Redundancy Descrip

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RAN Equipment RedundancyWCDMA RAN

Feature Description


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RAN Equipment Redundancy Feature Description

ZTE Confidential Proprietary 2008 ZTE Corporation. All rights reserved. I

RAN Equipment Redundancy Feature

Description

Version Date Author Approved By Remarks

V2.5 2009-1-20 LouDeGang YuFeng



2008 ZTE Corporation. All rights reserved.

ZTE CONFIDENTIAL: This document contains proprietary information of ZTE and is not to be disclosedor used without the prior written permission of ZTE.Due to update and improvement of ZTE products and technologies, information of the document is

subjected to change without notice.


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ZTE Confidential Proprietary 2008 ZTE Corporation. All rights reserved. II

TABLE OF CONTENTS

1 Functional Attribute ................................................................................................... 1

2 OVERVIEW.................................................................................................................. 12.1 ZWF21-20-010 RAN Equipment Redundancy Protection........................................... 1

3 Technical Descript ion ................................................................................................13.1 Board Redundancy Protection of RAN........................................................................13.1.1 Brief Introduction to Board Redundancy Protection ....................................................23.1.2 General Process of Board Switching...........................................................................23.1.3 Board Fault Detection.................................................................................................. 63.1.4 Redundancy Protection Solution for RNC Boards....................................................... 73.1.5 Redundancy Protection Solution for Node B Boards ................................................253.2 Port Redundancy Protection......................................................................................273.2.1 Backup of Ethernet Port.............................................................................................27

3.2.2 Backup of E1/T1 Port.................................................................................................303.2.3 Backup of SDH Port...................................................................................................303.2.4 Backup of Level-1 Switch Optical Port ......................................................................303.3 Redundancy Protection of Communication Link........................................................323.3.1 ATM Link Backup.......................................................................................................323.3.2 IP Link Backup...........................................................................................................323.3.3 SCTP Link Backup.....................................................................................................323.3.4 Data Division Transmission Backup..........................................................................32

4 Parameter Descript ion ............................................................................................. 334.1 Parameter List ...........................................................................................................334.1.1 Configuration Information on Board Redundancy Protection....................................334.1.2 Configuration Information on Port Redundancy Protection ....................................... 33

4.1.3 Configuration Information on Communication Link Redundancy Protection............. 334.2 Parameter Configuration............................................................................................334.2.1 Configuration Information on Board Redundancy Protection....................................334.2.2 Configuration Information on Port Redundancy Protection ....................................... 354.2.3 Configuration Information on Communication Link Redundancy Protection............. 35

5 Counter and Alarm ................................................................................................... 355.1 Counter List ...............................................................................................................355.2 Alarm List...................................................................................................................35

6 Glossary ....................................................................................................................38


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ZTE Confidential Proprietary 2008 ZTE Corporation. All rights reserved. III

Figures and Tables

Figure 1 Active/Standby Switching Process ................................................................................ 5

Figure 2 Active/Standby Interlock Circuit..................................................................................... 6

Figure 3 Connection of Major Boards in the RAN........................................................................ 8

Figure 4 Before Switching............................................................................................................9

Figure 5 After Switching of Optical Port .......................................................................................9

Figure 6 After Switching Because of the Fault of Network Port of Internal Media Plane .......... 10

Figure 7 After Switching Because the Active Board is Offline ...................................................10

Figure 8 APBI before switching.................................................................................................. 11

Figure 9 APBI after switching.....................................................................................................11

Figure 10 Before EIPI Switching .................................................................................................. 13Figure 11 After EIPI Switching ..................................................................................................... 13

Figure 12 Before GIPI Switching..................................................................................................14

Figure 13 Before EIPI Switching .................................................................................................. 14

Figure 14 Before IMAB Switching ................................................................................................ 17

Figure 15 After IMAB Switching ................................................................................................... 17

Figure 16 SDTA1:1backupbefore switching .........................................................................20

Figure 17 SDTA1:1backupAfter Switching of Optical Port Abnormal................................... 20

Figure 18 SDTA1:1backupAfter switchover caused by internal media plane Ethernet port fault

21

Figure 19 SDTA1+1 Backup Before switching of Internal Media Plane Ethernet Port Failure

21Figure 20 SDTA1+1backupAfter switching of Internal Media Plane Ethernet Port Failure.. 21

Figure 21 After switching of active board off-line......................................................................... 22

Figure 22 SDTB2 before switching .............................................................................................. 23

Figure 23 After switching of optical port.......................................................................................23

Figure 24 After switching of active board off-line......................................................................... 24

Figure 25 Typical Configuration of B8200....................................................................................25

Figure 26 FE Routing Interconnection Between UIM and UIM....................................................29

Figure 27 Trunk Interconnection of Control Plane .......................................................................29

Figure 28 GUIM-GLI Connection ................................................................................................. 31

Figure 29 Double-Shelf Interconnection Between GUIM Boards ................................................32

Table 1 Backup Modes of RNC Boards......................................................................................7

Table 2 Backup Modes of B8200 Boards ................................................................................. 25

Table 3 FE Routing Ports and Trunk Ports Supported by Various Boards .............................. 28

Table 4 GE Ports Supported by the GUIM/GLI......................................................................... 30


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1 2008 ZTE Corporation. All rights reserved. ZTE Confidential Proprietary

1 Functional Attribute

System version: [RNC V3.07.310, OMMR V3.17.310, Node B V4.00.200, OMMRV3.17.310, OMMB V4.00.200]

Attribute: [Optional]

Involved NEs:

UE Node B RNC MSCS MGW SGSN GGSN HLR

- - - - - -

Note:

*-: The NE is not involved.

*: The NE is involved.

Dependency: [None]

Mutual-exclusion function: [None]

Remarks: [None].

2 OVERVIEW

2.1 ZWF21-20-010 RAN Equipment RedundancyProtection

The 1+1 backup mode is configured for the key boards of the RNC and Node B, forexample, the system clock board, operation & maintenance board, and control planeprocessing board. The load sharing backup mode (also called the resource redundancypool) is configured for the user plane processing board and various interface boards.Thanks to the redundancy configuration, the functions and performance of the wholesystem are not affected in case one board is faulty. The interface board that processesfiber transmission is configured with automatic protection switching (APS), thus ensuringthe reliability of high-speed lines, especially optical port transmission.

3 Technical Description

There are three types of redundancy protections in the RAN, that is, board redundancyprotection, port redundancy protection, and communication link redundancy protection.

3.1 Board Redundancy Protection of RAN

The RAN system provides diversified board backup modes, so as to ensure normalsystem operation in case a board is faulty.


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3.1.1 Brief Introduction to Board Redundancy Protection

In the RAN system, the board redundancy backup mode can be configured through theBackUpMode parameter. The BackUpMode parameter can be configured to

BOARD_BACKUP_MODE_NONE (no backup) or the following values:

1+1 backup (BOARD_BACKUP_MODE_MASTERSLAVE)

For the mutual-backup boards, only one board carries services (including accessand processing) at a time and the standby board does not carry any service.

1:1 backup (BOARD_BACKUP_MODE_1TO1)

Only one board processes data at a time. The interface units can be distributed inthe mutual-backup boards.

