H3C s5800 series High Availability Configuration Manual

H3C S5820X&S5800 Switch Series

High Availability Configuration Guide

Hangzhou H3C Technologies Co., Ltd.

http://www.h3c.com

Software version: Release 1211

Document version: 6W100-20110415

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, , H

3

Care,

, TOP G, , IRF, NetPilot, Neocean, NeoVTL,

SecPro, SecPoint, SecEngine, SecPath, Comware, Secware, Storware, NQA, VVG, V

2

G, V

n

G, 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.

Preface

The H3C S5800&S5820X documentation set includes 12 configuration guides, which describe the

software features for the S5800&S5820X Switch Series 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 H3C S5800&S5820X 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 S5800 and S5820X series

Added and modified features

Compared to Release1110, Release1211 adds and modifies the following features:

Configuration guide Added and modified features

Ethernet OAM

Added features:

• Enable Ethernet OAM remote loopback on a specified port in

user view or system view

• Rejecting the Ethernet OAM remote loopback request from a

remote port

• Restore the default Ethernet OAM mode for an Ethernet port

• Configuring the Ethernet OAM connection detection timers

Configuration guide Added and modified features

CFD

Added features: ITU-T Y.1731

Modified features:

• Change configuring the LB function in system view to configuring

the LB function in any view

• Change configuring the LT function in system view to configuring

the LT function in any view

DLDP —

RRPP Added features: RRPP fast detection

Smart Link Added features: Collaboration between Smart Link and CC of CFD

Monitor Link —

VRRP —

Stateful failover Stateful failover is a newly added feature

BFD

Added features: BFD for OSPFv3, IPv6 IS-IS, IPv6 BGP, PIM, and IPv6

PIM

Track Added features: Associating track with PBR

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 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 Description

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.

Symbols

Convention Description

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.

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.

About the H3C S5800&S5820X documentation set

The H3C S5800&S5820X documentation set includes:

Category Documents Purposes

Marketing brochures Describe product specifications and benefits.

Product description and

specifications

Technology white papers

Provide an in-depth description of software features

and technologies.

PSR150-A [ PSR150-D ]

Power Modules User

Manual

Describes the appearances, features, specifications,

installation, and removal of the pluggable 150W

power modules available for the products.

PSR300-12A

[ PSR300-12D1 ] Power

Modules User Manual

Describes the appearances, features, specifications,

installation, and removal of the pluggable 300W

power modules available for the products.

Pluggable module

description

PSR750-A [ PSR750-D ]

Power Modules User

Manual

Describes the appearances, features, specifications,

installation, and removal of the pluggable 750W

power modules available for the products.

Category Documents Purposes

RPS User Manual

Describes the appearances, features, and

specifications of the RPS units available for the

products.

LSW1FAN and

LSW1BFAN Installation

Manual

Describes the appearances, specifications,

installation, and removal of the pluggable fan

modules available for the products.

LSW148POEM Module

User Manual

Describes the appearance, features, installation,

and removal of the pluggable PoE module available

for the products.

S5820X [ S5800 ] Series

Ethernet Switches

Interface Cards User

Manual

Describes the models, hardware specifications,

installation, and removal of the interface cards

available for the products.

H3C OAP Cards User

Manual

Describes the benefits, features, hardware

specifications, installation, and removal of the OAP

cards available for the products.

H3C Low End Series

Ethernet Switches

Pluggable Modules

Manual

Describes the models, appearances, and

specifications of the pluggable modules available

for the products.

S5800-60C-PWR

Ethernet Switch Hot

Swappable Power

Module Ordering Guide

Guides you through ordering the hot-swappable

power modules available for the S5800-60C-PWR

switches in different cases.

Power configuration

RPS Ordering Information

for H3C Low-End Ethernet

Switches

Provides the RPS and switch compatibility matrix and

RPS cable specifications.

• S5800 Series Ethernet

Switches Quick Start

• S5820X Series

Ethernet Switches

Quick Start

• S5800 Series Ethernet

Switches CE DOC

• S5820X Series

Ethernet Switches CE

DOC

Provides regulatory information and the safety

instructions that must be followed during

installation.

