ZTE CWDM Equipment ZXMP M600

ZXMP M600 is an "8 + 1" wavelength system at present (with scalability to 16 wavelength in the future). "8" means 8 CWDM wavelengths, and "1" means the 1 310 nm window.
It has 2 kinds of shelves: the CWDM Unit (CWU) Shelf and SubRate Mux Unit (SMU) Shelf. Both adopt the standard 19" shelf of 1U height, and able to be used in the stacked mode.
ZXMP M600 is fit for limited installation space, which is normally required in metropolitan switching buildings.

More information at:
http://www.zte.com.cn/English/03product/list1.jsp?CateID=191

1 CWDM Technology
The Coarse Wavelength Division Multiplexing (CWDM) technology is developed to improve the utility of optical fibers on the MAN, to provide multiple service interfaces, and to cut the network construction cost at the same time.
The working principle of CWDM is similar to that of Dense Wavelength Division Multiplexing (DWDM). At the transmitting side of the link, an optical multiplexer is used to multiplex the wavelengths transmitted in different fibers into one fiber for transmission, while at the receiving side, a demultiplexer is used to recover the original wavelengths from the combined signal.

    The wavelength selection and channel interval of the CWDM technology conforms to ITU-T Recommendation G694.2. The wavelength interval is 20 nm, while the working wavelength range is determined by the adopted fiber type. If an ordinary G.652 A&B, Single Mode Fiber (SMF) with water peak, is adopted, the working wavelength range will be 1 470 nm-1 610 nm; if full-wave fibers, that is, G.652 C&D fibers, water peak removed fibers, are adopted, the working wavelength range will be 1 270 nm-1 610 nm, as shown in Figure 1.

    The CWDM system adopts uncooled laser and multiplexer/demultiplexer. Compared to the DWDM system, it boasts simple structure and lower cost. It is suitable for the Metropolitan Area Network (MAN), with fewer bandwidth and shorter transmission spans when compared with the long haul DWDM system. Since no
Erbium-Doped Fiber Amplifiers (EDFA) are required, directly modulated CWDM equipment costs about 1/2 and even 2/3 less than a DWDM system with the same capacity.

2 ZTE CWDM Equipment ZXMP M600

2.1 Architecture of ZXMP M600
ZXMP M600 is an "8 + 1" wavelength system at present (with scalability to 16 wavelength in the future). "8" means 8 CWDM wavelengths, and "1" means the 1 310 nm window, as show in Table 1.

    ZXMP M600 has 2 kinds of shelves: the CWDM Unit (CWU) Shelf and SubRate Mux Unit (SMU) Shelf. Both adopt the standard 19" shelf of 1U height, and able to be used in the stacked mode. The equipment structure is illustrated in Figure 2.

    There are 4 shelves in Figure 2. The lower two are CWU shelves that perform the optical transfer and multiplex/demultiplex of CWDM wavelength, as well as the network element (NE) management. As shown in Figure 2, the left shelves is the fan slot, followed by the power supply, while the right side may plug in 4 boards that may be hybrid plugged, except the Network Control Protocol (NCP) board.

    The upper two are SMU shelves that practice the sub-rate convergence function. The left of the shelves is the fan slot, followed by the power supply, while the right may insert one piece of convergence board.

    The maximum configuration is 7 shelves of 1U height, and the typical configuration is 4 CWU and 3 SMU.
One NCP board is configured in one CWU shelf for managing the boards in all shelves. The CWU shelf should be numbered 1. And the NCP board can only be put in the slot 3. One NCP can manage a maximum of 7 shelves, e.g., 4 CWU plus 3 SMU shelves.

    The optical power budget for configuration of point-to-point networks is given in Table 2.

    In Table 2, the minimum output optical power is 0 dBm. And by following the requirements of ITU-T G.957, as to the STM-16 system, the receive sensitivity is -28 dBm when the Avalanche PhotoDiode (APD) detector used, which is the end-of-lifetime value in the worst case. Besides, the passive device loss of MUX 4/DEMUX 4 is 2.0 dB, and that of MUX 8/DEMUX 8 is 3.0 dB.

