System Reliability(RAN15.0 01)

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WCDMA RAN

System Reliability Feature Parameter

Description

Issue 01

Date 2013-04-28

HUAWEI TECHNOLOGIES CO., LTD.



Copyright © Huawei Technologies Co., Ltd. 2014. All rights reserved.

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and other Huawei trademarks are trademarks of Huawei Technologies Co., Ltd.

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Huawei Technologies Co., Ltd.

Address: Huawei Industrial Base

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Website: http://www.huawei.com

Email: [email protected]

Issue 01 (2013-04-28) Huawei Proprietary and Confidential

Copyright © Huawei Technologies Co., Ltd.

i

http://www.huawei.com/



Contents

1 About This Document..................................................................................................................1

1.1 Scope..............................................................................................................................................................................1

1.2 Intended Audience..........................................................................................................................................................1

1.3 Change History...............................................................................................................................................................1

2 System Redundancy......................................................................................................................3

3 RNC Resource Sharing.................................................................................................................8

4 Parameters.....................................................................................................................................10

5 Counters........................................................................................................................................11

6 Glossary.........................................................................................................................................14

7 Reference Documents.................................................................................................................15

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System Reliability Feature Parameter Description Contents



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1 About This Document

1.1 Scope

This document describes the functions provided by the System Reliability feature, including

system redundancy and BSC/RNC resource sharing.

This document applies to the following NE types.

NE Type NE Model

RNC BSC6900, BSC6910

NodeB Macro 3900 series macro base stations: BTS3900, BTS3900A,

BTS3900L, BTS3900AL, DBS3900, BTS3900C

3800 series macro base stations: DBS3800, BTS3812E,

BTS3812AE

Micro BTS3803E, BTS3902E

LampSite DBS3900

1.2 Intended Audience

This document is intended for personnel who:

l Need to understand the features described herein

l Work with Huawei products

1.3 Change History

This section provides information about the changes in different document versions. There are

two types of changes, which are defined as follows:

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l Feature change

Changes in features of a specific product version

l Editorial change

Changes in wording or addition of information that was not described in the earlier version

RAN15.0 01 (2013-04-28)

This issue does not include any changes.

RAN15.0 Draft A (2013-01-30)

Compared with Draft A (2012-04-30) of RAN14.0, Draft A (2013-01-30) of RAN15.0 includes

the following changes.

Change Type Change Description Parameter Change

Feature change Added BSC6910 redundancy

designs and resource sharing.

None

Editorial change Moved the operating system security

management description to the Base

Station Controller Equipment and

OM Security Feature Parameter

Description.

None

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2 System Redundancy

The system redundancy function, which corresponds to the MRFD-210101 System Redundancy

feature, provides reliability designs that improve system reliability. These designs include load

sharing and active/standby switchovers.

To ensure the reliable operation of the system, the Huawei UTRAN system adopts reliability

designs, such as load sharing and active/standby switchovers.

l Load sharing

In resource pool mode, load sharing is performed among processing units in the pool. When

one or multiple processing units are faulty, ongoing services are interrupted, and new

service requests are allocated to the normal processing units in the resource pool.

l Active/standby switchovers

In active/standby mode, the active board processes services while the standby board actsas a backup for the active one. When the active board is faulty or needs to be replaced,

services on the active board are switched over to the standby board to ensure normal service

operations.

There are two types of switchovers:

– Automatic switchover: automatically triggered by the system if the active board is

faulty.

– Manual switchover: performed by maintenance personnel on the LMT. Maintenance

personnel use the immediate switchover command to switch over the active and standby

boards.

A successful active/standby switchover requires the following:– The standby board works normally.

– No major or critical alarm is reported on the standby board.

When the standby board is switched over to the active state, the previously active board

is reset automatically. If this board restarts normally, it is switched over to the standby

state.

l Other reliability designs

Other reliability designs include the redundancy configuration of power and fan units. In

addition, software versions and important data configuration files are backed up so that the

system works normally even if an exception occurs in the software versions and files.

The following describes RNC and NodeB redundancy designs.

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RNC Redundancy Design

l Management plane

The BSC6900 MPU subsystems can be configured on multiple pairs of SPU boards working in

active/standby mode. The MPU subsystems manage the transport plane, control plane, and user plane.

