M Commands
This chapter describes the Cisco NX-OS Ethernet and virtual Ethernet commands that begin with M.
mac address-table aging-time
To configure the aging time for entries in the MAC address table, use the mac address-table aging-time command. To return to the default settings, use the no form of this command.
mac address-table aging-time seconds [ vlan vlan-id ]
no mac address-table aging-time [ vlan vlan-id ]
Syntax Description
Command Default
Command Modes
Command History
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The command syntax is changed to mac address-table aging-time. |
Usage Guidelines
Enter 0 seconds to disable the aging process.
The age value may be rounded off to the nearest multiple of 5 seconds. If the system rounds the value to a different value from that specified by the user (from the rounding process), the system returns an informational message.
When you use this command in EXEC mode, the age values of all VLANs for which a configuration has not been specified are modified and those VLANs with specifically modified aging times are not modified. When you use the no form of this command without the VLAN parameter, only those VLANs that have not been specifically configured for the aging time reset to the default value. Those VLANs with specifically modified aging times are not modified.
When you use this command and specify a VLAN, the aging time for only the specified VLAN is modified. When you use the no form of this command and specify a VLAN, the aging time for the VLAN is returned to the current global configuration for the aging time, which may or may not be the default value of 300 seconds depending if the global configuration of the switch for the aging time has been changed.
The aging time is counted from the last time that the switch detected the MAC address.
Examples
This example shows how to change the length of time an entry remains in the MAC address table to 500 seconds for the entire switch:
switch(config)#
mac address-table aging-time 500
Related Commands
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mac address-table notification
To configure a log message notification of MAC address table events, use the mac address-table notification command. To disable log message notifications, use the no form of this command.
mac address-table notification { mac-move | threshold [ limit percentage interval seconds ]}
no mac address-table notification { mac-move | threshold }
Syntax Description
Command Default
Command Modes
Command History
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The command syntax is changed to mac address-table notification. |
Examples
This example shows how to configure a log message notification when the threshold exceeds 45 percent, restricting the update interval to once every 1024 seconds:
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mac address-table static
To configure a static entry for the MAC address table, use the mac address-table static command. To delete the static entry, use the no form of this command.
mac address-table static mac-address vlan vlan-id { drop | interface { ethernet slot / port | port-channel number [ . subinterface-number ]} [ auto-learn ]
no mac address-table static mac-address { vlan vlan-id }
Syntax Description
Command Default
Command Modes
Command History
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Usage Guidelines
You cannot apply the mac address-table static mac-address vlan vlan-id drop command to a multicast MAC address.
When you install a static MAC address, it is associated with a port. If the same MAC address is seen on a different port, the entry is updated with the new port if you enter the auto-learn keyword.
Examples
This example shows how to add a static entry to the MAC address table:
Related Commands
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management
To configure a switch virtual interface (SVI) that should be used for in-band management, use the management command. To remove the in-band management access to a VLAN interface IP address, use the no form of this command.
Syntax Description
Command Default
Command Modes
Interface configuration mode
Switch profile configuration mode
Command History
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Usage Guidelines
Examples
This example shows how to configure a VLAN interface to allow in-band management access:
This example shows how to remove the in-band management access to a VLAN interface:
Related Commands
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Displays the running configuration information for an interface. |
monitor erspan origin ip-address
To configure the Encapsulated Remote Switched Port Analyzer (ERSPAN) origin IP address, use the monitor espan origin ip-address command. To remove the ERSPAN origin IP address configuration, use the no form of this command.
monitor erspan origin ip-address ip-address [ global ]
no monitor erspan origin ip-address ip-address [ global ]
Syntax Description
(Optional) Specifies the default virtual device context (VDC) configuration across all VDCs. |
Command Default
Command Modes
Command History
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Usage Guidelines
When you change the origin IP address in the default VDC, it impacts all the sessions.
Examples
This example shows how to configure the ERSPAN origin IP address:
This example shows how to remove the ERSPAN IP address:
Related Commands
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monitor session
To create a new Ethernet Switched Port Analyzer (SPAN) or an Encapsulated Remote Switched Port Analyzer (ERSPAN) session configuration for analyzing traffic between ports or add to an existing session configuration, use the monitor session command. To clear SPAN or ERSPAN sessions, use the no form of this command.
monitor session { session-number [ shut | type { local | erspan-source } | all shut }
no monitor session { session-number | all } [ shut ]
Syntax Description
Command Default
Command Modes
Command History
Usage Guidelines
To ensure that you are working with a completely new session, you can clear the desired session number or all SPAN sessions.
