ttl

Function

The ttl command sets the TTL value for the test packets of an NQA test instance.

The undo ttl command restores the default setting.

The default TTL value is 30.

Format

ttl number

undo ttl

Parameters

Parameter	Description	Value
number	Specifies the TTL value.	The value is an integer that ranges from 1 to 255. The default TTL value is 30.

Views

NQA view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

To prevent test packets from being transmitted endlessly, the test instance must be performed within certain hops.

When a test packet is created, you can run the ttl command to set the TTL value. When the test packet is transmitted along Layer 3 routing devices, each Layer 3 routing device decrements the TTL value by one when the packet arrives. When the TTL value is 0, the Layer 3 routing device discards the test packet and sends an error message to the sending end. This prevents test packets from being transmitted endlessly.

Prerequisites

The type of a test instance has been specified using the test-type command. The type of test instances that are not supported is as follows:

DNS
Trace
MAC Ping
Path Jitter

Configuration Impact

If you run the ttl command multiple times, only the latest configuration takes effect.

Precautions

The type of a running test instance cannot be changed.

Example

# Set the TTL value for the test packets of a test instance named user test to 10.

<HUAWEI> system-view
[HUAWEI] nqa test-instance user test
[HUAWEI-nqa-user-test] test-type icmp
[HUAWEI-nqa-user-test] ttl 10