The BSC6910 management plane consists of the central layer and local layer.

l The central layer manages global resources, including the control plane, user plane, and

transport plane resources, and isolates faulty global resources.

A pair of Resource Management Processing (RMP) boards perform the central layer

functions.

l The local layer manages board-level resources.

A UCUP board performs the local layer functions.

RMP boards have the following characteristics:

l The CPU usage does not increase noticeably with the increase in the Busy Hour Call

Attempt (BHCA) and throughput. A sudden increase in the CPU usage is allowed within

a short period of time.

l A temporary fault on the RMP board does not affect services. If the RMP board is faulty,

services can still be processed, but global resource scheduling is interrupted.

l Control plane

– For the BSC6900, the SPU boards, which work in active/standby mode, process control

plane data.

–

For the BSC6910, the UCUP boards process control plane data. Processes on the control plane work in active/standby mode. Every active CP process on a UCUP board has a

backup on another UCUP board, as shown in Figure 2-1.

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Figure 2-1 Redundancy design for the BSC6910 control plane

The redundancy design is similar for the BSC6900 and BSC6910 control planes. The differences

are as follows:

l A pair of BSC6900 active and standby control plane boards must be installed in adjacent

slots.

l The BSC6910 uses the process backup mechanism. The active process on the UCUP board

has a backup process. The backup process can be distributed on a UCUP board in any slots.

During system operations, the cell status, NodeB status, and online UE information on the activesubsystem are sent to the standby subsystem through the backup channel. The standby subsystem

then backs up the data. If the active subsystem is faulty, the standby subsystem takes over services

on the active subsystem to avoid service interruptions.

In addition to the redundancy design, the BSC6910 control plane also supports process

preemption. If a pair of active and standby CP processes of the BSC6910 are both faulty for a

certain period of time (less than 5 minutes), the BSC6910 preempts another standby CP process

to start the active CP process, thereby restoring services promptly.

l User plane

– For the BSC6900, the digital signal processors (DSPs) in DPU boards process user plane

data. The DSPs works in resource pool mode.

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– For the BSC6910, the UCUP board processes user plane data. The user plane resources

work in resource pool mode, as shown in Figure 2-2.

Figure 2-2 Redundancy design for the BSC6910 user plane

If a user plane subsystem is faulty, the common channels for the cells carried on the subsystem

are reestablished, and services are interrupted for less than 5 seconds and then restored. During

the service interruption, CS services are released, and PS services are interrupted and thenreconnected. The user plane processing capability decreases, but the other functional user plane

subsystems still work in resource pool mode.

The redundancy design is the same for the BSC6900 and BSC6910 user planes. Neither one

supports user-plane service backup.

l Transport plane

The redundancy design is the same for the BSC6900 and BSC6910 transport planes. They both

support board redundancy, port backup/load sharing, and resource pool mode.

An interface board supports the following:

l Board redundancy

When detecting that an interface board is faulty, the system performs an active/standby

switchover to reestablish the transmission links for the ongoing services on the standby

board. When detecting that the active channel is unavailable, the system performs an active/

standby switchover to enable the ongoing services to be transmitted through the standby

channel.

l Resource pool

l Port backup or load sharing

In conclusion, the control plane, user plane, and transport plane all support the redundancy

design. Therefore, the RNC does not experience a single point of failure.

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NodeB Redundancy Design

Huawei NodeBs(except micro stations) support board redundancy. Two boards of the same type

can work in active/standby mode. When the active board is faulty, the standby board takes over

as the active board, ensuring reliable NodeB operations.

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3 RNC Resource Sharing

This chapter describes the MRFD-210104 BSC/RNC Resource Sharing feature.

l BSC6900 control plane resource sharing

Control plane resource sharing is used to share the CPU usage and memory. When the CPU

usage of a certain control plane unit is too high or the memory of a certain control plane unit is

insufficient, a new call is forwarded to another control plane unit with a low load for processing.

l BSC6900 user plane resource sharing

The RNC implements dynamic resource sharing based on the resource pool and load balancing.

If a certain user plane unit is overloaded, a new service is forwarded to another user plane unit

with a low load for processing.

For details on load sharing, see the Controller Resource Sharing Feature Parameter

Description.

l BSC6910 user plane and control plane dynamic sharing

The BSC6910 dynamically adjusts the numbers of multi-core DSPs allocated to the control plane

and user plane based on service requirements. These adjustments improve hardware usage.

