GBSS15.0 Capacity Monitoring Guide(BSC6910-Based)(01)(PDF)-En

GBSS15.0

GBSS Capacity Monitoring Guide(BSC6910-Based)

Issue 01Date 2013-05-04

HUAWEI TECHNOLOGIES CO., LTD.

Copyright Huawei Technologies Co., Ltd. 2013. All rights reserved.No part of this document may be reproduced or transmitted in any form or by any means without prior writtenconsent of Huawei Technologies Co., Ltd. Trademarks and Permissions

and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.All other trademarks and trade names mentioned in this document are the property of their respective holders. NoticeThe purchased products, services and features are stipulated by the contract made between Huawei and thecustomer. All or part of the products, services and features described in this document may not be within thepurchase scope or the usage scope. Unless otherwise specified in the contract, all statements, information,and recommendations in this document are provided "AS IS" without warranties, guarantees or representationsof any kind, either express or implied.

The information in this document is subject to change without notice. Every effort has been made in thepreparation of this document to ensure accuracy of the contents, but all statements, information, andrecommendations in this document do not constitute a warranty of any kind, express or implied. Huawei Technologies Co., Ltd.Address: Huawei Industrial Base

Bantian, LonggangShenzhen 518129People's Republic of China

Website: http://www.huawei.comEmail: [email protected]

Issue 01 (2013-05-04) Huawei Proprietary and ConfidentialCopyright Huawei Technologies Co., Ltd.

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About This Document

OverviewThis document provides guidelines for GBSS capacity monitoring and provides methods fordiagnosing network capacity problems. It helps maintenance engineers and networkoptimization engineers monitor the usage of network resources in a timely manner, providesdata basis for adjusting, optimizing, and expanding network capacity, and prevents deteriorationin network quality and user experience due to insufficient network capacity.

Product VersionThe following table lists the product versions related to this document.

Product Name Product VersionBSC6910 V100R015C00BTS3900 V100R008C00

The mapping single-modebase station versions are:l GBTS: V100R015C00l eGBTS: V100R015C00

BTS3900ABTS3900LBTS3900ALDBS3900

Intended AudienceThis document is intended for:l Maintenance engineersl Network optimization engineers

Organization1 Change in the GBSS Capacity Monitoring Guide (BSC6910-Based)

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) About This Document


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The section provides information about the changes in different document versions of GBSSCapacity Monitoring Guide (BSC6910-Based).2 System Capacity Data CollectionThis section describes how to collect, monitor, and analyze measurement results of performancecounters related to GBSS capacity on the M2000 client.3 Capacity Counter Categories and Capacity Problem Locating MethodsThis chapter describes key performance counters related to all capacity resources and providesthe methods for identifying and troubleshooting resource bottleneck.4 Radio Resource MonitoringMonitoring radio resources involves monitoring the loads of PCHs, SDCCHs, TCHs, andPDCHs.5 Equipment Resource MonitoringMonitoring equipment resources involves monitoring the loads of EGPUa/EXPUa boards,interface boards, and inter-subrack BSC communication resources.6 Transmission Resource MonitoringMonitoring transmission resources involves monitoring the loads of A, Gb, and Abis interfacetransmission resources.

ConventionsSymbol ConventionsThe symbols that may be found in this document are defined as follows.

Symbol DescriptionIndicates a hazard with a high level or medium level of riskwhich, if not avoided, could result in death or serious injury.

Indicates a hazard with a low level of risk which, if notavoided, could result in minor or moderate injury.

Indicates a potentially hazardous situation that, if notavoided, could result in equipment damage, data loss,performance deterioration, or unanticipated results.Indicates a tip that may help you solve a problem or savetime.Provides additional information to emphasize or supplementimportant points of the main text.

General ConventionsThe general conventions that may be found in this document are defined as follows.



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Convention DescriptionTimes New Roman Normal paragraphs are in Times New Roman.Boldface Names of files, directories, folders, and users are in

boldface. For example, log in as user root.Italic Book titles are in italics.Courier New Examples of information displayed on the screen are in

Courier New.

Command ConventionsThe command conventions that may be found in this document are defined as follows.

Convention DescriptionBoldface The keywords of a command line are in boldface.Italic Command arguments are in italics.[ ] Items (keywords or arguments) in brackets [ ] are optional.{ x | y | ... } Optional items are grouped in braces and separated by

vertical bars. One item is selected.[ x | y | ... ] Optional items are grouped in brackets and separated by

vertical bars. One item is selected or no item is selected.{ x | y | ... }* Optional items are grouped in braces and separated by

vertical bars. A minimum of one item or a maximum of allitems can be selected.

[ x | y | ... ]* Optional items are grouped in brackets and separated byvertical bars. Several items or no item can be selected.

GUI ConventionsThe GUI conventions that may be found in this document are defined as follows.

Convention DescriptionBoldface Buttons, menus, parameters, tabs, window, and dialog titles

are in boldface. For example, click OK.> Multi-level menus are in boldface and separated by the ">"

signs. For example, choose File > Create > Folder.

Keyboard OperationsThe keyboard operations that may be found in this document are defined as follows.



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Format DescriptionKey Press the key. For example, press Enter and press Tab.Key 1+Key 2 Press the keys concurrently. For example, pressing Ctrl+Alt

+A means the three keys should be pressed concurrently.Key 1, Key 2 Press the keys in turn. For example, pressing Alt, A means

the two keys should be pressed in turn.

Mouse OperationsThe mouse operations that may be found in this document are defined as follows.

Action DescriptionClick Select and release the primary mouse button without moving

the pointer.Double-click Press the primary mouse button twice continuously and

quickly without moving the pointer.Drag Press and hold the primary mouse button and move the

pointer to a certain position.



