H3C S5120-EI Series User manual
H3C S5120-EI Switch Series
High Availability Configuration Guide
Hangzhou H3C Technologies Co., Ltd.
http://www.h3c.com
Software version: Release 2220
Document version: 6W100-20130810
Copyright © 2013, 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, , H3CS, H3CIE, H3CNE, Aolynk, , H3Care, , IRF, NetPilot, Netflow,
SecEngine, SecPath, SecCenter, SecBlade, Comware, ITCMM 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.
Preface
The H3C S5120-EI documentation set includes 10 configuration guides, which describe the software
features for the H3C S5120-EI Switch Series Release 2220, 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.
The High Availability Configuration Guide describes high availability fundamentals and configuration.
The high availability technologies include fault detection and fault failover. Failure detection technologies
focus on fault detection and isolation. Failover technologies focus on network recovery.
This preface includes:
•Audience
•Added and modified features
•Conventions
•About the S5120-EI documentation set
•Obtaining documentation
•Technical support
•Documentation feedback
Audience
This documentation is intended for:
•Network planners
•Field technical support and servicing engineers
•Network administrators working with the S5120-EI series
Added and modified features
Compared to Release 2210, Release 2220 adds and modifies the following features:
Confi
g
uration
g
uide Added and modified features
High Availability Overview N/A
Ethernet OAM N/A
CFD N/A
DLDP Modified features: Configuring the DLDP authentication mode and
authentication password
RRPP N/A
Smart Link N/A
Monitor Link N/A
Track N/A
Conventions
This section describes the conventions used in this documentation set.
Command conventions
Convention Descri
p
tion
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 select one choice, 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 Descri
p
tion
Boldface Window names, button names, field names, and menu items are in Boldface. For
example, the New User window appears; click OK.
> Multi-level menus are separated by angle brackets. For example, File > Create > Folder.
Convention Descri
p
tion
< > 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 Descri
p
tion
WARNING An alert that calls attention to important information that if not understood or followed can
result in personal injury.
CAUTION An alert that calls attention to important information that if not understood or followed can
result in data loss, data corruption, or damage to hardware or software.
IMPORTANT An alert that calls attention to essential information.
NOTE An alert that contains additional or supplementary information.
Convention Descri
p
tion
TIP An alert that provides helpful information.
Network topology icons
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.
Port numbering in examples
The port numbers in this document are for illustration only and might be unavailable on your device.
About the S5120-EI documentation set
The H3C S5120-EI documentation set includes:
Cate
g
or
y
Documents
Pur
p
oses
Product description and
specifications
Marketing brochure Describe product specifications and benefits.
Technology white papers
Provide an in-depth description of software features
and technologies.
Hardware specifications
and installation
Compliance and safety
manual
CE DOCs
Provide 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 your device.
Installation guide Provides a complete guide to switch installation and
specifications.
RPS Ordering Information
for H3C Low-End Ethernet
Switches
Helps you order RPSs for switches that can work with
an RPS.
User manuals for RPSs Describe the specifications, installation, and
replacement of RPSs.
User manuals for interface
cards
Describe the specifications, installation, and
replacement of expansion interface cards.
H3C Low End Series
Ethernet Switches
Pluggable Modules
Manual
Describes the specifications of pluggable transceiver
modules.
Pluggable SFP[SFP+][XFP]
Transceiver Modules
Installation Guide
Describe the installation, and replacement of
SFP/SFP+/XFP transceiver modules.
Cate
g
or
y
Documents
Pur
p
oses
Software configuration
Configuration guides Describe software features and configuration
procedures.
Command references Provide a quick reference to all available
commands.
Operations and
maintenance 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.
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.