The BSC6910 introduces a new service processing board: GPU. The GPU board can

simultaneously process user-plane and control-plane data. The BSC6910 monitors the resource

usage on the user plane and control plane and adjusts resources (multi-core DSPs) for each plane

proportionately.For details, see the RNC User Plane and Control Plane Resource Sharing Parameter Description.

l Automatic NodeB and cell allocation in the BSC6910

The BSC6910 automatically allocates a new base station or cell to an EGPUa board subsystem.

In addition, the BSC6910 monitors the distribution of base stations and cells on the control plane.

When EGPUa boards experience a load imbalance because there are hotspot base stations or

cells, the BSC6910 reallocates the base stations or cells to achieve load balancing.

Dynamic reallocation of cells can be performed during peak hours, whereas dynamic reallocation

of base stations must be performed during off-peak hours. During cell reallocation, UEs in the

CELL_DCH state in the cell do not drop from the network. During base station reallocation,

services carried by the base station are interrupted, and UEs controlled by the base station

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System Reliability Feature Parameter Description 3 RNC Resource Sharing



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experience call drops. Operators can schedule the time for base station reallocation. For details,

see the Controller Resource Sharing Feature Parameter Description.

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4 Parameters

There are no specific parameters associated with this feature.

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5 Counters

Table 5-1 Counter description

Counter ID Counter Name CounterDescription

NE Feature ID Feature Name

67194469 VS.SDH.SWAP

.REASON.REQ

UEST.COUNT

S

T7041:Number

of SDH Port

Switchovers on

Conditional

Requests

BSC6900 MRFD-210101 System

Redundancy


.REASON.KBY

TE.COUNTS

T7042:Number

of SDH Port

Switchovers onK byte Requests


Redundancy


.REASON.EXT

ERNAL.COUN

TS

T7043:Number

of SDH Port

Switchovers on

external

Requests


Redundancy

67194472 VS.SDH.FAUL

T.CHANNEL.P

ROTECT.COU

NTS

T7044:Number

of SDH

Protection

ChannelFailures


Redundancy


T.CHANNEL.

WORK.COUN

TS

T7045:Number

of SDH

Working

Channel

Failures


Redundancy

73436939 VS.Frame.Flux.

Peak.TxRate

HR9732a:Peak

Inter-Subrack

Transmitting

Traffic

BSC6900 MRFD-210104 BSC/RNC

Resource

Sharing

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Mean.TxRate

AR9732a:Avera

ge Inter-Subrack Transmitting

Traffic


ResourceSharing


DropPackets

R9732a:Numbe

r of Discarded

Inter-Subrack

Packets


Resource

Sharing


TxPackets

R9732b:Numbe

r of Sent Inter-

Subrack Packets


Resource

Sharing


.REASON.REQ

UEST.COUNT

S

T7041:Number

of SDH Port

Switchovers on

Conditional

Requests


Redundancy


.REASON.KBY

TE.COUNTS

T7042:Number

of SDH Port

Switchovers on

K byte Requests


Redundancy


.REASON.EXTERNAL.COUN

TS

T7043:Number

of SDH PortSwitchovers on

external

Requests


Redundancy


T.CHANNEL.P

ROTECT.COU

NTS

T7044:Number

of SDH

Protection

Channel

Failures


Redundancy


T.CHANNEL.WORK.COUN

TS

T7045:Number

of SDHWorking

Channel

Failures


Redundancy


Peak.TxRate

HR9732a:Peak

Inter-Subrack

Transmitting

Traffic


Resource

Sharing

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Mean.TxRate

AR9732a:Avera

ge Inter-Subrack Transmitting

Traffic


ResourceSharing


DropPackets

R9732a:Numbe

r of Discarded

Inter-Subrack

Packets


Resource

Sharing


TxPackets

R9732b:Numbe

r of Sent Inter-

Subrack Packets


Resource

Sharing

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6 Glossary

For the acronyms, abbreviations, terms, and definitions, see the Glossary.

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System Reliability Feature Parameter Description 6 Glossary



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7 Reference Documents

1. Controller Resource Sharing Feature Parameter Description

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System Reliability Feature Parameter Description 7 Reference Documents



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