WDM System Description

OpitX NG WDM System Description

1 Network application…………………………………………………………Page 3

2 Product functions and features …………………………………..………Page 10

3 Product architecture and capacity………………………………...………Page 37

Confidential Information of Huawei. No Spreading Without Permission


Before learn this course, you should have:

Known WDM Basic Principle

Studied OTN Basic Knowledge

Reference

OptiX OSN 8800 Product Description

OptiX OSN 8800 Hardware Description







This chapter introduce

Position in networkss

WDM system compositions

Classification of channels

Networking and applications



The OptiX OSN 8800 I is mainly applicable to the backbone core layers. It is also applicable to the metropolitan core layers and metropolitan convergence layers. The OptiX OSN 8800 I uses dense wavelength division multiplexing (DWDM) technologies to achieve transparent transmission with multiple services and large capacity. The OptiX OSN 8800 I can be used to construct the complete OTN end-to-end network with the OptiX OSN 6800/OptiX OSN 3800, to construct the WDM network with the OptiX BWS1600G/OptiX Metro 6100, and to construct a hybrid network with the OptiX NG-SDH/PTN equipment or data communication equipment. In this way, the OptiX OSN 8800 I can provide complete transport solutions.



On 2007 huawei launched first OTN WDM system OSN 38006800, which support both electrical service grooming and photonic cross-connection, both of this equipment using in metro network. On 2008 huawei plan to launch two kinds of new version equipment there are OSN 8800 and OSN 1800 on is stretching to backbone network and other is stretching to access network try to enhance cross-connect capacity .



Main functions for OTU is to convert the wavelength between client signals and wdm-side ITU-T standard signals (G.691/694) XCS provides flexible cross-connection between the OTU cards, which is the highlights of OSN8800 compared to traditional WDM equipments. Main functions for OM is to multiplex the individual channels into main path, OD realizes the reverse conversion. OA is used to compensate the line loss or component insertion loss to realize long-distance transmission.

There are two methods for the management, difference is that ESC depends on OTU cards and OSC depends on the SC1/2 cards



Point-to-point network is the basic application. It is used for end-to-end service transmission. The other network modes are based on point-to-point mode which is the most basic network. Chain network with OADM(s) is the suitable topology when it is required to add/drop some wavelengths while passing others on.



Ring with chain

Tangent rings

Intersecting rings



MESH networks have no node bottleneck and ensure unblocked services by alternative routes during equipment failure. In a MESH network, more than one route is available between two nodes so that the service transmission is highly reliable. As a result, the MESH topology is a mainstream mode for intelligent optical networks. The MESH topology is flexible with good expandability.




Optical layer technology

Electrical layer technology

Service access

Guaranteed reliability





BB back bone

MC maintenance control

M-D multiple dimension

OEQ Optical Equalizer

Single-hop capability 76dB for example G.652 fiber attenuation ratio is 0.25dB/km so transmission distance about 76/0.25=304 km

XFP 10-Gigabit small form-factor pluggable transceiver

eSFP enhance Small Form-Factor Pluggable



The OptiX OSN 8800 I provides L1 electrical grooming.The OptiX OSN 8800 I supports two types of cross-connect boards: XCH and XCM. Cross-connect capacity is 1.28T They support the electrical grooming of ODU2, ODU1, and ODU0. The OptiX OSN 8800 II provides L1 electrical grooming.The OptiX OSN 8800 II supports two types of cross-connect boards: XCT and SXM. Cross-connect capacity is 2.56T They support the electrical grooming of ODU2, ODU1, and ODU0.











Cross-connection granularity

Integrated grooming:

GE / ODU1/ ODU2. Distributed grooming:

GE / ODU1 / Any(100Mb/s ~2.5Gb/s). Support L2 electrical layer switching

Full configuration of cabinets of different heights

Item

2.2-m high cabinet

2.6-m high cabinet

Quantity of configurable subracks in a ETSI 300 mm middle-column cabinet

4

4

Quantity of configurable subracks in a standard ETSI 300 mm cabinet

3

4



BB back bone









Transmission distance affect by several facts such as dispersion, OSNR, attenuation and Non-linear effects Different accessing rate laser have different dispersion tolerance and different requirements of OSNR

The value of table is fit to OSN 8800 and OSN 6800

Transmission Distance of OSN 3800

For 10 Gbit/s rate, supports a maximum of 25x22 dB transmission without electrical regenerator. For 2.5 Gbit/s rate, supports a maximum of 25x22 dB transmission without electrical regenerator.

