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MAC Notification

Understanding MAC Notification on EX Series Switches

Juniper Networks EX Series Switches track clients on a network by storing Media Access Control (MAC) addresses in the Ethernet switching table on the switch. When switches learn or unlearn a MAC address, SNMP notifications can be sent to the network management system at regular intervals to record the addition or removal of the MAC address. This process is known as MAC notification.

The MAC Notification MIB controls MAC notification for the network management system. For general information on the MAC Notification MIB, see the Junos OS Network Management Configuration Guide.

The MAC notification interval defines how often these SNMP notifications are sent to the network management system. The MAC notification interval works by tracking all of the MAC address additions or removals on the switch over a period of time and then sending all of the tracked MAC address additions or removals to the network management server at the end of the interval. For instance, if the MAC notification interval is set to 10, all of the MAC address addition and removal SNMP notifications are sent to the network management system every 10 seconds.

Enabling MAC notification allows users to monitor the addition and removal of MAC addresses from the Ethernet switching table remotely using a network management system. The advantage of setting a high MAC notification interval is that the amount of network traffic is reduced because updates are sent less frequently. The advantage of setting a low MAC notification interval is that the network management system is better synchronized with the switch.

MAC notification is disabled by default. When MAC notification is enabled, the default MAC notification interval is 30 seconds.

Configuring MAC Notification on Switches with ELS Support

Note:

This task uses the Enhanced Layer 2 Software (ELS) configuration style. If your switch runs software that does not support ELS, see Configuring Non-ELS MAC Notification or Configuring Non-ELS MAC Notification. For ELS details, see Using the Enhanced Layer 2 Software CLI.

When a switch learns or unlearns a MAC address, SNMP notifications can be sent to the network management system at regular intervals to record the addition or removal of the MAC address. This process is known as MAC notification.

The MAC notification interval defines how often Simple Network Management Protocol (SNMP) notifications logging the addition or removal of MAC addresses on the switch are sent to the network management system.

MAC notification is disabled by default. When MAC notification is enabled, the default MAC notification interval is 30 seconds.

To enable or disable MAC notification, or to set the MAC notification interval, perform these tasks:

Enabling MAC Notification

MAC notification is disabled by default. You need to perform this procedure to enable MAC notification.

To enable MAC notification on the switch with the default MAC notification interval of 30 seconds:

To enable MAC notification on the switch with any other MAC notification interval (here, the MAC notification interval is set to 60 seconds):

Disabling MAC Notification

MAC notification is disabled by default. Perform this procedure only if MAC notification was previously enabled on your switch.

To disable MAC notification on the switch:

To disable MAC notification on a specific interface (here, the interface is ge-0/0/3):

Setting the MAC Notification Interval

The default MAC notification interval is 30 seconds. The procedure to change the MAC notification interval to a different interval is identical to the procedure to enable MAC notification on the switch with a nondefault value for the MAC notification interval.

To set the MAC notification interval on the switch (here, the MAC notification interval is set to 5 seconds):

Configuring Non-ELS MAC Notification

Note:

This task uses Junos OS for EX Series switches that do not support Enhanced Layer 2 Software (ELS) configuration style. If your switch runs software that supports ELS, see Configuring MAC Notification on Switches with ELS Support. For ELS details, see Using the Enhanced Layer 2 Software CLI.

When a switch learns or unlearns a MAC address, SNMP notifications can be sent to the network management system at regular intervals to record the addition or removal of the MAC address. This process is known as MAC notification.

The MAC notification interval defines how often Simple Network Management Protocol (SNMP) notifications logging the addition or removal of MAC addresses on the switch are sent to the network management system.

MAC notification is disabled by default. When MAC notification is enabled, the default MAC notification interval is 30 seconds.

To enable or disable MAC notification, or to set the MAC notification interval, perform these tasks:

Enabling MAC Notification

MAC notification is disabled by default. You need to perform this procedure to enable MAC notification.

To enable MAC notification on the switch with the default MAC notification interval of 30 seconds:

To enable MAC notification on the switch with any other MAC notification interval (here, the MAC notification interval is set to 60 seconds):

Disabling MAC Notification

MAC Notification is disabled by default. Perform this procedure only if MAC notification was previously enabled on your switch.

To disable MAC notification on the switch:

Setting the MAC Notification Interval

The default MAC notification interval is 30 seconds. The procedure to change the MAC notification interval to a different interval is identical to the procedure to enable MAC notification on the switch with a nondefault value for the MAC notification interval.

To set the MAC notification interval on the switch (here, the MAC notification interval is set to 5 seconds):

Verifying That MAC Notification Is Working Properly

Purpose

Verify that MAC notification is enabled or disabled, and that the MAC notification interval is set to the specified value.

Action

To verify that MAC notification is enabled or disabled on a QFX Series switch or an EX4600, and also to verify the MAC notification interval setting:

The output in the Notification Status field shows that MAC notification is enabled. The output in the Notification Status field would display Disabled if MAC notification was disabled.

The Notification Interval field output shows that the MAC notification interval is set to 60 seconds.

To verify that MAC notification is enabled on an EX Series switch while also verifying the MAC notification interval setting:

The output in the Notification Status field shows that MAC notification is enabled. The output in the Notification Status field would display Disabled if MAC notification was disabled.

The Notification Interval field output shows that the MAC notification interval is set to 30 seconds.