The link-quality command enables bit error detection on an interface and sets the thresholds for determining link quality.
The undo link-quality command disables bit error detection on an interface.
By default, bit error detection is disabled on an interface.
| Parameter | Description | Value |
|---|---|---|
| resume-ratio recovery-coefficient recovery-power |
Specifies the threshold for triggering link quality to change from low to good. The formula for calculating this threshold is recovery-coefficient×10-recovery-power. If the BER detected by an interface falls below this threshold, the link quality changes from low to good. |
The recovery-coefficient value is an integer ranging from 1 to 9. The recovery-power value is an integer ranging from 1 to 7. |
| low |
Indicates that the quality level of a link is LOW. After this parameter is specified, the system determines whether the link level is LOW. |
- |
| bit-error-threshold |
Indicates the statistics bit error rate of a specified link. |
- |
| error-ratio trigger-coefficient trigger-power |
Specifies the threshold for triggering link quality to change from good to low. The formula for calculating this threshold is trigger-coefficient×10-trigger-power. If the BER detected by an interface reaches or exceeds this threshold, the link quality changes from good to low. |
The trigger-coefficient value is an integer ranging from 1 to 9. The trigger-power value is an integer ranging from 1 to 7. |
Usage Scenario
A bit error refers to the deviation between a bit that is sent and the bit that is received. Bit errors caused by optical fiber aging or optical signal jitter are inevitable on carrier networks. During data transmission, a high BER will degrade or even interrupt services in extreme cases.
In a bit-error-triggered LDP LSP switching scenario, bit error detection is enabled on interfaces along the primary and secondary links of the LDP LSP and the switching type of each interface is set to trigger-section. If the BER detected by an interface reaches or exceeds the bit error alarm reporting threshold, the status of the interface changes to Down. If the primary and secondary links of the LDP LSP both have Down interfaces, traffic transmitted over the LDP LSP is interrupted. To prevent this problem, run the link-quality set the upper and lower thresholds used by an interface to determine link quality. Then, if the BER detected by an OSPF or IS-IS interface reaches or exceeds the set upper threshold, the OSPF or IS-IS interface changes its link quality to low and increases the link cost, so that this link, which has a higher BER, is not used by the optimal route. As a result, the LDP LSP always uses the link with a lower BER to transmit traffic, minimizing the impact of bit errors on services.Prerequisites
Before running the link-quality command, run the interface interface-type interface-number command to enter the specified physical interface view.
Configuration Impact
After the link-quality command is configured:
Precautions
When the link-quality command is run to configure the bit error detection function, ensure that the adjacent nodes on one LDP LSP must be configured with the same bit error detection mode and bit error rate threshold. Otherwise, the upstream and downstream traffic rates are different.
<HUAWEI> system-view [~HUAWEI] interface GigabitEthernet 0/1/0 [~HUAWEI-GigabitEthernet0/1/0] link-quality low bit-error-threshold error-ratio 1 3 resume-ratio 1 6