zxmp m800 optical channel shared protection

7/28/2019 ZXMP M800 Optical Channel Shared Protection

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Contents

OPCS protection principle

OPCS card function

OPCS protection configuration


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OPCS protection principle

A four-node system is used as an example to illustrate the

dual-fiber bidirectional channel shared protection of 100M

supervisory channel at the WDM channel layer. Figure below

shows the topology of a four-node network.


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A B C D A

Working path from A to B

Protection path from A to B

Working path from B to C

Protection path from B to C

Working path from C to D

Protection path from C to D

Working Path from D to A

Protection path from D to A

Protection path

form A to BA D BC

Protection path

from B to CB A CD

Protection path

from C to D C B DA

Protection path

from D to AD C AB

Below mentioned are the protection routes when no switch occurs.

Below mentioned are the protection routes when the switch occurs.

A B C D A

A B

A D

B C

B A

C D

C BD A

D C


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1. The fig. above shows the unidirectional services , the whole ring

occupies only one wavelength of the system.

2. The OPCS belongs to same-wavelength protection. The direction of

the protection path and the working path is opposite.

3. The protection path is shared by the whole ring, and OPCS

protection can only protects single-section failure.

4. The protection services from B to A, C to B, D to C, and A to D

occupy same wavelength number which is different with the

wavelength number occupied by the working services between

them.

5. The bidirectional services between A and B, between B and C,

between C and D, and between D and A are transmitted by different

wavelength number.

Descriptions above are the soul of the OPCS principle.


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D

Internal ring: Shared

protection path

External ring:

Working path

:

Optical switch

A

CB

The service path when OPCS

is in normal working state

E

OPCS in normal working state

The fig. above only shows the unidirectional services from A to D


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D

Internal

ring:

Shared

protection

path

External

ring:

Working

path

Opticalswitch

A

CB

The services

path when the

OPCS is in

normal state

The services

path when the

OPCS is in

switchover state

E

OPCS in switchover state

The fig. above only shows the unidirectional services from A to D


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Environment Description

Service configuration: Bidirectional service is configured between A

and B, between B and C, and between C and A. The wavelength

numbers occupied are 1 and 2.

NE A B C A

Wavelength 2 1 2 1 2 1

A B21

2

1

C 1

2


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A direction: Standing in the ring, we define the clockwise direction as

A direction.

B direction: Standing in the ring, we define the anti-clockwise

direction as B direction.

A side: Facing the equipment, we define the left side as the A side.

B side: Facing the equipment, we define the right side as the B side.

The even number of the A direction is defined as the working

wavelength and the odd number of the B direction is the working

wavelength.


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1

2

1

2

1

2

APIAWI

AWO

APO

BPOBWO

BPI

BWI

APIAWI

AWO

APO

1

2

BPOBWO

APIAWI

BWI AWO

APOBPI

AWOBPOAADD

BWOAPOBADD

ADROP

AWIBDROPBWI

A AB C

AADD

BADD

AADD

BADD

AADD

BADD

AADD

BADD

Services diagram of OPCS in

normal working state.

ADROP

ADROP

ADROP

BDROP

BDROP

BDROP

BPOBWO

BPI

BWI

AB Working path2AB Protection path2

BA Working path1BA Protection path1

112 2

2


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Service Analysis in OPCS Normal Working State

2. To some extent, the service transmission on the working and

protection channel is simultaneous, but the service of the protection

channel in the working state does not reach the destination NE. The

service of the protection channel stops transmission when it reachesthe next NE.

3. In the working state, all ADROPs of the OPCS choose to receive the

service transmitted by the working channel (AWI) on the A side of NE.

All BDROPs of the OPCS choose to receive the service transmitted

by the working channel (BWI) on the B side of NE.


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APIAWI

AWOAPO

BPOBWO

BPIBWI

APIAWI

AWOAPO

BPOBWO

BWI

BPI

The OPCS at this site is in

the pass state

AWOAADDBWOBADD

ADROPAWIBDROPBWI

BPOAPIAPOBPI

The OPCS at this point is

in the A direction

switchover state

AWOBPOAADD

BWO

APO

BADDADROPBPIBDROPBWI

B C

e at t s

point is in the B

direction switchover

state

AWOBPOAADD

BWOAPOBADD

ADROPAWI

BDROPAPI

BPOBWO

BWI

BPI

API

AWI

AWOAPO

1

2

1

2

A

Service Diagram after OPCS Switchover

AADD

BADD

AADD

BADD

AADD

BADD

BDROP

ADROP

ADROP

BDROP

BDROP

ADROP

AB Working path2AB Protection path2

BA Working path1BA Protection path1


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Fig. above shows that:

NE A:Because the fiber failure occurs on the B side of NE A,

the service of B direction working channel is interrupted. To

ensure that NE A can receives the service from B, the OPCS

must switch over and choose to receive the service transmitted

on the protection channel from A direction. It is called that Bdirection switchover occurs on NE A. At this time, the STA

indicator is green.