• S5800 Series Ethernet

Switches Quick Start

• S5820X Series

Ethernet Switches

Quick Start

Guides you through initial installation and setup

procedures to help you quickly set up and use your

device with the minimum configuration.

Hardware installation

• S5800 Series Ethernet

Switches Installation

Manual

• S5820X Series

Ethernet Switches

Installation Manual

Provides a complete guide to hardware installation

and hardware specifications.

Category Documents Purposes

Pluggable SFP[SFP+][XFP]

Transceiver Modules

Installation Guide

Guides you through installing SFP/SFP+/XFP

transceiver modules.

• S5800-60C-PWR

Switch Video

Installation Guide

• S5820X-28C Switch

Video Installation

Guide

Shows how to install the H3C S5800-60C-PWR and

H3C S5820X-28C Ethernet switches.

Configuration guide

Describe software features and configuration

procedures.

Software configuration

Command reference

Provide a quick reference to all available

commands.

H3C Series Ethernet

Switches Login Password

Recovery Manual

Tells how to find the lost password or recover the

password when the login password is lost.

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

customer_service@h3c.com

http://www.h3c.com

Documentation feedback

You can e-mail your comments about product documentation to [email protected].

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

Ethernet OAM configuration ······································································································································· 5

Ethernet OAM overview···················································································································································5

Background········································································································································································5

Major functions of Ethernet OAM ···································································································································5

Ethernet OAMPDUs··················································································································································5

How Ethernet OAM works ······································································································································7

Protocols and Standards··········································································································································9

Ethernet OAM configuration task list ······························································································································9

Configuring basic Ethernet OAM functions····················································································································9

Configuring the Ethernet OAM connection detection timers····················································································· 10

Configuring link monitoring ·········································································································································· 11

Configuring errored symbol event detection ······································································································ 11

Configuring errored frame event detection ········································································································ 11

Configuring errored frame period event detection···························································································· 11

Configuring errored frame seconds event detection ························································································· 12

Configuring OAM remote loopback···························································································································· 12

Enabling Ethernet OAM remote loopback ········································································································· 12

Rejecting the Ethernet OAM remote loopback request from a remote port···················································· 13

Displaying and maintaining Ethernet OAM configuration ························································································ 14

Ethernet OAM configuration example ························································································································· 14

CFD configuration······················································································································································17

Overview········································································································································································· 17

Basic concepts in CFD ·········································································································································· 17

CFD functions························································································································································· 19

Protocols and standards ······································································································································· 21

CFD configuration task list ············································································································································ 21

Configuring basic CFD settings ···································································································································· 22

Enabling CFD························································································································································· 22

Configuring the CFD protocol version················································································································· 22

Configuring service instances ······························································································································ 23

Configuring MEPs·················································································································································· 23

Configuring MIP generation rules························································································································ 24

Configuring CFD functions ············································································································································ 25

Configuration prerequisites ·································································································································· 25

Configuring CC on MEPs ····································································································································· 25

Configuring LB on MEPs ······································································································································· 26

Configuring LT on MEPs········································································································································ 26

Configuring AIS····················································································································································· 27

Configuring LM······················································································································································ 27

Configuring one-way DM····································································································································· 28

Configuring two-way DM ····································································································································· 28

Configuring TST····················································································································································· 28

ii

Displaying and maintaining CFD ································································································································· 29

CFD configuration example ·········································································································································· 30

DLDP configuration·····················································································································································36

Overview········································································································································································· 36

Background···························································································································································· 36

How DLDP works ··················································································································································· 37

DLDP configuration task list··········································································································································· 43

Enabling DLDP ································································································································································ 43

Setting DLDP mode························································································································································· 44

Setting the interval for sending advertisement packets ······························································································ 44

Setting the DelayDown timer········································································································································· 45

Setting the port shutdown mode ··································································································································· 45

Configuring DLDP authentication·································································································································· 46

Resetting DLDP state······················································································································································· 46

Displaying and maintaining DLDP································································································································ 47

DLDP configuration examples ······································································································································· 47

Automatically shutting down unidirectional links ······························································································· 47

Manually shutting down unidirectional links ······································································································ 51

Troubleshooting DLDP···················································································································································· 54

RRPP configuration ·····················································································································································55

RRPP overview ································································································································································ 55

Background···························································································································································· 55

