isis ipv6 cost
Function
The isis ipv6 cost command sets a link cost for an IS-IS interface in an IPv6 topology.
The undo isis ipv6 cost command restores the default link cost of an IS-IS interface in an IPv6 topology.
By default, the link cost of an IS-IS interface in an IPv6 topology is 10.
Format
isis ipv6 cost { cost | maximum } [ level-1 | level-2 ]
undo isis ipv6 cost [ cost | maximum ] [ level-1 | level-2 ]
Parameters
| Parameter | Description | Value |
|---|---|---|
| cost | Specifies the IPv6 link cost value, which is different from the IPv4 link cost value. | The value is an integer which varies with the cost
type.
The cost type can be configured using the cost-style command. |
| maximum | Sets the link cost of an interface to 16777215. NOTE:
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 can be used only for TE information transmission but not for route calculation. |
- |
| level-1 | Set the Level-1 link cost. | - |
| level-2 | Set the Level-2 link cost. If neither Level-1 nor Level-2 is specified, the same link cost is set for both Level-1 and Level-2 interfaces. |
- |
Views
Ethernet interface view, Ethernet sub-interface view, Eth-Trunk interface view, Eth-Trunk sub-interface view, Loopback interface view, Tunnel interface view, Dialer interface view, VLANIF interface view
Usage Guidelines
Usage Scenario
IS-IS uses the SPF algorithm to calculate an optimal route and transmits traffic over it. If the bandwidth of the link over which the optimal route runs is too low or the link is unstable, network resources may be wasted or traffic may be lost. In this situation, you can run the isis ipv6 cost command to change the IPv6 link cost so that traffic is forwarded along a desired route, which improves bandwidth utilization and network reliability.
Prerequisites
IS-IS has been enabled on a specified interface using the isis ipv6 enable [ process-id ] command in the interface view.
Configuration Impact
If the link cost of an interface is changed, routes will be re-calculated on the whole network, causing the changes in traffic forwarding paths.
Precautions
The priority of the ipv6 circuit-cost command is lower than that of the isis ipv6 cost command.
If the IPv6 topology type is compatible or standard, the IPv6 and IPv4 link costs are the same on an interface even though the IPv6 link cost set using the isis ipv6 cost command is different from the IPv4 link cost. The IPv6 link cost set using the isis ipv6 cost command takes effect only when the IPv6 topology type is compatible enable-mt-spf or ipv6.
Example
# Set the IPv6 link cost value of GigabitEthernet0/0/0 to 50.
<sysname> system-view
[sysname] ipv6
[sysname] isis
[sysname-isis-1] ipv6 enable
[sysname-isis-1] quit
[sysname] interface GigabitEthernet 0/0/0
[sysname-GigabitEthernet0/0/0] ipv6 enable
[sysname-GigabitEthernet0/0/0] isis ipv6 enable
[sysname-GigabitEthernet0/0/0] isis ipv6 cost 50
<sysname> system-view
[sysname] ipv6
[sysname] isis
[sysname-isis-1] ipv6 enable
[sysname-isis-1] quit
[sysname] interface GigabitEthernet0/0/0
[sysname-GigabitEthernet0/0/0] ipv6 enable
[sysname-GigabitEthernet0/0/0] isis ipv6 enable
[sysname-GigabitEthernet0/0/0] isis ipv6 cost maximum