Technical support
servi[email protected]
http://www.h3c.com
Documentation feedback
We appreciate your comments.
i
Contents
High availability overview··········································································································································· 1
Availability requirements··················································································································································1
Availability evaluation······················································································································································1
High availability technologies ·········································································································································2
Fault detection technologies ····································································································································2
Protection switchover technologies·························································································································3
Configuring Ethernet OAM ········································································································································· 4
Ethernet OAM overview···················································································································································4
Major functions of Ethernet OAM ··························································································································4
Ethernet OAMPDUs··················································································································································4
How Ethernet OAM works ······································································································································5
Standards and protocols ·········································································································································7
Ethernet OAM configuration task list ······························································································································7
Configuring basic Ethernet OAM functions····················································································································8
Configuring the Ethernet OAM connection detection timers························································································8
Configuring link monitoring ·············································································································································9
Configuring errored symbol event detection ·········································································································9
Configuring errored frame event detection ···········································································································9
Configuring errored frame period event detection·······························································································9
Configuring errored frame seconds event detection ························································································· 10
Configuring Ethernet OAM remote loopback············································································································· 10
Enabling Ethernet OAM remote loopback ········································································································· 10
Rejecting the Ethernet OAM remote loopback request from a remote port···················································· 11
Displaying and maintaining Ethernet OAM configuration ························································································ 12
Ethernet OAM configuration example ························································································································· 12
Configuring CFD ························································································································································15
Overview········································································································································································· 15
Basic CFD concepts··············································································································································· 15
CFD functions························································································································································· 17
Protocols and standards ······································································································································· 19
CFD configuration task list ············································································································································ 19
Configuring basic CFD settings ···································································································································· 20
Enabling CFD························································································································································· 20
Configuring the CFD protocol version················································································································· 20
Configuring service instances ······························································································································ 20
Configuring MEPs·················································································································································· 21
Configuring MIP generation rules························································································································ 22
Configuring CFD functions············································································································································ 22
Configuration prerequisites ·································································································································· 22
Configuring CC on MEPs ····································································································································· 22
Configuring LB on MEPs ······································································································································· 23
Configuring LT on MEPs········································································································································ 23
Configuring AIS····················································································································································· 24
Configuring LM······················································································································································ 24
Configuring one-way DM····································································································································· 25
Configuring two-way DM ····································································································································· 25
Configuring TST····················································································································································· 26
Displaying and maintaining CFD ································································································································· 26
ii
CFD configuration example ·········································································································································· 27
Configuring DLDP·······················································································································································33
DLDP overview································································································································································ 33
Background···························································································································································· 33
How DLDP works ··················································································································································· 34
DLDP configuration task list··········································································································································· 40
Configuring the duplex mode and speed of an Ethernet interface··········································································· 40
Enabling DLDP ································································································································································ 41
Setting DLDP mode························································································································································· 41
Setting the interval to send advertisement packets ····································································································· 41
Setting the delaydown timer ········································································································································· 42
Setting the port shutdown mode ··································································································································· 42
Configuring DLDP authentication·································································································································· 43
Resetting DLDP state······················································································································································· 43
Displaying and maintaining DLDP································································································································ 44
DLDP configuration examples ······································································································································· 44
Automatically shutting down unidirectional links······························································································· 44
Manually shutting down unidirectional links ······································································································ 48
Troubleshooting DLDP···················································································································································· 51
Configuring RRPP ·······················································································································································52
RRPP overview ································································································································································ 52
Background···························································································································································· 52
Basic concepts in RRPP ········································································································································· 52
RRPPDUS································································································································································· 54
RRPP timers····························································································································································· 55
How RRPP works···················································································································································· 55
Typical RRPP networking······································································································································· 57
Protocols and standards ······································································································································· 60
RRPP configuration task list············································································································································ 60
Creating an RRPP domain············································································································································· 61