    ZXMP M600 can access the following:

• Synchronous Digital Hierarchy (SDH) services, including the STM-1/4/16 service
• Synchronous Optical Network (SONET) services, including the OC-3/12/48 service
• Asynchronous Transfer Mode (ATM) services or Point Of Synchronization (POS) services including VC4, VC4-4c and VC4-16c services
• Ethernet services, including 100 Mb/s and 1Gb/s services
• Enterprise interconnection services, such as the ESCON service
• Fiber Channel (FC) services
• Services of any rates between 34 Mb/s-2.5 Gb/s
  

    ZXMP M600 can multiplex and demultiplex low-rate signals.

• Each SRM 42 board can multiplex 4 channels of 155 Mb/s and 622 Mb/s SDH signals or ATM signals.
• Each GEM2 board can multiplex channels of GbE signals.
  

    The protection function of ZXMP M600 implements link-based "1 + 1" optical multiplex section protection (Unidirectional Line Switched Ring), as shown in Figure 3, as well as "1 + 1" optical channel protection based on a ring network (Unidirectional Path Switched Ring), as shown in Figure 4.

2.2 Features of ZXMP M600
Adopting the standard 19" shelf of 1U height, ZXMP M600 is compact and able to be used in stacked mode. And with 2U height, it can support 8 channels. It is fit for limited installation space, which is normally required in metropolitan exchange buildings.

    Besides, ZXMP M600 has other features as shown below:

(1) CWDM technology adopted to implement large-capacity transmission
    With an ordinary G.652 fiber, ZXMP M600 can provide "8 + 1" channels and the rate of each channel reaches
2.5 Gb/s. Here, "plus 1" indicates the channel with a wavelength of 1 310 nm.

(2) Open multi-service access mode
    ZXMP M600 adopts an open design. It uses the optical/ electrical/ optical wavelength conversion technique to convert the optical signals into wavelength signals that conform to ITU-T Recommendation G.694.2.

    It can transparently transmit STM-N (N =1, 4, 16), POS, GbE, ATM optical signals and also directly access wavelength signals that conform to ITU-T Recommendation G.694.2.

(3) Service convergence capability
    ZXMP M600 can converge 4 channels of STM-1/STM-4 services into one 2.5 Gb/s channel.

(4) Flexible filter design
    ZXMP M600 adopts a modular structure, supports flexible add/drop of 1 - (8+1) wavelengths and supports smooth upgrade.

(5) Supporting multiple networking modes
    ZXMP M600 supports chain, ring and tangent networks.

(6) Providing multiple power access modes
    The ZXMP M600 equipment can access -48 V DC, +24 V DC or -60 V DC power supplies.
Each subrack can adopt two power boards to implement "1 + 1" power hot backup to guarantee the reliable power supply of the system.

(7) Supporting mixed board plugging and hot plugging/unplugging
    Except for the power board and the NCP board, all boards at CWU and SMU shelves can be plugged in a mixed way and can be plugged/unplugged in a hot way. This makes its configuration flexible and maintenance convenient.

(8) Providing a powerful and unique Network Management System (NMS)
    The ZXONM E300 NMS adopted by ZXMP M600 provides friendly and convenient user interfaces and supports management of the NE layer, NE management layer and network management layer. It can implement such functions as fault management, performance management, security management, configuration management, maintenance management and system management.

    Besides, the object-oriented techniques are adopted during the design and development, and 3-layered C/S structure with the interface, service and data layers is implemented. Thus, the system features perfect expandability and adaptability.

    It adopts the standard L2 Ethernet switching technology, which greatly facilitates the construction of complicated networks.

    It can implement real-time synchronization and automatic changeover between data of active/standby nodes, greatly improving system reliability and availability.The system also supports online upgrade of foreground and background NM software and board-embedded software without interrupting running services.

    Moreover, ZXMP M600 manages the CWDM, DWDM and SDH equipment in a unified way.

Manuscript received: 2005-03-09