Load sharing (BOARD_BACKUP_MODE_MULTI_ONE)

All boards in the resource pool are active to share the load. In the redundancyconfiguration mode, the system is not affected in case one board is faulty.

The comparison between the 1+1 mode and 1:1 mode is as follows:

Common feature

The two mutual-backup boards share one logical address (compared with physicaladdress, a logical address indicates a logical node for service. When function isimplemented, the active/standby board configuration is not concerned) and one suite

of bearer resources (for example, the circuit resource and internal media streamresource)

Difference

1+1 backup: Only one board is running in active status at a time.

1:1 backup: Resources and interfaces are divided into groups, and protectionswitching is implemented in each group. The two mutual-backup boards workcooperatively. The groups in a board can be in different working states. However,make sure that if one group in a board is active, it must be standby in the other boardFor example, in one board, Group A is active and Group B is standby. Then, in theother board, Group A is standby and Group B is active. As a result, the two boards

may both have active resources at the same time and can process the accessservice. For the SDTB and APBE boards, the corresponding optical ports in theactive board and standby board compose an APS group. The active/standby state ofa board is independent from the active/standby state of the external optical port ofthe board.

3.1.2 General Process of Board Switching

For the boards or devices in the 1+1 backup mode or 1:1 backup mode, the system notonly reports an alarm, but also takes preventive and self-healing measures (for example,switching) in case a board is faulty. When the active board is faulty, the standby board


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takes over its work, thus preventing the service functions from being affected for a longtime.

In addition, the system also provides some means to adjust the active board manually.

To verify whether the current standby board can work normally, manual switching can beinitiated to switch the standby board to the active state.

The RAN system provides the basic common switching reasons for the boards in 1+1backup mode and in 1:1 backup mode. For different boards, the RAN provides differentswitching reasons for different devices and functions on the boards. The following sectiondescribes the general switching reasons and switching process.

3.1.2.1 Reason for Board Switching

The general switching reasons are as follows:

1 Man-machine Command

The system allows user to initiate a switching to the specified board from the OMCby command.

2 Key-press switching

Each board supports the switching that is initiated through manual intervention froma panel key-press. Press EXCH key in the panel of the active board, and then usercan initiate the active/standby switching.

3 Abnormal switching due to reset of active board

This is an abnormality processing flow after the active board is reset. If the activeboard is reset due to manual intervention or its abnormal operation, the originalstandby board automatically initiates the abnormal switching process, thus switchesitself into the active board. In this switching mode, the active board is suddenly reset,so some service data cannot be synchronized to the standby board. After thestandby board takes over the work, some service data is lost.

4 Abnormality of network interface of the control plane

Boards work on the basis of messages of the control plane. When the networkinterface of the control plane is abnormal, the normal operation of boards is surelyaffected. If detecting that the network interface of the control plane does not receiveany packet, the system resets the board and thus attempts to restart the networkinterface. Before the reset, the system instructs the standby board to initiate theswitching process through the primary channel so that the standby board can takesover the ongoing services.

5 Removal of board

Each board is configured with an unplugging switch. Before a board is removed, thesystem initiates the active/standby switching through an interrupt notice. Thestandby board takes over the work first before the active board is out of position.Meanwhile, the system reports the switch-on alarm and lights up. During theswitching, the ENUM indicator flashes quickly at a frequency of 5 Hz. Uponcompletion of the switching, the ENUM indicator flashes at a frequency of 1 Hz.Before the ENUM indicator flashes at a frequency of 1 Hz, do not remove the board.


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Otherwise, the system triggers the abnormal switching process due to the reset ofthe active board, as described in 3).

Besides the common reasons described above, other reasons, such as operation faults

of board, may trigger the active/standby switching.

3.1.2.2 Switching Priority Control

Board switching is intended to restore the system from the faulty state. If the standbyboard has severer problem than the active board , the switching process is of no use. Toavoid this problem, user can configure the switching reason according to the faultseverity.

Except for the switching initiated by manual intervention, other types of switching areinitiated by the system automatically, that is, each switching reason corresponds to aspecific board fault. If detecting a fault in the active board, the system initiates the

active/standby switching. If detecting a fault in the standby board, the system sets a faultflag (hereinafter referred to as the switching barring reason). According to the severity offaults, the system sets some levels for the switching reasons and switching barringreasons. The higher the level is, the severe the fault is. When the active board initiatesthe active/standby switching, the standby board compares the level of the switchingreason with the level of the switching barring reason. If the level of the switching reason ishigher, it indicates that the fault of the active board is severer and thus the system allowsthe active/standby switching. Otherwise, the fault of the standby board is severer andthus the system bars the active/standby switching.

To avoid frequent active/standby switching and switching-back, the system sets alow-level 5-minute switching barring every time a switching process is complete.

3.1.2.3 Switching Flow

When both the active and standby boards work normally, every functional module in theactive board synchronizes the key information to the standby board at real time.

A normal switching process comprises three phases including preliminary switching,standby-to-active (SM) switching, and active-to-standby (MS) switching, thus switchingthe board process and communication link, as shown in Figure 1.


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Active board Standby board

Begin

communication

link switchSM

End

communication

link switch

back

MS

Pre

Sync data

Hardware

active/standby

switch

Starting switch

Figure 1 Active/Standby Switching Process

After receiving a switching request, a board first makes necessary judgment, for example,whether the current board is an active board, and whether the standby board is in

position. If the switching conditions are met, the active board sends a preliminaryswitching command. The standby board compares the level of the switching barringreason with the level of the switching reason. If the level of the switching barring reason ishigher, the system bars the active/standby switching. Otherwise, the system implementsthe preliminary switching operation, that is, instruct the active board and standby board ofthe registered process to perform necessary active/standby data synchronization. In thisphase, the active board is always in active state and can implement normal servicefunctions. After the preliminary switching is complete, the system implements theactive/standby switching between the active process and standby process. The activeprocess and standby process are in different boards, so the ongoing services areaffected transiently. To minimize the impact, the system implements link switching uponcompletion of the preliminary switching, that is, instruct another service board to cachemessages and send the cached messages to the new active board upon completion of

the active/standby switching.

In the SM(Slave to Master) phase and MS(Master to Slave) phase, the system instructsthe registered processes to implement the active/standby switching. The detailedswitching is implemented in each process respectively.

After the SM switching and MS switching are complete, the system switches to theoriginal link and sends the messages cached by another service board to the new activeboard.

All normal active/standby switching processes follows the above flow. For the abnormalswitching due to reset of the active board, the system cannot follow the above switchingflow because the active board is not in position. After receiving the interrupt message


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because the active board is reset or out of position, the original standby boardimmediately implements the SM switching and link switching and then takes over theservices of the original active board.

3.1.3 Board Fault Detection

The RAN provides diversified mechanisms for checking whether a board works normally.The following section describes some fault detection mechanisms common to multipleboards. In addition, different functional boards also provide other fault detectionmechanisms.

3.1.3.1 Partner Board In-Position Detection

Through an interlock circuit, the active and standby boards implement the active/standbycompetition and check whether the partner board is in position. Figure 2 shows theinterlock circuit.