For CWDM systems, supports a maximum of 80 km transmission distance.



FE: Fast Ethernet

GE: Gigabit Ethernet

ESCON: Enterprise systems connection

FICON: Fiber connection

FC: Fiber channel

HDTV: High Definition TV

DVB-ASI: Digital video broadcasting-asynchronous serial interface

DVB-SDI: Digital video broadcasting-serial digital interface

FDDI: Fiber distributed data interface



OTN frame structure 4 rows and 4080 columns An Optical Transport Network (OTN) is composed of a set of Optical Network Elements connected by optical fiber links, able to provide functionality of transport, multiplexing, routing, management, supervision and survivability of client signals, according to the requirements given in Rec. G.872



OTN have abundant overhead bytes The figure shows the overall electrical layer overhead, include frame alignment overhead, OTUk layer overhead, ODUk layer overhead, and OPUk layer overhead. The frame alignment overhead is used for the framing. It is composed of 6-byte frame alignment signal overhead FAS and 1-byte multiframe alignment overhead MFAS. OTUk layer overhead supports the transmission operation function connected through one or more optical channel. It is composed of 3-byte SM, 2-byte GCC0, and 2-byte RES. It is terminated at the OTUk signal assembly and dissemble places.

ODUk layer overhead is used to support the operation and maintenance of the optical channel. It is composed of 3-byte PM for end-to-end ODUk channel monitoring, 6-level TCM1-TCM6 with 3 bytes respectively, 1-byte TCMACT, 1-byte FTFL, 2-byte EXP, 2-byte GCC1, 2-byte GCC2, 4-byte APS/PCC, and 6-byte reservation overhead. The ODUk overhead is terminated at the ODUK assembly and disassemble places. TC overhead is added at the source, and is terminated at the sink. OPUk overhead is used to support the customer signal adaptation. It is composed of 1byte PSI, 3-byte JC, 1-byte NJO, and 3-byte reservation overhead. It is terminated at the OPUk assembly and disassemble places. And also have optical overhead separate to OCh OMS and OTS



Optical line protection need OLP card after FIU, The OLP aims to protect fibers of the line, which adopts the dual feeding and selective receiving function of the OLP board. This kind of protection is performed between two sites segmentally for the optical signal that is multiplexed. This makes that the working path and the protection path of the protected site must adopt the diverse route.

Client side och 1+1 protection:

The client-side 1+1 protection of the OTU uses the dual feeding and the selective receiving function of the OLP/SCS board to protect the OTU board and units after it.

The client-side 1+1 protection performs the switching based on the client-side ports. And it has the larger extent of protection that other protection types

Intra-borad Och 1+1:

As for the ring networking, the OTU intra-board 1+1 protection uses the separated paths in the ring to perform the protection, that is, services are transmitted in both the positive and opposite direction of the ring before arriving at the destination node.

As for the chain networking, it is much similar to the optical line protection explained in chapter one in that the diverse route is required to provide between the adjacent sites. We need to note that in the actual configuration, line fibers of the OTU board that are dually fed are sent to the eastward and westward lines of the node through different equipment types: MUX/DMUX and OA. This process is omitted in this figure.



SNC/I: Inherent monitoring The trigger conditions are decided by the SM section overhead status. SNC/S: Sub-layer monitoring The trigger conditions are decided by the SM and TCM section overhead status,. SNC/N: Non-intrusive monitoring The trigger conditions are decided by the SM, TCM and PM section overhead status,



The ODUk SPRing protection mainly applies to the ring network with distributed services. This protection uses two different wavelengths to achieve the protection of multiple distributed services between all stations. Compared with SNCP, multiple services share one protection channel in the ODUk SPRing protection. As a result, the ODUk SPRing protection effectively saves resources. Currently, the ODU1-level protection can be achieved. The ODUk SPRing protection applies to ring networks and thus requires the support of a network protection protocol. The protection adopts dual-ended switching mode, namely, when the receiving end of the working channel fails, both the receive and transmitting ends of the working channel are switched to the protection channels.



8-channel optical add/drop multiplexing unit with VOA Realizes the adding/dropping and multiplexing of eight signals and adjusts the input optical power of each channel.



