H3C S5510 Series Operating instructions

Operation Manual – OAM

H3C S3610&S5510 Series Ethernet Switches Tabel of Contents

Table of Contents

Chapter 1 OAM Configuration......................................................................................................1-1

1.1 OAM Overview...................................................................................................................1-1

1.1.1 Types of OAMPDUs................................................................................................1-1

1.1.2 OAM Connection Establishment.............................................................................1-2

1.1.3 Standards and Protocols.........................................................................................1-4

1.2 OAM Configuration ............................................................................................................1-5

1.2.1 OAM Configuration Task List..................................................................................1-5

1.2.2 Configuring Basic OAM Basic Functions ................................................................1-5

1.2.3 Configuring the Periods and Thresholds for OAM Link Error Event Detection.......1-6

1.2.4 Enabling OAM Loopback Testing............................................................................1-7

1.3 Displaying and Maintaining OAM Configuration................................................................1-8

1.4 OAM Configuration Example.............................................................................................1-9

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Chapter 1 OAM Configuration

When performing OAM configuration, go to these sections for information you are

interested in:

z OAM Overview

z OAM Configuration

z Displaying and Maintaining OAM Configuration

z OAM Configuration Example

1.1 OAM Overview

Ethernet OAM (meaning operation, administration, and maintenance) is a tool for

monitoring network. It operates on data link layer and can report information about

networks to network administrators through the OAMPDUs exchanged between

devices, enabling network administrators to manage the network more effectively.

Currently, Ethernet OAM is mainly used for detecting data link layer problems occurred

in the “last mile”. By enabling Ethernet OAM on two devices connected by a

point-to-point connection, you can monitor the link status of the link between the two

devices. Ethernet OAM provides the following functions.

z Link performance monitoring, for detecting link errors

z Fault detection and alarm, for reporting link errors to the administrators

z Loopback testing, for detecting link errors through non-OAMPDUs

1.1.1 Types of OAMPDUs

Figure 1-1 shows the format of different types of OAMPDU.

Dest addr

Source addr Type Subtype Flags Code Data/Pad CRC

Code Local info TLV Remote info TLV ...

12126 42~1496 4

Information OAMPDU

Event Notification OAMPDU

Loopback control OAMPDU

Code

seq Link event TLV ...

OAM Remote Loopback command

Figure 1-1 The format of different types of OAMPDU

The fields in an OAMPDU are described as follows.

z The Dest addr field holds the destination MAC address of an OAMPDU, which is

the multicast MAC address 0180c2000002.

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z The Source addr field holds the source MAC address of an OAMPDU, which is the

bridge MAC address of the sending side.

z The Type field indicates the protocol type of an OAMPDU, which is fixed to

0x8809.

z The Subtype field holds the protocol sub-type of an OAMPDU, which is fixed to

0x03.

z The Flags field contains the information about an OAM entity.

z The Code field indicates the type of an OAMPDU. The value of this field can be

0x00, 0x01, and 0x04, which identifies Information OAMPDU, Event notification

OAMPDU, and Loopback control OAMPDU.

As mentioned above, Information OAMPDU, Event Notification OAMPDU, and

Loopback control OAMPDU are commonly used, which are described as follows.

z Information OAMPDUs are used for passing the state information about an

Ethernet OAM entity (including the information about the local device and remote

devices, and customized information) to another Ethernet OAM entity and

maintain OAM connections.

z Event notification OAMPDUs are used for link monitoring. They are sent as an

alarm in case a failure occurs to the link connecting the local OAM entity and a

remote OAM entity.

z Loopback control OAMPDUs are 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.

1.1.2 OAM Connection Establishment

Following are the four OAM functions.

z OAM connection establishment

z Link monitoring

z Remote fault detection

z Remote loopback testing

Note that OAM connection is the base of all the other Ethernet OAM functions.