B A

O_MS-VIEO_MS-VIE

I_MS-VIE I_MS-VIE

MASCT MASCT

Figure 2 Active/Standby Interlock Circuit

MASCT (reverses the phase of output signals or MASCT inside the logic) is theactive/standby competition signal controlled by software, and is used for theactive/standby competition between boards. I_MS-VIE and O_MS-VIE are the interlocksignals between boards. If the actual level of MASCT is a high level, it indicates that theboard is competing for the active state. If the actual level of MASCT is a low level, itindicates that the board does not compete for the active state. If the actual level ofO_MS-VIE (I_MS-VIE signal of the peer board) is a low level, it indicates that the board isin active state. Otherwise, it indicates that the board is in standby state.

If the active board detects that the standby board is in position, the active boardsynchronizes its data to the standby board through the primary channel. If the standbyboard detects that the active board is offline, the standby board is switched to an activeboard.

3.1.3.2 Communication Check for the Internal Media Plane

If a board (for example, APBE, RUIB, and EUIP) has the internal media planecommunication capability, the board can also provide a mechanism of checking thecommunication in the internal media plane. Through this mechanism, a board can trigger


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the active/standby switching if detecting the abnormal communication in its internalmedia plane.

The port check mechanism in the internal media plane is as follows: The board regularly

sends a check packet to the switching board GUIM from the specified media plane port.After receiving the check packet, the GUIM loops back the check packet. If the boarddoes not receive the looped check packet within a certain period, the board determinesthat the communication of the media plane is abnormal.

After detecting the abnormal communication of the media plane, the active board triggersthe switching.

3.1.3.3 Internal HW Communication Detection

If a board (for example, the IMAB and EUIP) has the internal HW communicationcapability, the board can also provide a mechanism of checking the internal HW

communication. The check mechanism is as follows: The board sends a check packet tothe switching board GUIM at Timeslot 0 of HW. The GUIM loops back Timeslot 0. Theboard checks whether the received loop back data is consistent with the sent data. If not,the board determines that the HW link is faulty.

The active board triggers the switching process after detecting the fault of the HW link.

3.1.4 Redundancy Protection Solution for RNC Boards

Table 1 describes the backup mode of each board in the RNC.

Table 1 Backup Modes of RNC Boards

FunctionalBoard

Backup Mode Remarks

APBE

1:1 backup

When the active board isswitched to a standbyboard, the original activeboard is not reset.

The 1:1 backup mode must be configured ifAPS between boards is required.

Support the APS of two pairs of STM-1interfaces in a board or one pair of STM-1interfaces between boards.

THUB 1+1 backup None

DTB No backup None

EIPI 1+1 backup None

GIPI1+1 backup, and loadsharing

None

GLI Load sharing None

GUIM 1+1 backup None

ICM 1+1 backup None

IMAB 1+1 backup None

PSN Load sharing None

PWRD No backup None

RCB 1+1 backup None


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FunctionalBoard

Backup Mode Remarks

ROMB 1+1 backup None

RUB Load sharing None

SBCX 1+1 backup None

UIMC 1+1 backup None

Figure 3 shows the connections of the main boards in Table 1 .

Figure 3 Connection of Major Boards in the RAN

3.1.4.1 APBE Troubleshooting Process

The APBE provides four external STM-1 optical ports. The APBE boards support the 1:1backup between boards. In this case, APS should be configured for the optical portsbetween the APBE boards. When the inter-board APS is configured, 4 optical port APS

protection groups between boards are supported. The protection of optical ports of theAPBE boards complies with G.841[1], and supports the 1:1 bidirectional protection ofAPS. For details on APS, refer to ZTE UMTS ATM Transmission Feature Description.

The switching of the APBE boards can be triggered by the following reasons:

1. The active optical port is abnormal.

2. The communication to the internal media plane is abnormal.

3. The active board is offline.


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Figure 4 shows the switching triggered by the fault of the active optical port. The coloredlines indicate the connection that data transits currently. The colored blocks indicate theprocessing units that data transits currently. Before switching:

Figure 4 Before Switching

Through the APS mechanism for optical ports, the system initiates the switching afterdetecting that the frame of the active optical port is lost. Meanwhile, the media planeprocessing units of the faulty APBE are switched to the APBE where the protected opticalport is located. After switching:

Figure 5 After Switching of Optical Port

After the active board detects that the communication to the internal media plane is

abnormal (for details, see Section 3.1.3.2Communication Check for the Internal MediaPlane), the active board is switched over. After switching:


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Figure 6 After Switching Because of the Fault of Network Port of Internal Media Plane

When the active board is reset or is removed, the standby board detects that the activeboard is offline through the interlock circuit (for details, see Section 3.1.3.1Partner BoardIn-Position Detection). Then, the standby board is switched to the active board, andcompletely functions as the active board. After switching:

Figure 7 After Switching Because the Active Board is Offline

3.1.4.2 APBI Troubleshooting Process

APBI doesnt provide physical interface directly, it provides physical interface (E1/T1,CSTM-1) by trunk board (DTB, SDTB2) through inter-board HW switch. APBI supports1+1 backup between boards.

The following reasons may cause faulty switch of APBI:

Communication to internal media plane is abnormal

HW communication is abnormal

Active board is offline

The switching process of APBI board is shown in the following figures. The lines in colordepict the active path where data is currently carried on. Whilst, the blocks in color showsthe active unit where data is currently processed.

Before switching:


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Figure 8 APBI before switching

After switching for any reasons

Figure 9 APBI after switching

Switching processing will start when active board detects abnormal communication tointernal media plane. Please refer to 3.1.3.2 for detection mechanism.

When active board resets or is removed, standby board will detect active board offline(please refer to 3.1.3.1) and switch to active board to take over all active boards function.

3.1.4.3 THUB Troubleshooting Process

In the RAN system, the THUB is the center of data exchange between control planes indifferent shelves. The THUB boards work in the 1+1 backup mode. The port of the controlplane undergoes high-resistance multiplexing. The communication of the control plane isimplemented through the active port of the active board. When a port of the THUB isabnormal, the control plane communication is interrupted between the shelf connected tothis port and other shelves and thus the shelf cannot work normally. When the THUB isabnormal, the control plane communication is interrupted among all shelves and thus thesystem cannot work normally. To avoid the problem, the THUB boards provide port


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redundancy backup and board redundancy backup. There are the following backupscenarios:

1. The control plane communication between shelves is abnormal

In the TRUNK interconnection mode, the system checks the link of the control planeaccording the hardware status of the control plane and packet receiving/transmittingstatus. If detecting that one or more ports in a TRUNK group in the active board areabnormal for at least one minute, the system switches over the board, so as toensure normal communication of the control plane.

2. GE port protection inside BCTC shelf

The THUB is interconnected to the UIMC in the same shelf through the GE port ofthe backplane. If the link is interrupted, the control plane communication betweenother shelves and the other service boards in this shelf is interrupted, thus causing agreat impact. The THUB checks the receiving/transmitting status of the packets

between the THUB and the GE port of the backplane of the UIMC. If detecting thatdata receiving/transmitting is abnormal, the THUB performs board switching andthus attempts to recover itself.

For further information on THUB backup, see Section 3.2.1.

3.1.4.4 EIPI Troubleshooting Process

The EIPI does not provide any external physical interface directly. Instead, the EIPI isconnected through the inter-board HW switching and digital trunk board (DTB). The DBTdirectly provides an external physical interface (E1). The EIPI boards support the 1+1backup mode.