Configuring control VLANs ··········································································································································· 61
Configuration guidelines ······································································································································ 61
Configuration procedure ······································································································································ 62
Configuring protected VLANs······································································································································· 62
Configuring RRPP rings·················································································································································· 63
Configuring RRPP ports ········································································································································· 63
Configuring RRPP nodes ······································································································································· 64
Activating an RRPP domain··········································································································································· 65
Configuring RRPP timers ················································································································································ 66
Configuring an RRPP ring group ·································································································································· 66
Configuration restrictions and guidelines ··········································································································· 67
Configuration procedure ······································································································································ 67
Displaying and maintaining RRPP ································································································································ 67
RRPP configuration examples········································································································································ 68
Single ring configuration example ······················································································································ 68
Intersecting ring configuration example·············································································································· 70
Dual homed rings configuration example ·········································································································· 76
Intersecting-ring load balancing configuration example··················································································· 86
Troubleshooting······························································································································································ 95
Configuring Smart Link ··············································································································································96
Smart Link overview ······················································································································································· 96
Background···························································································································································· 96
Terminology ··························································································································································· 97
iii
How Smart Link works ·········································································································································· 98
Smart Link collaboration mechanisms ················································································································· 98
Smart Link configuration task list ·································································································································· 99
Configuring a Smart Link device ·································································································································· 99
Configuration prerequisites ·································································································································· 99
Configuring protected VLANs for a smart link group······················································································100
Configuring member ports for a smart link group ···························································································101
Configuring role preemption for a smart link group························································································101
Enabling the sending of flush messages ···········································································································102
Configuring the collaboration between Smart Link and CC of CFD······························································102
Configuring an associated device ·····························································································································103
Configuration prerequisites ································································································································103
Enabling the receiving of flush messages ·········································································································103
Displaying and maintaining Smart Link·····················································································································103
Smart Link configuration examples ····························································································································104
Single smart link group configuration example ·······························································································104
Multiple smart link groups load sharing configuration example····································································108
Smart Link and CFD collaboration configuration example ·············································································112
Configuring Monitor Link········································································································································ 118
Monitor Link overview ·················································································································································118
Terminology ·························································································································································118
How Monitor Link works·····································································································································119
Configuring Monitor Link ············································································································································119
Configuration prerequisites ································································································································119
Creating a monitor link group ···························································································································119
Configuring monitor link group member ports·································································································119
Displaying and maintaining Monitor Link ·················································································································120
Monitor Link configuration example ··························································································································120
Configuring track ···················································································································································· 124
Track overview ·····························································································································································124
Introduction to collaboration ······························································································································124
Collaboration fundamentals·······························································································································124
Collaboration application example···················································································································125
Track configuration task list·········································································································································125
Associating the track module with a detection module ···························································································125
Associating track with NQA ······························································································································125
Associating track with interface management ·································································································126
Associating the track module with an application module······················································································127
Associating track with static routing··················································································································127
Displaying and maintaining track entries··················································································································128
Track configuration examples·····································································································································128
Static routing-track-NQA collaboration configuration example ·····································································128
Index ········································································································································································ 134
1
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.
The following are the 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.
Table 1 Availability requirements
Level Re
q
uirement Solution
1 Decrease system software and
hardware faults
•Hardware—Simplifying circuit design, enhancing
production techniques, and performing reliability tests.
•Software—Reliability design and test
2 Protect system functions from being
affected if faults occur
Device and link redundancy and deployment of switchover
strategies
3 Enable the system to recover as fast
as possible
Performing fault detection, diagnosis, isolation, and
recovery technologies
The level 1 availability requirement should be considered during the design and production process of
network devices. Level 2 should be considered during network design. Level 3 should be considered
during network deployment, according to the network infrastructure and service characteristics.
Availability evaluation
Mean Time Between Failures (MTBF) and Mean Time to Repair (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
in the unit of hours. A higher MTBF means a high availability.
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.
2
High availability technologies
Increasing MTBF or decreasing MTTR can enhance the availability of a network. The high availability
technologies described in this section meet the level 2 and level 3 high availability requirements by
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. CFD, DLDP, and Ethernet
OAM are data link layer fault detection technologies. 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.
Table 2 Fault detection technologies
Technolo
gy
Introduction Reference
CFD
Connectivity Fault Detection (CFD), which conforms to IEEE
802.1ag Connectivity Fault Management (CFM) and ITU-T
Y.1731, is an end-to-end per-VLAN link layer Operations,
Administration and Maintenance (OAM) mechanism used for
link connectivity detection, fault verification, and fault
location.
"Configuring CFD" in High
Availability Configuration
Guide
DLDP
The Device link detection protocol (DLDP) deals with
unidirectional links that may occur in a network. Upon
detecting a unidirectional link, DLDP, as configured, can shut
down the related port automatically or prompt users to take
actions to avoid network problems.
"Configuring DLDP" in
High Availability
Configuration Guide
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.
