OptiX NG-SDH Lower Order Cross-Connection Topic-A

Document No. Product Name OptiX NG-SDH

Intended Audience Technical support engineers Product Version V100R001 and later

versions

Compiled by Product Development Dept in Optical Network Division

Document Version

OptiX NG-SDH Lower Order Cross-Connection Topic

Written by Xie Qi Date 2007-11-24

Reviewed by Date

Reviewed by Date

Approved by Date

Huawei Technologies Co., Ltd.

All Rights Reserved

OptiX NG-SDH Lower Order Cross-Connection Topic Confidentiality Level:

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2008-03-10 Huawei Confidential. No disclosure without permission. of 21

Revision Record

Date Revision Version Author Description

2007-11-24 V1.0 Xie Qi The intial draft is completed. 2007-11-30 V2.0 Xie Qi This document is revised according to review comments from the R&D personnel.

2007-12-06 V3.0 Xie Qi This document is revised according to review comments from the marketing and technical support engineers.


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Table of Contents

Chapter 1 Preface............................................................................................................................. 6

Chapter 2 Usage of the Lower Order Resource of the Cross-Connect Board........................... 7 2.1 Lower Order Resources Required by the Ordinary SDH Service ........................................ 7 2.2 Occasions Where Many Lower Order Resources Are Used ................................................ 9

2.2.1 Service in Disorder..................................................................................................... 9 2.2.2 Lower Order Resources Required by the SNCP/SNCMP/PPS/DLAG Lower Order Service .............................................................................................................................. 12 2.2.3 Lower Order Resources Required by the 1+1 LMSP Lower Order Service ............ 15 2.2.4 Lower Order Resources Required by the 1:1 LMSP Lower Order Service ............. 16 2.2.5 Lower Order Resources Required by the Lower Order Service in an MSP Ring .... 17 2.2.6 Lower Order Resources Required by the SNCTP Lower Order Service ................. 17

Chapter 3 Command for Querying Lower Order Resource Margin........................................... 18

Chapter 4 How to Use Fewer Lower Order Resources............................................................... 20

Chapter 5 How to Handle the Case Where Lower Order Resources Are Insufficient ............. 21


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List of Figures

Figure 2-1 Chip connection for the ordinary SDH lower order service ..................................... 7

Figure 2-2 Chip connection for the lower order services of the same source and sink.......... 11

Figure 2-3 Chip connection for the unidirectional services of different sources and sinks..... 12

Figure 2-4 Chip connection for the lower order SNCP/SNCMP/PPS/DLAG service at the selective receiving end..................................................................................................... 13

Figure 2-5 Chip connection for the lower order SNCP/SNCMP/PPS/DLAG service at the dual fed end ............................................................................................................................. 14

Figure 2-6 Chip connection for the lower order 1+1 LMSP service at the selective receiving end.......................................................................................................................................... 15

Figure 2-7 Chip connection for the 1+1 LMSP lower order service at the dual fed end......... 16


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Key words:

Lower order resource

Abstract:

This document uses the rules for using the lower order chip resources of the cross-connect board to explain why lower order resources are insufficient. This document mainly describes the number of lower order resources used by lower order services in the case of various protection networking schemes.

Acronyms and abbreviations:

None

References:

None


Internal Use Only


Chapter 1 Preface

With improvement made in several earlier versions, the lower order cross-connect chip for the OptiX OSN equipment has a capacity increased from 5G to 40G. For the OptiX OSN 7500, the SST1IXCS has an 80G lower order cross-connect capacity. Compared with the large capacity (hundreds of Gbit/s) of the higher order cross-connect chip, the capacity of the lower order cross-connect chip is small and thus becomes rare. The lower order resources are always used for lower order services, and are also used on other conditions. How the cross-connect chip on the board processes services is not known to users. Hence, the customers always raise the question that why lower order resources are insufficient when only a few lower order services are configured. This document aims to clarifying the doubt with the rules for using the lower order chip resources of the cross-connect board.


Internal Use Only


Chapter 2 Usage of the Lower Order Resource of

the Cross-Connect Board

2.1 Lower Order Resources Required by the Ordinary SDH Service

Figure 2-1 shows how an ordinary lower order SDH service is cross-connected in the chips on the cross-connect board.