Note The Cisco Nexus 5000 Series switch supports two active SPAN sessions. The Cisco Nexus 5548 Switch supports four active SPAN sessions. When you configure more than two SPAN sessions, the first two sessions are active. During startup, the order of active sessions is reversed; the last two sessions are active. For example, if you configured ten sessions 1 to 10 where 1 and 2 are active, after a reboot, sessions 9 and 10 will be active. To enable deterministic behavior, explicitly suspend the sessions 3 to 10 with the monitor session session-number shut command.
Note Beginning with Cisco NX-OS Release 5.0(2)N2(1), the limit on the number of egress (TX) sources in a monitor session has been lifted. Port-channel interfaces can be configured as egress sources.
After you create an ERSPAN session, you can describe the session and add interfaces and VLANs as sources and destinations.
Examples
This example shows how to create a SPAN session:
This example shows how to enter the monitor configuration mode for configuring SPAN session number 9 for analyzing traffic between ports:
This example shows how to configure any SPAN destination interfaces as Layer 2 SPAN monitor ports before activating the SPAN session:
This example shows how to configure a typical SPAN destination trunk interface:
This example shows how to create an ERSPAN session:
Related Commands
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Sets the maximum transmission value (MTU) for ERSPAN packets. |
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mst (STP)
To configure the Multiple Spanning Tree (MST) designated bridge and root bridge priority, use the mst command. To revert to the default settings, use the no form of this command.
mst instance-id [{ designated | root } priority priority-value ]
no mst instance-id [{ designated | root } priority priority-value ]
Syntax Description
Command Default
Command Modes
Spanning-tree pseudo configuration mode
Command History
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Usage Guidelines
You can enter the instance-id argument as a single instance or a range of instances, for example, 0-3,5,7-9.
Examples
This example shows how to configure a spanning-tree domain:
Related Commands
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Displays the running configuration information of the Spanning Tree Protocol (STP). |
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mvr group
To configure a Multicast VLAN Registration (MVR) group for an interface, use the mvr group command. To remove the MVR group from an interface, use the no form of this command.
mvr group { group_IP_address | IP_prefix / length } [ count count_value ] [ vlan vlan_ID [... vlan vlan_ID ]]
no mvr group { group_IP_address | IP_prefix / length } [ count count_value ] [ vlan vlan_ID [... vlan vlan_ID ]]
Syntax Description
IP prefix and network mask length in the format x. x. x. x / m. |
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Specifies the global default MVR VLAN. The range is from 1 to 4094. |
Command Default
Command Modes
Interface configuration mode
Virtual Ethernet interface configuration mode
Command History
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Usage Guidelines
You can use this command on the following interfaces:
Before you use a virtual Ethernet interface, you must enable the Cisco Virtual Machine Fabric Extender (VM-FEX) on the switch by using the feature vmfex command.
Examples
This example shows how to configure an MVR VLAN group for an interface:
Related Commands
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mvr type
To configure a Multicast VLAN Registration (MVR) port type for an interface, use the mvr type command. To remove the MVR port type for an interface, use the no form of this command.
mvr type { source | receiver }
no mvr type { source | receiver }
Syntax Description
Command Default
Command Modes
Interface configuration mode
Virtual Ethernet interface configuration mode
Command History
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Usage Guidelines
You can use this command on the following interfaces:
Before you use a virtual Ethernet interface, you must enable the Cisco Virtual Machine Fabric Extender (VM-FEX) on the switch by using the feature vmfex command.
Examples
This example shows how to configure an MVR source port for an interface:
Related Commands
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mvr vlan
To configure a Multicast VLAN Registration (MVR) VLAN for an interface, use the mvr vlan command. To remove the MVR VLAN from an interface, use the no form of this command.
Syntax Description
Command Default
Command Modes
Interface configuration mode
Virtual Ethernet interface configuration mode
Command History
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Usage Guidelines
You can use this command on the following interfaces:
Before you use a virtual Ethernet interface, you must enable the Cisco Virtual Machine Fabric Extender (VM-FEX) on the switch by using the feature vmfex command.
Examples
This example shows how to configure an MVR VLAN for an interface:
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