Link Monitoring; Monitoring Interface Errors; Monitoring Interface Flapping - Alcatel-Lucent OmniSwitch 9900 Series Network Configuration Manual

Configuring Ethernet Ports

Link Monitoring

The Link Monitoring feature is used to monitor interface status to minimize the network protocol re-
convergence that can occur when an interface becomes unstable. To track the stability of an interface, this
feature monitors link errors and link flaps during a configured timeframe. If the number of errors or link
flaps exceeds configured thresholds during this time frame, the interface is shut down.
Note. Link Monitoring can be enabled on individual ports that make up a virtual port such as a link
aggregate or VFL, but not on the entire link aggregate or VFL virtual port.
There are no explicit Link Monitoring commands to recover a port from a Link Monitoring shutdown. See
"Clearing Ethernet Port Violations" on page 1-19

Monitoring Interface Errors

When physical errors occur on an interface, control and data traffic is dropped causing unnecessary re-
convergence for the network protocol running on the interface. The Link Monitoring feature monitors the
physical errors such as CRC, lost frames, error frames and alignment errors. When a configurable number
of errors is detected within the duration of a link monitoring window, the interface is shut down.
To configure the number of errors allowed before the port is shut down, use the
monitoring link-error-threshold
-> interfaces 1/1 link-monitoring link-error-threshold 50
In this example, the port is shutdown if the number of link errors exceeds the threshold value of 50 during
the link monitoring window timeframe.

Monitoring Interface Flapping

When physical connectivity errors occur on an interface, the interface becomes unstable and causes
unnecessary re-convergence for the network protocols running on the interface. The Link Monitoring
feature monitors these interface flaps and shuts down the interface when excessive flapping is detected.
•
The shutdown action is a physical port shutdown (the PHY and LED are down).
•
Whenever an interface comes up and it is not an administrative action (admin-up), the link flap counter
is incremented.
The interfaces link-monitoring link-flap-threshold
allowed before the interface is shutdown. For example:
-> interfaces 1/1 link-monitoring link-flap-threshold 5
In this example, the port is shutdown if the number of link flaps exceeds the threshold value of five during
the link monitoring window timeframe.
OmniSwitch AOS Release 8 Network Configuration Guide
for information of clearing port violations.
command. For example:
command is used to configure the number of flaps
December 2017
Link Monitoring
interfaces link-
page 1-20