Ethernet Port Monitoring - Alcatel-Lucent 7750 Configuration Manual

Ethernet Port Monitoring

Ethernet ports can record and recognize various medium statistics and errors. There are two main
types of errors:
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CRC-Monitor and Symbol-Monitor allows the operator to monitor ingress error conditions on the
Ethernet medium and compare these error counts to the thresholds. CRC-Monitor monitors CRC
errors. Symbol-Monitor monitors symbol errors. Symbol Error is not supported on all Ethernet
ports. Crossing a signal degrade (SD) threshold will cause a log event to be raised. Crossing the
configured signal failure (SF) threshold will cause the port to enter an operation state of down.
The operator may consider the configuration of other protocols to convey the failure, through
timeout conditions.
The error rates are in the form of M*10E-N. The operator has the ability to configure both the
threshold (N) and a multiplier (M). By default if the multiplier is not configured the multiplier is 1.
As an example, sd-threshold 3 would result in a signal degrade error rate of 1*10E-3 (one error per
1000). Changing the configuration to would sd-threshold 3 multiplier 5 result in a signal degrade
rate of 5*10E-3 (5 errors per 1000). The signal degrade value must be a lower error rate than the
signal failure threshold. This threshold can be used to provide notification that the port is
operating in a degraded but not failed condition. These do not equate to a bit error rate (BER).
CRC-Monitor provides a CRC error rate. Symbol-Monitor provides a symbol error rate.
The configured error thresholds are compared to the operator specified sliding window to
determine if one or both of the thresholds have been crossed. Statistics are gathered every second.
This means that every second the oldest statistics are dropped from the calculation. The default 10
second sliding window means that at the 11th second the oldest 1 second statistical data is dropped
and the 11th second is included.
Symbol error crossing differs slightly from CRC based error crossing. The error threshold
crossing is calculated based on the window size and the fixed number of symbols that will arrive
(ingress) that port during that window. The following configuration is used to demonstrate this
concept.
7750 SR Interface Configuration Guide
Frame Based — Frame based errors are counted when the arriving frame has an error that
means the frame is invalid. These types of errors are only detectable when frames are
presents on the wire.
Symbol Based — Symbol errors are invalidly encoded symbols on the physical medium.
Symbols are always present on an active Ethernet port regardless of the presence of
frames.
Interface Configuration
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