show mld statistics

Syntax

Syntax (MX Series)

Description

Display information about Multicast Listener Discovery (MLD) statistics.

By default, Junos OS multicast devices collect statistics of received and transmitted MLD control messages that reflect currently active multicast group subscribers.

Some devices also automatically maintain continuous MLD statistics globally on the device in addition to the default active subscriber statistics—these are persistent, continuous statistics of received and transmitted MLD control packets that account for both past and current multicast group subscriptions processed on the device. With continuous statistics, you can see the total count of MLD control packets the device processed since the last device reboot or clear mld statistics continuous command. The device collects and displays continuous statistics only for the fields shown in the MLD packet statistics... output section of this command, and does not display the MLD Global statistics section.

Devices that support continuous statistics maintain this information in a shared database and copy it to the backup Routing Engine at a configurable interval to avoid too much processing overhead on the Routing Engine. These actions preserve statistics counts across the following events or operations (which doesn’t happen for the default active subscriber statistics):

Routing daemon restart
Graceful Routing Engine switchover (GRES)
In-service software upgrade (ISSU)
Line card reboot

You can change the default interval (300 seconds) using the cont-stats-collection-interval configuration statement at the [edit routing-options multicast] hierarchy level.

You can display either the default currently active subscriber statistics or continuous subscriber statistics (if supported), but not both at the same time. Include the continuous option to display continuous statistics, otherwise the command displays the statistics only for currently active subscribers.

Run the clear mld statistics command to clear the currently active subscriber statistics. On devices that support continuous statistics, run the clear command with the continuous option to clear all continuous statistics. You must run these commands separately to clear both types of statistics because the device maintains and clears the two types of statistics separately.

Options

none	Display MLD statistics for all interfaces. These statistics represent currently active subscribers.
continuous	(Optional) Display continuous MLD statistics that account for both past and current multicast group subscribers instead of the default statistics that only reflect currently active subscribers. This option is not available with the `interface` option for interface-specific statistics.
interface `interface-name`	(Optional) Display statistics about the specified interface. This option is not available with the `continuous` option.
logical-system (all \| `logical-system-name`)	(Optional) Perform this operation on all logical systems or on a particular logical system.

Required Privilege Level

view

Output Fields

Table 1 describes the output fields for the show mld statistics command. Output fields are listed in the approximate order in which they appear.

Table 1: show mld statistics Output Fields
Field Name	Field Description
MLD Packet Statistics...	Heading for MLD packet statistics for all interfaces or for the specified interface name. Note: Shows currently active subscriber statistics in this section by default, or when the command includes the `continuous` option, shows continuous, persistent statistics that account for all MLD control packets processed on the device.
Received	Number of received packets.
Sent	Number of transmitted packets.
Rx errors	Number of received packets that contained errors.
MLD Message type	Summary of MLD statistics. Listener Query (v1/v2)—Number of membership queries sent and received. Listener Report (v1)—Number of version 1 membership reports sent and received. Listener Done (v1/v2)—Number of Listener Done messages sent and received. Listener Report (v2)—Number of version 2 membership reports sent and received. Other Unknown types—Number of unknown message types received. MLD v2 source required for SSM—Number of MLD version 2 messages received that contained no source. MLD v2 mode not applicable for SSM—Number of MLD version 2 messages received that did not contain a mode applicable for source-specific multicast (SSM).
MLD Global Statistics	Summary of MLD statistics for all interfaces. Note: These statistics are not supported or displayed with the `continuous` option. Bad Length—Number of messages received with length errors so severe that further classification could not occur. Bad Checksum—Number of messages received with an invalid IP checksum. No further classification was performed. Bad Receive If—Number of messages received on an interface not enabled for MLD. Rx non-local—Number of messages received from nonlocal senders. Timed out—Number of groups that timed out as a result of not receiving an explicit leave message. Rejected Report—Number of reports dropped because of the MLD group policy. Total Interfaces—Number of interfaces configured to support IGMP.