isis ipv6 link-quality low incr-cost

Function

The isis ipv6 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 ipv6 link-quality low incr-cost command disables the function.

By default, the function is enabled.

Format

isis ipv6 link-quality low incr-cost { cost-value | max-reachable }

isis process-id process-id-value ipv6 link-quality low incr-cost { cost-value | max-reachable }

undo isis ipv6 link-quality low incr-cost [ { cost-value | max-reachable } ]

undo isis process-id process-id-value ipv6 link-quality low incr-cost [ { cost-value | max-reachable } ]

Parameters

Parameter	Description	Value
cost-value	Specifies a link cost adjustment value. After this parameter is specified: When the link quality becomes low, the actual link cost of the interface equals the original link cost plus the specified adjustment value. When the link quality reverts, the actual link cost of the interface equals the original link cost.	The value is an integer ranging from 1 to 16777213.
max-reachable	Adjusts the link cost to the maximum link cost. The maximum link cost is 63 if the cost type is narrow, narrow-compatible, or compatible. The maximum link cost is 16777214 if the cost type is wide or wide-compatible.	-
process-id process-id-value	Specifies the IS-IS multi-instance process ID when multi-instance is enabled under the relevant process.	The value is an integer ranging from 1 to 4294967295.
low	Indicates that the link cost of an interface is adjusted when its link quality is low.	-

Views

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

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

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 ipv6 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

Before running this command, run the ipv6 enable topology ipv6 command in the IS-IS process to enable the IPv6 function for the process. In the interface view, run the ipv6 enable command to enable the IPv6 function on the interface. Then, run the isis ipv6 enable command to enable the IS-IS function on the interface.

Configuration Impact

If the isis ipv6 link-quality low incr-cost command is run more than once in the same view, the latest configuration overrides the previous one.

Example

# Configure a device to increase the link cost of the specified interface to the maximum value when the interface's link quality is low.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] ipv6 enable topology ipv6
[*HUAWEI-isis-1] quit
[*HUAWEI] interface GigabitEthernet0/1/0
[*HUAWEI-GigabitEthernet0/1/0] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/0] isis ipv6 enable 1
[*HUAWEI-GigabitEthernet0/1/0] isis ipv6 link-quality low incr-cost max-reachable