3com S7906E Manuel De Montage

 

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After a port on a device receives a packet with an unknown source MAC address, the device checks the 

list of MAC address-to-VLAN mappings for a match. If a match is found, the device dynamically learns 

the MAC address and assigns the receiving port to the corresponding VLAN. Then, subsequent packets 

with this source MAC address can be directly forwarded through the port. This feature is referred to as 

MAC-based dynamic port assignment. It allows different ports in a same VLAN to use the same MAC 

address bundled with the VLAN. 

The device periodically checks whether dynamic MAC address entries are updated. If a dynamic MAC 

address entry is not updated within a certain period of time, the device deletes the MAC address entry, 

thus removing the port included in the entry from the corresponding VLAN.  

Do not enable this function together with 802.1X or MAC authentication. This is to allow ports to 

dynamically join VLANs with no authentication performed.  

 

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MAC-based VLANs are available only on hybrid ports.  

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With MAC-based dynamic port assignment enabled, packets with unknown source MAC 

addresses are sent to the CPU for processing. Because this packet processing mode has the 

highest priority, the configuration of MAC learning limit and disabling MAC address learning 

becomes invalid in this case. Therefore, you are recommended not to configure these two features 

together with MAC-based dynamic port assignment.  

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In MAC-based dynamic port assignment, the port that receives a packet with an unknown source 

MAC address can be successfully assigned to the matched VLAN only when the matched VLAN is 

a static VLAN.  

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With MAC-based dynamic port assignment enabled, the port that receives a packet with no mask 

MAC address. 

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Because MAC-based dynamic port assignment is mainly configured on the downlink ports of the 

user access devices, do not enable this function together with link aggregation. 

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With MSTP enabled, if the MST instance for the corresponding VLAN is blocked, the packet with 

the unknown source MAC address will fail to be sent to the CPU. As a result, the receiving port 

cannot be dynamically assigned to the corresponding VLAN. Since MAC-based dynamic port 

assignment is mainly configured on the access side, you are recommended not to configure it 

together with MSTP.  

 

Follow these steps to configure a MAC-based VLAN: 

Enter system view 

— 

Associate MAC addresses 
with a VLAN 

 

mac-address [ mask mac-mask ]

 

vlan vlan-id [ priority priority ] 

Required 

Support for the mask keyword in 
this command depends on the 
device model.