NE B:Because the fiber failure occurs on the A side of NE B,

the service of A direction working channel is interrupted. The

OPCS executes the protection action and chooses to receivethe service transmitted on the protection channel from B

direction. It is called that A direction switchover occurs on NE

B. At this time, the STA indicator is red


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NE C: Take the service from NE A to NE B as an example:

After the fiber failure occurs, the transmission path of the

protected service is ACB. But in the working state, the

service transmitted on the protection channel of NE A (APO)

does not reach the destination NE B. Instead, the service stops

at NE C. To enable the service on the protection channel to

reach the destination NE B, the OPCS optical switch of NE Cperforms an action to allow the direct connection between API

and BPO. This state is called PASS state. In the same manner,

the BPI and APO will also be directly connected.

The services added on AADD and BADD are respectively

transmitted on the working channels AWO and BWO. At thistime, the protection channel transmits the protected service of

NE A and NE B. The protected service of NE C is not

transmitted.


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NE C: The ADROP still chooses to receive the service sent by

the working channel AWI and BDROP chooses to receive the

service sent by the working channel BWI.


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Contents

OPCS Protection Principle

OPCS card function


OPCS Protection trouble shooting


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The OPCS provides shared channel protection in the ZXMP M800.

It does so by detecting channel failures and switching optical

channels in case of line failures. The OPCS receives and executesthe protection handover or recovery command from the OSCF

board. The handover and recovery are implemented via the

optical switch on the board.

OPCS (Optical Channel Shared Protection Board )


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Function Schematic Diagram of the OPCS

Opticalswitch

control

Prot ecting path

Working path

Working path

Protecting path

Protecting path

Working path

Working pathProtecting path

Detection andcontrol circuit

Direc

tion

A

Direction A dropopt ical signal

Direction-A addopt ical signal

Direction B dropopt ical signal

Direction-B addopt ical signal


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OPCS Panel

1. Card running indicator

2. Laser alert flag

3. Optical switch state indicator

4. Optical interface

External

ring

interface

Internal

ring

interface

AWI API BWI

BWOWO APO

BPI

BPO

AADD BADD

ADROP BDROP


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Working Principle

T41

Adding channel,dropping channel

T31

T11

Reserved wavelength channel (1) inInternal ring

CBA

E DF

T21

Changeover nodeChangeover node


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A

AWO

A

AWI

A

APO

AAPI

B

BWI

B

BWO

B

BPI

BBPO

A

A

B

B

A

AADD

B

BADD

A

ADROP

B

BDROP

AWO

APO

API

AWI

OPCS Working Principle

BPO

AADD ADROP BDROP BADD

BWI

BPI

BWO

A-direction

Access switch

A-direction

handover switch

B-direction

handover switch

B-direction

Access switch


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Four working states of OPCS card A direction switchover state

A direction optical switch1X2 optical switch switches to BPI, all the

other optical switches keep the original working states.

B direction switchover state

B direction optical switch 1X2 optical switch switches to API, all theother optical switches keep the original working states.

Pass state

The A direction and B direction access optical switch are in the pass state,

namelyAPIBPOBPIAPO.

Idle state

Both A direction and B direction optical switches are in the crossover state.

I.e. API and BPI are stopped to send the services to the next NE. Both A

direction and B direction optical switches do no action. I.e. ADROPAWI

BDROPBWI


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The STA indicator of OPCS card

Green: It indicates that the B direction optical switch is in

crossover state.

Red: It indicates that the A direction optical switch is in crossover

state.

Orange: It indicates that no protection events occur.

Dark: It indicates that the optical switch is in pass state.


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OPCS working statenormally working stateA four-node system is consisted of NE A, NE B, NE C and NE D in a ring of

clockwise layout.

A BD

BADD

BWO AWI

ADROP BADD

BWO AWI

ADROP

APOBPI

AADD

AWOBWI

BPO

BDROP

AWOBWI

BDROP AADD

API

APO

BPO

BPI

API BPO API

APOBPI

AADD=AWO=BPO BADD=BWO=APO ADROP=AWI

BDROP=BWI


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Pass stateAccess switch is inpass state

AWO=AADD

ADROP=AWIBWO=BADD

BDROP=BWI

API=BPO

APO=BPI

OPCS working statepass and changeover state

A BD

BADD

BWO AWI

ADROP BADD ADROP

APOBPI

AADD

AWOBWI

BDROP BDROP AADD

APO

BPO

BPI

API BPO API

Changeover state

A direction changeover state

AADD=BPO ADROP=BPI

BADD=BWO BDROP=BWI

B direction changeover state

AADD=AWO ADROP=AWI

BADD=APO BDROP=API


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Location of OPCS

FixAttenuator

OSCL

Line

ODF

ODF

OPA

OBA

OBA

OPA

OPCS

OTU

OTU

Client ODF

ODU

OMU

LAC

OMU

ODU

Client ODF

FC/PC Connector

AWI

API

AWO

APO

BWO

BPO

BWI

BPI


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Triggering Mechanism of Protection Switchover

Multiplex Section Triggering Mechanism

Multiplex section triggering mechanism is a type of detection at

the optical layer. The incoming optical power of OPA is used

as the detection point and the LOS alarm generated by theOPA is used as the triggering condition. After the processing of

APS protocol, the internal optical switch of the OPCS of each

site is triggered to take actions to realize the protection

purpose. When the line failure is removed, the system resumes

its original working state.