Illustration:External bus of the cross-connect board

Cross-connection of the cross-connect chip

Internal bus of the cross-connect board

Lo wer order

cross- connect chip

CD

Lower order ingressBE

Higher order

cross- connect chipA F

Figure 2-1 Chip connection for the ordinary SDH lower order service

The user configures a lower order service. For the chips of the cross-connect board, this lower order service is registered in three cross routes, that is, A-B, C-D, and E-F. (D-E, and B-C indicate the fixed physical connection between the higher order chip and lower order chip.)

A-B and E-F are connections in the higher order chip, which cross-connects the lower order service in the VC-4 path.

C-D is the connection in the lower order chip, which cross-connects the lower order service in the VC-12 or VC-3 path.


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2008-03-10 Huawei confidential. No spreading without permission. of 21

A is the source of the lower order service and F is the sink. As shown in Figure 2-1, one lower order service uses one lower order ingress B of the higher order chip, and one lower order ingress C and egress D of the lower order chip. Each lower order ingress (B) of the higher order chip can be considered as a VC-4 path. Each ingress C or egress D of the lower order chip can be considered as a lower order timeslot in the VC-4 path.

For example, in the case of a cross-connect board of a 5G lower order capacity, it can be considered that the higher order chip on the cross-connect board has 32 lower order ingresses.

In the case of the VC-12 level, the lower order chip has 32 x 63 VC-12 ingresses or egresses. In the case of the VC-3 level, the lower order chip has 32 x 3 ingresses or egresses.

To successfully configure a lower order service, a lower order ingress of the higher order chip must be available. Generally, the source VC-4 for a lower order service should have one lower order ingress on the higher order chip. Several lower order services that share the same source VC-4 use the same low order ingress of the higher order chip. Several lower order services that have different source VC-4s use different lower order ingresses of the higher order chip. Consider this as an example.

Source VC-4 Source Timeslot Sink VC-4 Sink Timeslot Lower order service 1 1 1 2 1 Lower order service 2 1 2 3 2 Lower order service 3 2 1 4 1

The lower order services 1–2 have the same source VC-4 but different source timeslots. For the cross-connect chip, the two lower order services use the same ingress B on the higher order chip. The lower order service 3 has a different source VC-4 from the lower order services 1–2, but uses a new ingress B' on the higher order chip.

To check whether any spare lower order ingress on the higher order chip is available, run the cfg-get-lowxc-capacity command and check the returned parameter, that is, LEFT-SRC-VC4-NUM.

If the value of the parameter is not 0, the lower order services that are of different source VC-4s from those for the existing lower order services can be configured. If the parameter is 0, only the lower order services that have the same VC-4 as the existing lower order services can be configured. In this way, none of new lower order ingresses on the higher order chip should be used.

Consider this as an example.

:cfg-get-lowxc-capacity:9

LOW-XC-CAPACITY


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BID MAX-CAPACITY MAX-VC4-NUM LEFT-SRC-VC4-NUM LEFT-DST-VC4-NUM LEFT-DST-VC12-NUM LEFT-DST-VC3-NUM

9 5 32 7 2 582 24

Total records :1

The value of the LEFT-SRC-VC4-NUM parameter is 7. This indicates that lower order services of different source VC-4s from those for the existing services can be configured. In this case, the value of the LEFT-DST-VC4-NUM parameter indicates that only two lower order egresses of the VC-4 are available.

To successfully configure a lower order service, one lower order ingress on the higher order chip, one spare lower order egress C and one spare lower order ingress D must be available. The following sections focus on the usage of the ingresses and egresses of the lower order chip.

2.2 Occasions Where Many Lower Order Resources Are Used

Sometimes, the lower order resources are insufficient even when a few lower order services are configured. The customer always has doubts about this. Actually, the usage of lower order ingresses and egresses is related to the configured service timeslots and protocol protection in the existing network. On the following conditions, many lower order resources are used. In the case of the ordinary lower order services, the usage of these lower order resources is different.

Note: In the following sections, the service is a unidirectional service, unless otherwise specified.

