H3C S9500E Series User manual

H3C S9500E Series Routing Switches
High Availability Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Document Version:
Product Version:

Copyright © 2003-2010, Hangzhou H3C Technologies Co., Ltd. and its licensors
All Rights Reserved
No part of this manual may be reproduced or transmitted in any form or by any means without prior
written consent of Hangzhou H3C Technologies Co., Ltd.
Trademarks
H3C, , Aolynk, , H3Care, , TOP G, , IRF, NetPilot, Neocean, NeoVTL,
SecPro, SecPoint, SecEngine, SecPath, Comware, Secware, Storware, NQA, VVG, V2G, VnG, PSPT,
XGbus, N-Bus, TiGem, InnoVision and HUASAN are trademarks of Hangzhou H3C Technologies Co.,
Ltd.
All other trademarks that may be mentioned in this manual are the property of their respective owners.
Notice
The information in this document is subject to change without notice. Every effort has been made in the
preparation of this document to ensure accuracy of the contents, but all statements, information, and
recommendations in this document do not constitute the warranty of any kind, express or implied.
Environmental Protection
This product has been designed to comply with the requirements on environmental protection. The
storage, use, and disposal of this product must meet the applicable national laws and regulations.

Preface
The H3C S9500E documentation set includes 13 configuration guides, which describe the software
features for the H3C S9500E Series Routing Switches and guide you through the software configuration
procedures. These configuration guides also provide configuration examples to help you apply software
features to different network scenarios.
This preface includes:
•Audience
•Conventions
•About the H3C S9500E Documentation Set
•Obtaining Documentation
•Documentation Feedback
Audience
This documentation is intended for:
Network planners
Field technical support and servicing engineers
Network administrators working with the S9500E series

4
Conventions
This section describes the conventions used in this documentation set.
Command conventions
Convention Description
Boldface Bold text represents commands and keywords that you enter literally as shown.
italic Italic text represents arguments that you replace with actual values.
[ ] Square brackets enclose syntax choices (keywords or arguments) that are
optional.
{ x | y | ... }
Braces enclose a set of required syntax choices separated by vertical bars, from
which you select one.
[ x | y | ... ]
Square brackets enclose a set of optional syntax choices separated by vertical
bars, from which you select one or none.
{ x | y | ... } *
Asterisk marked braces enclose a set of required syntax choices separated by
vertical bars, from which you select at least one.
[ x | y | ... ] *
Asterisk marked square brackets enclose optional syntax choices separated by
vertical bars, from which you may select multiple choices or none.
&<1-n> The argument or keyword and argument combination before the ampersand (&)
sign can be entered 1 to n times.
# A line that starts with a pound (#) sign is comments.
GUI conventions
Convention Description
< > Button names are inside angle brackets. For example, click <OK>.
[ ] Window names, menu items, data table and field names are inside square
brackets. For example, pop up the [New User] window.
/ Multi-level menus are separated by forward slashes. For example,
[File/Create/Folder].
Symbols
Convention Description
Means reader be extremely careful. Improper operation may cause bodily
injury.
Means reader be careful. Improper operation may cause data loss or damage
to equipment.
Means an action or information that needs special attention to ensure successful
configuration or good performance.
Means a complementary description.
Means techniques helpful for you to make configuration with ease.

5
Network topology icons
Convention Description
Represents a generic network device, such as a router, switch, or firewall.
Represents a routing-capable device, such as a router or Layer 3 switch.
Represents a generic switch, such as a Layer 2 or Layer 3 switch, or a router
that supports Layer 2 forwarding and other Layer 2 features.