The failover of the EIPI boards is caused for the following reasons:

1 The communication to the internal media plane is abnormal.

2 The HW communication is abnormal.

3 The active board is offline.

Figure 10 shows the EIPI switching process. The colored lines indicate the connectionthat data transits currently. The colored blocks indicate the processing units that datatransits currently.

Before switching:


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Figure 10 Before EIPI Switching

Figure 11 shows the result after the switching triggered by any reason:

Figure 11 After EIPI Switching

After the active board detects that the communication of the internal media plane isabnormal, the system initiates the switching. For details on the check mechanism, seeSection 3.1.3.2Communication Check for the Internal Media Plane.

After the active board detects that the internal HW communication is abnormal, thesystem initiates the switching. For details on the check mechanism, see Section3.1.3.3Internal HW Communication Detection.

When the active board is reset or is removed, the standby board detects that the activeboard is offline through the interlock circuit (for details, see Section 3.1.3.1Partner BoardIn-Position Detection"). Then, the standby board is switched to the active board, andcompletely functions as the active board.

3.1.4.5 GIPI Troubleshooting Process

The GIPI provides an external 1000/100M GE port directly. The GIPI boards support the1+1 backup mode and load sharing mode.

The failures of the GIPI boards that may trigger switching are as followings:


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1 The external Ethernet port is faulty.

2 Within 2 seconds, the external Ethernet port receives more than 128 bad frames.


Figure 12 shows the GIPI switching process. The colored lines indicate the connectionthat data transits currently. The colored blocks indicate the processing units that datatransits currently. Before switching:

Figure 12 Before GIPI Switching


Figure 13 Before EIPI Switching

The external Ethernet faults are judged according to standard Ethernet circuit signals. Incase frames are lost, the system determines that the Ethernet is faulty and thus triggersthe switching process.

Bad frame detection is implemented according to the check result of the Ethernet framesreceived by the bottom-layer chip. If more than 128 bad Ethernet frames are receivedwithin 2 seconds, the system determines that the Ethernet works abnormally and thustriggers the switching process.


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When the active board is reset or is removed, the standby board detects that the activeboard is offline through the interlock circuit (for details, see Section 3.1.3.1Partner BoardIn-Position Detection"). Then, the standby board is switched to the active board, andcompletely functions as the active board.

3.1.4.6 GLI Troubleshooting Process

The GLI is the exchange center of the media plane data between shelves. The boardbackup mode is load sharing.

The GLI has four media-plane GE optical ports. In a Level-1 switching system, thecorresponding GE interfaces of the GLI work in the 1+1 backup mode. The

active/standby states of the GE interfaces are independent from each other. A whole GLIhas four independent active/standby GE modules. Two GLIs in the load sharing modemay both have active GE modules. If one active GE module is abnormal, the associatedservices are affected. If the whole GLI is abnormal, none of the GE modules in the GLIcan work normally, and the related services are interrupted. The redundancy backup ofthe GLI and GE interfaces can prevent this problem effectively without affecting theservices. For details, see Section 3.2.4Backup of Level-1 Switch Optical Port.

In addition, the GLI is interconnected to the PSN through the HSSL. The switching chip inthe FLI can identify the status of the HSSL. If the HSSL is interrupted, no packets aresent from the HSSL to the PSN for switching.

3.1.4.7 GUIM Troubleshooting Process

The GUIM is the switching center for media plane communication, control planecommunication, and HW communication in the resource shelf (BGSN). During inter-shelfcommunication, the GUIM has the routing function for the control plane and media plane.The GUIM boards work in the 1+1 backup mode. The rear insertion card provides a pairof external routing interfaces and one pair of TRUNK interfaces for interconnection of thecontrol plane. The panel provides two external GE interfaces. Like the THUB and GLI,the system takes the redundancy backup measure without affecting the system when thecontrol plane link or media plane link in the GUIM is abnormal.

The GUIM is protected in following respects:

1 Redundancy protection for the control plane link, including board protection and portprotection. For details, see Section 3.1.2General Process of Board Switching andSection 3.2.1Backup of Ethernet Port.

2 Media plane link protection: The media plane of the GUIM forwards the

active/standby state of the GE ports together with the active/standby state of boards.

The system checks a link by receiving and transmitting the link check packet. If

detecting that the link of the optical port in the active board is faulty, the system

switches over the optical module or the board. For details, see Section 3.2.4Backup

of Level-1 Switch Optical Port.


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3 For the network interface of the internal control plane, the system periodicallyqueries the receiving/transmitting statistics of the network interface of the controlplane. If detecting that the network interface of the control plane is abnormal, thesystem switches over the board and thus the original standby board takes over the

work.4 For the network interface of the internal media plane, the board in the shelf with the

media plane communication capability checks whether the link is normal through

packet interaction. If a faulty board cannot heal itself, the board with the media plane

communication capability sends a message to instruct the GUIM to switch over the

faulty board, thus removing the fault of the network interface in the active GUIM.

5 The GUIM periodically checks the status of the HW communication links used in the

shelf. If all HW links are faulty, the system switches over the GUIM.

3.1.4.8 ICM Troubleshooting Process

The ICM provides the clock management and output function, and works in the 1+1backup mode. In case a clock is faulty, the system has an extremely high requirement forthe recovery time. Therefore, the ICM is automatically switched over in hardware, andsoftware switching follows hardware switching. After software receives the interruptcaused by hardware switching, the switching flow is the same as described in Section3.1.2General Process of Board Switching. The ICM mainly provides the followingprotection mechanisms:

The ICM checks the GPS module periodically. In case the active ICM is abnormal, thesystem initiates the switching process. In case the standby ICM is abnormal, the systemsets switching barring.

The hardware in the ICM checks the status of the active and standby boards andcompares hardware signals. If the active board is abnormal but the standby board isnormal, the hardware automatically initiates hardware switching. After the hardwareswitching is complete, the interrupt informs the software that the hardware switching iscomplete. After receiving the interrupt, the software implements software switching, thuskeeping the active/standby consistency between the software and hardware.

The ICM supports the input of multiple clock benchmarks, thus providing redundancyprotection between clock benchmarks. The ICM checks the validity of each access clockbenchmark. If detecting that the clock benchmark is invalid, the ICM gives an alarm andswitches over the clock benchmark as configured.

3.1.4.9 IMAB Troubleshooting Process

The IMAB does not provide any external physical interface directly. It is connected withthe digital trunk board (DTB) through the inter-board HW switch.. The DTB board directlyprovides external physical interface (E1). The IMAB board supports the 1+1 backupmode.

The failures of IMAB board that may trigger switching are as followings:

6 The inloop from the network processor to the ATM switching chip board is abnormal.



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8 The HW communication is abnormal.

9 The active board is offline.

Figure 14 shows the IMAP switching process. The colored lines indicate the connectionthat data transits currently. The colored blocks indicate the processing units that datatransits currently.

Before switching:

Figure 14 Before IMAB Switching


Figure 15 After IMAB Switching

A check mechanism is provided between the network processor in the board and theATM switching chip in the board. The network processor periodically sends a checkpacket the port connected to the ATM switching chip. After switched by the ATMswitching chip, the check packet is returned to the network processor again. If thenetwork processor does not receive the looped check packet within a certain period, thesystem determines that the connection is abnormal between the network processor andATM switching chip and thus triggers the switching process.


