mld max-response-time

Function

The mld max-response-time command sets the maximum response time for MLD General Query messages on an interface.

The undo mld max-response-time command restores the default maximum response time for General MLD Query messages.

By default, the maximum response time for MLD General Query messages is 10s on an interface.

Format

mld max-response-time interval

undo mld max-response-time

Parameters

Parameter	Description	Value
interval	Specifies the maximum response time for MLD General Query messages.	The value is an integer that ranges from 1 to 25, in seconds.

Views

GE interface view, XGE interface view, MultiGE interface view, 25GE interface view, 40GE interface view, 100GE interface view, Eth-Trunk interface view, VLANIF interface view, loopback interface view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

If hosts send Multicast Listener Report messages immediately after receiving MLD General Query messages, the querier on the local network segment may receive a large number of Multicast Listener Report messages from the hosts at the same time. This may cause congestion on the network.

To avoid such situations, MLD messages specify the maximum response time for MLD General Query messages. When a host receives an MLD Query message, the host starts a timer for the multicast group that it joins. The timer length is a random value between 0 and the maximum response time. When the timer times out, the host sends a Multicast Listener Report message to the querier.

The maximum response time specifies the deadline for the host to send a Multicast Listener Report message. A proper maximum response time allows hosts to respond to MLD Query messages and prevents hosts from sending Report messages at the same time.

Prerequisites

Layer 3 IPv6 multicast has been enabled using the multicast ipv6 routing-enable command in the system view.

Precautions

A shorter response time allows a multicast device to obtain multicast group member information more quickly, but consumes more bandwidth and system resources.
The function of the mld max-response-time command is the same as that of the max-response-time (MLD view) command used in the MLD view. The configuration in the MLD view takes effect for all interfaces, whereas the configuration in the interface view takes effect only for the specified interface. The configuration in the interface view takes precedence over the configuration in the MLD view. The configuration in the MLD view is used only when no configuration is performed in the interface view.

Example

# Set the maximum response time for MLD General Query messages to 8 seconds on VLANIF100.

<HUAWEI> system-view
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface vlanif 100
[HUAWEI-Vlanif100] mld max-response-time 8

# Set the maximum response time for MLD General Query messages to 8 seconds on GE0/0/1.

<HUAWEI> system-view
[HUAWEI] multicast ipv6 routing-enable
[HUAWEI] interface gigabitethernet 0/0/1
[HUAWEI-GigabitEthernet0/0/1] undo portswitch
[HUAWEI-GigabitEthernet0/0/1] mld max-response-time 8