2.2.1 Service in Disorder

In the case of service disorder, VC-3/VC-12 lower order resources are wasted.

I. Timeslot conflict causes waste of the lower order resources.

In one VC-4 path, there are 63 VC-12 timeslots or 3 VC-3 timeslots. In the case of Huawei OptiX OSN equipment, the mapping relations of VC-12 and VC-3 timeslots in each VC-4 path for SDH services are as follows: The first VC-3 corresponds to these VC-12 timeslots (1, 4, 7, 10, 13,… 61).

The second VC-3 corresponds to these VC-12 timeslots (2, 5, 8, 11, 14,…62).

The third VC-3 corresponds to these VC-12 timeslots (3, 6, 9, 12, 15,…63).

When one VC-3 timeslot in a VC-4 path is used to configure a VC-3 service, all VC-12 timeslots in this VC-3 timeslot are used. When one VC-12 timeslot in a


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VC-4 path is used to configure a VC-12 service, the VC-3 timeslot containing this VC-12 timeslot is used. Thus, this VC-3 timeslot is not available to configure another VC-3 service.

Example I: When the first VC-3 in one VC-4 is used to configure a VC-3 service, all VC-12 timeslots (1, 4, 7, 10,…61) in this VC-3 timeslot are used. These VC-12 timeslots cannot be used to configure VC-3 or VC-12 lower order services. Consider this as an example.

Configure a VC-3 service from the first VC-3 timeslot in the first VC-4 of the board in slot 1 to the first VC-3 timeslot in the first VC-4 of the board in slot 3.

:cfg-add-xc:0,1,1,1,1,3,1,1,1,vc3

:cfg-verify

In this case, the attempt to configure a lower order service from the first VC-12 timeslot in the first VC-4 of the board in slot 2 to the fourth VC-12 timeslot in the first VC-4 of the board in slot 3 fails. The returned result shows that the sink timeslots conflict. This is because the fourth VC-12 timeslot in the first VC-4 of the board in slot 3 is used to configure the lower order service for which the first VC-3 timeslot in the first VC-4 of the board in slot 3 is used.

:cfg-add-xc:0,2,1,1,1,3,1,1,4,vc12

failed! cmd:0x8600 error:0x975b NSERR_CFG_XC_DST_CONFLICT

Example II. The first VC-12 timeslot in a VC-4 is used to create a VC-12 service. That is, the first VC-3 containing this VC-12 in the VC-4 is used. In this case, this VC-3 timeslots cannot be used to create any VC-3 service. Consider this as an example.

Configure a VC-12 service from the first VC-12 timeslot in the first VC-4 of the board in slot 4 to the first VC-12 timeslot in the first VC-4 of the board in slot 6.

:cfg-add-xc:0,4,1,1,1,6,1,1,1,vc12

:cfg-verify

In this case, the attempt to configure a VC-3 service from the first VC-3 timeslot in the first VC-4 of the board in slot 5 to the first VC-3 timeslot in the first VC-4 of the board in slot 6 fails. The returned result shows that the sink timeslots conflict. This is because the first VC-3 timeslot in the first VC-4 of the board in slot 6 is used to configure the VC-12 service for which the first VC-12 timeslot in the first VC-4 of the board in slot 6 is used.

:cfg-add-xc:0,5,1,1,1,6,1,1,1,vc3

failed! cmd:0x8600 error:0x975b NSERR_CFG_XC_DST_CONFLICT


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Sum-up: If VC-12 and VC-3 lower order services are configured in one VC-4 path, the lower order timeslots may easily conflict or be wasted. Hence, do not configure both the VC-12 and VC-3 lower order services in the same VC-4 path.

II. Services of different sources or sinks waste lower order resources.

If the configured services are of the same source and sink, the lower order resources can be saved. If the configured services are of different sources or sinks, more lower order resources are used.

Example I. Same source and same sink: Configure unidirectional services from VC-12 timeslots 1–63 in the first VC-4 of the board in slot 1 to VC-12 timeslots 1–63 in the first VC-4 of the board in slot 2. In this case, only one VC-4 ingress and one lower order VC-4 egress are used. See Figure 2-2.