Basic concepts in RRPP ········································································································································· 56

RRPPDUs ································································································································································· 58

RRPP timers····························································································································································· 59

How RRPP works···················································································································································· 59

Typical RRPP networking······································································································································· 61

Protocols and standards ······································································································································· 64

RRPP configuration task list············································································································································ 64

Creating an RRPP domain············································································································································· 65

Configuring control VLANs ··········································································································································· 65

Configuring protected VLANs······································································································································· 66

Configuring RRPP rings·················································································································································· 66

Configuring RRPP ports ········································································································································· 67

Configuring RRPP nodes ······································································································································· 67

Activating an RRPP domain··········································································································································· 69

Configuring RRPP timers ················································································································································ 69

Configuring RRPP fast detection ··································································································································· 70

Enabling fast detection ········································································································································· 70

Configuring fast detection timers························································································································· 70

Configuring an RRPP ring group ·································································································································· 71

Displaying and maintaining RRPP ································································································································ 72

RRPP configuration examples········································································································································ 72

Single ring configuration example ······················································································································ 72

Intersecting ring configuration example·············································································································· 74

Intersecting-ring load balancing configuration example··················································································· 80

Fast detection configuration example ················································································································· 89

Troubleshooting······························································································································································ 92

Smart Link configuration············································································································································93

Smart Link overview ······················································································································································· 93

Background···························································································································································· 93

Terminology ··························································································································································· 94

How Smart Link works ·········································································································································· 95

iii

Smart Link collaboration mechanisms ················································································································· 96

Smart Link configuration task list ·································································································································· 96

Configuring a smart link device ··································································································································· 97

Configuration prerequisites ·································································································································· 97

Configuring protected VLANs for a smart link group························································································ 97

Configuring member ports for a smart link group ····························································································· 97

Configuring role preemption for a smart link group·························································································· 98

Enabling the sending of flush messages ············································································································· 98

Configuring the collaboration between Smart Link and CC of CFD································································ 99

Configuring an associated device ······························································································································· 99

Enabling the receiving of flush messages ··········································································································· 99

Displaying and maintaining Smart Link·····················································································································100

Smart Link configuration examples ····························································································································100

Single smart link group configuration example ·······························································································100

Multiple smart link groups load sharing configuration example····································································104

Monitor Link configuration······································································································································ 109

Overview·······································································································································································109

Terminology ·························································································································································109

How Monitor Link works·····································································································································110

Configuring Monitor Link ············································································································································110

Configuration prerequisites ································································································································110

Creating a monitor link group ···························································································································110

Configuring monitor link group member ports·································································································110

Displaying and maintaining Monitor Link ·················································································································111

Monitor Link configuration example ··························································································································111

VRRP configuration·················································································································································· 115

VRRP overview······························································································································································115

VRRP standard protocol mode ····································································································································116

Introduction to VRRP group·································································································································116

VRRP timers ··························································································································································118

Packet format ·······················································································································································118

Principles of VRRP················································································································································120

VRRP tracking·······················································································································································120

VRRP application ·················································································································································121

VRRP load balancing mode ········································································································································122

Overview······························································································································································122

Assigning virtual MAC addresses ·····················································································································123

Virtual forwarder ·················································································································································125

Packet types ·························································································································································127

Configuring VRRP for IPv4···········································································································································127

VRRP for IPv4 configuration task list ··················································································································127

Configuring a VRRP working mode···················································································································128

Specifying the type of MAC addresses mapped to virtual IP addresses·······················································128

Creating a VRRP group and configuring virtual IP address············································································129

Configuring router priority, preemptive mode and tracking function····························································130

Configuring VF tracking······································································································································131

Configuring VRRP packet attributes···················································································································132

Enabling the trap function for VRRP···················································································································133

Displaying and maintaining VRRP for IPv4·······································································································133

Configuring VRRP for IPv6···········································································································································134

VRRP for IPv6 configuration task list ··················································································································134

Specifying the type of MAC addresses mapped to virtual IPv6 addresses ··················································134

Creating a VRRP group and configuring a virtual IPv6 address ····································································135

iv

Configuring router priority, preemptive mode and tracking function····························································136

Configuring VF tracking······································································································································137

Configuring VRRP packet attributes···················································································································138

