.



SOSC and OPM: Monitoring platform in Figure 32. SOSC transmits and receives monitoring information, while OPM tests the optical performance of the optical interfaces.

4 192-Wavelength System Applications

Take a unidirectional 2-segment transmission for example, and the whole network application of the 192-wavelength ZXWM M920 is illustrated in Figure 22. Figure 22 Whole Network Application with the ZXWM M920 (the System with 192-Wavelength)



C band at 25 GHz spacing




OMU, ODU, OCI: The OM and OD platform in Figure 33.



OMU/ODU: Multiplex/de-multiplex C1001 sub-band (191.300 THz ~ 196.000 THz), C1002 sub-band (191.350 THz ~ 196.050 THz), C1003 sub-band (191.325 THz ~ 196.025 THz) and C1003 sub-band (191.375 THz ~ 196.075 THz) with the channel spacing of100 GHz.

OCI:

OCI1 and OCI2, By adopting the inter-leaver technology, it multiplexes/de-multiplexes C1001 sub-band and C1002 sub-band, C1003sub-band and C1004 sub-band integrates them into the C band multiplexing signals with 50 GHz channel spacing.

OCI3, By adopting the inter-leaver technology, it multiplexes/de-multiplexes C501 and C502 sub-band integrates them into the C band multiplexing signals with 25 GHz channel spacing

EOBA and EOPA: Optical amplifying platform in Figure 32. In 192-wavelength system, they amplify the C band signals. At the receiving end of the OTM, modules should be added for dispersion compensation and power balance after long distance transmission.


SOSC and OPM: Monitoring platform in Figure 32. SOSC transmits and receives monitoring information, while OPM tests the optical performance of the optical interfaces.

3.2.2 Networking Modes

To satisfy the need of various networking modes and functions, ZXWM M920 can be configured as an OTM, OADM and OLA.

1 Point-to-Point Networking

For short-haul transmission, ZXWM M920 can provide point-to-point network without OLA, as shown in Figure 23.

Figure 23 Point-to-Point Networking (Short-Haul)

OTM OTM

For long-haul distance, trunk amplification mode is employed. An EOLA is added between OTMs, as shown in Figure 24, which consists of three optical amplifying segments.

Figure 24 Point-to-Point Networking (Long-Haul)

OTM OLA OLA OTM

2 Chain Networking



The chain networking application with the OADM function is shown in Figure 25. Figure 25 Application of Chain Networking

OTM OLA OADM OTM

3 Ring Networking

The ring networking application is shown in Figure 26. Figure 26 Application of Ring Networking

OADM

OADM

OADM

OADM

OADM

4 Ring-with-Chain Networking

The ring-with-chain networking application is shown in Figure 27.



Figure 27 Ring-with-Chain Networking

OADM

OADM

OADM

OLAOADM OTM

5 Cross Connection Networking

Cross connection networking is shown in Figure 28. Figure 28 Cross Connection Networking

OLAOADM OTM

OLA

OTM

OLA

OTM

OTM

3.3 Transmission Codes Supported By adopting the ultra-long-haul distance optical source and optical amplifying technologies, the transmission codes supported by ZXWM M920 are listed in the following Table 7 .



Table 7

Documents

ZXWM M920 Product Description