ttl-copymode (VPLS PW trace test instance)

Function

The ttl-copymode command specifies a TTL propagation mode for multi-segment PW detection in an NQA VPLS PW trace test instance.

The undo ttl-copymode command deletes the TTL propagation mode configured in the NQA view.

By default, the TTL propagation mode configured using the mpls ldp ttl-mode command is used.

Format

ttl-copymode ttlModeVal

undo ttl-copymode

Parameters

Parameter	Description	Value
ttlModeVal	Specifies the TTL propagation mode.	Pipe or Uniform.

Parameter

Description

Value

ttlModeVal

Specifies the TTL propagation mode.

Pipe or Uniform.

Views

NQA view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
sla	write

Usage Guidelines

Usage Scenario

When you monitor a multi-segment PW, you can run the ttl-copymode command to control the TTL values in labels.

The system differently processes TTL values in either pipe or uniform propagation mode.If you set the propagation mode to pipe, the system removes the outer label, decreases the TTL value in the inner label by 1, and sets the TTL value in the outer label to 255 after receiving a packet.If you set the propagation mode to uniform, the system copies the TTL value in the outer label to the inner label, decreases the TTL value in the inner label by 1, and sets the TTL value in the outer label to the TTL value in the inner label after receiving a packet.

Precautions

If parameters need to be changed during the running of the test instance, the system prompts you whether to terminate the test instance. Press "Y" or "N" as required.

If you press "Y", the test instance is terminated and parameters changed. The settings take effect after being committed. To restart the test instance, run the start command.
If you press "N", the test instance keeps running, and the parameters fail to be modified.

Example

# Set the TTL propagation mode.

<HUAWEI> system-view
[~HUAWEI] nqa test-instance admin pwe3
[*HUAWEI-nqa-admin-pwe3] test-type vplspwtrace
[*HUAWEI-nqa-admin-pwe3] ttl-copymode pipe