"Configuring Ethernet
OAM" in High Availability
Configuration Guide
NQA
Network Quality Analyzer (NQA) analyzes network
performance, services and service quality through 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.
"Configuring NQA" in
Network Management
and Monitoring
Configuration Guide
Monitor Link
Monitor Link works together with Layer 2 topology protocols to
adapt the up/down state of a downlink port to the state of an
uplink port. This feature enables fast link switchover on a
downstream device in response to the uplink state change on
its upstream device.
"Configuring Monitor Link"
in High Availability
Configuration Guide
3
Technolo
gy
Introduction Reference
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. That is, 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.
"Configuring track" in
High Availability
Configuration Guide
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 faults, to ensure continuity of network services.
Table 3 Protection switchover technologies
Technolo
gy
Introduction Reference
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 an aggregate link. It allows for link
redundancy because the member physical links can dynamically
back up one another.
"Configuring Ethernet
ink aggregation" in
Layer 2
—
LAN
Switching
Configuration Guide
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.
"Configuring Smart
Link" in High
Availability
Configuration Guide
MSTP
As a Layer 2 management protocol, the Multiple Spanning Tree
Protocol (MSTP) eliminates Layer 2 loops by selectively blocking
redundant links in a network, and in the mean time, allows for link
redundancy.
"Configuring
spanning tree" in
Layer 2—LAN
Switching
Configuration Guide
RRPP
The Rapid Ring Protection Protocol (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 is disconnected on the ring.
"Configuring RRPP" in
High Availability
Configuration Guide
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.
4
Configuring Ethernet OAM
Ethernet OAM overview
Ethernet Operation, Administration and Maintenance (OAM) is a tool that monitors Layer 2 link status
and addresses common link-related issues on the "last mile." You can use it to monitor the status of the
point-to-point link between two directly connected devices.
Major functions of Ethernet OAM
Ethernet OAM provides the following functions:
•Link performance monitoring—Monitors the performance indices of a link, including packet loss,
delay, and jitter, and collects traffic statistics of various types
•Fault detection and alarm—Checks the connectivity of a link by sending OAM protocol data units
(OAMPDUs) and reports to the network administrators when a link error occurs
•Remote loopback—Checks link quality and locates link errors by looping back OAMPDUs
Ethernet OAMPDUs
Ethernet OAM works on the data link layer. Ethernet OAM reports the link status by periodically
exchanging OAMPDUs between devices so that the administrator can effectively manage the network.
Ethernet OAMPDUs fall into the following types: Information, Event Notification, and Loopback Control.
Figure 1 Formats of different types of Ethernet OAMPDUs
Table 4 Fields in an OAMPDU
Field Descri
p
tion
Dest addr
Destination MAC address of the Ethernet OAMPDU
It is a slow protocol multicast address, 0180c2000002. Bridges cannot forward
slow protocol packets, so Ethernet OAMPDUs cannot be forwarded.
Source addr Source MAC address of the Ethernet OAMPDU
It is the bridge MAC address of the sending side and is a unicast MAC address.
Type Type of the encapsulated protocol in the Ethernet OAMPDU
The value is 0x8809.
5
Field Descri
p
tion
Subtype The specific protocol being encapsulated in the Ethernet OAMPDU
The value is 0x03.
Flags Status information of an Ethernet OAM entity
Code Type of the Ethernet OAMPDU
NOTE:
Throughout this document, a port with Ethernet OAM enabled is an Ethernet OAM entity or an OAM
entity.
Table 5 Functions of different types of OAMPDUs
OAMPDU t
yp
e Function
Information OAMPDU
Used for transmitting state information of an Ethernet OAM entity—including the
information about the local device and remote devices and customized
information—to the remote Ethernet OAM entity and maintaining OAM connections.
Event Notification
OAMPDU
Used by link monitoring to notify the remote OAM entity when it detects problems on
the link in between.
Loopback Control
OAMPDU
Used for remote loopback control. By inserting the information used to
enable/disable loopback to a loopback control OAMPDU, you can enable/disable
loopback on a remote OAM entity.
How Ethernet OAM works
This section describes the working procedures of Ethernet OAM.