VC-12 timeslots 1-63 of the firstVC-4 of the board in slot 1



Lower order cross-connect chip

CD

Lower order ingress BE

Higher order cross-connect chip

A F

One lower order VC-4 egress used


One lower order VC-4ingress used

Figure 2-2 Chip connection for the lower order services of the same source and sink

Note: Figure 2-2 depicts the connection of the chips in the case of unidirectional services. In the case of bidirectional services, two lower order VC-4 ingresses and two lower order VC-4 egresses are used.

If the configured services are of different sources and different sinks, more lower order resources are required. For example, configure VC-12 services from VC-12 timeslots 1–20 in the first VC-4 of the board in slot 1 to VC-12 timeslots 1–20 in the first VC-4 of the board in slot 2, and configure VC-12 services from


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VC-12 timeslots 21–63 of the first VC-4 of the board in slot 1 to VC-12 timeslots 21–63 of the second VC-4 of the board in slot 2. In this case, the unidirectional services use one lower order VC-4 ingress and two lower order VC-4 egresses.







VC-12 timeslots 1-20 of thesecond VC-4 of the board in slot 2

Two lower order VC-4egresses used

One lower order VC-4ingress used

VC-12 timeslots 21-63 of thefirst VC-4 of the board in slot 1


Figure 2-3 Chip connection for the unidirectional services of different sources and sinks

Note: Figure 2-3 depicts the connection of the chips in the case of unidirectional services. In the case of bidirectional services, three lower order VC-4 ingresses and three lower order VC-4 egresses are used.

Sum-up: One bidirectional service of the same source and sink requires two ingresses and two egresses. One bidirectional service of different sources or sinks require three ingresses and three egresses.

Hence, configure services of the same source and sink into the same VC-4 instead of configuring them into different VC-4s; otherwise, lower order resources are wasted.

2.2.2 Lower Order Resources Required by the SNCP/SNCMP/PPS/DLAG Lower Order Service

I. In the case of the SNCP/SNCMP/PPS/DLAG, the working and protection channels at the selective receiving end require two lower order ingresses and one lower order egress.

In the case of the SNCP/SNCMP/PPS/DLAG, the protection channel at the selective receiving end uses one lower order ingress, though the protection channel carries no service. This is because the SNCP/SNCMP/PPS/DLAG


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switching of the working and protection channels is performed in the lower order chip. Figure 2-4 shows the chip connection.

I

H


CD

Lower orderingress

BE

Higher order cross-connect chipA F

Service in theworking channel

Service in theprotection channel

Illustration:

External bus of the cross-connect board



Cross-connection of the protection channel

G

Figure 2-4 Chip connection for the lower order SNCP/SNCMP/PPS/DLAG service at the selective receiving end

As shown in Figure 2-4, before the service is switched to the protection channel, connection I-D is not established. When the service is switched from the working channel to the protection channel, connection C-D is selected to establish connection I-D. Though connection I-D is not established before the service is switched to the protection channel, the lower order ingress I of the lower order chip on the cross-connect board is used, and cannot be used to configure any other lower order service.

Hence, at the selective receiving end, one SNCP/SNCMP/PPS/DLAG lower order service requires two lower order ingresses and one lower order egress.

II. In the case of the SNCP/SNCMP/PPS/DLAG, the two services at the dual fed end require one lower order ingress and two lower order egresses.

In the case of the SNCP/SNCMP/PPS/DLAG, the lower order chip performs the dual feeding of the lower order services. In this case, more lower order egresses are required. Figure 2-5 shows the chip connection for this case.


Internal Use Only


SNCP/SNCMP/PPS/DLAG working channel

SNCP/SNCMP/PPS/DLAGprotection channel

/

Illustration:

External bus of the cross-connect boardCross-connection of the cross-connect chipInternal bus of the cross-connect board



Ordinary lowerorder SDH service

Figure 2-5 Chip connection for the lower order SNCP/SNCMP/PPS/DLAG service at the dual fed end

As shown in Figure 2-5, the two lower order services use one lower order ingress, and two lower order egresses.

Sum-up: One SNCP/SNCMP/PPS/DLAG service requires three lower order ingresses and three lower order egresses.