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When the active board is reset or is removed, the standby board detects that the activeboard is offline through the interlock circuit (for details, see Section 3.1.3.1Partner BoardIn-Position Detection"). Then, the standby board is switched to an active board, andcompletely functions as an active board.

3.1.4.10 PSN Troubleshooting Process

The PSN mainly exchanges the media stream data between the GLIs. The PSN boardswork in the load sharing mode. If two PSN boards are normal, the media streams areshared by the two boards for forwarding. In case one PSN cannot work normally or theHSSL is interrupted, the switching chip in the GLI automatically stops sending packets inthe HSSL. Instead, packets are sent only in a normal HSSL.

In case one PSN board is abnormal, the maximum switching capacity is halved. Basedon the current design, one PSN board is enough to satisfy the needs of service switching.

3.1.4.11 RCB Troubleshooting Process

The RCB and ROMB are both a MP board. Except the functions and orientations, theirtroubleshooting modes are similar to each other. The following section describes theRCB troubleshooting process in detail.

The RCB is connected to the switching unit, and is responsible for protocol processing of

the control planes of Iu, Iub, and Iur. The active RCB is connected to the standby RCBthrough a 100M Ethernet. The RCB boards work in the 1+1 backup mode.

The software running in the active RCB is the same as that running in the standby RCBexcept for their working state (active or standby). During the initial power-on operation,the two RCB boards compete for the working state. Hardware interlocking is configuredbetween the active RCB and standby RCB (for details, see Section 3.1.3.1Partner BoardIn-Position Detection"), thus avoiding the dual-active or dual-standby inclination. After theactive/standby competition is complete, the active and standby RCB boards are up indifferent capacities respectively. The active RCB needs to read the configuration dataand receives the requests of other boards. The standby RCB actively interacts with theactive RCB, so as to ensure the consistency of software versions and static data. If thedata of the active RCB is changed during the normal operation, the system synchronizes

the changing data to the standby RCB through regular synchronization or real-timesynchronization. During the normal operation, the standby RCB receives thesynchronized data of the active RCB and keeps the consistency of static data betweenthe active RCB and active RCB, thus taking over the work of the active RCB smoothly inreal time.

In case the active RCB fails (for details on the reason, see Section 3.1.2.1Reason forBoard Switching), the standby RCB is automatically switched into an active RCB, itslogical address becomes the logical address of the active RCB, and the bottom-layercommunication link is also switched, thus ensuring normal communication between thenew active RCB and other boards. The original active RCB is automatically reset. Afterthe rest, the original active RCB becomes a standby RCB.


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3.1.4.12 ROMB Troubleshooting Process

The ROMB processes a global process, controls the operation and maintenance of theentire system (including the operation and maintenance proxy), connects itself to the

OMC through a 100M Ethernet, and isolates the internal network segments from theexternal network segments. The ROMB also serves as the core of operation andmaintenance of the ZXWR RNC. It monitors and manages the boards in the systemdirectly or indirectly. The ROMB boards work in the 1+1 backup mode.

The ROMB troubleshooting process is similar to the RCB troubleshooting process.

3.1.4.13 RUB Troubleshooting Process

The backup mode of the RUB boards is load sharing, or called the resource redundancypool.

The RNC can be configured with multiple resource shelves, each resource shelf isconfigured with multiple RUB boards, and each RUB board is configured with one CPUand 14 (VTCD board) OR 15 (VTCD_2) DSPs. For RUB troubleshooting, the minimumresource unit is a DSP.

When configuring a RCP module (the RcpModule parameter) through the OMC, youneed to configure the subsystem number (the SubSystem parameter) corresponding tothe preferred shelf for the RCP module. To obtain the RUB resources for new servicesetup in the RCP, the RUB boards in the preferred resource shelf are polled. If a RUBboard is available, the RUB board is selected for service setup. Otherwise, a RUB boardis selected from another alternative shelf.

After the RCP selects a RUB board, a DSP will be selected in the RUB according to acertain strategy. After the DSP is selected, the RUB board notifies the DSP number to theRCP.

When a DSP in a RUB board is faulty, the status of the DSP is Unavailable. Afterreceiving the Unavailable notice, the RCP releases the DSP-related service, thusavoiding resource deadlock. When a subsequent service is set up, the faulty DSP in theRUB board is not selected for service setup until the DSP becomes normal again. If allDSPs in the RUB board are faulty or the CPU of the RUB board is faulty, the RCP doesnot select the RUB board for setting up a new service.

3.1.4.14 SDTA Troubleshooting Process

SDTA provides 2 CSTM-1 optical ports, and supports 126 E1 (each optical port supportmaximum 63 E1) and maximum 60 IMA groups.

SDTA supports inter-board 1:1 backup, and 2 groups of APS optical ports are provided inthis case. APS supports the following protection types: 1+1 uni-direction, 1+1 bi-direction,1:1 uni-direction and 1:1 bi-direction. All E1s accessed to the active optical port of backupboard are transferred to active board for processing.

SDTA board supports inter-board 1+1 hybrid backup. All E1s accessed to backup boardare transferred to active board for processing.

SDTA faulty switching includes the following reasons:

Communication to internal media plane is abnormal


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Active board is offline

The switching process of SDTA board is shown in the following figures. The lines in colordepict the active path where data is currently carried on. Whilst, the blocks in color shows

the active unit where data is currently processed.

For 1:1 backup, diagram of before switching is shown below:

Figure 16 SDTA1:1backupbefore switching

For 1:1 board backup mode, when detecting active optical port abnormal, active boardswitching over will be triggered. Status after switching over is shown below:

Figure 17 SDTA1:1backupAfter Switching of Optical Port Abnormal

n this case, when SDTA detecting abnormal communication to internal media plane, itwill3 trigger switchover. Diagram after switchover is shown below:


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Media

Plane

Processing

Unit

Control

Plane

Processing

unit

Media

Plane

Processing

unit

Active Board Standby Board

Working portProtection Port

Internal Media plane

Ethernet PortInternal Media plane

Ethernet Port

Internal control

plane Ethernet portInternal control

Plane Ethernet port

Path for active and

standby data

Control

Plane

Processing

unit

Figure 18 SDTA1:1backupAfter switchover caused by internal media plane Ethernet port fault

For 1+1 hybrid backup, before switching is shown below:

Figure 19 SDTA1+1 Backup Before switching of Internal Media Plane Ethernet Port Failure

For 1+1 hybrid backup, when active board detecting internal media plane communicationabnormal (refer to 3.1.3.2), switching will be triggered. After switching status is shownbelow:

Figure 20 SDTA1+1backupAfter switching of Internal Media Plane Ethernet Port Failure


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When active board resets or it is removed, standby board will detect active boardoff-line(refer to 3.1.3.1) through inter-lock circuit and switch to active board to take overall active boards function.

Figure 21 After switching of active board off-line

3.1.4.15 SDTB2 Troubleshooting Process

SDTB2 can provide 2 groups of STM-1 channelized interfaces. Each group has twooptical ports(W,P), and only one port can be used when internal board APS is notused.

SDTB2 supports internal-board APS, including: 1+1, 1:1, bi-direction anduni-direction. The reason of optical port switching includes: LOS, LOF, SF, SD onthe port.