The first flash show as the Fix OADM ,3 wavelengths form F to A, D, G, which wavelength to use depend on the card you design on station A,D,C and F The second scenarios show us ROADM you can configure the wavelengths’ direction by NMS, it’s very dynamical .



The WSS is the core component. The two types of WSS are MEMS-based WSS and the LCD-based WSS. The WSS cross-connected a wavelength to a multiplexer corresponding to the designated output port, according to the wavelength routing information. In this way, the WSS accomplish the wavelength grooming function. In the NG WDM system, there are two types of WSS: WSD9 and WSM9. Considering the optical channel revertive principle, the WSM9 and the WSD9 are the same in the interior structure and the mechanism. And here, we are talking about the WSD9. Firstly, the chromatic optical signal is demultiplexed to monochromatic optical signals in multiplex channels. The in-built VOAs adjust the power of each monochromatic optical signal, and then guide each of the monochromatic signals to different optical multiplexer by controlling the 1 x N (that is N=9 in the figure) optical switch array. Finally, the signals are multiplexed and output. In this way, we can accomplish transmitting of any monochromatic optical signal to any output port. Compared with the PLC and the WB, the WSS has the following advantages: It has better functionality than the WB and the PLC. It can choose a wavelength to be switched in multiple directions. The WSS can be directly used as a DMUX, which can add/drop any wavelength at any port. Besides, it can also groom optical signals in multiple directions.



The first flash show as the Fix OADM ,3 wavelengths form F to A, D, G, which wavelength to use depend on the card you design on station A,D,C and F The second scenarios show us ROADM you can configure the wavelengths’ direction by NMS, it’s very dynamical .



The OptiX OSN 8800 provides grooming on L1 electrical layer. Granularities that can be groomed at L1 electrical layer are ODU1 signals and ODU2 signals. The electrical layer processing and grooming are added between the client side interface signals and the WDM-side interface signals. Thus, the wavelength utilization of the line is improved. In addition, the OptiX OSN 8800 can connect seamlessly to traditional electrical layer equipment. The OptiX OSN 6800 provides grooming on L1 electrical layer and L2 electrical layer. Granularities that can be groomed at L1 electrical layer are GE services, ODU1 signals, ODU2 signals and Any services. Because the electrical layer processing and grooming are added between the client-side interface signals and the WDM-side ones, wavelength utilization of the line is improved. In addition, the OptiX OSN 6800 can therefore connect seamlessly to traditional electrical layer equipment. The OptiX OSN 6800 supports L2 electrical layer switching based on VLAN and Stack VLAN. The L4G board realizes basic Ethernet management, including management of the Ethernet private line (EPL) services, Ethernet virtual private line (EVPL) services, the quality of service (QoS), port basic attribute configuration, and test frames.



TOM board have 6 different scenarios :

Application Scenario 1: Realizes the Conversion between Eight Optical Signals at the Rate between 100 Mbit/s - 2.5 Gbit/s and Four ODU1 Electrical Signals Application Scenario 2: Realizes the Conversion between Eight Optical Signals at the Rate between 100 Mbit/s - 2.5 Gbit/s and One ODU1 Electrical Signals Application Scenario 3: Realizes the Conversion between Four Optical Signals at the Rate between 100 Mbit/s-2.5 Gbit/s and Four ITU-T Recommendation compliant WDM Signals

Application Scenario 4: Realizes the Conversion between Seven Optical Signals at the rate between 100 Mbit/s-2.5 Gbit/s and ITU-T Recommendation-compliant WDM Signals Application Scenario 5: Realizes the Conversion between Six Optical Signals at the rate between 100 Mbit/s-2.5 Gbit/s and ITU-T Recommendation-compliant WDM Signals, and the Dual Fed and Selective Receiving Function on the WDM Side Application Scenario 6: Realizes the Electrical Regeneration of One/Four OTU1 Optical Signals





The OptiX OSN 8800 supports master-slave subrack management. When multiple subracks are used to form an NE, the master-slave subrack mode is required to realize the unified management. This ensures less IP resources. Also the ASON function is realized only in one NE. This ensures easier maintenance and less management overheads. The Main-Slave sub-rack is adopted to deploy the optical layer grooming.