Ethernet OAM connection establishment
Ethernet OAM connection is the basis of all the other Ethernet OAM functions. OAM connection
establishment is also known as the "Discovery phase", where an Ethernet OAM entity discovers remote
OAM entities and establishes sessions with them.
In this phase, interconnected OAM entities determine whether Ethernet OAM connections can be
established, by exchanging Information OAMPDUs to notify the peer of their OAM configuration
information and the OAM capabilities of the local nodes. An Ethernet OAM connection can be
established between entities that have matching Loopback, link detecting, and link event settings. After
an Ethernet OAM connection is established, Ethernet OAM takes effect on both sides.
For Ethernet OAM connection establishment, a device can operate in active Ethernet OAM mode or
passive Ethernet OAM mode, but a switch role will be somewhat different depending on the mode.
Table 6 Active Ethernet OAM mode and passive Ethernet OAM mode
Item Active Ethernet OAM mode
Passive Ethernet OAM mode
Initiating OAM Discovery Available Unavailable
Responding to OAM Discovery Available Available
Transmitting Information
OAMPDUs Available Available
6
Item Active Ethernet OAM mode
Passive Ethernet OAM mode
Transmitting Event Notification
OAMPDUs Available Available
Transmitting Information
OAMPDUs without any TLV Available Available
Transmitting Loopback Control
OAMPDUs Available Unavailable
Responding to Loopback Control
OAMPDUs
Available—if both sides operate in
active OAM mode Available
NOTE:
•Only OAM entities operating in active OAM mode can initiate OAM connections. OAM entities
operating in passive mode wait and respond to the connection requests sent by their peers.
•No OAM connection can be established between OAM entities operating in passive OAM mode.
After an Ethernet OAM connection is established, the Ethernet OAM entities on both sides exchange
Information OAMPDUs at the handshake packet transmission interval to check whether the Ethernet
OAM connection is normal. If an Ethernet OAM entity receives no Information OAMPDU within the
Ethernet OAM connection timeout time, the Ethernet OAM connection is considered disconnected.
Link monitoring
Error detection in an Ethernet is difficult, especially when the physical connection in the network is not
disconnected but network performance is degrading gradually. Link monitoring is used to detect and
indicate link faults in various environments. Ethernet OAM implements link monitoring through the
exchange of Event Notification OAMPDUs. When detecting one of the link error events listed in Table 7,
the local OAM entity sends an Event Notification OAMPDU to notify the remote OAM entity. With the
log information, network administrators can keep track of network status promptly.
Table 7 Ethernet OAM link error events
Ethernet OAM link events Descri
p
tion
Errored symbol event
An errored symbol event occurs when the number of detected symbol
errors during a specified detection interval exceeds the predefined
threshold.
Errored frame event An errored frame event occurs when the number of detected error
frames during a specified interval exceeds the predefined threshold.
Errored frame period event
An errored frame period event occurs if the number of frame errors in
a specific number of received frames exceeds the predefined
threshold.
Errored frame seconds event
An errored frame seconds event occurs when the number of error
frame seconds detected on a port during a specified detection
interval reaches the error threshold.
The system transforms the period of detecting errored frame period events into the maximum number of
64-byte frames (excluding the interframe spacing and preamble) that a port can send in the specified
period. The system takes the maximum number of frames sent as the period. The maximum number of
frames sent is calculated using this formula: the maximum number of frames = interface bandwidth (bps)
× errored frame period event detection period (in ms)/(64 × 8 × 1000).
7
A second in which errored frames appear is called an "errored frame second."
Remote fault detection
Information OAMPDUs are exchanged periodically among Ethernet OAM entities across established
OAM connections. In a network where traffic is interrupted due to device failures or unavailability, the
flag field defined in information OAMPDUs allows an Ethernet OAM entity to send error
information—the critical link event type—to its peer. You can use the log information to track ongoing link
status and troubleshoot problems promptly.
Table 8 Critical link events
T
yp
e Descri
p
tion OAMPDU transmission fre
q
uencies
Link Fault Peer link signal is lost. Once per second
Dying Gasp A power failure or other unexpected error
occurred. Non-stop
Critical Event An undetermined critical event occurred. Non-stop
This Switch Series is able to receive information OAMPDUs carrying the critical link events listed in Table
8.
