display mac-address dynamic

Function

The display mac-address dynamic command displays information about dynamic MAC address entries.

Format

display mac-address dynamic [ ineffective ] { [ source-slot slot-id2 ] | [ slot slot-id1 ] [ interface { interface-type interface-number | interface-name } ] [ ce-vlan ] } [ verbose | last-change ]

Parameters

Parameter	Description	Value
ineffective	Displays information about dynamic MAC address entries of ineffective.	-
source-slot slot-id2	Displays dynamic MAC address entries on the board on which the specified outbound interface resides.	-
slot slot-id1	Displays dynamic MAC address entries on a specified board. If no slot is specified, dynamic MAC address entries on all boards are displayed.	-
interface interface-name	Specifies the interface name.	-
interface-type	Specifies the interface type.	-
interface-number	Specifies the interface number.	-
ce-vlan	Displays the inner tag carried in the packets received by the QinQ stacking sub-interface.	-
verbose	Displays detailed information about dynamic MAC address entries.	-
last-change	Displays the date and time when MAC address entries are last updated.	-

Views

All views

Default Level

1: Monitoring level

Task Name and Operations

Task Name	Operations
mac	read

Usage Guidelines

Usage Scenario

A MAC address table is an interface-based Layer 2 forwarding table. It stores information about MAC addresses learned by a device. A MAC address entry contains a MAC address, an interface on which a packet is forwarded to this MAC address, and a VLAN to which the specified interface belongs or a VSI to which the specified interface is bound. Before forwarding a packet, the device searches the MAC address table based on the destination MAC address of the packet and locate the outbound interface quickly. This facilitates packet forwarding and reduces broadcast traffic.

Dynamic MAC address entries: obtained by a device through source MAC address learning and will be aged based on the aging time.

A MAC address table needs to be updated constantly to meet requirements for network changes. To view information about dynamic MAC address entries learned by a device, run the display mac-address dynamic command.

Prerequisites

MAC address learning has been enabled on a device.

If MAC address learning is disabled on a device, run the undo mac-address learning disable command in the VLAN view to enable MAC address learning.

Precautions

If a device has learned a large number of dynamic MAC addresses, specifying parameters, such as interface, in the display mac-address dynamic command is recommended; otherwise, excessive output information causes the following problems:

The displayed information is repeatedly refreshed, and required information cannot be obtained.
The system does not respond because of long-time information traversing and searching.

Example

The actual command output varies according to the device. The command output here is only an example.

# Display dynamic MAC address entries of a interface.

<HUAWEI> display mac-address dynamic interface GigabitEthernet0/1/17
MAC address table of slot GigabitEthernet0/1/17:
-------------------------------------------------------------------------------
MAC Address    VLAN/       PEVLAN CEVLAN Port/Peerip     Type      LSP/LSR-ID
               VSI/SI/EVPN                                         MAC-Tunnel
-------------------------------------------------------------------------------
00e0-fc12-3460 1           -      -      GE0/1/17         dynamic   -
-------------------------------------------------------------------------------
Total matching items on slot 1 displayed = 1

**Table 1** Description of the **display mac-address dynamic** command output
Item	Description
MAC Address	Learned dynamic MAC address.
PEVLAN	Single VLAN tag or outer VLAN tag in a received packet.
CEVLAN	Inner VLAN tag in a received packet.
Port/Peerip	Outbound interface for the MAC address.
Type	Type of MAC address entries. dynamic indicates that MAC address entries are obtained by learning source MAC addresses. MAC address entries age after a specified aging time elapses. MAC address entries are lost after the system is reset or the interface board is hot swapped.
LSP/LSR-ID MAC-Tunnel	LSP: information about the board that learns the MAC address. LSR-ID: allocated information about MAC address learning. For example, 1/- indicates that the MAC address is learned by the board in slot 1 and no information about MAC address learning is allocated. MAC-Tunnel: the name of a tunnel. This field exists in a MAC address entry for a specific SI.
Total matching items on slot 1 displayed	Total number of MAC address entries.
VLAN/VSI/SI/EVPN	VLAN: VLAN to which the outbound interface belongs. BD: VLAN to which the outbound interface belongs. VSI: VSI to which the outbound interface belongs. SI: SI to which the outbound interface belongs. EVPN: EVPN to which the outbound interface belongs.