Configuring a Dot1q Termination Sub-interface to Implement Inter-VLAN Communication
Context
When a Layer 3 switch connects to users located in different VLANs through a Layer 3 Ethernet interface, configure Dot1q termination sub-interfaces on this Layer 3 Ethernet interface to implement inter-VLAN communication. This allows the users to communicate with each other.
NOTE: To implement inter-VLAN communication, hosts in each VLAN must use the IP address of the corresponding sub-interface as the default gateway address.
- When VLAN IDs terminated by a sub-interface are used for Layer 3 forwarding, only the first VLAN takes effect even if multiple inner VLAN IDs are specified.
Procedure
- Run system-view
The system view is displayed.
- Run interface interface-type interface-number
The interface view is displayed.
- Run port link-type { hybrid | trunk }
The link type of the interface is set.
- Run quit
Exit from the interface view.
- Run interface interface-type interface-number.subinterface-number
The sub-interface view is displayed.
- Run ip address ip-address { mask | mask-length } [ sub ]
An IP address is assigned to the sub-interface.
- Run dot1q termination vid low-pe-vid [ to high-pe-vid ]
Dot1q termination is configured on the sub-interface.
Sub-interfaces of different main interfaces can be associated with the same VLAN, whereas sub-interfaces of the same main interface cannot be associated with the same VLAN.
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NOTE: When VLAN IDs terminated by a sub-interface are used for Layer 3 forwarding, it is recommended that a maximum of 128 VLANs be in all VLAN ranges.
- Run arp broadcast enable
ARP broadcast is enabled on the sub-interface.
When you enable or disable ARP broadcast on a sub-interface, the routing status of the sub-interface alternates between Down and Up. This may result in route flapping on the entire network, affecting normal operation of services.
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