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Contents

About This Document.....................................................................................................................ii1 Change in the GBSS Capacity Monitoring Guide (BSC6910-Based)..................................12 System Capacity Data Collection...............................................................................................33 Capacity Counter Categories and Capacity Problem Locating Methods...........................43.1 Capacity Counter Categories..........................................................................................................................................53.2 Capacity Monitoring and Problem Locating Methods...................................................................................................93.2.1 Methods for Locating Capacity Problems...................................................................................................................93.2.2 Methods for Troubleshooting Capacity Problems.....................................................................................................104 Radio Resource Monitoring......................................................................................................134.1 PCH Load.....................................................................................................................................................................144.2 SDCCH Load................................................................................................................................................................154.3 TCH Load.....................................................................................................................................................................164.4 PDCH Load..................................................................................................................................................................165 Equipment Resource Monitoring.............................................................................................185.1 GSM CP Subsystem Resources....................................................................................................................................195.2 GSM UP Subsystem CS Resources..............................................................................................................................205.3 GSM UP Subsystem PS Resources..............................................................................................................................205.4 Interface Board Load....................................................................................................................................................215.5 Inter-Subrack BSC Communication Bandwidth and Load..........................................................................................226 Transmission Resource Monitoring........................................................................................246.1 A over IP (Signaling)....................................................................................................................................................256.2 A over IP (Traffic)........................................................................................................................................................266.3 Gb over IP.....................................................................................................................................................................276.4 Abis Interface...............................................................................................................................................................286.4.1 Abis over TDM .........................................................................................................................................................286.4.2 Abis over IP...............................................................................................................................................................29

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) Contents


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1 Change in the GBSS Capacity MonitoringGuide (BSC6910-Based)

The section provides information about the changes in different document versions of GBSSCapacity Monitoring Guide (BSC6910-Based).

01 (2013-05-04)This is the first commercial release of GBSS14.0.Compared with issue Draft A (2013-02-27) of GBSS14.0, this issue includes the following newtopics:l 3.2 Capacity Monitoring and Problem Locating MethodsCompared with issue Draft A (2013-02-27) of GBSS14.0, this issue includes the followingincorporate changes:

Content Description3 Capacity Counter Categories andCapacity Problem Locating Methods

Changed the name of this chapter fromCapacity Counter Categories andCapacity Expansion Specifications toCapacity Counter Categories andCapacity Problem Locating Methods.

4.1 PCH Load4.2 SDCCH Load4.3 TCH Load4.4 PDCH Load5.4 Interface Board Load5.5 Inter-Subrack BSC CommunicationBandwidth and Load

Added the description about monitoringprinciples in the Related Counters.

Compared with issue Draft A (2013-02-27) of GBSS14.0, this issue excludes the following newtopics:

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based)

1 Change in the GBSS Capacity Monitoring Guide(BSC6910-Based)


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l Capacity Monitoring and Problem Location Methods

Draft A (2013-02-27)This is the Draft A release of GBSS15.0.


1 Change in the GBSS Capacity Monitoring Guide(BSC6910-Based)


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2 System Capacity Data CollectionThis section describes how to collect, monitor, and analyze measurement results of performancecounters related to GBSS capacity on the M2000 client.

Prerequisitesl You have logged in to the M2000 client. The M2000 client communicates with NEs

properly.l You have been granted the performance management permission.

ContextFor the ease of daily capacity load monitoring, collect measurement results of performancecounters on the M2000. The performance counters are measured in a 15-minute, 60-minute, or24-hour measurement period. In normal cases, you are advised to analyze 60-minute trafficstatistics measured in peak hours every day and use an Excel file to make a graph of the capacityload trend.

NOTE

l For details about how to collect performance counters and monitor the counters in real time, see"Performance Management" in the M2000 online help.

l Peak hours in a day refer to the time when the BSC traffic volume reaches the maximum.

ProcedureStep 1 On the M2000 client, register a user-defined measurement task for collecting measurement

results of capacity-related counters.Step 2 On the M2000 client, periodically collect the measurement results.Step 3 Analyze and evaluate the measurement results by using the methods and standards provided in

this document. In addition, provide an analysis report on capacity monitoring.----End

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) 2 System Capacity Data Collection


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3 Capacity Counter Categories and CapacityProblem Locating Methods

About This Chapter

This chapter describes key performance counters related to all capacity resources and providesthe methods for identifying and troubleshooting resource bottleneck.3.1 Capacity Counter CategoriesGBSS capacity resources are categorized into radio resources, equipment resources, andtransmission resources. This section describes key performance counters and capacity expansionspecifications for these resources.3.2 Capacity Monitoring and Problem Locating MethodsThis chapter describes the methods for monitoring capacity-related counters and locatingcapacity problems during routine capacity maintenance.


3 Capacity Counter Categories and Capacity ProblemLocating Methods


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3.1 Capacity Counter CategoriesGBSS capacity resources are categorized into radio resources, equipment resources, andtransmission resources. This section describes key performance counters and capacity expansionspecifications for these resources.

CAUTIONl With the network development, network capacity is dynamically changing. Therefore, the

capacity expansion specifications for capacity-related counters are changeable. If a newservice is deployed or a new charging policy is used, the traffic model and number ofsubscribers may change abruptly. This leads to a sudden change in the loads of networkcapacity resources. In this situation, you are advised to predict and analyze the changes anddetermine the capacity optimization solution for the network where traffic volume increasesrapidly, a new service needs to be deployed, or a new charging policy is used. Contact localHuawei engineers if you require capacity evaluation and optimization services, includingcapacity prediction, evaluation, adjustment, and expansion.

l The capacity expansion specifications described in this document are defined for the networkwith a stable increase in the traffic volume and for reference only. These specifications canbe customized according to the actual situation.

l The capacity expansion specifications described in this section are lower than the actual alarmgeneration thresholds so that capacity problems can be located in advance.