Only the Gigabit fiber ports are able to send information OAMPDUs carrying Link Fault events.
This Switch Series is able to send information OAMPDUs carrying Dying Gasp events when the device is
rebooted or relevant ports are manually shut down. Physical IRF ports, however, are unable to send this
type of OAMPDU. For more information about physical IRF ports, see IRF Configuration Guide.
This Switch Series is unable to send information OAMPDUs carrying Critical Events.
Remote loopback
Remote loopback is available only after the Ethernet OAM connection is established. With remote
loopback enabled, the Ethernet OAM entity operating in active Ethernet OAM mode sends
non-OAMPDUs to its peer. After receiving these frames, the peer does not forward them according to
their destination addresses. Instead, it returns them to the sender along the original path.
Remote loopback enables you to check the link status and locate link failures. Performing remote
loopback periodically helps to detect network faults promptly. Furthermore, performing remote loopback
by network segments helps to locate network faults.
Standards and protocols
Ethernet OAM is defined in IEEE 802.3ah (Carrier Sense Multiple Access with Collision Detection
(CSMA/CD) Access Method and Physical Layer Specifications.
Ethernet OAM configuration task list
Task Remarks
Configuring basic Ethernet OAM functions Required
Configuring the Ethernet OAM connection detection timers Optional
Configuring link
monitoring
Configuring errored symbol event detection Optional
Configuring errored frame event detection Optional
8
Task Remarks
Configuring errored frame period event detection Optional
Configuring errored frame seconds event detection
Optional
Configuring Ethernet
OAM remote
loopback
Enabling Ethernet OAM remote loopback Optional
Rejecting the Ethernet OAM remote loopback
request from a remote port Optional
Configuring basic Ethernet OAM functions
For Ethernet OAM connection establishment, an Ethernet OAM entity operates in active mode or passive
mode. Only an Ethernet OAM entity in active mode can initiate connection establishment. After Ethernet
OAM is enabled on an Ethernet port, according to its Ethernet OAM mode, the Ethernet port establishes
an Ethernet OAM connection with its peer port.
To change the Ethernet OAM mode on an Ethernet OAM-enabled port, you must first disable Ethernet
OAM on the port.
To configure basic Ethernet OAM functions:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view.
interface interface-type
interface-number N/A
3. Set the Ethernet OAM mode. oam mode { active | passive }
Optional.
The default is active Ethernet OAM
mode.
4. Enable Ethernet OAM on the
current port. oam enable Ethernet OAM is disabled by
default.
Configuring the Ethernet OAM connection
detection timers
After an Ethernet OAM connection is established, the Ethernet OAM entities on both sides exchange
Information OAMPDUs at the handshake packet transmission interval to check whether the Ethernet
OAM connection is normal. If an Ethernet OAM entity receives no Information OAMPDU within the
Ethernet OAM connection timeout time, the Ethernet OAM connection is considered disconnected.
By adjusting the handshake packet transmission interval and the connection timeout timer, you can
change the detection time resolution for Ethernet OAM connections.
After the timeout timer of an Ethernet OAM connection expires, the local OAM entity ages out its
connection with the peer OAM entity, causing the OAM connection to be disconnected. H3C
recommends that you set the connection timeout timer to at least five times the handshake packet
transmission interval, ensuring the stability of Ethernet OAM connections.
To configure the Ethernet OAM connection detection timers:
9
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the Ethernet OAM
handshake packet
transmission interval.
oam timer hello interval Optional.
1000 millisecond by default.
3. Configure the Ethernet OAM
connection timeout timer. oam timer keepalive interval Optional.
5000 milliseconds by default.
Configuring link monitoring
After Ethernet OAM connections are established, the link monitoring periods and thresholds configured
in this section take effect on all Ethernet ports automatically.
Configuring errored symbol event detection
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the errored
symbol event detection
interval. oam errored-symbol period period-value Optional.
1 second by default.
3. Configure the errored
symbol event triggering
threshold.
oam errored-symbol threshold
threshold-value
Optional.