In the case of a 5G lower order chip, a maximum of INT (32/3) x 63 VC-12 SNCP/SNCMP/PPS/DLAG services, or INT (32/3) x 3 VC-3 services can be configured if the services are configured in order.

Note: The previous description is based on the assumption that the number of the SNCMP protection unit is 1. If the number of the SNCMP protection units is N, one SNCMP lower order service requires 2+N lower order ingresses and 2+N lower order egresses. In the case of a 5G lower order chip, a maximum of INT (32/(2+N)) x 63 VC-12 SNCP/SNCMP/PPS/DLAG services, or INT (32/(2+N)) x 3 VC-3 services can be configured if the services are in order.


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2.2.3 Lower Order Resources Required by the 1+1 LMSP Lower Order Service

I. In the case of the 1+1 LMSP, the working and protection channels at the selective receiving end require one lower order ingress and one lower order egress.

In the case of the 1+1 LMSP switching, the higher order chip switches the lower order service. This protection switching is different from the SNCP/SNCMP/PPS/DLAG protection switching.

Lower orderingress

BE

G


CD

Higher order cross-connect chipA F

Illustration:External bus of the cross-connect boardCross-connection of the cross-connect chipInternal bus of the cross-connect board

Cross-connection of the protection channel

Service in theworking channel

Service in theprotection channel

Figure 2-6 Chip connection for the lower order 1+1 LMSP service at the selective receiving end

Hence, in the case of the MSP, the protection channel does not require a lower order ingress. In this way, the lower order resources are saved. The MSP, however, only provides protection at the optical interface level rather than the timeslot level.

II. In the case of the LMSP, the two services at the dual fed end require one lower order ingress and two lower order egresses.

The 1+1 LMSP lower order service is dual fed by the lower order chip, which is the same as the lower order SNCP/SNCMP/PPS/DLAG service. In this case, more lower order egresses are used. See Figure 2-7.


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Illustration:

External bus of the cross-connect boardCross-connection of the cross-connect chipInternal bus of the cross-connect board


Higher ordercross-connect chip

1+1 LMSP working channel

1+1 LMSPprotection channel

Ordinary lower orderSDH service

Figure 2-7 Chip connection for the 1+1 LMSP lower order service at the dual fed end

As shown in Figure 2-7, the two lower order services use one lower order ingress, and two lower order egresses.

Sum-up: One 1+1 LMSP service requires two lower order ingresses and three lower order egresses. The maximum number of lower order services that can be configured depends on the lower order egresses. If no lower order egress is available, lower order services cannot be created even when some lower order ingresses are available.

In the case of a 5G lower order chip, a maximum of INT (32/3) x 63 VC-12 1+1 LMSP services, or INT (32/3) x 3 VC-3 services can be configured if the services are configured in order.

2.2.4 Lower Order Resources Required by the 1:1 LMSP Lower Order Service

In the case of the 1:1 LMSP, the protection channel carries the extra service. For a 5G lower order chip, a maximum of 32 x 63 VC-12 or 32 x 3 VC-3 lower order services can be configured.


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2.2.5 Lower Order Resources Required by the Lower Order Service in an MSP Ring

In the case of a two-fiber bidirectional MSP ring, the protection channel can carry the extra service. Hence, the accessed service is similar to the ordinary SDH service. For the cross-connect board of a 40G higher capacity and a 5G lower order capacity, a maximum of 224 unidirectional VC-4 services can be accessed, and a maximum of 112 bidirectional services can be accessed. One bidirectional service uses two VC-4s of the lower order chip. In the case of the 5G lower order chip, a maximum of

INT (32/2) x 63 VC-12 or INT (32/2) x 3 VC-3 bidirectional services can be configured.

If protection channels do not carry extra services, half of the timeslots are used for protection. In this way, only 56 (224/4) VC-4 bidirectional services can be accessed. The number of lower order services that can be accessed is the same as when protection channels carry extra services, as the resources used for protection are related to the higher order chip, rather than the lower order chip.

2.2.6 Lower Order Resources Required by the SNCTP Lower Order Service

In the case of the SNCTP, the higher order chip dual feeds the two lower order services. Hence, one lower order ingress and one lower order egress are required. At the selective receiving end, the higher order chip switches the service from the working channel to the protection channel. In this case, one lower order ingress and one lower order egress are required.