The system provides the intelligent power adjustment (IPA) function. When there is a fiber break on the line, the upstream optical amplifier is shutdown to prevent exposed optical fibers hurting human body. In the DWDM system, optical fiber break, equipment failure or optical connector removal may lead to the loss of optical signals on the main optical channel and on the optical auxiliary channels. To prevent exposed optical fibers hurting human body, especially eyes, and to avoid surge of the optical amplifier, the system provides the IPA functions. Where the loss of optical power signals happens on one or more optical trunk sections on the main optical channel and the optical supervisory channels, the system can detect the loss of optical signals on the link and instantly shut down the upstream optical amplifier.

The system provides the automatic level control (ALC) function. When ALC function is enabled,the increase in the line attenuation in a section causes the decrease in the input power of the amplifier in that section. Its output power and the input and output power of the downstream amplifiers remain the same.

The system provides the automatic power equilibrium (APE). With the APE function, you can keep the flatness of the optical power of the receiving end and to maintain the OSNR.



A stable clock is the basic condition for an NE to function properly. The clock must be configured according to clock configuration principles, to ensure the stability of the clock. Physical clock ensures frequency synchronization, which is the prerequisite for clock synchronization. Physical clock directly uses the features of the physical layer of the synchronous transmission network. That is, physical clock directly restores clock frequency from the physical optical signals, to ensure the frequency synchronization between the upstream and downstream. In this manner, the services can be transmitted normally. Table lists the board in the OptiX OSN 8800 I, equipment version, and NM version that support the physical clock. In addition, the relation between the board type, equipment version, and NM version are provided. Board Type STG EGSH, SLO16, SLQ64, SLH41, NS2, ND2

Equipment Version OptiX OSN 8800 I V100R002

NM Version T2000 V200R008C00 T2000 Web LCT V200R008C00



To deploy the ASON function:

The network topology should be complex enough to provide the redundant routes. The NE is upgraded to the intelligent NE, which has the GMPLS Control Plane. The flexible grooming function (optical layer grooming or electrical layer grooming ) is available.



The OptiX GCP is the ASON software provided by Huawei, which can be applied to the OptiX OSN series products to support the evolution from traditional network to ASON network. The GCP stands for the GMPLS control plane. The GCP complies with the ITU and IETF ASON/GMPLS-related standards.

Compared with the WDM network, the transmission network that applies the new ASON technology shows advantages in service configuration, bandwidth utilization and protection schemes.

In the traditional transmission network, the WDM transmission equipment functions as fibers. Currently, the WDM transmission equipment also carries services. As a result, more requirements are for the operability of the WDM equipment. The traditional network has the following problems:

The service configuration is complex and capacity expansion or service provision takes a long period.

The bandwidth utilization is of a low rate and low efficiency. In a ring network, half of the bandwidth should be reserved.

Just a few protection schemes are available and the performance of self-healing protection is poor.

The ASON has been developed to solve these problems. This technology involves signaling switching and a control plane to enhance its network connection management and recovery capability. It supports end-to-end service configuration and the service level agreement (SLA).






Product architecture

Board list



The unique innovation of OSN8800 system is the two-level traffic grooming infrastructure integrating dynamic optical cross-connect (Multi-degree ROADM) flexible electric grooming (Any ADM). L0 (Optical layer).

Agile photonic layer has multi-degree wavelength cross-connect capacity, and therefore provides the ability to route wavelengths to speed up service delivery and reduce the cost of O-E-O conversion.

L1(High order electrical layer).

In the case of the electrical-layer grooming scheme, the OptiX OSN 8800 supports L1 grooming to groom ODU0, ODU1 and ODU2 services.



Board area: All service boards, SCC boards and XCS boards are in this area. Totally 49slots are available. Fiber cabling area: Fiber jumpers from the ports on the front panel of the boards are routed to the area before reaching the matched side of the cabinet. Fan tray assembly: This area contains 3 fans for ventilation and heat dissipation of the subrack. There are altogether four subrack indicators in different colors on the fan tray assembly to indicate the status of running. The EFI1, EFI2 and ATE boards are the interface board of OSN 8800, they implement functions, such as alarm input, alarm output, and alarm cascading, to monitor the remote external systems. The AUX board provides the inter-board and inter-subrack communication. The AUX board does not provide external interfaces but only four indicators.



IU1-IU8, IU12-IU27, IU29-IU36 are for service boards.