1 by default.
Configuring errored frame event detection
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the errored frame
event detection interval. oam errored-frame period
period-value
Optional.
1 second by default.
3. Configure the errored frame
event triggering threshold. oam errored-frame threshold
threshold-value
Optional.
1 by default.
Configuring errored frame period event detection
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the errored
frame period event
detection period.
oam errored-frame-period period
period-value
Optional.
1000 milliseconds by default.
10
Ste
p
Command
Remarks
3. Configure the errored
frame period event
triggering threshold.
oam errored-frame-period threshold
threshold-value
Optional.
1 by default.
Configuring errored frame seconds event detection
IMPORTANT:
Make sure the errored frame seconds tri
gg
erin
g
threshold is less than the errored frame seconds detection
interval. Otherwise, no errored frame seconds event can be generated.
To configure errored frame seconds event detection:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Configure the errored frame
seconds event detection
interval.
oam errored-frame-seconds
period period-value
Optional.
60 second by default.
3. Configure the errored frame
seconds event triggering
threshold.
oam errored-frame-seconds
threshold threshold-value
Optional.
1 by default.
Configuring Ethernet OAM remote loopback
Enabling Ethernet OAM remote loopback
CAUTION:
Use this function with caution, because enabling Ethernet OAM remote loopback impacts other services.
When you enable Ethernet OAM remote loopback on a port, the port sends Loopback Control
OAMPDUs to a remote port, and the remote port enters the loopback state. The port then sends test
frames to the remote port. By observing how many of these test frames return, you can calculate the
packet loss ratio on the link to evaluate the link performance.
You can enable Ethernet OAM remote loopback on a specific port in user view, system view, or Layer 2
Ethernet interface view. The configuration effects are the same.
Configuration guidelines
•Ethernet OAM remote loopback is available only after the Ethernet OAM connection is established
and can be performed only by Ethernet OAM entities operating in active Ethernet OAM mode.
•Remote loopback is available only on full-duplex links that support remote loopback at both ends.
•Ethernet OAM remote loopback must be supported by both the remote port and the sending port.
•Enabling Ethernet OAM remote loopback interrupts data communications. After Ethernet OAM
remote loopback is disabled, all the ports involved will shut down and then come up. Ethernet OAM
remote loopback can be disabled by any of the following actions: executing the undo oam enable
command to disable Ethernet OAM; executing the undo oam loopback interface or undo oam
11
loopback command to disable Ethernet OAM remote loopback; and Ethernet OAM connection
timing out.
•Ethernet OAM remote loopback is only applicable to individual links. It is not applicable to link
aggregation member ports. In addition, do not assign ports where Ethernet OAM remote loopback
is being performed to link aggregation groups. For more information about link aggregation
groups, see Layer 2—LAN Switching Configuration Guide.
•Enabling internal loopback test on a port in remote loopback test can terminate the remote
loopback test. For more information about loopback test, see Layer 2—LAN Switching
Configuration Guide.
Configuration procedure
To enable Ethernet OAM remote loopback in user view:
Task Command
Remarks
Enable Ethernet OAM remote
loopback on a specific port.
oam loopback interface
interface-type interface-number Disabled by default.
To enable Ethernet OAM remote loopback in system view:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Enable Ethernet OAM remote
loopback on a specific port.
oam loopback interface
interface-type interface-number Disabled by default.
To enable Ethernet OAM remote loopback in Layer 2 Ethernet interface view:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view.
interface interface-type
interface-number N/A
3. Enable Ethernet OAM remote
loopback on the port. oam loopback Disabled by default.
Rejecting the Ethernet OAM remote loopback request from a
remote port
The Ethernet OAM remote loopback function impacts other services. To solve this problem, you can
disable a port from being controlled by the Loopback Control OAMPDUs sent by a remote port. The local
port then rejects the Ethernet OAM remote loopback request from the remote port.
To reject the Ethernet OAM remote loopback request from a remote port:
Ste
p
Command
Remarks
1. Enter system view. system-view N/A
2. Enter Layer 2 Ethernet
interface view.
interface interface-type
interface-number N/A
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