6
About the H3C S9500E Documentation Set
The H3C S9500E documentation set includes:
Category Documents Purposes
Product description and
specifications
Marketing brochures Describe product specifications and benefits.
Technology white papers Provide an in-depth description of software features
and technologies.
Card datasheets Describe card specifications, features, and standards.
Hardware specifications
and installation
Compliance and safety
manual
Provides regulatory information and the safety
instructions that must be followed during installation.
Quick start
Guides you through initial installation and setup
procedures to help you quickly set up and use your
device with the minimum configuration.
Installation guide Provides a complete guide to hardware installation
and hardware specifications.
Card manuals Provide the hardware specifications of cards.
Cabinet Installation and
Remodel Introduction
Guides you through installing and remodeling H3C
cabinets.
H3C Pluggable SFP
[SFP+][XFP] Transceiver
Modules Installation
Guide
Guides you through installing SFP/SFP+/XFP
transceiver modules.
Adjustable Slider Rail
Installation Guide
Guides you through installing adjustable slider rails to
a rack.
H3C High-End Network
Products Hot-Swappable
Module Manual
Describes the hot-swappable modules available for the
H3C high-end network products, their external views,
and specifications.
Software configuration
Configuration guides Describe software features and configuration
procedures.
Command references Provide a quick reference to all available commands.
Configuration examples Describe typical network scenarios and provide
configuration examples and instructions.
Operations and
maintenance
System log messages Explains the system log messages.
Trap messages Explains the trap messages.
MIB Companion Describes the MIBs for the software release.
Release notes
Provide information about the product release,
including the version history, hardware and software
compatibility matrix, version upgrade information,
technical support information, and software
upgrading.
Error code reference Explains the error codes for the QoS module.

7
Obtaining documentation
You can access the most up-to-date H3C product documentation on the World Wide Web at
http://www.h3c.com.
Click the links on the top navigation bar to obtain different categories of product documentation:
[Technical Support & Documents > Technical Documents] – Provides hardware installation, software
upgrading, and software feature configuration and maintenance documentation.
[Products & Solutions] – Provides information about products and technologies, as well as solutions.
[Technical Support & Documents > Software Download] – Provides the documentation released with the
software version.
Documentation feedback
You can e-mail your comments about product documentation to [email protected].
We appreciate your comments.

8
Table of Contents
Preface ·········································································································································································· 3
Audience············································································································································································3
Conventions ·······································································································································································4
About the H3C S9500E Documentation Set··················································································································6
High availability overview·········································································································································13
Availability requirements··············································································································································· 13
Availability evaluation··················································································································································· 13
High availability technologies ······································································································································ 14
Fault detection technologies ································································································································· 14
Protection switchover technologies······················································································································ 15
Active and standby switchover configuration··········································································································17
Introduction to active and standby switchover············································································································ 17
Ignoring version check of the SMB ······························································································································ 18
Restarting the SMB························································································································································· 18
Manually configuring active and standby switchover································································································ 19
Displaying and maintaining active and standby switchover····················································································· 19
Ethernet OAM configuration ·····································································································································20
Ethernet OAM overview················································································································································ 20
Types of Ethernet OAMPDUs ······························································································································· 20
Ethernet OAM implementation····························································································································· 21
Standards and protocols ······································································································································ 24
Configuring basic Ethernet OAM functions················································································································· 24
Configuring link monitoring ·········································································································································· 25
Configuring errored symbol event detection ······································································································ 25
Configuring errored frame event detection ········································································································ 25
Configuring errored frame period event detection···························································································· 26
Configuring errored frame seconds event detection ························································································· 26
Enabling OAM remote loopback ································································································································· 26
Displaying and maintaining Ethernet OAM configuration ························································································ 27
Ethernet OAM Configuration Example························································································································ 28
DLDP configuration·····················································································································································31
Overview········································································································································································· 31
Background···························································································································································· 31
How DLDP works ··················································································································································· 32
Enabling DLDP ································································································································································ 38
Setting DLDP mode························································································································································· 39
Setting the interval for sending advertisement packets ······························································································ 40

