TP-Link T2600G-28TS User Manual page 131

Item
Transmitting
OAMPDUs
Responding to Loopback Control
OAMPDUs
Transmitting
OAMPDUs
Table 8-1 Differences between active OAM mode and passive OAM mode
After an OAM connection is established, the OAM entities on both sides exchange Information
OAMPDUs periodically to keep the OAM connection valid. The OAM entity considers the OAM
connection invalid if it does not receive the Information OAMPDU from the peer entity for 5
seconds.
Link Monitoring
Link Monitoring is for detecting and locating link faults under a variety of circumstances. When
there are problems detected on the link, the device will send its remote peer the Event Notification
OAMPDUs to report link events. The link events are described as follows:
OAM Link Events
Symbol Period Error
Frame Error
Frame Period Error
Frame Seconds Error
Remote Failure Indication
Faults in Ethernet are difficult to detect, especially when the physical connection in the network is
not interrupted but network performance degrades gradually. A flag in the OAMPDU allows an
OAM entity to convey failure conditions to its peer. The failure conditions are as follows:
Link Fault: Peer link signal is lost. This is sent once per second in the Information OAMPDU.
Dying Gasp: An unrecoverable fault, such as power failure, occurs. This is sent immediately and
continuously.
Critical Event: Unspecified critical event occurs. This is sent immediately and continuously.
Loopback Control
organization-specific
Description
A Symbol Period Error event occurs if the number of
symbol errors exceeds the threshold during a
specific period of time.
A Frame Error event occurs if the number of frame
errors exceeds the threshold during a specific period
of time.
A Frame Period Error event occurs if the number of
frame errors in specific number of received frames
exceeds the threshold.
A Frame Seconds Error event occurs if the number
of error frame seconds exceeds the threshold during
a specific period of time. A second is called an error
frame second if error frames occur in the second.
Table 8-2 OAM Link Events
Active OAM mode
Available
Available
(if both sides operate
in active OAM mode)
Available
119
Passive OAM mode
Unavailable
Available
Available