SDTB2 supports 1:1 board backup, media plane unit and control plane unit switchseparately. APS backup configuration is independent to board configuration, and itsupports maximum 2 groups of inter-board APS, including: 1+1, 1:1, bi-direction,uni-direction. Switching of two groups APS is independent to each other. HW insideboard: in the direction from UIM to board is open on both boards. Transmittinginformation on both optical ports of a APS group is consistent. BGSN shelf isneeded to support two groups inter-board APS, HW rate is configured to 16M. Onlyone APS group is supported if BUSN or HW rate is configured to 8M. Under 1:1board backup condition, active optical port must configure APS.

Board failure switching includes the following reasons:

Active board is off-line or resets.

APS switching includes the following reasons:

LOS, LOF, SF, SD on optical port.

Board is off-line or resets.

Switching process triggered by the first active optical port is shown as the followingfigure. In the figure, line in color represents the active connection where data is


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carried on. Block in color represents active units where data is under processing.The following figure is before switching:

Figure 22 SDTB2 before switching

Optical port switching will be triggered when active optical port frame loss isdetected through APS protection mechanism. At the same time, media planeprocess unit will switch to standby board. After switching status is shown below:

Figure 23 After switching of optical port

In case active board resets or is removed, standby board will switch to active boardwhen it detects active board is off-line through interlock circuit and take over activeboards function. Status after switching is shown below:


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Figure 24 After switching of active board off-line

3.1.4.16 UIMC Troubleshooting Process

The UIMC board is the switching board of the control plane communication in the controlshelf (BCTC) and switching shelf (BPSN). The UIMC provides the shelf interconnectioninterfaces (including the FE routing interface and trunk interface) through a rear insertioncard, and provides the control plane network interface internally.

The UIMC boards are under the redundancy protection in the following respects:

1 Redundancy protection for the control plane link between shelves, including board

protection and port protection.

2 For the network interface of the internal control plane, the system periodically

queries the receiving/transmitting statistics of the network interface of the control

plane. If detecting that the network interface of the control plane is abnormal, the

system switches over the board and thus the original standby board takes over the

work.

For details, see Section 3.1.2General Process of Board Switching and Section3.2.1Backup of Ethernet Port.

3.1.4.17 SBCX Troubleshooting Process

When acting as OMM server, SBCX managers all the NE of RNC and adopts 1+1 backupto avoid OMM service single point failure.

The reason of SBCX failure switching is shown below:

Active SBCX is off-line

Active SBCX abandons active status

The rear insertion board of SBCX is off-line


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Active OMM software is fault

Active and standby SBCX have the same software running on them, including OmmHost,OMMservice and Oracle database software. Two SBCX boards will compete for activeand standby during starting up. There is a hardware inter-lock mechanism(refer to 3.1.3.1)which will prevent system from double active or double standby. After the active andstandby competitive status end up, active board and standby boards work in its statusrespectively. Only the OMM server software starting up with active status will work andmanage RNC, OMM in standby board only runs active-standby process to ensurereal-time data synchronization between active and standby boards.

When active board is faulty, standby board will automatically switch to active status.Original communication links between former active OMM and RNC as well as MINOSwill automatically switch to new active board. Former active board will start up intostandby status.

3.1.5 Redundancy Protection Solution for Node B Boards

Figure 25 Typical Configuration of B8200

Table 2 describes the backup mode of each board in the B8200.

Table 2 Backup Modes of B8200 Boards

Functional Board Backup Mode Remarks

CC 1+1 backup

FS None

PM 1+1 backup

SA None

BPC Resource pool

3.1.5.1 CC Troubleshooting Process

Primary control

The active and standby CC boards work in the 1+1 backup mode. The active andstandby CC boards have completely the same hardware, run the same software,

PM

SA

CC

FS

FAM


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and implement NBAP processing and the processing of the IP/ATM protocol stackbetween the control plane and user plane. At a time, only one CC board is active.The active CC board carries services, including access and processing. The standbyCC board does not carry any service, but receives the synchronized data of the

active CC board and keeps the same running conditions as the active CC board.

There exists an independent communication channel between the active CC boardand standby CC board. The active and standby CC boards run the same software,but are in different modes. During the initial power-on operation, the two CC boardscompete for the active/standby state. Upon completion of the competition, thestandby CC board actively interacts with the active CC board, so as to ensure theconsistency of software versions and static data. During the normal operation, theactive CC board synchronizes the changing data (for example, database data,control information of the control plane and user plane of the current access,software parameters, and software versions) to the standby CC board throughregular synchronization or real-time synchronization. During the normal operation,the standby CC board receives the synchronized data of the active CC board and

keeps the consistency of static data between the active CC board and active CCboard, thus taking over the work of the active CC board smoothly in real time.

The system can initiate the active/standby switching in the OMC. Alternatively, theactive/standby switching is triggered by a severe fault of the active CC board. In thiscase, the current active CC board switches the current hardware and software to thestandby state, and only processes the synchronized data of the new active CC boardwithout processing any service. The original standby CC board switches its softwareand hardware to the active state and takes over the work of the original active CCboard by using the synchronized static data and real-time operation data, thusminimizing the impact of the fault of the original CC board on the entire system.

Clock

In case the active CC board is faulty, the active CC board is automatically to thestandby CC board.

Clock extraction redundancy design for multiple E1/T1 links: In case an E1/T1 link isfaulty, the system can automatically switch the faulty E1/T1 link to another normalone for clock extraction.

Configuration of multiple clock reference sources: In case the current clockreference source is faulty, the current clock reference source is automaticallyswitched to the standby clock reference source.

Clock holdover: When all clock reference sources are faulty, the system can keepworking normally for at least 90 days. (the BB8200 can be held over for at least 180days)

3.1.5.2 PM Troubleshooting Process

The PM troubleshooting process is divided into two parts:

1 Active/standby switching mechanism of the PM board itself (including the PMhardware/software processing)

2 Processing in the CC board


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Active/standby switching of the PM board itself

The PM boards work in the active/standby mode. Both PM boards have an voltageover a channel (in the 8200 device, every slot has a separate power supply channel)

to be powered. In terms of final selection, the hardware mechanism ensures that thevoltage of only one PM board acts on a specific power supply channel. In case of theactive/standby PM switching, switching is implemented immediately, thus avoidingpower-off of the boards.

Processing in the CC board

In the CC, the active/standby PM backup mode has three actions:

When the active PM board detects that a new board is inserted to a specific slot,the active PM board immediately sends a message to the CC board. If the CCboard decides to supply power for the newly inserted board, the CC board

sends a power supply command to both the active and standby PM boards,thus ensuring that both PM boards enable the output of the correspondingchannel.

The CC board sends the active/standby state reported by a PM board to theOMC in real time, so that the OMC can display the active/standby state of eachPM board correctly.

The CC board periodically checks whether each PM board enables each powersupply channel, and synchronizes the result returned by the active PM board tothe standby PM board, thus ensuring that the active power supply and standbypower supply in the same power supply state.

3.1.5.3 BPC Troubleshooting Process

The cells set up in a baseband pool share all the baseband resources in the basebandpool.

In case a baseband board is faulty, Node B assigns the cell setup and radio link setupinitiated by the RNC to another available baseband board in the baseband pool.