9
Setting the DelayDown timer ········································································································································ 40
Setting the port shutdown mode ··································································································································· 41
Configuring DLDP authentication·································································································································· 41
Resetting DLDP state······················································································································································· 42
Resetting DLDP state in system view ···················································································································· 42
Resetting DLDP state in port view/port group view ··························································································· 42
Displaying and maintaining DLDP································································································································ 43
DLDP configuration example········································································································································· 43
Troubleshooting······························································································································································ 46
RRPP configuration ·····················································································································································47
RRPP overview ································································································································································ 47
Background···························································································································································· 47
Basic concepts in RRPP ········································································································································· 47
RRPPDUs ································································································································································· 50
RRPP timers····························································································································································· 51
How RRPP works···················································································································································· 51
Typical RRPP networking······································································································································· 54
Protocols and standards ······································································································································· 57
RRPP configuration task list············································································································································ 57
Creating an RRPP domain············································································································································· 58
Configuring control VLANs ··········································································································································· 58
Configuring protected VLANs······································································································································· 59
Configuring RRPP rings·················································································································································· 59
Configuring RRPP ports ········································································································································· 60
Configuring RRPP nodes ······································································································································· 61
Activating an RRPP domain··········································································································································· 62
Configuring RRPP timers ················································································································································ 63
Configuring RRPP fast detection ··································································································································· 64
Enabling fast detection ········································································································································· 64
Configuring fast detection timers························································································································· 64
Configuring an RRPP ring group ·································································································································· 65
Displaying and maintaining RRPP ································································································································ 66
RRPP configuration examples········································································································································ 66
Single ring configuration example ······················································································································ 66
Intersecting ring configuration example·············································································································· 69
Intersecting-ring load balancing configuration example··················································································· 74
Fast detection configuration example ················································································································· 84
Troubleshooting······························································································································································ 87
Smart Link configuration ············································································································································89
Smart Link overview ······················································································································································· 89
Terminology ··························································································································································· 90
Operating mechanism of Smart Link ··················································································································· 91
Configuring a Smart Link switch··································································································································· 92

10
Configuration prerequisites ·································································································································· 92
Configuring protected VLANs for a Smart Link group······················································································· 92
Configuring member ports for a Smart Link group ···························································································· 93
Configuring role preemption for a Smart Link group ························································································ 93
Enabling the sending of flush messages ············································································································· 94
Smart Link switch configuration example············································································································ 94
Configuring an associated switch ································································································································ 95
Configuring an associated switch ······················································································································· 95
Associated switch configuration example ·········································································································· 96
Displaying and maintaining Smart Link······················································································································· 96
Smart Link configuration examples ······························································································································ 96
Single Smart Link group configuration example ································································································ 96
Multiple Smart Link groups load sharing configuration example····································································· 99
Monitor link configuration ······································································································································ 104
Overview·······································································································································································104
Terminology ·························································································································································104
How monitor link works······································································································································104
Configuring monitor link··············································································································································105
Configuration prerequisites ································································································································105
Configuration procedure ····································································································································105
Displaying and maintaining monitor link ··················································································································105
Monitor link configuration example ···························································································································106
VRRP configuration·················································································································································· 109
VRRP overview······························································································································································109
VRRP standard protocol mode ····································································································································110
Introduction to VRRP group·································································································································110
VRRP timers ··························································································································································112
Packet format ·······················································································································································112
Principles of VRRP················································································································································114
VRRP tracking·······················································································································································114
VRRP application (using IPv4-based VRRP for example) ·················································································115
VRRP load balancing mode ········································································································································116
Overview······························································································································································116
Allocating virtual MAC addresses·····················································································································117
Virtual forwarder ·················································································································································118
Packet types ·························································································································································120
Configuring VRRP for IPv4···········································································································································121
Configuring the association between virtual IP address and MAC address ················································121
Configuring VRRP working mode ······················································································································121
Creating VRRP group and configuring virtual IP address ···············································································122
Configuring router priority, preemptive mode, and tracking function···························································123
Configuring VF tracking······································································································································124
Configuring VRRP packet attributes···················································································································125

