The isis topology link-quality low incr-cost command enables the function to adjust the link cost of an interface when its link quality is low.
The undo isis topology link-quality low incr-cost command disables the function.
By default, an IS-IS interface cannot adjust the link cost based on link quality.
| Parameter | Description | Value |
|---|---|---|
| low |
Indicates that the link cost of an interface is adjusted when its link quality is low. |
- |
| cost-value |
Specifies a link cost adjustment value. After this parameter is specified:
|
The value is an integer ranging from 1 to 16777213. |
| max-reachable |
Adjusts the link cost to the maximum link cost.
|
- |
| topology topology-name |
Specifies the name of an IPv4 topology instance. If this parameter is not specified, the command configuration applies to the interface in the IPv4 base topology. |
The value is a string of 1 to 31 case-sensitive characters without spaces. The value must start with a letter (a to z or A to Z, case sensitive) and can contain numbers, hyphens (-), or underlines (_). When double quotation marks are used around the string, spaces are allowed in the string. |
100GE interface view, 10GE interface view, 25GE sub-interface view, 25GE interface view, 400GE interface view, 40GE interface view, 50GE sub-interface view, 50GE interface view, Eth-Trunk interface view, FlexE interface view, GE optical interface view, GE interface view, GE electrical interface view, Global VE sub-interface view, VE sub-interface view, VE interface view
Usage Scenario
A bit error indicates 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 bit error rate will degrade or even interrupt services in extreme cases.
To ensure network reliability, run the isis link-quality low incr-cost command to enable the device to adjust the link cost of an IS-IS interface when its link quality is low. If the IS-IS interface detects that its link quality is low, the device increases the link cost of the interface, so that this link, which has a higher bit error rate, is not selected as the optimal link. After the link quality reverts, the device automatically restores the link cost of the IS-IS interface.Prerequisites
IS-IS has been enabled on the interface using the isis enable command.
Configuration Impact
If the isis link-quality low incr-cost command is run more than once in the same view, the latest configuration overrides the previous one.
Precautions
For an IS-IS interface that adjusts the cost based on the link quality, the configuration priority in the specified IPv4 topology is higher. If you have configured the isis link-quality low incr-cost { cost-value | max-reachable } command and the isis topology topology-name link-quality low incr-cost { cost-value | max-reachable } command, The IPv4 topology uses the behavior of the latter command configuration. The other topologies use the behavior configured by the previous command.
<HUAWEI> system-view [~HUAWEI] ip topology red [*HUAWEI] isis 1 [*HUAWEI-isis-1] cost-style wide [*HUAWEI-isis-1] topology red topology-id 10 [*HUAWEI-isis-1-topology-red] quit [*HUAWEI-isis-1] quit [*HUAWEI] interface GigabitEthernet0/1/0 [*HUAWEI-GigabitEthernet0/1/0] isis enable [*HUAWEI-GigabitEthernet0/1/0] ip topology red enable [*HUAWEI-GigabitEthernet0/1/0] isis topology red link-quality low incr-cost max-reachable