isis ipv6 cost

Function

The isis ipv6 cost command configures a link cost in an IPv6 topology.

The undo isis ipv6 cost command restores the default value.

By default, the link cost value in an IPv6 topology is 10.

Format

isis ipv6 [ topology topology-name ] cost cost-value [ level-1 | level-2 ]

undo isis ipv6 [ topology topology-name ] cost [ cost-value ] [ level-1 | level-2 ]

Parameters

Parameter	Description	Value
topology topology-name	Specifies the name of an IPv6 topology. If no topology name is specified, the link cost is configured for an IPv6 base topology by default.	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.
cost-value	Specifies IPv6 link cost.	The value is an integer and varies with the cost type. When the cost type is wide or wide-compatible, the value ranges from 1 to 16777214. For other cost types, the value ranges from 1 to 63. The default value is 10. The maximum parameter can be configured only when the cost-style of IS-IS is wide or wide-compatible. The neighbor TLV generated after the cost of an interface is set to 16777215 is used for TE information transmission, not for route calculation. The cost type can be configured using the cost-style command.
level-1	Configures a link cost for Level-1 links.	-
level-2	Configures a link cost for Level-2 links. If no IPv6 link level is specified, an IPv6 link cost is set for both Level-1 and Level-2 interfaces.	-

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 electrical interface view, Global VE sub-interface view, Loopback interface view, Tunnel interface view, VBDIF interface view, VE sub-interface view, VE interface view, VLANIF interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

On a large-scale network, there are multiple valid routes destined for the same destination in most cases. IS-IS calculates an optimal route based on the SPF algorithm and transmits traffic over it. This feature may cause the following problems:

All traffic is transmitted over the optimal route, causing load imbalance.
If the optimal route fails, traffic transmitted over it will be discarded.
To address this problem, run the isis ipv6 cost command to configure different link costs for different interfaces so that traffic can be transmitted over different physical links.

Configuration Impact

If the link cost is changed, routes of the entire network are recalculated, and the traffic forwarding path changes accordingly.

Precautions

The isis ipv6 cost command takes effect only when links are active and an IPv6 topology is enabled.

If the IPv6 topology type is compatible or standard, the IPv6 link cost is the same as the IPv4 link cost. When an IPv6 topology type is compatible enable-mt-spf or ipv6, IPv6 and IPv4 link costs need to be configured separately.

If the isis ipv6 cost and ipv6 circuit-cost commands are both run, the value set using the isis ipv6 cost takes effect.

Example

# Set the IPv6 link cost value of GigabitEthernet 0/1/0 to 50.

<HUAWEI> system-view
[~HUAWEI] isis 1
[*HUAWEI-isis-1] ipv6 enable
[*HUAWEI-isis-1] quit
[*HUAWEI] interface GigabitEthernet 0/1/0
[*HUAWEI-GigabitEthernet0/1/0] ipv6 enable
[*HUAWEI-GigabitEthernet0/1/0] isis ipv6 enable 1
[*HUAWEI-GigabitEthernet0/1/0] isis ipv6 cost 50