Table 3-1 Radio resourcesResource Counter Capacity Expansion

Specification4.1 PCH Load OVERLOAD rate of paging 2%

orPCH load

70%

4.2 SDCCH Load Congestion Rate on SDCCHper CELL

2%

4.3 TCH Load Congestion Rate on TCH 2%4.4 PDCH Load TBF congestion rate 3%

Table 3-2 Equipment resourcesResource Counter Capacity Expansion

Specification5.1 GSM CP SubsystemResources

Average CPU Usage of theCPU

70%




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Resource Counter Capacity ExpansionSpecification

5.2 GSM UP Subsystem CSResources

TC load of UP subsystem 70%

5.3 GSM UP Subsystem PSResources

PDCH load of the UPsubsystem

70%

5.4 Interface Board Load Average Forwarding Ratio ofInterface Boards

70%

5.5 Inter-Subrack BSCCommunicationBandwidth and Load

Peak inter-subrack trafficusage

60%

Average inter-subrack trafficusage

40%

Inter-subrack packet loss rate 0.01%

Table 3-3 Transmission resources (TDM transmission mode)Resource Counter Capacity Expansion

Specification6.4.1 Abis over TDM l Flex Abis:

Congestion Rate ofDynamic ResourceAssignment (16 kbit/s)orCongestion Rate ofDynamic ResourceAssignment (8 kbit/s)

3%

l Non-Flex Abis:Percentage of failedapplication attempts ofAbis timeslots because ofno idle timeslot (in non-Flex Abis mode)

3%




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Table 3-4 Transmission resources (IP transmission mode)Resource Counter Capacity Expansion

SpecificationA over IP (Signaling) Receive bandwidth

requirement/Bandwidthallocated by the transportbearer networkorTransmit bandwidthrequirement/Bandwidthallocated by the transportbearer network

70%

A over IP (Traffic) Forward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorBackward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorMean Receive Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet portorMean Transmit Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet port

70%




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Resource Counter Capacity ExpansionSpecification

Gb over IP Forward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorBackward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorMean Receive Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet portorMean Transmit Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet port

70%

6.4.2 Abis over IP Forward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorBackward BandwidthAllocated to IP TransportAdjacent Node/Bandwidthallocated by the bearernetworkorMean Receive Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet portorMean Transmit Rate of theFEGE Ethernet Port/Bandwidth of the physicalEthernet port

70%




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3.2 Capacity Monitoring and Problem Locating MethodsThis chapter describes the methods for monitoring capacity-related counters and locatingcapacity problems during routine capacity maintenance.

3.2.1 Methods for Locating Capacity ProblemsThis section describes how to locate capacity problems.In most cases, an abnormal KPI triggers the troubleshooting process. Determining the possibletop N problem cells facilitates follow-up troubleshooting. Figure 3-1 shows the generaltroubleshooting process.You are advised to analyze accessibility-related KPIs to identify the resource insufficiency thatcauses access congestion. For details about resource insufficiency analysis and relevantsolutions, see3.2.2 Methods for Troubleshooting Capacity Problems.




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Figure 3-1 Flowchart for capacity problem location

NOTEThe analysis report on the capacity problem is provided after capacity data collection and analysis arecomplete.

3.2.2 Methods for Troubleshooting Capacity ProblemsThis section describes how to troubleshoot capacity problems.




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The BSS capacity resources are correlated because of resource sharing. Insufficiency in a certaintype of resource unnecessarily indicates resource insufficiency in the entire BSS. Some capacityproblems can be resolved by resource adjustment and optimization, and others require capacityexpansion. Before expanding capacity, you are advised to comprehensively analyze relatedresources. Table 3-5 lists the recommended solutions to common capacity problems.For example, TCHs, PDCHs, and SDCCHs can be mutually converted. Therefore, insufficiencyin TCHs, PDCHs, or SDCCHs unnecessarily requires capacity expansion. If SDCCHs areinsufficient, you can decrease the number of TCHs or enable the dynamic SDCCH conversionfunction. If SDCCHs, TCHs, and PDCHs are insufficient at the same time, comprehensivelyanalyze the three types of channels and determine whether the problem can be resolved bychannel optimization. If the problem persists, perform capacity expansion on the BSS.Overall capacity evaluation is necessary especially for the networks where the traffic volumeincreases rapidly and before a new charging policy is used. Based on the capacity evaluation,formulate a feasible plan for monitoring network capacity and detecting resource insufficiency.

Table 3-5 Solutions to common capacity problemsIf... Then...PCHs areoverloaded

1. Enable the dynamic CCCH conversion function.2. Split location areas (LAs).

SDCCHs arecongested

Enable the dynamic SDCCH conversion function.

TCHs arecongested

1. Enable TCHHs and lower the threshold for enabling TCHHs.2. Add TRXs.

PDCHs arecongested

Check whether TCHs are congested.1. If TCHs are congested, add TRXs.2. If TCHs are not congested, modify the PDCH proportion threshold.

The controlplane (CP) isoverloaded

Expand EGPUa/EXPUa(Logical function type is set to GCUP) boards.

CS serviceprocessingboards areoverloaded


PS serviceprocessingboards areoverloaded


Transmissionresources areoverloaded

Expand the transmission resource capacity.




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NOTEIf the BSC has been fully configured and board expansion is required, add a BSC.