For the existing UEs in the faulty baseband board, Node B sends a reset request to theRNC, requesting the RNC to reset the UEs in the faulty baseband board. The publicresources (for example, cells) in the faulty baseband board are deleted, and Node Bnotifies the deletion result to the RNC through an audit response. The RNC initiates cellsetup and radio link setup again, and Node B assigns them to another availablebaseband board in the baseband pool.

3.2 Port Redundancy Protection

3.2.1 Backup of Ethernet Port

Ethernet port backup mainly refers to the backup of the Ethernet ports between theinterconnected shelves. The shelves are interconnected to each other by different means,mainly routing interconnection and TRUNK interconnection.


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1 Routing interconnection: A pair of networks cables is used in two ends respectively.At every end, one network cable is active and the other network cable is standby. Incase a working port is faulty, the faulty port is switched to another port for continuouscommunication.

2 TRUNK interconnection: Through LACP protocol defined in IEEE802.3, the four

physical ports of the same attributes are aggregated, thus increasing bandwidth and

redundancy.

Port backup is also accompanied by board backup. The board backup mode is 1+1backup. At a time, the Ethernet port in the active board receives and transmits data. Incase the port of the active board is faulty, the active/standby switching is triggered. TheEthernet port of the new active board is active for transmitting and receiving data.

Table 3 lists the FE routing ports and trunk ports supported by various boards.

Table 3 FE Routing Ports and Trunk Ports Supported by Various Boards

Board Routing Port (two FE ports in each pair)Trunk Port (four FE ports in eachgroup)

UIMC In the BCTC shelf and BPSN: 3 In the BCTC shelf: 1

GUIM 1 1

THUB 1

In a minor environment, the FE routing interconnection between UIM (including UIMCand GUIM) boards can be used for networking. In a major environment, a THUB boardneeds to be interconnected to other shelves for networking. In Table 3 , a pair of routingports or a group of trunk ports can be interconnected between two shelves.

3.2.1.1 Routing Interconnection

Routing interconnection is also called FE interconnection. The UIM (including UIMC andGUIM) board and UIM/THUB board can each provide one pair of FE ports forinterconnection. The boards work in the 1+1 backup mode. The Ethernet between theactive board and standby board communicates with the external world through highresistance. Figure 26 shows the connection mode. The blue channels indicate theavailable communication links, and the read channels indicate the high-resistancechannels. The two available communication links include an active link and a standby link.All control plane communication streams are in the active link. When the active link isfaulty, the system switches the faulty link to the standby link. In this communication mode,the traffic is only 100M because only one channel is really used.


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Active

UIM UIM

Active

Standby Standby

Figure 26 FE Routing Interconnection Between UIM and UIM

3.2.1.2 TRUNK Interconnection

The routing scheme only supports the traffic of 100M, and cannot satisfy the needs ofhigh traffic. Therefore, the inter-shelf cascaded boards are interconnected through atrunk, so as to increase the inter-shelf cascading traffic (theoretically, the maximum trafficis as high as 400M). Trunk interconnection complies with the link aggregation protocol.The physical links with the same transmission media type and transmission rate arebundled together. Logically, these bundled physical links appear to be one link. Linkaggregation is also called trunking, which allows the peer physical link between switchesor between a switch and a server to multiply its bandwidth. Therefore, trunking is animportant technology whereby to increase the link bandwidth and ensure the flexibilityand redundancy of link transmission.

Figure 27 shows the connection mode. The blue channels indicate the available

communication links, and the red channels indicate the high-resistance channels. Thefour available communication links are aggregated into a group of trunk ports. In caseone link is faulty, communication is implemented through another link.

Figure 27 Trunk Interconnection of Control Plane


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3.2.2 Backup of E1/T1 Port

In the ATM mode, multiple E1 ports, as IMA links, are bundled in an AIM group. Whensome E1 links are interrupted, the services carried over the E1 ports are transferred to

other E1 links.

In the IP mode, multiple E1 ports, as PPP links, are bundled in a MLPPP group. Whensome E1 links are interrupted, the services carried over the E1 ports are transferred toother E1 links.

3.2.3 Backup of SDH Port

SDH ports can be backed up in three modes: port backup plus board backup, APS, andload sharing of optical port.

Port backup plus board backup: The board backup mode is 1+1 backup. At a time, theoptical port in the active board receives and transmits data. In case the port of the activeboard is faulty, the active/standby switching is triggered. The optical port of the newactive board is active for transmitting and receiving data.

APS: Support the APS for the optical ports in a board and the optical ports betweenboards. For details on APS, refer to ZTE UMTS ATM Transmission Feature Description.

Load sharing of optical port: The board backup mode is 1:1 backup. At a time, the opticalports of the active and standby boards both transmit and receive data. The data receivedby the optical port of the standby board is forwarded to the active board.

3.2.4 Backup of Level-1 Switch Optical Port

The Level-1 switch system is an IP packet switching system, which mainly comprisesGUIM, GLI, and PSN boards. The GLI and the PSN are cross-connected through a HSSL.The PSN boards work in the load sharing mode, that is, two PSN boards switch packetsat the same time. The port backup mode is applied between GLI boards. The GLI boardsare cross-connected to the GUIM boards in another shelf respectively. At each end,every GE port has two optical modules for backup. Through active/standby port backupand optical module backup, the backup proportion between physical links and logicallinks is 4:1, thus providing a reliable link assurance for the access of IP packets to theswitching center.

The GUIM has two GE ports. Active/standby GE port backup is accompanied by board

backup. Every GE port has two optical modules. The GLI has four GE ports, and everyGE port has two optical modules. The two GE ports with the same GLI sequence numberhave an active/standby relation. The active/standby relation between the GE ports withdifferent sequence numbers is independent from each other. Table 4 lists the GE portssupported by the GUIM/GLI.

Table 4 GE Ports Supported by the GUIM/GLI

Board Number of GE Ports Number of Optical Modules per GE Port

GUIM 2 2

GLI 4 2


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Every GE port has two optical modules, thus enabling the double-transmitting &one-receiving mechanism through hardware. Both optical modules transmit data to theexternal world. At a time, only the active optical port receives data. The hardware alsoprovides the switching function for the packet-receiving optical module.

The following section describes the inter-shelf fiber interconnection mode in detail.

3.2.4.1 GUIM-GLI Interconnection

In the GUIM, there are two optical ports interconnected to the GLI. The active/standbyrelation between the two optical ports is also accompanied by board backup. In normalcases, the two optical ports both forward the media streams. Traffic balance is attainedbetween the two GE ports in the GUIM through a certain algorithm. The systemcompares the number of the available GE ports in the boards. The system prefers theGUIM with a larger number of available optical ports as the active end. In case the GEport of the active GUIM is faulty, board switching is initiated. Figure 28 shows the detailed

connection mode.

1

2

3

4

G

L

I

#

1

1

2

3

4

G

L

I

#

2

2

1

GUIM

#1

2

1

GUIM

#2

Figure 28 GUIM-GLI Connection

3.2.4.2 Interconnection between GUIM Boards in Two Shelves

In a small switch office, the GLI-PSN switch mode is not needed. Instead, theGUIM-GUIM double-shelf interconnection mode is enough for the service traffic. In thiscase, the following double-shelf interconnection mode can be used. Unlike the GUIM-GLIinterconnection, only one optical port is provided for interconnection in this mode, asshown in Figure 29.