I. OAM connection establishment

OAM connection establishment is also known as the Discovery phase, where an OAM

entity discovers other OAM entities and sessions between OAM entities are

established.

In this phase, interconnected OAM entities notify the peer of their OAM configuration

information and the OAM capabilities of the local nodes to support OAM by exchanging

Information OAMPDUs and determine whether OAM connections can be established.

An OAM connection can be established only when the settings concerning Loopback,

link detecting, and link event of the both side match. After an OAM connection is

established, OAM takes effect on it.

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As for OAM connection establishment, a device can operate in two modes: active OAM

mode and passive OAM mode. Only devices operating in active OAM mode can initiate

OAM connection establishment processes. Those operating in passive OAM mode,

however, wait and respond to OAM connection establishment requests and take

corresponding operations.

Table 1-1 compares active OAM mode with passive OAM

mode.

Table 1-1 Active OAM mode and passive OAM mode

Item Active OAM mode Passive 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

with the Data/Pad field being empty

Available Available

Transmitting Loopback Control

OAMPDUs

Available Unavailable

Responding to Loopback Control

OAMPDUs

Available (if both

sides operate in

active OAM mode)

Available

Transmitting organization-specific

OAMPDUs

Available Available

After an OAM connection is established, the OAM entities on both sides exchange

Information OAMPDUs periodically to keep the OAM connection valid. If an OAM entity

receives no Information OAMPDU for five seconds, the OAM connection is considered

invalid. In this case, to enable the OAM entities to communicate with each other again,

a new OAM connection is required.

The interval to send Information OAMPDUs is determined by a timer. Up to ten

Information OAMPDUs can be sent in a second.

II. Link Monitoring

Link monitoring is used to detect and locate link faults in various environments. In OAM,

link faults are categorized into link events.

OAM implements link monitoring through the exchange of Event Notification

OAMPDUs. Upon detecting a link fault, the local device sends an Event Notification

OAMPDU to the remote OAM entity to report the fault event. Link monitoring enables

network administrators to be informed of network status in time.

Table 1-2 describes the

link events.

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Table 1-2 OAM link error events

OAM link events Description

Error signal event

A signal error event occurs if the number of signal errors in

specific period exceeds the threshold.

Error frame event

A Frame error event occurs if the number of frame errors in

specific period exceeds the threshold.

Frame-percentage

error event

A frame-percentage error event occurs if the number of frame

errors in specific number of received frames exceeds the

threshold

Second-percentag

e error event

A second-percentage error second event occurs if the number

of error seconds in specific period (measured in seconds)

exceeds the threshold.

A second is called an error second if error frames occur in the

second.

III. Remote Fault Detection

Error detection in an Ethernet is difficult, especially when the physical connection in the

network is not interrupted but network performance degrades gradually. The flag field

defined in OAMPDUs allows an OAM entity to send error information to its peer. It can

identify the following link faults.

z Link Fault: Peer link signal is lost.

z Dying Gasp: An unexpected fault, such as power failure, occurred.

z Critical Event: An undetermined critical event happened.

As Information OAMPDUs are sent periodically across OAM connections, an OAM

entity can inform one of its OAM peers of link faults through Information OAMPADUs to

enable the network administrator to get informed of link status and troubleshoot in time.

IV. Remote loopback testing

Remote loopback testing is available only after the OAM connection is established.

With remote loopback enabled, the OAM entity operating in active OAM mode issues

remote loopback requests and the peer responds to them. If the peer operates in the

loopback mode, it returns all the PDUs except OAMPDUs to the senders along the

original paths.

Performing remote loopback testing periodically helps to detecting network faults in

time. Furthermore, performing remote loopback testing by network segments helps to

locate network faults.

1.1.3 Standards and Protocols

OAM is defined in IEEE 802.3h.

