eNSP - Super-Vlan (Vlan aggregation)

Inter-vlan communication is achieved by configuring a ip address on the Vlanif interfaces. If a network as a large number of vlans, it will require an excessive use of ip addresses.

The concept of Super-vlans was introduced to save ip address space. A Super-vlan is a group of sub-vlans. It has a vlan interface, but no physical ports can be added to it. A sub-vlan has physical ports but no ip address assigned to the vlanif interface. Packets cannot be forward between sub-vlans at Layer 2, if Layer 3 communication is needed from a sub-vlan it will use the ip address of the Super-vlan as the gateway ip address.

The local  Address Resolution Protocol  (ARP) proxy function is used to perform Layer 3 communications between sub-vlans and between sub-vlans and other networks.

topology:

1 - Create vlans:

[S1] vlan batch 10 20

[S2] vlan batch 10 20

[S3] vlan batch 10 20 100

2 - Configure Trunk ports:

[S1] interface g0/0/1

[S1-GigabitEthernet0/0/1] port link-type trunk

[S1-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 20

[S1-GigabitEthernet0/0/1] interface g0/0/2

[S1-GigabitEthernet0/0/2] port link-type trunk

[S1-GigabitEthernet0/0/2] port trunk allow-pass vlan 10 20

[S2] interface g0/0/1

[S2-GigabitEthernet0/0/1] port link-type trunk

[S2-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 20

[S2-GigabitEthernet0/0/1] interface g0/0/2

[S2-GigabitEthernet0/0/2] port link-type trunk

[S2-GigabitEthernet0/0/2] port trunk allow-pass vlan 10 20

[S3] interface g0/0/1

[S3-GigabitEthernet0/0/1] port link-type trunk

[S3-GigabitEthernet0/0/1] port trunk allow-pass vlan 10 20

[S3-GigabitEthernet0/0/1] interface g0/0/2

[S3-GigabitEthernet0/0/2] port link-type trunk

[S3-GigabitEthernet0/0/2] port trunk allow-pass vlan 10 20

3 - Configure Access ports:

[S1] interface e0/0/1

[S1-Ethernet0/0/1] port link-type access

[S1-Ethernet0/0/1] port default vlan 10 

[S1-Ethernet0/0/1] interface e0/0/2

[S1-Ethernet0/0/2] port link-type access

[S1-Ethernet0/0/2] port default vlan  20

[S2] interface e0/0/1

[S2-Ethernet0/0/1] port link-type access

[S2-Ethernet0/0/1] port default vlan 10 

[S2-Ethernet0/0/1] interface e0/0/2

[S2-Ethernet0/0/2] port link-type access

[S2-Ethernet0/0/2] port default vlan  20

4 - Configure Super-Vlan:

[S3] vlan 100

[S3-vlan100] aggregate-vlan

[S3-vlan100] access-vlan 10 20

[S3-vlan100] quit

[S3] interface vlanif 100

[S3-Vlanif100] ip address 192.168.0.254 24

[S3-Vlanif100] arp-proxy inter-sub-vlan-proxy enable

Connectivity test:

client1 - 192.168.0.1 24

client2 - 192.168.0.2 24

client3 - 192.168.0.3 24

client4 - 192.168.0.4 24