H3C S3610 Series User manual

Operation Manual – OAM
H3C S3610&S5510 Series Ethernet Switches Tabel of Contents
i
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:
zOAM Overview
zOAM Configuration
zDisplaying and Maintaining OAM Configuration
zOAM 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.
zLink performance monitoring, for detecting link errors
zFault detection and alarm, for reporting link errors to the administrators
zLoopback 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
6
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
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.
zThe Dest addr field holds the destination MAC address of an OAMPDU, which is
the multicast MAC address 0180c2000002.

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zThe Source addr field holdsthe source MAC address of an OAMPDU, which is the
bridge MAC address of the sending side.
zThe Type field indicates the protocol type of an OAMPDU, which is fixed to
0x8809.
zThe Subtype field holds the protocol sub-type of an OAMPDU, which is fixed to
0x03.
zThe Flags field contains the information about an OAM entity.
zThe 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.
zInformation 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.
zEvent 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.
zLoopback 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.
zOAM connection establishment
zLink monitoring
zRemote fault detection
zRemote 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 errorsecond 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.
zLink Fault: Peer link signal is lost.
zDying Gasp: An unexpected fault, such as power failure, occurred.
zCritical 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:
zOAM 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.
zNo OAM connection can be established between two OAM entities operating in
passive OAM mode.
zWith 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:
zAn 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.
zAn 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.
zA 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.
zAs 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).
zA 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.)
zThe 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:
zCurrently, 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.
zOAM loopback testing is available only after the OAM connection is established.
zOAM loopback testing can be performed by OAM entities operating in the active
OAM mode only.
zOAM loopback testing needs the support of the peer hardware.
zOAM 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.
zEnabling 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.
zOAM 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
zEnable OAM on Device A and Device B to manage links on data link layer.
zMonitor link performance and collect statistics about the error frames received by
Device A.
II. Network diagram
Device A Device B
Eth1/0/1
Eth1/0/1
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.