Displaying and maintaining VRRP for IPv6·······································································································139

IPv4-based VRRP configuration examples ·················································································································139

Single VRRP group configuration example·······································································································139

VRRP interface tracking configuration example ·······························································································142

VRRP with multiple VLANs configuration example···························································································145

VRRP load balancing mode configuration example························································································148

IPv6-based VRRP configuration examples ·················································································································156

Single VRRP group configuration example·······································································································156

VRRP interface tracking configuration example ·······························································································159

VRRP with multiple VLANs configuration example···························································································163

VRRP load balancing mode configuration example························································································166

Troubleshooting VRRP··················································································································································175

Stateful failover configuration ································································································································ 177

Overview·······································································································································································177

Introduction to stateful failover ···························································································································177

Introduction to stateful failover states ················································································································178

Introduction to stateful failover configuration············································································································179

Enabling stateful failover ·············································································································································179

Configuring the backup VLAN ···································································································································180

Displaying and maintaining stateful failover·············································································································180

Stateful failover configuration example ·····················································································································180

Configuration guidelines ·············································································································································182

BFD configuration···················································································································································· 183

Introduction to BFD·······················································································································································183

How BFD works ···················································································································································183

BFD packet format···············································································································································185

Supported features ··············································································································································187

Protocols and standards ·····································································································································187

Configuring BFD basic functions ································································································································188

Configuration prerequisites ································································································································188

Configuration procedure ····································································································································188

Enabling trap································································································································································189

Displaying and maintaining BFD································································································································190

Track configuration ················································································································································· 191

Track overview ·····························································································································································191

Introduction to collaboration ······························································································································191

Collaboration fundamentals·······························································································································191

Collaboration application example···················································································································192

Track configuration task list·········································································································································192

Associating the track module with a detection module····························································································193

Associating track with NQA ······························································································································193

Associating track with BFD·································································································································194

Associating track with interface management ·································································································194

Associating the track module with an application module······················································································195

Associating track with VRRP·······························································································································195

Associating track with static routing··················································································································197

Associating track with PBR ·································································································································198

Displaying and maintaining track entries··················································································································199

Track configuration examples·····································································································································199

VRRP-track-NQA collaboration configuration example (the master monitors the uplink) ····························199

v

Configuring BFD for a VRRP backup to monitor the master············································································202

Configuring BFD for the VRRP master to monitor the uplinks··········································································205

Static routing-track-NQA collaboration configuration example ·····································································209

Static routing-track-BFD collaboration configuration example········································································213

VRRP-track-interface management collaboration configuration example (the master monitors the uplink

interface)·······························································································································································

217

Index ········································································································································································ 220

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, 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 test

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

Mean Time Between Failures (MTBF) and Mean Time to Repair (MTTR) 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.

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.

2

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. CFD, DLDP, Ethernet OAM,

and MPLS 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. For more information about these technologies, see

Table 2.

Table 2 Fault detection technologies

Technology 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.

CFD configuration in

the High Availability

Configuration Guide

DLDP

The Device link detection protocol (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.

DLDP configuration in

the 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.

Ethernet OAM

configuration in the

High Availability

Configuration Guide

BFD

Bidirectional forwarding detection (BFD) 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.

BFD configuration in

the 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.

NQA configuration in

the Network

Management and

Monitoring

Configuration Guide

3

Technology Introduction Reference

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.

Monitor link

configuration in the

High Availability

Configuration Guide

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. 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. Upon aware of the changes of network status, the

application modules deal with the changes to avoid

communication interruption and network performance

degradation.

Track configuration in

the 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.

For more information about protection switchover technologies, see

Table 3.

Table 3 Protection switchover technologies

Technology 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 called an aggregate link. It

allows for link redundancy because the member physical links

can dynamically back up one another.

Ethernet link

aggregation

configuration in the

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.

Smart link

configuration in the

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.

MSTP configuration in

the 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.

RRPP configuration in

the High Availability

Configuration Guide

4

Technology Introduction Reference

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

Graceful Restart (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. It needs

other devices to implement routing information backup and

recovery.

Related chapters in

Layer 3—IP Routing

Configuration Guide

and MPLS

Configuration Guide

NSR

Non-stop Routing (NSR) is a new feature used to ensure non-stop

data transmission during an active/standby switchover. It backs

up IP/MPLS forwarding information from the Master device to the

Slave device. 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.