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4 Radio Resource MonitoringAbout This Chapter

Monitoring radio resources involves monitoring the loads of PCHs, SDCCHs, TCHs, andPDCHs.4.1 PCH Load4.2 SDCCH Load4.3 TCH Load4.4 PDCH Load

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) 4 Radio Resource Monitoring


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4.1 PCH LoadRelated Counters

The PDCH load is indicated by the following counters:l RL3188: OVERLOAD rate of pagingThis counter provides the percentage of CS and

PS paging overload times over the PCH on the Abis interface to all paging times.l PCH loadThis counter is a calculation counter, which reflects the percentage of paging

times to the PCH paging capability. The formula for calculating the PCH load is as follows:PCH load = (A330: Delivered Paging Messages for CS Service + A331: Delivered PagingMessages for PS Service)/PCH paging capability x 100%where, the PCH paging capability provides a basis for planning location areas (LAs)because paging messages are sent on a basis of LA. The formula for calculating the PCHpaging capability is as follows:PCH paging capability = [(Number of CCCH blocks - Number of CCCH blocks reservedfor AGCH) x Time for sending a BCCH multiframe] x Paging message combinationefficiency x Um interface usage between paging groups x 3600

NOTE

l Time for sending a BCCH multiframe: 0.2354s.l Paging message combination efficiency: Efficiency for encapsulating paging messages on the Um

interface. (The efficiency is determined by the IMSI-based or TMSI-based paging policy.)l Um interface usage between paging groups: The imbalance between paging groups and between

services imbalance regarding time decreases the Um interface usage.For example, paging capability using common configurations in most scenarios is calculated as follows:Paging capability = [(Number of CCCH blocks - Number of CCCH blocks reserved for AGCH) x Pagingmessage combination efficiency x Um interface usage between paging groups]/(51 x TDMA period)Number of CCCH blocks: The number of message blocks for a non-combined CCCH is 9.Number of CCCH blocks reserved for AGCH: 2Paging message combination efficiency: 2.87 (The first paging adopts the TMSI-based paging policy andthe second paging adopts the IMSI-based paging policy.)Um interface usage between paging groups: 80%Therefore, the paging capability in this example is calculated as follows: Paging capability = (9-2)/0.2354x 2.87 x 80% x 3600 = 245791 times/hour

Capacity Expansion ThresholdRL3188: OVERLOAD rate of paging > 2%orPCH load > 70%, and the network traffic volume is increasing constantly.

Impact on Systeml Call MSs are paged on PCHs. In the GSM system, paging is performed on a basis of location

area (LA). If the actual paging volume in an LA exceeds the theoretical PCH pagingcapacity, PCHs become congested and even overloaded. This decreases the paging successrate and deteriorates user experience.



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l The BSS reports ALM-21822 Cell PCH Congestion when PCHs in a cell are congested.

Relationship with Other CountersNone

Recommended Measuresl Enable the GBFD-511503 Dynamic Multiple CCCH feature to expand the PCH capacity.l Split an LA to reduce its capacity.

4.2 SDCCH LoadRelated Counters

GSM signaling services are carried on SDCCHs. An MS needs to occupy an SDCCH each timethe MS initiates an SMS, performs a location update, or sets up a call. If SDCCHs are insufficient,an MS cannot perform services. In this situation, the BSS considers SDCCHs as congested andincrements the number of SDCCH congestion occurrences by 1. Causes for insufficient SDCCHsinclude inappropriate network planning and service surge during regional events.The SDCCH load is indicated by the following counter:RR370: Congestion Rate on SDCCH per CELL This counter provides the percentage oftimes that all requested SDCCHs are occupied to all SDCCH request times. It indicates theSDCCH congestion due to insufficient resources.

Capacity Expansion ThresholdRR370: Congestion Rate on SDCCH per CELL > 2%

Impact on SystemGSM signaling services are carried on SDCCHs. An MS needs to occupy an SDCCH each timethe MS initiates an SMS, performs a location update, or sets up a call. If SDCCHs are insufficient,an MS fails to initiate SMS, a calling MS cannot access the network, and a called MS cannotrespond. SDCCHs are vital to process services, and therefore normal operation of SDCCHsneeds to be preferentially ensured. In normal cases, enable the dynamic SDCCH conversionfunction to ensure that SDCCHs are sufficient.

Relationship with Other CountersSDCCHs, TCHs, and PDCHs need to be analyzed comprehensively because Huawei GBSS hasimplemented dynamic conversions among SDCCHs, TCHs, and PDCHs.

Recommended Measuresl Enable the dynamic SDCCH conversion function.l Expand TRX capacity if SDCCHs, TCHs and PDCHs are all congested at the same time

or SDCCHs are still congested after the dynamic SDCCH conversion function is enabled.



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4.3 TCH LoadRelated Counters

CS services are carried on TCHs. If TCHs are insufficient, an MS cannot perform CS services.In this situation, the BSS considers TCHs as congested and increments the number of TCHcongestion occurrences by 1.The TCH load is indicated by the following counter:K3045: Congestion Rate on TCH This counter provides the TCH congestion rate. Itindicates the percentage of TCH request failures due to no idle TCHs to all TCH requests.

Capacity Expansion ThresholdK3045: Congestion Rate on TCH > 2%

Impact on SystemIf TCHs are insufficient, CS services have difficulties accessing the network. This greatlydeteriorates user experience.


Recommended Measuresl Enable TCHHs and lower the threshold for enabling TCHHs. Note that the voice quality

of TCHHs is a little poorer than that of TCHFs.l Expand TRX capacity.

4.4 PDCH LoadRelated Counters

PS signaling and data are carried on PDCHs. A PDCH can be shared by a maximum of 16 MSsin the downlink. PDCHs can be preempted by CS services. Therefore, TCHs and PDCHs needto be analyzed comprehensively.The PDCH load is indicated by the counters related to the temporary block flow (TBF)congestion rate. TBFs are data blocks transmitted over PDCHs. The TBF congestion rate consistsof the uplink TBF congestion rate and the downlink TBF congestion rate. In normal cases, thedownlink PS data throughput is higher than the uplink PS data throughput. Therefore, thedownlink TBF congestion rate is the primary focus of PDCH load monitoring.l Uplink TBF Congestion Rate: This counter provides the percentage of TBF establishment

failures on the uplink due to insufficient resources.