11
Enabling the trap function of VRRP····················································································································126
Displaying and maintaining VRRP for IPv4·······································································································126
Configuring VRRP for IPv6···········································································································································127
Configuring the association between virtual IPv6 address and MAC address ············································127
Creating VRRP group and configuring virtual IPv6 address ···········································································128
Configuring router priority, preemptive mode and tracking function····························································129
Configuring VF tracking······································································································································130
Configuring VRRP packet attributes···················································································································131
Displaying and maintaining VRRP for IPv6·······································································································131
IPv4-based VRRP configuration examples ·················································································································132
Single VRRP group configuration example·······································································································132
VRRP interface tracking configuration example ·······························································································135
Multiple VRRP group configuration example····································································································138
VRRP load balancing mode configuration example ························································································141
IPv6-based VRRP configuration examples ·················································································································147
Single VRRP group configuration example·······································································································147
VRRP interface tracking configuration example ·······························································································150
Multiple VRRP group configuration example····································································································154
VRRP load balancing mode configuration example ························································································158
Troubleshooting VRRP··················································································································································164
GR overview···························································································································································· 166
Introduction to GR ························································································································································166
Basic concepts in GR ···················································································································································166
GR communication procedure ····································································································································167
GR mechanism for commonly used protocols···········································································································169
BFD configuration···················································································································································· 170
Introduction to BFD·······················································································································································170
How BFD works ···················································································································································170
BFD packet format···············································································································································173
Supported features ··············································································································································174
Protocols and standards ·····································································································································175
Configuring BFD basic functions ································································································································175
Configuration prerequisites ································································································································175
Configuration procedure ····································································································································176
Displaying and maintaining BFD································································································································177
Track configuration ················································································································································· 178
Track overview ·····························································································································································178
Collaboration between the track module and the detection modules ···························································178
Collaboration between the track module and the application modules························································179
Configuring collaboration between the track module and the detection modules ···············································179
Configuring track-NQA collaboration ··············································································································179
Configuring track-BFD collaboration ·················································································································180

12
Configuring collaboration between the track module and the interface management module ····························181
Configuring collaboration between the track module and the application modules············································181
Configuring track-VRRP collaboration ···············································································································181
Configuring track-static routing collaboration ··································································································183
Configuring track-policy routing collaboration ································································································184
Displaying and maintaining track entries··················································································································185
Track configuration examples·····································································································································185
VRRP-track-NQA collaboration configuration example (the master monitors the uplink) ····························185
Configuring BFD for a VRRP backup to monitor the master············································································189
Configuring BFD for the VRRP master to monitor the uplinks··········································································193
Static routing-track-NQA collaboration configuration example ·····································································196
Static routing-track-BFD collaboration configuration example········································································199
VRRP-track-interface management collaboration configuration example (the master monitors the uplink
interface)·······························································································································································201
Obtaining support for your product······················································································································· 205
Register your product···················································································································································205
Purchase value-added services ···································································································································205
Troubleshoot online······················································································································································205
Access software downloads········································································································································206
Telephone technical support and repair····················································································································206
Contact us ·····································································································································································206
Acronyms································································································································································· 207
Index ········································································································································································ 221

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High availability overview
Communication interruptions can seriously affect widely-deployed value-added services such as
IPTV and video conference. Therefore, the basic network infrastructures must be able to provide
high availability.
There are three effective ways to improve availability:
•Increasing fault tolerance
•Speeding up fault recovery
•Reducing impact of faults on services
Availability requirements
Availability requirements fall into three levels based on purpose and implementation, as shown in
Table 1.
Table 1 Availability requirements
Level Requirement Solution
1 Decrease system software and
hardware faults
•Hardware: Simplified circuit design, enhanced
production techniques, and reliability tests.
•Software: Reliability design and tests
2 Protect system functions from being
affected by failures Device and link redundancy and switchover
3 Enable the system to recover as fast
as possible
Fault detection, diagnosis, isolation, and recovery
technologies
The level 1 availability requirement should be considered during the design and production
process of network devices. The level 2 availability requirement should be considered during
network design. The level 3 availability requirement should be considered during network
deployment, according to the network infrastructure and service characteristics.
Availability evaluation
Typically, MTBF and MTTR are used to evaluate the availability of a network.
MTBF
MTBF is the predicted elapsed time between inherent failures of a system during operation. It is
typically expressed in hours. A higher MTBF means a higher availability.