Hence, one SNCTP lower order service uses two lower order ingresses and two lower order egresses. In the case of a 5G lower order chip, a maximum of INT (32/2) x 63 VC-12 SNCTP services, or INT (32/2) x 3 VC-3 services can be configured if the services are configured in order.

The SNCTP, however, provides protection at the VC-4 path level, rather than the VC-3 or VC-12 timeslot level.

Hence, the number of lower order services that can be configured does not depend on the existing capacity of lower order services. Compared with ordinary SDH lower order services, lower order services of protection require more lower order services. Clarify customer's doubts by stating these aforementioned conditions.


Internal Use Only


Chapter 3 Command for Querying Lower Order

Resource Margin

Command cfg-get-lowxc-capacity

Function Query the lower order resource margin.

Command Level System maintenance

Availability Range Users

Version 5.36.13.XX&5.21.13.XX and later versions

Input Format :cfg-get-lowxc-capacity:any-value; One parameter

Parameter No. Indication Value Range Input Parameter

1 None 0–255

Output Format

Returned message in the case of a failure Parameters for successful operation are as follows: BID : slot number for the cross-connect board MAX-CAPACITY : maximum lower order cross-connect capacity (G) MAX-VC4-NUM : maximum number of VC-4s LEFT-SRC-VC4-NUM : number of left source VC-4s LEFT-DST-VC4-NUM : number of left sink VC-4s LEFT-DST-VC12-NUM : number of left VC-12s LEFT-DST-VC3-NUM : number of left VC-3s

Supported Board Type

Example :cfg-get-lowxc-capacity:0

Precaution This command can be used to query only the lower order capacity.

Remarks The OptiX OSN1500/2500/3500/7500 support this command.

The indication of the returned parameter need be stated. This command is used to query the lower order capacity margin.

BID: slot number of the cross-connect board

MAX-CAPACITY: maximum lower order cross-connect capacity (G), that is, the maximum capacity of the lower order chip of the cross-connect board

MAX-VC4-NUM: maximum number of VC-4 paths of the lower order chip. In the case of a 5G lower order chip, the maximum number of VC-4 paths is 32.

LEFT-SRC-VC4-NUM: number of left source VC-4s in the lower order chip.

Note: The number of left source VC-4s indicate the VC-4s that are not used to configure any lower order services. If a VC-4 is used to configure even one


Internal Use Only


VC-12 or VC-3 service, this VC-4 path is used, and is not counted in the left source VC-4s. If the query result shows that the number of the source VC-4s is 0, it probably indicates that not all timeslots in VC-4 paths are used. In this case, lower order serivces can still be configured.

LEFT-DST-VC4-NUM: number of left sink VC-4s. Refer to the previous note.

LEFT-DST-VC12-NUM: number of left sink VC-12s Note: If the query result shows that the number of sink VC-12s is not 0, it does not indicate that lower order services can be configured. In this case, the source VC-12s may all be used. For example, as described in section 2.2.2 "Lower Order Resources Required by the SNCP/SNCMP/PPS/DLAG Lower Order Service", the protection channel still uses the order order ingress, even when it does not carry any extra service.

LEFT-DST-VC3-NUM: number of VC-3s. Refer to the previous note.


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Chapter 4 How to Use Fewer Lower Order

Resources

1 Configure fewer SNCP services. Configure MSP ring services instead, because the SNCP services require many lower order resources.

2 Configure services in order. Configure services of the same source or sink into the same VC-4.


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Chapter 5 How to Handle the Case Where Lower

Order Resources Are Insufficient

1. Transform the SNCP ring into the MSP ring, and modify the network configuration accordingly. In this case, services are interrupted.

2. Optimize the services that are in disorder. Configure the services of the same source and sink into the same VC-4. Configuration on related nodes should be modified, and services are interrupted.

3. Use the cross-connect board with more lower order capacity to replace the cross-connect board with less lower order capacity. For example, replace the EXCSA with the UXCSA. If cross-connect boards are of 1+1 protection in the existing network, the board replacement does not interrupt services.

OptiX NG-SDH Lower Order Cross-Connection Topic-A

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