IU37 is for the EFI2.

IU38 is for the EFI1.

IU48 is for the ATE.

IU39, IU40, IU45 and IU46 are for the PIU.

IU41 and IU43 are for the AUX.

IU42, IU44 and IU47 are reserved for future use.

IU28 is for the active SCC.

IU11 is available for the standby SCC or the other service boards.

IU9 and IU10 are for the XCS



Note:

Only the ODUk layer service cross-connect is supported by the OSN 8800 I.



The unique innovation of OSN 6800 system is the three-level traffic grooming infrastructure integrating dynamic optical cross-connect (Multi-degree ROADM) flexible electric grooming (Any ADM) embedded L2 switch processing capability. L0 (Optical layer).

L1(High order electrical layer).

Agile photonic layer has multi-degree wavelength cross-connect capacity, and therefore provides the ability to route wavelengths to speed up service delivery and reduce the cost of O-E-O conversion.

Huawei GE ADM is the first commercialized integrated GE transport and switching system in the industry designed with Huawei own patents. Today, Huawei has extended ADM solution to any service, Any ADM/MADM solution implements any data channel end to end automated creation, performance monitoring, fault detection, protection and traffic grooming between different wavelengths across complicated network topologies.

L2(Low order electrical layer).

Embedded LAN switching processor implements local Ethernet traffic aggregation, including convergence of n*GE to m* GE (m


The EFI and AUX boards are the interface board of OSN 6800. The EFI provides various functional interfaces such as management interfaces, intersubrack communication interfaces, and alarm input/output interfaces. The AUX board provides various functional interfaces such as inter-subrack communication interfaces, NM interface and NM cascading interface.

NM_ETH1/2: It is NM interface or NM cascading interface

ETH: It is for master/slave subrack communication

EFI



The slot 17 can be used for the common boards if the SCC 1+1 protection is not selected.



Different slots have different pairs of backplane bus connected to the XCS.

The OSN 6800 supports the cross-connect of GE, ANY, ODUk(ODU1, ODU2)

GE and ODU1 support both centralized and inter-board (distributed) crossconnect.

ODU2 only supports the centralized cross-connect.

ANY only supports the inter-board (distributed) cross-connect.

Thought:

Are the tributary boards and line boards able to be inserted in slot 17?



The AUX board is the interface board of OSN 3800, it implements functions such as alarm input, alarm output and alarm cascading.

NM_ETH1/2: It is NM interface or NM cascading interface.

EXT: The testing connectors



IU1 and IU11 can either hold two OADM boards respectively, or hold one service board as IU11. Full MESH cross-connection between IU2～IU5, supports the electrical grooming of: GE services, ODU1 services and Any services (100Mbit/s～2.5Gbit/s) The OptiX OSN 3800 provides alternating current (AC) and direct current (DC) power supplies. The arrangement of boards of IU6, IU7, IU8, and IU9 is different for the two power supply modes. In DC mode

IU6 and IU7 are for the PIU. IU8 and IU9 are for the SCC。IU9 is for the active SCC. IU8 is available for either the standby SCC or the OADM board.

In AC mode

IU6，IU7，IU8 are for two APIU boards. The IU9 is for the SCC. The IU8 is occupied. The standby slot for the SCC is not available.



The capacity between different slots is 8 pairs of GE/ODU1/ANY.



Here list some types of OTU but not all.

Depend on different requirements choose different cards

Indicator STAT

Name Board hardware status

Color Red, green

indicator ACT

Service active status indicator

Green

PROG

Board software status

Red, green

indicator SRV

Service alarm indicator

Red, green, yellow



TMX and LWX are old name in traditional product so here out of rule





Tributary cards only have clients side

Line card only has wdm side

NS2

All tributary units and line units provide four indicators

Indicator

Name

STAT ACT PROG SRV CLASS 1 LASER PRODUCT

Color Red, green

ACT


Green

PROG

Board software status indicator

Red, green

SRV


Red, green, yellow

IN

Board hardware status indicator

OUT

STAT

NS2



Tributary units only access client service and each of them have cross connect chips can make the cross connection via the XCS card with line units



TN11ND2 is 20Gbit/s card, single card outputs two individual wavelengths.

TN51NQ2 is 40Gbit/s cards with four wavelength output.