14
MTTR
MTTR is the average time required to repair a failed system. MTTR in a broad sense also involves
spare parts management and customer services.
MTTR = fault detection time + hardware replacement time + system initialization time + link
recovery time + routing time + forwarding recovery time. A smaller value of each item means a
smaller MTTR and a higher availability.
High availability technologies
As previously mentioned, increasing MTBF or decreasing MTTR can enhance the availability of a
network. The high availability technologies described in this section meet the level 3 high
availability requirements in the aspect of decreasing MTTR.
High availability technologies can be classified as fault detection technologies or protection
switchover technologies.
Fault detection technologies
Fault detection technologies enable detection and diagnosis of network faults.
•DLDP and Ethernet OAM are data link layer fault detection technologies.
•BFD is a generic fault detection technology that can be used at any layer
•NQA is used for diagnosis and evaluation of network quality
•Monitor Link and Track work along with other high availability technologies to detect faults
through a collaboration mechanism.
See Table 2 for the details of these technologies.
Table 2 Fault detection technologies
Technology Introduction Reference
DLDP
DLDP deals with unidirectional links that may occur in a network. On
detecting a unidirectional link, DLDP, as configured, can shut down the
related port automatically or prompt users to take actions to avoid
network problems.
High Availability
Configuration
Guide/DLDP
Configuration
Ethernet OAM
As a tool monitoring Layer 2 link status, Ethernet OAM is mainly used
to address common link-related issues on the “last mile”. You can
monitor the status of the point-to-point link between two directly
connected devices by enabling Ethernet OAM on them.
High Availability
Configuration
Guide/Ethernet
OAM
Configuration
BFD
BDF provides a single mechanism to quickly detect and monitor the
connectivity of links or IP forwarding in networks. To improve network
performance, devices must quickly detect communication failures to
restore communication through backup paths as soon as possible.
High Availability
Configuration
Guide/BFD
Configuration

15
Technology Introduction Reference
NQA
NQA analyzes network performance, services and service quality by
sending test packets, and provides you with network performance and
service quality parameters such as jitter, TCP connection delay, FTP
connection delay and file transfer rate.
Network
Management and
Monitoring
Configuration
Guide/NQA
Configuration
Monitor link
Monitor link is a port collaboration function. It is usually used in
conjunction with Layer 2 topology protocols. The idea is to monitor the
states of uplink ports and adapt the up/down state of downlink ports
to the up/down state of uplink ports, triggering link switchover on the
downstream device in time.
High Availability
Configuration
Guide/Monitor Link
Configuration
Track
The track module is used to implement collaboration between different
modules. The collaboration here involves three parts: the application
modules, the track module, and the detection modules. These modules
collaborate with one another through collaboration entries. In other
words, the detection modules trigger the application modules to
perform certain operations through the track module. More
specifically, the detection modules probe the link status, network
performance and so on, and inform the application modules of the
detection result through the track module. Once notified of network
status changes, the application modules deal with the changes to
avoid communication interruption and network performance
degradation.
High Availability
Configuration
Guide/Track
Configuration
Protection switchover technologies
Protection switchover technologies aim at recovering network faults. They back up hardware, link,
routing, and service information for switchover in case of network failures, to ensure continuity of
network services. See Table 3 for the details of protection switchover technologies.
Table 3 Protection switchover technologies
Technology Introduction Reference
Active and
standby
switchover
Devices supporting active and standby switchover are normally
equipped with two main boards: one is the AMB and the other is
the SMB. The configurations on the SMB are the same as those on
the AMB. When the AMB fails or is plugged out, the SMB
automatically becomes the AMB to ensure non-stop operating of the
devices.
High Availability
Configuration
Guide/Active and
Standby Switchover
Configuration
Ethernet link
aggregation
Ethernet link aggregation, most often simply called link
aggregation, aggregates multiple physical Ethernet links into one
logical link to increase link bandwidth beyond the limits of any one
single link. This logical link is called an aggregate link. It allows for
link redundancy because the member physical links can
dynamically back up one another.
Layer 2 – LAN
Switching
Configuration
Guide/Ethernet Link
Aggregation