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1.2 OAM Configuration

1.2.1 OAM Configuration Task List

Complete the following tasks to configure OAM:

Task Remarks

Configuring Basic OAM Basic Functions Required

Configuring the Periods and Thresholds for OAM Link

Error Event Detection

Optional

Enabling OAM Loopback Testing Optional

1.2.2 Configuring Basic OAM Basic Functions

Follow these steps to configure basic OAM functions:

To do… Use the command… Remarks

Enter system view

system-view

—

Enter Ethernet port view

interface interface-type

interface-number

—

Set OAM operating mode

oam mode { active |

passive }

Optional

The default is active OAM

mode.

Enable OAM on the

current port

oam enable

Required

OAM is disabled by

default.

After OAM is enabled, the

OAM entity tries to

establish OAM connection

with its peer.

 Note:

z OAM connections can be initiated only by OAM entities operating in active OAM

mode, while those operating in passive mode wait and respond to the connection

requests sent by their peers.

z No OAM connection can be established between two OAM entities operating in

passive OAM mode.

z With OAM enabled, you cannot change the OAM operating mode. To do so, you

need to disable OAM first.

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1.2.3 Configuring the Periods and Thresholds for OAM Link Error Event

Detection

Follow these steps to configure the periods and thresholds for OAM link error event

detection:

To do… Use the command… Remarks

Enter system view

system-view

—

Configure the period for

error signal event

detection

oam errored-symbol

period period-value

Optional

The default is one

second.

Configure the threshold

for error signal event

detection

oam errored-symbol

threshold

threshold-value

Optional

The default is 1.

Configure the period for

error frame event

detection

oam errored-frame

period period-value

Optional

The default is one

second.

Configure the threshold

for error frame event

detection

oam errored-frame

threshold

threshold-value

Optional

The default is 1.

Configure the period for

frame-percentage error

event detection

oam

errored-frame-period

period period-value

Optional

The default is 1,000

milliseconds.

Configure the threshold

for frame-percentage

error event detection

oam

errored-frame-period

threshold

threshold-value

Optional

The default is 1.

Configure the period for

second-percentage error

event detection

oam

errored-frame-seconds

period period-value

Optional

The default is 60 seconds.

Configure the threshold

for second-percentage

error event detection

oam

errored-frame-seconds

threshold

threshold-value

Optional

The default is 1.

Make sure the threshold

for second-percentage

error event detection is

less than the period for

second-percentage error

event detection for

second-percentage error

events to be detected.

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 Note:

z An error signal event occurs when a period for error signal event detection expires

and the number of the signal errors occurred on an Ethernet port is larger than or

(equal to) the threshold for error signal event detection.

z An error frame event occurs when a period for error frame event detection expires

and the number of the frame errors occurred on an Ethernet port is larger than (or

equal to) the threshold for error frame event detection.

z A frame-percentage error event occurs when a period for frame-percentage error

event detection expires and the number of the frame errors occurred on an Ethernet

port is larger than (or equal to) the threshold for frame-percentage error event

detection.

z As for frame-percentage error event detection, the system first uses the following

expression to convert the period for frame-percentage error event detection to the

maximum number of 64-byte frames that can be transmitted through an Ethernet

port in the period: bandwidth * period / (64 * 8 * 1000), where “bandwidth” is the port

bandwidth (in bps) and “period” is the configured period (in milliseconds).

z A second-percentage error event occurs when a period for second-percentage error

event detection expires and the number of the error seconds of an Ethernet port is

larger than (or equal to) the threshold for second-percentage error event detection.

(A second is called an error second if error frames occur in the second.)

z The periods and the thresholds configured apply to all the Ethernet ports on which

OAM connections are established.

1.2.4 Enabling OAM Loopback Testing

Follow these steps to enable OAM loopback testing:

To do… Use the command… Remarks

Enter system view

system-view

—

Enter Ethernet port view

interface interface-type

interface-number

—

Enable OAM loopback

testing

oam loopback

Required

Disabled by default.