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l Downlink TBF Congestion Rate: This counter provides the percentage of TBFestablishment failures on the downlink due to insufficient resources.

Capacity Expansion ThresholdUplink TBF Congestion Rate > 3%OrDownlink TBF Congestion Rate > 3%

Impact on SystemIf PDCHs are insufficient, the GPRS/EDGE service rate decreases, and even some MSs cannotprocess PS services.


Recommended Measuresl Take measures based on specific causes for insufficient PDCHs.

1. The PDCH proportion threshold for a cell is set to a small value, and therefore fewTCHs can be converted to PDCHs. As a result, PDCHs are insufficient but some TCHsare idle during peak hours. In this situation, increase the PDCH proportion threshold.

2. The channels in a cell are insufficient, and therefore TCHs and PDCHs are insufficientfor processing services during peak hours. In this situation, optimize relatedparameters or expand TRX capacity.

l Check the following counters to determine the root causes for insufficient PDCHs: Percentage of PDCH application failures due to the limited PDCH proportion threshold

= R9395: Number of PDCH Application failures For CELL PDCH Ratio Thresh/R9393:Number Of PDCH Application Attempts Percentage of PDCH application failures due to no TCH available = R9394: Number

of PDCH Application Failures due to no Convertable TCHs/R9393: Number Of PDCHApplication Attempts

If the PDCH proportion threshold is set to a value that is too small, increase the threshold.If TCHs and PDCHs in a cell are insufficient during peak hours, expand TRX capacity.



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5 Equipment Resource MonitoringAbout This Chapter

Monitoring equipment resources involves monitoring the loads of EGPUa/EXPUa boards,interface boards, and inter-subrack BSC communication resources.

5.1 GSM CP Subsystem Resources5.2 GSM UP Subsystem CS Resources5.3 GSM UP Subsystem PS Resources5.4 Interface Board Load5.5 Inter-Subrack BSC Communication Bandwidth and Load

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) 5 Equipment Resource Monitoring


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5.1 GSM CP Subsystem ResourcesRelated Counters

For BSC6910, the load of control plane (CP) and user plane (UP) subsystems is indicated by theload of the EGPUa or EXPUa board that functions as the GCUP. Specifically, the load of theCP subsystem is indicated by the following counter:AR9720: Average CPU Usage of the CPU This counter provides the mean CPU usage ofa board in a measurement period. It indicates the load and operating performance of the CPUon the board in a measurement period.

NOTEThe EGPUa or EXPUa board is used to process services on the GSM BSC control plane and user plane.For details about the functions of the EGPUa or EXPUa board, see Technical Specifications of the EGPUaBoard and Technical Specifications of the EXPUa Board, respectively.

Capacity Expansion Threshold[AR9720: Average CPU Usage of the CPU] > 70%

Impact on Systeml When the CPU becomes overloaded, the BSC triggers the flow control during which paging

messages or channel request messages are discarded. This results in access problems. Ifthe CPU is severely overloaded, a large number of subscribers cannot access the network.When this occurs, the BSS automatically forbids maintenance activities such as collectinglogs and obtaining traffic statistics files.

l If the CPU of the EGPUa or EXPUa board becomes overloaded, the BSS reportsALM-20256 CPU Overload.


Recommended MeasuresMonitor the CPU load on the EGPUa or EXPUa board based on the value of the AR9720:Average CPU Usage of the CPU counter during peak hours of a day. You are advised to:l Expand EGPUa or EXPUa boards when the value of this counter exceeds 70% during peak

hours for successive three or more days on a network with slow service growth.l Analyze capacity requirements and formulate a capacity expansion solution when the value

of this counter exceeds 50% on a network with rapid service growth.



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5.2 GSM UP Subsystem CS ResourcesRelated Counters

For BSC6910, the load of CP and UP subsystems is indicated by the load of the EGPUa orEXPUa board that functions as the GCUP. Specifically, the CS load of the UP subsystem isindicated by the CS load of the EGPUa or EXPUa board during peak hours.CS load of the UP subsystem = [ZK3014: Traffic Volume on TCH (Traffic Channel) per BSC]/[Maximum traffic volume supported by the EGPUa or EXPUa board Number of EGPUa orEXPUa boards that function as the GCUP]

NOTE

l If the EGPUa or EXPUa board functions as the GCUP, the maximum traffic volume supported by anEGPUa or EXPUa board is 6250 Erl.

l If the EGPUa or EXPUa board functions as the GCUP and works in resource pool mode, you areadvised to configure at least two EGPUa or EXPUa boards for a BSC6910.

Capacity Expansion Threshold[CS load of UP subsystem] > 70%

Impact on SystemInsufficient CS resources cause call setup failures, severely deteriorating user experience. Thisis because CS resources of the UP subsystem are used to process speech coding and decoding.


Recommended MeasuresExpand EGPUa or EXPUa boards.

5.3 GSM UP Subsystem PS ResourcesRelated Counters

For BSC6910, the load of CP and UP subsystems is indicated by the load of the EGPUa orEXPUa board that functions as the GCUP. Specifically, the PS load of the UP subsystem isindicated by the PDCH load of the EGPUa or EXPUa board during peak hours.PS load of the UP subsystem = [AS9204: AverageNumber of PDCHs Occupied per BSC]/[Maximum number of PDCHs supported by the EGPUa or EXPUa board x Number of EGPUaor EXPUa boards that function as the GCUP]



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NOTE

l If the EGPUa or EXPUa board functions as the GCUP, the maximum number of PDCHs supported byan EGPUa or EXPUa board is 3000.

l If the EGPUa or EXPUa board functions as the GCUP and works in resource pool mode, you areadvised to configure at least two EGPUa or EXPUa boards for a BSC6910.