All Optical multiplexer and demultiplexer unit provide four indicators： D40 STAT ACT PROG SRV

D13

D27

D14

D28

D15

D29

D16

D30

D17

D31

D18

D32

D19

D33

D20

D34

D21

D35

D22

D36

D23

D37

D24

D38

D25

D39

D26

D40

Red, green, yellow

D12


D11

SRV

D10

Red, green

D09


D08

PROG

D07

Green

D06


D05

ACT

D04

Red, green

D03


D02

STAT

CLASS 1 LASER PRODUCT

D40


D31 193.00 D32 192.90 D33 192.80 D34 192.70 D35 192.60 D36 192.50 D37 192.40 D38 192.30 D39 192.20 D40 192.10

D01

Color

D21 194.00 D22 193.90 D23 193.80 D24 193.70 D25 193.60 D26 193.50 D27 193.40 D28 193.30 D29 193.20 D30 193.10

IN

Name

D11 195.00 D12 194.90 D13 194.80 D14 194.70 D15 194.60 D16 194.50 D17 194.40 D18 194.30 D19 194.20 D20 194.10

MON

Indicator

D01 196.00 D02 195.90 D03 195.80 D04 195.70 D05 195.60 D06 195.50 D07 195.40 D08 195.30 D09 195.20 D10 195.10


Functional modules and signal flow of the M40V board



All Reconfigurable OADM units provide four indicators. RMU9

Indicator

Name

Color

STAT ACT PROG SRV CLASS 1 LASER PRODUCT

ACT


Green

PROG


Red, green

SRV


Red, green, yellow

TOA ROA

Red, green

OUT EXPI


MONO MONI

STAT

AM1 AM2 AM3 AM4 AM5 AM6 AM7 AM8

RMU9



Functional modules and signal flow of the WSMD4 board



OTU

M U4 X0

OA

M OA4 0

OTU

Booster amplifier

Line Amplifier

M OA4 0

M D 4M 0U X

OTU

OTU

Pre-amplifier



The TN11OAU1/ OBU1 board does not support adjustment of the input optical power, whereas the TN12OAU1/ OBU1 board does.

TN12OAU1/ OBU1 has VO/VI port on front panel

Functional modules and signal flow of the TN12OAU1 board



Indicators: There are eight indicators on the front panel.

Board hardware status indicator (STAT) - dual-colored (red, green)

Service active status indicator (ACT) - green

Board software status indicator (PROG) - dual-colored (red, green)

Service alarm indicator (SRV) - triple-colored (red, green, yellow)

System power supply indicator (PWRA)- dual-colored (red, green)

System power supply indicator (PWRB)- dual-colored (red, green)

Protection power indicator (PWRC)- dual-colored (red, green)

Alarm cut-off indicator (ALMC)- yellow

Buttons: There are three buttons on the front panel. Table lists the function of each button. Button

Function

RESET

Used to reset the SCC.

ALM CUT

Used to clear the sound alarm.

LAMP TEST

Used to test all the indicators in the subrack.

OSN 3800 OSN 6800/8800 Confidential Information of Huawei. No Spreading Without Permission


XCH/XCM is fit for OSN 8800.

XCS is fit for OSN 6800

STG of OSN 8800 is different with OSN 6800’s. STG of OSN 8800 need work with interface board STI.

STG and STI board of OSN 8800

STG of OSN 6800







1.28Tbit/s / 2.56Tbit/s

Optical Transponder Unit

Tributary Unit and Line Unit

Cross-connect Unit

Optical Multiplexer and Demultiplexer Unit

Optical Add and Drop Multiplexing Unit

Optical Amplifying Unit

System Control and Communication Unit

Optical Supervisory Channel Unit





Type

Scheme

Function It uses the dual fed and selective receiving function of

ODUk SNCP

the electrical layer grooming, to protect the line board

protection

and the OCh fibers. The cross-connect granularity is ODU1 and ODU2 signals.

SNCP Protects the tributary service by using the dual-fed and Tributary SNCP

selectively-receiving function at the electrical crossconnect layer. The cross-connect granularity is ODU1 signals and ODU2 signals.

ODUk SPRing

It applies to the ring networks. This protection uses two ODUk SPRing

different channels to achieve the protection of one channel of service between all stations. It applies to the ring networks. This protection uses two

OWSP

OWSP

different channels to achieve the protection of one channel of service between all stations.




WDM System Description

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