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New Member

vlan creation

can we have 2 or more VLAN's in the same LAN on the same subnet. I have to design vlan for my organisation. I have trouble in desinging the vlan for the same


Re: vlan creation

each VLAN has got it's own subnet. so you can have more than 2 VLANs in your LAN but each VLAN will have unique network or subnet if you want to communicate between VLANs.

hope this URL will give you more information.

rate if it helps ...

Re: vlan creation

it is not possible to have 2 vlan 's on the same subnet. because when you say 2 subnet, it means to different network. eg.

so create vlans on different subnet or network.

hope this helps.

rate this post if cleared.

Hall of Fame Super Blue

Re: vlan creation


Just to clarify. It is perfectly possible to have more than one vlan on the same subnet, you just need a device that bridges the two vlans together.

This is how firewalls work in transparent mode and how load-balancers like the CSM work when in bridge mode.



Re: vlan creation

Post is somewhat confusing as to what you are asking . In a good design you have 1 subnet address range per vlan such as . Is it possible to have more than 1 subnet range per vlan or too make 1 subnet bigger , sure . You can either make the mask smaller which gives you more addresses per subnet or you can use secondary addresses on each assigned vlan which I do "not" advocate at all . This will work much better if you use 1 subnet address range per vlan and will make any troubleshooting a lot easier .

New Member

Re: vlan creation

I have a flat network with 10.200.x.x with subnet mask

Now that accounts for Host with broadcast address Now how could I design vlans in this case. I have to design 6 vlans. Thanks

New Member

Re: vlan creation

The flat network must be not so flat, so u have to change it. And separate the range 0.0 - to 255.255 into 6.


Subnet 1 : .0.0 - .41.255

Subnet 2 : .42.0 - .83.255

Subnet 3 : .84.0 - .125.255

Subnet 4 : .126.0 - .167.255

Subnet 5 : .168.0 - .209.255

Subnet 6 : .210.0 - .249.255

Loopback : .250.0 - .255.255

As u could easily see, each vlan has many addresses, so u can range it differently, according to ur needs.

I believe u must perform routing in this environment with the command ip routing in where they are created. (If MLS)

U need to pay attention if the hosts are addressing fixedly the ip, or having an DHCP to address them the ip.

If they are fixed... U have to change it one by one, accordingly with the right vlan.

If they are learning by DHCP, the 6 scope's address's must be created refering the range address's for host / subnet / and Default Gateway (IP from Vlan).

In the Vlan config u must specify that the broadcast for DHCP server is allowed, in order to perform the dhcp process.

ip helper-address (dhcp ip address).

Hope it helps,