Capacity Expansion Threshold[PS load of the UP subsystem] > 70%

Impact on SystemIf EGPUa or EXPUa boards which processes PS services are insufficient, some PDCHs cannotbe activated. This causes a decrease in PS service rate and difficult access.


Recommended MeasuresExpand EGPUa or EXPUa boards.

5.4 Interface Board LoadRelated Counters

When monitoring the load of interface boards, check whether the forwarding rate of data flowexceeds the designed maximum forwarding rate and whether the CPU of the interface board isoverloaded.The user-plane interface board load is indicated by the following counters:AR9705a: Average Forwarding Ratio of Interface BoardsThis counter provides the averageforwarding load of an interface board within a measurement period. The forwarding load refersto the percentage of the actual forwarding rate to the designed maximum forwarding rate of aninterface board. It indicates the load and operating performance of an interface board within ameasurement period.AR9720: Average CPU Usage of the CPUThis counter provides the mean CPU usage of aboard in a measurement period. It indicates the load and operating performance of the CPU onthe board in a measurement period.

NOTEInterface boards are A, Abis, Gb interface boards on the BSC.

Capacity Expansion Threshold[AR9705a: Average Forwarding Ratio of Interface Boards] > 70%or[AR9720: Average CPU Usage of the CPU] > 70%



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Impact on Systeml If the forwarding load over an interface is too high, the BSS may discard some messages.

This deteriorates the quality of service (QoS) of CS and PS services.l If the forwarding load of an interface board is too high, the BSS reports ALM-20275

Forwarding Overload of An Interface Board.


Recommended MeasuresExpand the capacity of interface boards.

5.5 Inter-Subrack BSC Communication Bandwidth andLoad

Related CountersMessages are forwarded between subracks in a BSC. If the forwarding load is too high, the SCUboard may become overloaded and discard some messages.Inter-subrack BSC communication bandwidths are as follows:l The inter-subrack BSC communication bandwidth is 40 Gbit/s when active and standby

SCUb boards are configured.l The preceding bandwidths are halved when a standalone SCUb is running.Inter-subrack BSC communication is monitored by using the following counters:l Peak inter-subrack traffic usage:

Peak inter-subrack traffic usage = [HR9732a: Peak Inter-Subrack Transmitting Traffic]/Inter-subrack bandwidth x 100%

l Average inter-subrack traffic usage:Average inter-subrack traffic usage = [AR9732a: Average Inter-Subrack TransmittingTraffic]/Inter-subrack bandwidth x 100%

l Inter-subrack packet loss rateInter-subrack packet loss rate = [R9732a: Number of Discarded Inter-Subrack Packets]/[R9732b: Number of Sent Inter-Subrack Packets] x 100%

Capacity Expansion Thresholdl Peak inter-subrack traffic usage > 60% (Prewarning and analysis is required.)l Average inter-subrack traffic usage > 40% (Prewarning and analysis is required.)l Inter-subrack packet loss rate > 0.01% (Prewarning and analysis is required.)



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Impact on Systeml If the forwarding load over an interface is too high, the BSS may discard some messages.

This deteriorates the quality of service (QoS) of CS and PS services. The Main ProcessingSubrack (MPS) is connected to the Extended Processing Subrack (EPS) using the port trunkgroup on the SCU panel. When the inter-subrack BSC communication capacity is close tothe overload threshold, the QoS of CS and PS services and network KPIs deteriorate, andthe BSS becomes unstable.

l If the actual link bandwidth usage of the port trunk group on the SCU panel exceeds thecongestion threshold (70%) or the packet loss rate over a link exceeds the congestionthreshold (0.02%) for 5 minutes or longer, the BSS reports ALM-20277 CommunicationCongestion Between Subracks.


Recommended MeasuresThe inter-subrack BSC communication capacity seldom becomes overloaded. If this occurs,contact Huawei maintenance engineers for in-depth analysis and troubleshooting.



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6 Transmission Resource MonitoringAbout This Chapter

Monitoring transmission resources involves monitoring the loads of A, Gb, and Abis interfacetransmission resources.6.1 A over IP (Signaling)6.2 A over IP (Traffic)6.3 Gb over IP6.4 Abis InterfaceThe Abis interface is between the BSC and the BTS, carries CS and PS services, radio signalinglinks (RSLs) and operation and maintenance links (OMLs). The Abis interface can use eitherthe TDM or IP transmission.

GBSS15.0GBSS Capacity Monitoring Guide (BSC6910-Based) 6 Transmission Resource Monitoring


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6.1 A over IP (Signaling)Related Counters

In IP transmission mode, the BSC and BTS are configured with FE or GE ports and use 100 or1000 MHz transmission bandwidth. This basically meets the actual bandwidth requirements.Therefore, monitor the transmission resource load from two perspectives in IP transmissionmode: transmission load of ports on the BSC or the BTS, and transmission load allocated by thebearer network.The load of SS7 links over the A interface is indicated by the following counters:T7263: Average Transmit Rate of an SCTP Link IP LayerThis counter provides the transmitrate of an SCTP link at the IP layer within a measurement period.T7268: Average Receive Rate of an SCTP Link IP LayerThis counter provides the receiverate of an SCTP link at the IP layer within a measurement period.

Capacity Expansion Threshold[T7263: Average Transmit Rate of an SCTP Link IP Layer]/Bandwidth allocated by thetransmission bearer network > 70%Or[T7268: Average Receive Rate of an SCTP Link IP Layer]/Bandwidth allocated by thetransmission bearer network > 70%

NOTE

l SCTP links have no bandwidth configurations. Therefore, when STCP links are used, monitor thebandwidth resources occupied by SCTP links and check whether the transmission resources on thebearer network meet the bandwidth requirements.

