auto-cost enable (IS-IS topology view)

Function

The auto-cost enable command enables IS-IS to automatically calculate the link cost of interfaces according to the interface bandwidth.

The auto-cost enable compatible command enables IS-IS to automatically calculate the link cost of interfaces according to the interface bandwidth in compatible.

The undo auto-cost enable command disables the function.

By default, automatic interface cost calculation is disabled.

Format

auto-cost enable [ compatible ]

undo auto-cost enable

Parameters

None

Views

IS-IS topology view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
isis	write

Usage Guidelines

Usage Scenario

You can configure a link cost for interfaces or run the auto-cost enable command to enable automatic interface cost calculation.

Prerequisites

No interface cost has been set in the interface view, and no global cost has been configured in the IS-IS view.

Configuration Impact

After automatic interface cost calculation is enabled, the system automatically calculates the interface cost.

If the cost style of the system is wide or wide-compatible:

When auto-cost enable command is configured, Interface cost = (Bandwidth-reference/Interface bandwidth) * 10.

When auto-cost enable compatible command is configured, Interface cost = (Bandwidth-reference/Interface bandwidth).

When the cost type is narrow, narrow-compatible, or compatible, the cost of each interface is determined as follows:

Interface bandwidth ≤ 10 Mbit/s, cost = 60
10 Mbit/s < interface bandwidth ≤ 100 Mbit/s, cost = 50
10 Mbit/s < interface bandwidth ≤ 155 Mbit/s, cost = 40
155 Mbit/s < interface bandwidth ≤ 622 Mbit/s, Cost = 30
622 Mbit/s < Interface bandwidth ≤ 2.5 Gbit/s, cost = 20
2.5 Gbit/s < interface bandwidth, Cost = 10

Precautions

The auto-cost enable command cannot change the cost of a loopback interface.

The auto-cost enable command can be run on Eth-Trunk interfaces as well as on physical interfaces. If the command is run on an Eth-Trunk interface, the bandwidth of the Eth-Trunk interface is equal to the total bandwidth of all its member interfaces.

If the command is run in the IS-IS view, it takes effect only in the base topology. If the command is run in the IS-IS topology view, it takes effect only in the current topology.

Example

# Enable automatic cost calculation on IS-IS interfaces in the topology named multicast.

<HUAWEI> system-view
[~HUAWEI] ip topology multicast
[*HUAWEI] isis 1
[*HUAWEI-isis-1] cost-style wide
[*HUAWEI-isis-1] topology multicast topology-id multicast
[*HUAWEI-isis-1-topology-multicast] auto-cost enable