16
Technology Introduction Reference
Smart Link
Smart Link is a feature developed to address the slow convergence
issue with STP. It provides link redundancy as well as fast
convergence in a dual uplink network, allowing the backup link to
take over quickly when the primary link fails.
High Availability
Configuration
Guide/Smart Link
Configuration
MSTP
As a Layer 2 management protocol, MSTP eliminates Layer 2 loops
by selectively blocking redundant links in a network, while allowing
for link redundancy.
Layer 2 – LAN
Switching
Configuration
Guide/MSTP
Configuration
RRPP
RRPP is a link layer protocol designed for Ethernet rings. RRPP can
prevent broadcast storms caused by data loops when an Ethernet
ring is healthy, and rapidly restore the communication paths
between the nodes in the event that a link on the ring is
disconnected.
High Availability
Configuration
Guide/RRPP
Configuration
FRR
Fast Reroute (FRR) provides a quick per-link or per-node protection
on an LSP. In this approach, once a link or node fails on a path,
FRR comes up to reroute the path to a new link or node to bypass
the failed link or node. This can happen as fast as 50 milliseconds,
minimizing data loss. Protocols such as RIP, OSPF, IS-IS, static
routing, and RSVP-TE support this technology.
Layer 3 – IP Routing
Configuration Guide,
MPLS Configuration
Guide/Configuration
Guide of the
corresponding
protocols
GR
GR ensures the continuity of packet forwarding when a protocol
such as BGP, IS-IS, OSPF, LDP, or RSVP-TE restarts, or during an
active/standby switchover process. GR needs other devices to
implement routing information backup and recovery.
High Availability
Configuration
Guide/GR Overview
NSR
NSR is a new feature used to ensure non-stop data transmission
during an active/standby switchover. NSR backs up IP/MPLS
forwarding information from the AMB to the SMB. Upon an
active/standby switchover, NSR can complete link state recovery
and route re-generation without requiring the cooperation of other
devices. IS-IS supports this feature.
Layer 3 – IP Routing
Configuration
Guide/IS-IS
Configuration
VRRP
VRRP is an error-tolerant protocol, which provides highly reliable
default links on multicast and broadcast LANs such as Ethernet,
avoiding network interruption due to failure of a single link.
High Availability
Configuration
Guide/VRRP
Configuration
A single availability technology cannot solve all problems. Therefore, a combination of
availability technologies, chosen on the basis of detailed analysis of network environments and
user requirements, should be used to enhance network availability. For example, access-layer
devices should be connected to distribution-layer devices over redundant links, and core-layer
devices should be fully meshed. Also, network availability should be considered during planning
prior to building a network.

17
Active and standby switchover configuration
•The switch operates in IRF or standalone (the default) mode. For more information about the IRF mode,
see IRF in the IRF Configuration Guide.
•When the device works in standalone mode, you can use the features and functions in this manual to
restart the SMB to perform an active and standby switchover, to implement redundant backup between
the AMB and the SMB. When the device works in IRF mode, you can only use the display
switchover state command to view the backup state of the main boards, and other functions and
commands do not take effect.
Introduction to active and standby switchover
If a device has two main boards, the main board that forwards and processes packets is called
the AMB, and the main board that is in the standby state is called the SMB. The system uses the
main board with a smaller slot number as the AMB, and the other main board as the SMB. The
SMB keeps its configuration the same as the AMB through the synchronization function. When
the AMB fails, the SMB becomes the AMB to process services to ensure the normal operation of
the device. This switchover process is called an active and standby switchover.
Active and standby switchover functions in the following ways:
•Automatic active and standby switchover. If the AMB fails or is disconnected, the system
automatically performs an active and standby switchover to enable the SMB to function as
the AMB.
•Manual active and standby switchover, which is an active and standby switchover
performed at the command line interface. For example, when you upgrade a device, you
can upgrade the SMB first, and then perform an active and standby switchover to upgrade
the AMB, to upgrade the entire device. This greatly reduces the interruption time of services.
When you upgrade the device by performing an active and standby switchover, the current
software version must be gracefully upgraded (that is, the differences between the new version
and the current version are relatively small.); otherwise, the SMB may not be started. To upgrade
a device by performing an active and standby switchover:
1. Download the newest software version to the AMB and SMB.
2. Specify the boot file to be used at the next startup of the AMB and SMB as the newest
software version.
3. Ignore version check for the SMB.
4. Manually restart the SMB to upgrade the SMB.
5. Manually perform an active and standby switchover. Then the SMB becomes the AMB,
taking over from the original AMB, and the original AMB automatically restarts, using the
new version to upgrade the device.

