MAC address learning through a Layer 3 device

Introduction

This feature enables the device to learn the MAC address of a terminal (a PC for example) when a Layer 3 device (typically a gateway) exists between the device and the terminal for network traffic control.

Figure 1 MAC address learning through a Layer 3 device workflow

As shown in Figure 1, MAC address learning through a Layer 3 device proceeds as follows:

2.     The Layer 3 device learns the IP-MAC binding of the terminal, and then generates an ARP entry.

3.     The device sends SNMP requests to the Layer 3 device at the specified intervals to request the ARP entry.

4.     The Layer 3 device sends a response that contains the ARP entry.

5.     Upon receiving the response, the device saves the ARP entry in the memory. Then it can learn the MAC address of the terminal.

Restrictions and guidelines

·     Make sure the Layer 3 device supports SNMPv2c or SNMPv3, has SNMP agent enabled, and has a community name configured.

·     Only MAC addresses mapped from IPv4 addresses can be learned.

·     Make sure no NAT devices exist between the device and the Layer 3 device.

·     This feature is not applicable to a VRF network.

Configure MAC address learning through a Layer 3 device

Procedure

1.     Select System > Maintenance > MAC Learning Through L3 Device > L3 Device Access Setting.

2.     Click Enable to enable MAC address learning through a Layer 3 device.

3.     (Optional.) Set the polling interval and idle timeout

Table 1 Configuration items for MAC address learning through a Layer 3 device

4.     Click Apply.

5.     Add a Layer 3 device:

a.     Click Add.

b.     Configure the following settings:

6.     Click OK.