Impact on Systeml SS7 link overload causes congestion and packet loss. This affects the signaling procedure

and CS service processing.l If SCTP links are congested, the BSS reports ALM-21542 SCTP Link Congestion.


Recommended MeasuresAdd SCTP links. To ensure the control plane reliability, configure SCTP links in load sharingmode. The configuration rule is as follows:1. At least two SCTP links are configured.2. At least one SCTP link is configured for each pair of EGPUa/EXPUa boards.3. A maximum of one SCTP link is configured for each subsystem on a EGPUa/EXPUa board.



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6.2 A over IP (Traffic)Related Counters

In IP transmission mode, the BSC and BTS are configured with FE or GE ports and use 100 or1000 MHz transmission bandwidth. This basically meets the actual bandwidth requirements.Therefore, whether the transmission resources allocated by the bearer network meetrequirements is the focus of capacity monitoring in IP transmission mode.In A over IP mode, the BSC6910 uses the resource pool networking in which multiple pairs ofinterface boards form a transmission pool and share the A interface transmission resources.The traffic load of A interface transmission resources is indicated by the load of the bearernetwork and the load of the Ethernet port.l Load of the bearer network = [T6519: Forward Bandwidth Allocated to IP Transport

Adjacent Node]/Bandwidth allocated by the bearer network, or [T6520: BackwardBandwidth Allocated to IP Transport Adjacent Node]/Bandwidth allocated by the bearernetwork

l Load of the Ethernet port = [T7123: Mean Receive Rate of the FEGE Ethernet Port]/Bandwidth of the physical Ethernet port, or [T7128: Mean Transmit Rate of the FEGEEthernet Port]/Bandwidth of the physical Ethernet port

NOTE

l In IP transmission mode, the BSC and BTS are configured with FE or GE ports and use 100 or 1000MHz transmission bandwidth.

l The bandwidth allocated by the bearer network refers to the bandwidth allocated by the A interfacebackbone network.

Capacity Expansion ThresholdLoad of the bearer network > 70%OrLoad of the Ethernet port > 70%

Impact on Systeml Insufficient circuit transmission resources on the A interface lead to circuit assignment and

call setup failures. This deteriorates user experience.l If the load of physical ports exceeds the alarm threshold, the BSS reports ALM-21583 Port

Congestion.


Recommended Measuresl Ask the bearer network vendor to increase the network capacity when the load of the bearer

network exceeds 70%.



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l Expand interface boards when the load of the Ethernet port exceeds 70%.

6.3 Gb over IP

Related CountersIn IP transmission mode, the BSC and BTS are configured with FE or GE ports and use 100 or1000 MHz transmission bandwidth. This basically meets the actual bandwidth requirements.Therefore, whether the transmission resources allocated by the bearer network meetrequirements is the focus of capacity monitoring in IP transmission mode.The load of Gb transmission resources is indicated by the following counters:l T6519: Forward Bandwidth Allocated to IP Transport Adjacent Nodel T6520: Backward Bandwidth Allocated to IP Transport Adjacent Nodel T7123: Mean Receive Rate of the FEGE Ethernet Port This counter provides the

receive rate of an FE or GE Ethernet port at the data link layer within a measurement period.It indicates the data flow on an FE or GE Ethernet port at the data link layer.

l T7128: Mean Transmit Rate of the FEGE Ethernet Port This counter provides thetransmit rate of an FE or GE Ethernet port at the data link layer within a measurementperiod. It indicates the data flow on an FE or GE Ethernet port at the data link layer.

Capacity Expansion Thresholdl [T7123: Mean Receive Rate of the FEGE Ethernet Port/Bandwidth of the physical Ethernet

port] > 70%l [T7128: Mean Transmit Rate of the FEGE Ethernet Port/Bandwidth of the physical

Ethernet port] > 70%l [T6519: Forward Bandwidth Allocated to IP Transport Adjacent Node]/Bandwidth

allocated by the bearer network > 70%l [T6520: Backward Bandwidth Allocated to IP Transport Adjacent Node]/Bandwidth

allocated by the bearer network > 70%NOTE


Impact on Systeml Insufficient transmission resources on the Gb interface lead to a low GPRS or EDGE service

rate and even network access failures.l If the load of physical ports exceeds the alarm threshold, the BSS reports ALM-21583 Port

Congestion.




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Recommended MeasuresIn Gb over IP mode, the BSC interface board capacity is generally sufficient. Therefore, focuson the transmission resources allocated by the bearer network on the Gb interface. You areadvised to:l Expand Gb interface boards when the following condition is met: [T7123: Mean Receive

Rate of the FEGE Ethernet Port]/Bandwidth of the physical Ethernet port > 70%, or [T7128:Mean Transmit Rate of the FEGE Ethernet Port]/Bandwidth of the physical Ethernet port> 70%.

l Ask the bearer network vendor to increase the network capacity when the followingcondition is met: [T6519: Forward Bandwidth Allocated to IP Transport Adjacent Node/Bandwidth allocated by the bearer network] > 70%, or [T6520: Backward BandwidthAllocated to IP Transport Adjacent Node/Bandwidth allocated by the bearer network] >70%.

l Apply for a license for the Gb over IP mode and ensure that license resources are sufficient.

6.4 Abis InterfaceThe Abis interface is between the BSC and the BTS, carries CS and PS services, radio signalinglinks (RSLs) and operation and maintenance links (OMLs). The Abis interface can use eitherthe TDM or IP transmission.