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GUIM#1

GUIM#2

GUIM#3

GUIM#4

Figure 29 Double-Shelf Interconnection Between GUIM Boards

3.3 Redundancy Protection of Communication Link

3.3.1 ATM Link Backup

ATM link backup is configured through the bottom-layer redundant link. According to thelink status, the upper-layer application selects an available link for backup. The link statusis fed back by monitoring the on/off state of the physical layer, and is obtained throughthe OAM check of the ATM.

3.3.2 IP Link Backup

IP link backup is configured through route redundancy. According to the link status, theupper-layer application selects an available route for backup. The link status can beobtained by monitoring the on/off state of the physical layer or through the IP layerdetection protocol (for example, BFD). In case an external interface of the system is faulty,the route related to the faulty interface also fails. When sending data, an applicationselects another route. If the BFD mechanism detects that the corresponding route is notavailable, the application does not select the corresponding route, either. Instead, theapplication selects another normal route.

For details about BFD, refer to ZTE UMTS IP UTRAN Feature Description.

3.3.3 SCTP Link Backup

SCTP uses the Multihomed SCTP mechanism, that is, support the multi-access mode. Ina SCTP couple, there are multiple pairs of IP addresses that support the transmission ofSCTP data. In case a pair of IP channels is interrupted, the status of the SCTP couple is

not affected.

3.3.4 Data Division Transmission Backup

When multiple interfaces (of the same type or different types) support the transmission ofthe same service, the data transmitted through a faulty interface is migrated to anothernormal interface.


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4 Parameter Description

4.1 Parameter List

4.1.1 Configuration Information on Board Redundancy Protection

No. Abbreviated name Parameter name

1 BackUpMode Backup Mode

2 RcpModule RCP Module

3 SubSystem SubSystem

4.1.2 Configuration Information on Port Redundancy Protection

For details on the parameters related to APS of optical ports, refer to ZTE UMTS ATMTransmission Feature Description.

4.1.3 Configuration Information on Communication Link RedundancyProtection

For details on the BFD parameters of the IP link, refer to ZTE UMTS IP UTRAN FeatureDescription.

4.2 Parameter Configuration

4.2.1 Configuration Information on Board Redundancy Protection

4.2.1.1 Backup Mode

OMC Path

Path View->Configuration Management ->RNC NE->RNC Ground Resource

Management-> RACK->Create->Board->Available Board

Parameter Configuration

Related description

None

Interface parameter description:

The parameter indicates the backup mode of boards. Its value is as follows:


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0 No backup

1 1+1 backup (the name is BOARD_BACKUP_MODE_MASTERSLAVE ; only oneboard is running normally at any time)

2 Load sharing (load sharing or port backup only applies to the boards in adjacentslots)

3 Back-to-back backup (not used currently)

4 N+1 backup

5 1:1 backup

Note: The backup mode is specified when the corresponding boards are configured.

Recommendation: Configure the backup mode according to the field networking

mode

4.2.1.2 Rcp Module

OMC Path


Management-> RACK->Create->Board->RCP-> Module 1 / Module 2


Related description

None

Interface parameter description:

The parameter indicates the module number of the RCP. Its value is 3 to 127.

Recommendation: none

4.2.1.3 Sub System

OMC Path


Management-> RACK->Create->Board->RCP-> Module 1 / Module 2


Related description

None

Parameter description: none


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The parameter indicates the subsystem number of the resource shelf of the RCP. Itsvalue is 0 to 19. The invalid value is 0xFF. When the Iub interface is carried in theATM, the available SubSystem [0] of the RCP must be the resource shelf that isaccessed by Node B under the jurisdiction of the RCP, and the number of available

shelves is 1.

4.2.2 Configuration Information on Port Redundancy Protection

N/A.

4.2.3 Configuration Information on Communication Link RedundancyProtection

N/A.

5 Counter and Alarm

5.1 Counter List

N/A.

5.2 Alarm ListAlarm Code 198005376

Description Internal Port of Board Is Down

Severity Level Level 2

Cause 1. The number of internal ports configured for this board and the

neighboring slots exceeds the number of physical slots.

2. Pin Healthy of this slot on the backplane is damaged.

Alarm Code 198066003

Description Control plane communication abnormal between board and its home

module


Cause 1. The board is configured in the database but not powered on.

2. The board is powered on but the control plane link to its home MP

is broken.

3. The board is powered on and DIP switch ENUM is switched on.


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Description Board HW Error


Cause 1.The NE clock is abnormal.

2. The TDM connection chip is abnormal.

4. The board hardware has faults.

5. The back board hardware has faults.


Description Board Doesn't Exist/ CPU is in Reset Status for a Long Time


Cause 1. The board configured in the database is not on position.

2. An error occurs during board resetting.

3. Pin Healthy of this slot on the backplane is damaged.


Description Control plane communication abnormal between MP and OMP


Cause 1. The MP board is configured in the database but not powered on.2. The MP board is powered on but the control plane link to the OMP

is broken.

3. The MP board is powered on and DIP switch ENUM is switched on.


Description Input Clock Abnormal


Cause The clock board runs exceptionally, and is not in the normal working

status. No clock reference is input to the clock board or the clockreference is exceptional.


Description External Port of Board Is Down


Cause 1.The network interface at the local end or the peer end is faulty.

2.The work modes of network interfaces at both ends do not match.

3. Physical connection has faults.


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4.The GEMAC on this board does not support the 100M speed of the

negotiate mode.


Description DSP Resource Unavailable


Cause 1. DSP does not succeed in loading the version and can not work

normally.

2. DSP has HPI interface exception.

3. The media plane loop back fails.

4. Lan91 link is broken.

5. The link of 5328 port is broken.

6. DSP running halts.

7. The system initialization of the Tone resource DSP fails. Different

formats of tone resources or even no tone resource exists on the

board.


Description Clock reference source lost (Level 3 alarm)


Cause Clock reference lost is detected for the first time.




Cause Clock reference lost has been detected for more than 10 minutes.




Cause Clock reference lost has been detected for more than 24 hours.

Alarm Code198005122

Description Communication Link between Active and Standby Boards Off



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Cause 1. Active and standby boards are configured on OMC, but no standby

board is physically plugged.

2. The communication link between active and standby boards is off.

Alarm Code198005189

Description Notification of Active/Standby Changeover

Severity Level Notification Level 4

Cause It is hardware system fault. The active and standby boards switch

over due to artificial operation.

Alarm Code198005660

Description Physical link down between active port and standby port


Cause Physical Link Down Between Active Port and Standby Port

Alarm Code198066058

Description The rate of error code in a mate link is high at GUIM


Cause The rate of error code in a mate link is high. It is adventive

6 Glossary

AC Access Control

APBI ATM Process Board Interface

APBE ATM Process Board Enhanced Version

APS Automatic Protection Switching

ATM Asynchronous Transfer Mode

BHCA Busy-Hour Call Attempts

BME Base station Multiplex Equipment

BM-SC Broadcast Multicast Service Centre

BRS Bearer Subsystem


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CBC Cell Broadcast Centre

THUB Trunk HUB

CN Core Network

DASF Dynamic Radio Bearer Control

DBS Data Base Subsystem

DDN Digital Data Network

Documents

Redundancy Descrip