IS-IS configuration in

the Layer 3—IP Routing

Configuration Guide

Stateful Failover

Two devices back up the services of each other to ensure that the

services on them are consistent. If one device fails, the other

device can take over the services by using VRRP or dynamic

routing protocols. Because the other device has already backed

up the services, service traffic can pass through the other device,

avoiding service interruption.

Stateful failover

configuration in the

High Availability

Configuration Guide

VRRP

Virtual Router Redundancy Protocol (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.

VRRP configuration in

the 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.

5

Ethernet OAM configuration

This chapter includes these sections:

•

Ethernet OAM overview

•

Ethernet OAM configuration task list

•

Configuring basic Ethernet OAM functions

•

Configuring the Ethernet OAM connection detection timers

•

Configuring OAM remote loopback

•

Displaying and maintaining Ethernet OAM configuration

•

Ethernet OAM configuration example

Ethernet OAM overview

Background

Ethernet, because of its ease of use and low price, has become the major underlying technology for local

area networks (LANs). With the emergence of Gigabit Ethernet and 10-Gigabit Ethernet, Ethernet is

gaining popularity in metropolitan area networks (MANs) and wide area networks (WANs) as well,

increasing the need for an effective management and maintenance mechanism for Ethernet. This makes

it urgent to implement Operation, Administration and Maintenance (OAM) on Ethernet networks.

As a tool monitoring Layer 2 link status, Ethernet OAM mainly addresses common link-related issues on

the “last mile.” When you enable Ethernet OAM on two devices connected by a point-to-point link, you

can monitor the status of the link.

Major functions of Ethernet OAM

Ethernet OAM is an effective tool for management and maintenance of Ethernet networks, helping to

ensure network stability. It includes the following major 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.

6

Figure 1 Formats of different types of Ethernet OAMPDUs

Table 4 Description of the fields in an OAMPDU

Field Description

Dest addr

Destination MAC address of the Ethernet OAMPDU

It is a slow protocol multicast address 0180c2000002. As slow protocol

packet cannot be forwarded by bridges, 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.

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 type 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.

7

How Ethernet OAM works

This section describes the working procedures of Ethernet OAM.

Ethernet OAM connection establishment

Ethernet OAM connection is the base 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 notify the peer of their OAM configuration information and

the OAM capabilities of the local nodes by exchanging Information OAMPDUs and determine whether

Ethernet OAM connections can be established. An Ethernet OAM connection can be established only

when the settings concerning loopback, link detecting, and link event of the both sides match. After an

Ethernet OAM connection is established, Ethernet OAM takes effect on both sides.

As for Ethernet OAM connection establishment, a device can operate in active Ethernet OAM mode or

passive Ethernet OAM mode.

Table 6 Active and passive Ethernet OAM modes

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

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:

• OAM connections can be initiated only by OAM entities operating in active OAM mode, and those

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 a specified interval—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

8

exchange of Event Notification OAMPDUs. When detecting a link error event 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 in time.

Table 7 Ethernet OAM link error events

Ethernet OAM link events Description

Errored symbol event

An errored symbol event occurs when the number of

detected symbol errors over a specific detection

interval exceeds the configured threshold.

Errored frame event

An errored frame event occurs when the number of

detected error frames over a specific interval exceeds

the configured threshold.

Errored frame period event

An errored frame period event occurs if the number of

frame errors in a specified number of received frames

exceeds the configured threshold.

Errored frame seconds event

An errored frame seconds event occurs when the

number of error frame seconds detected on a port

over a detection interval reaches the error threshold.

NOTE:

• The system transforms the period of detectin

g

errored frame period events into the maximum number of

64-byte frames that a port can send in the specific 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)

• If errored frames appear in a certain second, this second is 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. In this way, you can keep track of link status in time

through the log information and troubleshoot in time.

Table 8 Critical link events

Type Description

OAMPDU transmission

frequencies

Link Fault Peer link signal is lost. Once per second

Dying Gasp

An unexpected fault, such as

power failure, occurred.

Non-stop

Critical Event

An undetermined critical event

happened.

Non-stop

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