VLAN aggregation, also called super-VLAN, partitions broadcast domain into multiple VLANs (sub-VLANs) on a physical network and aggregates the sub-VLANs into a single logical VLAN (super-VLAN). The sub-VLANs use the same IP subnet and default gateway address, so the number of IP addresses used is reduced.

Step 1: Create super-VLAN and sub-VLANs. Configure VLAN 10 and VLAN 20 as sub-VLANs of VLAN 100.

•Sub-VLAN: contains only physical interfaces, and is used to isolate broadcast domains. A sub-VLAN cannot be used to create a Layer 3 VLANIF interface.
Hosts in each sub-VLAN use the VLANIF interface of its super-VLAN to communicate with external devices at Layer 3.
• Super-VLAN: A super-VLAN contains only Layer 3 VLANIF interfaces and does not contain physical interfaces. A super-VLAN corresponds to a subnet gateway, Different from a common VLAN, the VLANIF interface status of a super-VLAN depends on the physical interface status of the sub-VLANs in the super-VLAN.

*******************************************LSW1
system-view
sysname LSW1
vlan batch 10 20
interface GigabitEthernet 0/0/1
port link-type trunk
port trunk allow-pass vlan 10
#
interface GigabitEthernet 0/0/2
port link-type trunk
port trunk allow-pass vlan 20
#
vlan 100
aggregate-vlan
access-vlan 10 20
#
interface vlanif 100
ip address 192.168.1.1 24
#
vlan 200
quit
interface GigabitEthernet 0/0/3
port link-type access
port default vlan 200
#
interface vlanif 200
ip address 192.168.200.1 24

Step 2: Configure VLANs on interfaces of Access Switches.

*******************************************LSW2
ystem-view
sysname LSW2

vlan 10 
quit 
interface Ethernet 0/0/1
port link-type trunk 
port trunk allow-pass vlan 10
quit 
interface Ethernet 0/0/2
port link-type access 
port default vlan 10 

*******************************************LSW3
system-view
sysname LSW3
vlan 20 
quit 
interface Ethernet 0/0/2
port link-type trunk 
port trunk allow-pass vlan 20
quit 
interface Ethernet 0/0/3
port link-type access 
port default vlan 20 

Step 3 : Result verification.

Run the command Display Vlan on LSW1

Ping the Server from a Host.

The communication between LSW1 configured with VLAN aggregation and other devices is similar to normal Layer 2 communication without the super-VLAN. When a PC in a sub-VLAN needs to communicate with other networks at Layer 3, the PC sends data to the default gateway, that is, the VLANIF interface corresponding to the super-VLAN, and then routes the data.

Test communication between Host in different sub-VLANs.

When hosts in different sub-VLANs communicate with each other, the hosts send ARP Request packets because IP addresses of the sub-VLANs belong to the same network segment. Actually, different sub-VLANs belong to different broadcast domains. As a result, ARP packets cannot be transmitted to other sub-VLANs, there is no response to ARP Request packets, and the device cannot learn the MAC address of the peer end. As a result, sub-VLANs cannot communicate with each other. To implement communication between sub-VLANs, enable proxy ARP on the VLANIF interface of the super-VLAN.

Step 4: Enable proxy ARP on the super-VLAN on LSW1 and Ping PC2 from PC1.

*******************************************LSW1
interface vlanif 100
arp-proxy inter-sub-vlan-proxy enable