6.4.1 Abis over TDM

Flex Abisl Related Counters

In Flex Abis mode, all Abis TDM timeslots on the BTS can be dynamically allocated. Whenthe BTS receives a CS or PS service request, Abis timeslots are allocated based on theactual requirements in real time. In this mode, the load of Abis transmission resources isindicated by the following counters:RR2752: Congestion Rate of Dynamic Resource Assignment (16 kbit/s)This counterprovides the congestion rate of dynamic allocation of 16 kbit/s Abis resources.RR2751: Congestion Rate of Dynamic Resource Assignment (8 kbit/s)This counterprovides the congestion rate of dynamic allocation of 8 kbit/s Abis resources.

l Capacity Expansion Threshold[RR2752: Congestion Rate of Dynamic Resource Assignment (16 kbit/s)] > 3%Or[RR2751: Congestion Rate of Dynamic Resource Assignment (8 kbit/s)] > 3%

l Impact on SystemInsufficient transmission resources on the Abis interface lead to network access failures.This deteriorates user experience.

l Relationship with Other CountersNone

l Recommended MeasuresExpand transmission resources over the Abis interface.



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Non-Flex Abis Model Related Counters

In non-Flex Abis mode, Abis timeslots, except idle Abis timeslots, bear one-to-one mappingwith the TCHs and PDCHs. Therefore, Abis timeslot capacity expansion is required if TCHand PDCH capacity expansion is performed. In this mode, the usage of idle Abis timeslotsis indicated by the following counters:Percentage of Abis timeslot application failures due to no idle timeslot (in non-Flex Abismode) = [R9109: Number of Unsuccessful Application Attempts of Abis Timeslot Becauseof No Idle Timeslot]/[R9101: Number of Application Attempts of Abis Timeslot]

l Capacity Expansion Threshold[Percentage of Abis timeslot application failures due to no idle timeslot (in non-Flex Abismode)] > 3%

l Impact on SystemInsufficient transmission resources on the Abis interface lead to difficulties in improvingthe PS service rate.

l Relationship with Other CountersNone

l Recommended MeasuresExpand transmission resources over the Abis interface.

6.4.2 Abis over IPRelated Counters

The BTS in IP transmission mode is typically configured with FE ports and uses 100 MHztransmission bandwidth. This basically meets the GSM service requirements. Therefore, monitorthe transmission resource load of a BTS from two perspectives in Abis over IP mode: bandwidthusage of physical Abis interface boards on the BSC, and whether the transmission resourcesallocated by the bearer network meet Abis transmission bandwidth requirements. The load ofIP transmission resources over the Abis interface is indicated by forward or backward bandwidthallocated to IP transport adjacent node and transmit or receive rate of the FE/GE Ethernet port.l T6519: Forward Bandwidth Allocated to IP Transport Adjacent Nodel T6520: Backward Bandwidth Allocated to IP Transport Adjacent Nodel T7123: Mean Receive Rate of the FEGE Ethernet Port This counter provides the

receive rate of an FE or GE Ethernet port at the data link layer within a measurement period.It indicates the data flow on an FE or GE Ethernet port at the data link layer.

l T7128: Mean Transmit Rate of the FEGE Ethernet Port This counter provides thetransmit rate of an FE or GE Ethernet port at the data link layer within a measurementperiod. It indicates the data flow on an FE or GE Ethernet port at the data link layer.

Capacity Expansion Thresholdl [T7123: Mean Receive Rate of the FEGE Ethernet Port/Bandwidth of the physical Ethernet

port] > 70%l [T7123: Mean Receive Rate of the FEGE Ethernet Port/Bandwidth of the physical Ethernet

port] > 70%



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l [T6519: Forward Bandwidth Allocated to IP Transport Adjacent Node/Bandwidthallocated by the bearer network] > 70%

l [T6519: Forward Bandwidth Allocated to IP Transport Adjacent Node/Bandwidthallocated by the bearer network] > 70%

NOTE


Impact on Systeml Insufficient transmission resources on the Abis interface decrease PS service rate, degrade

voice quality and even lead to network access failures.l If the load of physical ports exceeds the alarm threshold, the BSS reports ALM-21583 Port

Congestion.


Recommended Measuresl Expand Abis interface boards when the following condition is met: [T7123: Mean Receive

Rate of the FEGE Ethernet Port/Bandwidth allocated by the bearer network] > 70%, or[T7123: Mean Receive Rate of the FEGE Ethernet Port/Bandwidth allocated by the bearernetwork] > 70%

l Focus on checking whether the bandwidth allocated by the IP bearer network is sufficient.Ask the bearer network vendor to increase the network capacity when the followingcondition is met: [T6519: Forward Bandwidth Allocated to IP Transport Adjacent Node/Bandwidth allocated by the bearer network] > 70%, or [T6520: Backward BandwidthAllocated to IP Transport Adjacent Node/Bandwidth allocated by the bearer network] >70%.



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About This DocumentContents1 Change in the GBSS Capacity Monitoring Guide (BSC6910-Based)2 System Capacity Data Collection3 Capacity Counter Categories and Capacity ProblemLocating Methods3.1 Capacity Counter Categories3.2 Capacity Monitoring and Problem Locating Methods3.2.1 Methods for Locating Capacity Problems3.2.2 Methods for Troubleshooting Capacity Problems

4 Radio Resource Monitoring4.1 PCH Load4.2 SDCCH Load4.3 TCH Load4.4 PDCH Load

5 Equipment Resource Monitoring5.1 GSM CP Subsystem Resources5.2 GSM UP Subsystem CS Resources5.3 GSM UP Subsystem PS Resources5.4 Interface Board Load5.5 Inter-Subrack BSC Communication Bandwidth and Load

6 Transmission Resource Monitoring6.1 A over IP (Signaling)6.2 A over IP (Traffic)6.3 Gb over IP6.4 Abis Interface6.4.1 Abis over TDM6.4.2 Abis over IP

Documents

GBSS15.0 Capacity Monitoring Guide(BSC6910-Based)(01)(PDF)-En