18
•When the device operates normally, do not disconnect the AMB. Perform an active and standby
switchover first, and disconnect it when it is no longer acting as the AMB.
•You cannot execute any command on the SMB. Instead, you perform configurations at the command
line interface on the AMB, which will synchronize the configurations to the SMB.
Ignoring version check of the SMB
When the SMB is powered on, the system checks the versions of the AMB and SMB. If the
versions of the AMB and SMB are not consistent, the SMB cannot be started.
Follow these steps to disable the system from checking the version of the SMB:
To do… Use the command… Remarks
1. Enter system view system-view —
2. Ignore version check of the
SMB ha slave-ignore-version-check Required
Enabled by default.
Ignoring version check of the SMB does not ensure that the SMB can be started in all situations (for
example, when the host software of the SMB and the AMB is greatly different, the SMB may not be able to
be started.).
Restarting the SMB
If the SMB fails, or is to be upgraded, you can restart the SMB to validate the newest version or
configuration. However, before restarting, check the consistency of the versions of the AMB and
SMB. If they are not consistent, configure the system to ignore version check of the SMB.
To do… Use the command… Remarks
1. Enter system view system-view —
2. Manually restart the SMB slave restart Required
When the SMB is restarted, the AMB performs initial synchronization on the SMB. During this process, the
system does not respond to your input. When the initial synchronization is completed, you can execute any
configuration commands on the AMB, and the AMB and SMB keep a real-time synchronization process,
meaning your configuration on the AMB will be copied to the SMB to ensure the consistency of the current
configuration of the AMB and SMB.

19
Manually configuring active and standby
switchover
The original AMB is restarted when an AMB and SMB switchover is performed. Therefore, check the
consistency of the software version of the AMB and SMB before performing AMB and SMB switchover. If
their software versions are not consistent, configure to ignore version check of the SMB first.
To upgrade the AMB, restart the AMB. However, to avoid service interruption, first perform a
manual active and standby switchover to enable the SMB to take over as the AMB. This makes
the original AMB the SMB, and restarts it.
To do… Use the command… Remarks
1. Enter system view system-view —
2. Enable manual active and
standby switchover
slave switchover { disable |
enable }
Optional
Enabled by default
3. Manually perform active and
standby switchover slave switchover Required
Displaying and maintaining active and standby
switchover
To do… Use the command… Remarks
Display the switchover state of the
specified main board (standalone
mode)
display switchover state [
slot slot-id ]
Available in any view
Display the switchover state of the
specified main board (IRF mode)
display switchover state [
chassis chassis-number slot
slot-number ]

20
Ethernet OAM configuration
Ethernet OAM overview
Ethernet OAM is a tool that monitors Layer-2 link status by sending OAMDPUs between switches.
Currently, Ethernet OAM is mainly used to address common link-related issues on the “last mile.”
You can enable Ethernet OAM on two switches connected by a point-to-point connection, to
monitor the status of the link.
Ethernet OAM provides the following functions:
•Link performance monitoring, for detecting link errors
•Fault detection and alarm, for reporting link errors to the administrators
•Remote loopback, for detecting link errors through non-OAMPDUs
Throughout this document, a port with Ethernet OAM enabled is called an Ethernet OAM entity or an OAM
entity.
Types of Ethernet OAMPDUs
There are three types of OAMPDUs: information, event notification, and loopback control. Figure
1shows their formats, and Table 4 describes their fields.
Figure 1 Formats of different types of Ethernet OAMPDUs
Table 4 OAMPDU fields
Field Description