How to implement communication between some sub-VLANs in a super-VLAN


When VLAN aggregation is configured, hosts in a super-VLAN use IP addresses on the same network segment and share the same gateway address. Hosts in different sub-VLANs belong to the same subnet, so the switch forwards packets between the hosts by searching for ARP entries but not through the gateway. Proxy ARP allows the switch to establish ARP entries for all sub-VLANs for interworking.

To implement interworking between some sub-VLANs, configure static ARP entries to bind destination MAC addresses to the gateway IP address on hosts in the sub-VLANs.

For example, when host A with the gateway IP address of wants to access host B with the MAC address of 00-aa-00-62-c6-09, perform the following operations:
Choose Start > Run, enter cmd, and press Enter.
Enter arp -s 00-aa-00-62-c6-09.
After the preceding configuration is complete, host A can access host B. If host B needs to access host A, configure a static ARP entry to bind host A's MAC address to the gateway IP address on host B.

Other related questions:
How do I configure an Ethernet sub-interface to implement inter-VLAN communication
Generally, only one primary IP address can be configured for a physical interface. When a Layer 3 device connects to a Layer 2 network device through a Layer 3 Ethernet interface and interfaces on the Layer 2 network device are assigned to different VLANs, one primary IP address of the Layer 3 physical interface cannot implement inter-VLAN communication. You can configure secondary IP addresses or sub-interfaces for the Layer 3 Ethernet interface to solve this problem. The secondary IP addresses depend on the primary IP address. When the primary IP address becomes invalid, the secondary IP addresses also become invalid. The sub-interfaces and main interface are independent. Sub-interfaces share physical layer parameters of their main interface, and are configured with their respective link layer parameters and network layer parameters. The IP address of the main interface and IP addresses of sub-interfaces are independent. You can create sub-interfaces on the Ethernet interface connecting the Layer 3 device to the Layer 2 device so that users in different VLANs can communicate.

Can a traffic policy be configured in a super-VLAN or sub-VLAN to make the traffic policy take effect
The packets received and sent by the switch configured with VLAN aggregation carry sub-VLAN tags but not super-VLAN tags, so a traffic policy must be configured in all sub-VLANs of a super-VLAN. A traffic policy in the super-VLAN does not take effect.

How to configure a super-VLAN on an AR router
1. In the VLAN view, run the aggregate-vlan command to create a super-VLAN which does not contain any interface. 2. Run the access-vlan { vlan-id1 [ to vlan-id2 ] } &<1-10> command to add VLANs (sub-VLANs) to the super-VLAN. 3. Create a VLANIF interface for the super-VLAN, and configure a route. After the configuration, users under different VLANs can access the Internet over the super-VLAN.

Configuring communication between interfaces in different VLANs
A Fat AP can connect to a switch or router. If interfaces of a device are added to two VLANs, the interfaces can communicate with each other by default. If interfaces are added to two VLANs on different devices, routes need to be configured to enable communication between the interfaces.

How are VRRP packets of an S series switch sent in a super-VLAN
For S series switches (except the S1700), you are not advised to create a VRRP group on the corresponding VLANIF interface for a super-VLAN. If such a VRRP group has been created, the total number of VLANs (including common VLANs, super-VLANs, and sub-VLANs) in the VRRP group cannot exceed 256 to minimize impact on host performance. By default, if a VRRP group is configured for a super-VLAN, the master switch sends VRRP Advertisement packets to the super-VLAN's sub-VLAN that is in Up state and has the smallest VLAN ID among all the sub-VLANs. You can run a related command to configure VRRP Advertisement packets to be sent in a specified sub-VLAN. This prevents VRRP Advertisement packets from being broadcast in all sub-VLANs, reducing network bandwidth consumption. The configuration procedure is as follows: 1. Run the system-view command to enter the system view. 2. Run the interface vlanif vlan-id command to enter the VLANIF interface view. 3. Run the vrrp advertise send-mode { sub-vlan-id | all } command to configure a mode in which the master switch sends VRRP Advertisement packets in a super-VLAN. - sub-vlan-id: specifies the ID of a sub-VLAN where the master switch sends VRRP Advertisement packets. - all: indicates that the master switch sends VRRP Advertisement packets to all sub-VLANs in a super-VLAN. Note: The parameter all is not recommended. If all is configured, a super-VLAN broadcasts a VRRP Advertisement packet to all its sub-VLANs, which increases bandwidth usage.

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