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 Note:

z Currently, OAM external loopback is only available on 1000 Mbps Ethernet ports

(SFP ports with electrical ports installed not included) operating at a speed of 1000

Mbps, 100 Mbps, or 10 Mbps.

z OAM loopback testing is available only after the OAM connection is established.

z OAM loopback testing can be performed by OAM entities operating in the active

OAM mode only.

z OAM loopback testing needs the support of the peer hardware.

z OAM loopback testing is only applicable to individual links. It is not applicable to

aggregation links. So when performing OAM loopback testing, make sure none of

the ports involved belongs to an aggregation group.

z Enabling OAM loopback testing results in all the data communications being

stopped. After OAM loopback testing is disabled, all the ports involved will be shut

down and then brought up.

z OAM loopback testing is disabled when you execute the undo oam enable

command to disable OAM; when you execute the undo oam loopback command

to disable OAM loopback testing; or when the OAM connection is timed out.

1.3 Displaying and Maintaining OAM Configuration

To do… Use the command… Remarks

Display global OAM

configuration

display oam configuration

Display the statistics on

critical events after an OAM

connection is established

display oam critical-event

[ interface interface-type

interface-number ]

Display the statistics on OAM

link error events after an OAM

connection is established or

after you clear the statistics

display oam link-event { local |

remote } [ interface

interface-type interface-number ]

Display the information about

an OAM connection

display oam { local | remote }

[ interface interface-type

interface-number ]

Available in any

view

Clear statistics on OAM

packets and OAM link error

events

reset oam [ interface

interface-type interface-number ]

Available in

user view only

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1.4 OAM Configuration Example

I. Network requirements

z Enable OAM on Device A and Device B to manage links on data link layer.

z Monitor link performance and collect statistics about the error frames received by

Device A.

II. Network diagram

Device A Device B

Eth1/0/1

Eth1/0/2

Host

Figure 1-2 Network diagram for OAM configuration

III. Configuration procedure

1) Configure Device A:

# Configure Ethernet 1/0/1 to operate in passive OAM mode and enable OAM for it.

<DeviceA> system-view

[DeviceA] interface ethernet 1/0/1

[DeviceA-Ethernet1/0/1] oam mode passive

[DeviceA-Ethernet1/0/1] oam enable

[DeviceA-Ethernet1/0/1] quit

# Set the period for error frame event detection to 20 seconds.

[DeviceA] oam errored-frame period 20

# Set the threshold for error frame event detection to 10.

[DeviceA] oam errored-frame threshold 10

# Display global OAM configuration.

[DeviceA] display oam configuration

Configuration of the errored symbol/frame event window/threshold :

--------------------------------------------------------

Errored-symbol Event period : 1

Errored-symbol Event threshold : 1

Errored-frame Event period : 20

Errored-frame Event threshold : 10

Errored-frame-period Event period : 1000

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Errored-frame-period Event threshold : 1

Errored-frame-seconds Event period : 60

Errored-frame-seconds Event threshold : 1

2) Configure Device B:

# Configure Ethernet 1/0/1 to operate in active OAM mode (the default OAM mode) and

enable OAM for it.

<DeviceB> system-view

[DeviceB] interface ethernet 1/0/1

[DeviceB-Ethernet1/0/1] oam enable

[DeviceB-Ethernet1/0/1] quit

# Display OAM link error event statistics.

[DeviceB] display oam link-event remote

Port :Ethernet1/0/1

Link Status :Up

OAMRemoteErrFrameEvent : (ms = milliseconds)

---------------------------------------------------------------------

Event Time Stamp : 5789 Errored FrameWindow : 10(100ms)

Errored Frame Threshold : 1 Errored Frame : 3

Error Running Total : 35 Event Running Total : 17

The above information indicates that 35 errors occurred since OAM is enabled on

Device A, 17 of which are caused by error frames. The link is instable.

H3C S5510 Series, S3610 Series Operating instructions

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