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Triggering Mechanism of Protection Switchover

Multiplex Section Triggering Mechanism

This triggering mechanism detects the main optical power of

the line. The change of main line optical power caused by the

failure of one channel is insufficient to meet the triggeringcondition. Thus, the protection of service on a single channel

cannot be realized. The protection is triggered only when the

optical fiber on the OMS span is faulty. The triggering

sensitivity is limited and the protection for the service channel

cannot be realized.


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OPCS Triggering Mechanism

OPCS triggering mechanism is a type of triggering mechanism at

the optical layer. The optical power of the OPCS working

channel configured with the service is detected and the LOS

alarm generated is used as the triggering condition. The OSC

board receives the APS failure information generated by theOPCS board, transmits and monitors the K1 and K2 bytes in real

time, and generates a control word according to the APS

algorithm. Then it sends the APS switchover command to the

OPCS to realize the channel protection. When the LOS alarm of

the working channel disappears, the OPCS optical switch

recovers the working state.


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OUT Triggering Mechanism

OUT triggering mechanism is a detection mechanism at the

electronic layer. The quality of the transmitted service is

detected by the service board OUT or GEM and the LOS, LOF,

and B1 error code generated by the service board are used as

the triggering conditions. After the processing of APS protocol

algorithm, the APS switchover command is sent to the OPCSso that the optical switch of the board take action immediately

to allow the OUT or GEM to receive the service from the

protection channel. This triggering mechanism has one defect:

The OUT or GEM board can detect either the service from the

working channel or service from the protection channel at atime and cannot detect them at the same time. After the

switchover, the OUT board carries the service from the

protection board. Even if the service of working channel is

recovered, the OPCS switchover cannot be triggered. Thus,

this switchover is irreversible.


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OUT Triggering Mechanism

But this triggering mechanism features high sensitivity. Upon

the commissioning of the site or before the service is added, it

is recommended not to use this method. The number of

switchovers of the OPCS optical switch is limited. Too frequent

switchover will reduce the service life of the OPCS.


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Contents

OPCS Protection Working Principle

OPCS card introducing


OPCS Protection trouble shooting


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OTU

OTU

OTU

OTU

TX1

TX2

TX3

TXn

OMU

OBA

OTU

OTU

OTU

OTU

RX1

RX2

RX3

RXn

ODU

OPA

1

2

3

n

1

2

3

nOTS

OMS

OCHOAC OAC

Hierarchy of DWDMSystem

OLA

OTS



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Optical transmission network can be divided into four layers: OTSOMS

OCH and OAC, the relationship between the contiguous layers is client and

server.

OAC: Consisted of various client traffic (SDHPDHATMIPetc.) ,in E300SNMS service research view, its called service.

OCH: providing P2P optical channel for transmitting various client traffic

transparently, OH of optical channel configuring is processed in this layer.

OMS: Providing connection function for multi-wavelength.

OTS: Transmitting optical signal on different media(G.652,G.653,G.655 Fiber).


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Mainly steps:

Link configuration including inter link configuration and inner

configuration

Service search

Configure Protection Group

Calculate Multicast Group Route


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configuration


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Inter Link configurationSelect SrcNE and DestNEthen select the correlative cards such as OA or SDMT, click add

button and apply button. No need to configure the link of LAC and LACG card.


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Inner connection of NEs:

This is the most important step of OPCS protection configuration,GUI can search

OTS/OMS/OCH services depended on it. If any mistake made here, the OPCS changeover will

fail.


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Mainly configuration steps:


configuration

Service search

Set up Protection Group



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Open the WDM SNMS view:


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Open the Resource Management menusearch OTS/OMS/OCH services.


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If some traffic already exists, it will be displayed in the window.


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If need to find out new traffic, click Service Search button.


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New services will be found out and displayed in blue color, select

all the services marked invalid flag and click Apply button, active

all the services.


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configuration

Service search

Configure Protection Group



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Click OMS Protect menu, then start to configure the OPCS protection on EMS:

Caution: Select the NES in clockwise direction, or abnormal issue will happen if the

OPCS switches.


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Create a new protection named WDM OCH shared protection Ring Optical-cross

Wavelength, add the Nes to the new protection group one by one in clockwise direction,

then click the sendpart button.


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After the command successfully, click the next button


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Click set all ne button marked NO.1 in the below fig., after it

indicates success, then choose Simple Resist menu bar options

marked NO.2, click set all ne button marked NO.3, then click the

next button.


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Configure the correlative ports and choose the working services, before you start this step,

please keep the WDM SNMS VIEW running. Choose the ports as per the desire. If the

service drop between two sites named A and B, then select two working services between

these two sites, one is from A to B, another is from B to A, at the same time, please noticethe wavelength numben.


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configuration

Searching service in SNMS

Set up Protection Group



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Final step: Calculate NE Multicast Group Route, this has to be done, otherwise, protection

group cant work.


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Selecting protection group first, then calculate it, 225.X.0.0 indicates multicast group of

rings, each ring has one.


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zxmp m800 optical channel shared protection

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