Inter-VLAN Configuration

[benedictp]

Hi Guys,

I'm new to network and to ALU OmniSwitch. I want to ask several questions.
How to create inter VLan, as example I have one switch 6850, and i have created 3 VLAN.
I want all VLAN to communicate to each other. Is it possible ?

Also I have one public IP Address, is it possible that this 3 VLAN could access the internet by this one public IP Address ?

Best Regards,

Benedict

[benny]

You have to create an IP interface per VLAN. This way the VLANs/clients can communicate with each other using the IP address of the switch as gateway (the IP address of the subnet/vlan respectively).

The OmniSwitch 6850 doesn't support NAT.

[benedictp]

Hi Sir,

Thank you for your reply.

So if i created such command :

vlan 2 enabled
vlan 3 enabled
vlan 4 enabled
ip interface vlan2 address 192.168.2.1 vlan 2
ip interface vlan3 address 192.168.3.1 vlan 3
ip interface vlan4 address 192.168.4.1 vlan 4
vlan 2 port default 1/4-5
vlan 3 port default 1/6-10
vlan 4 port default 1/11-15

Where should I add the gateway and how to connect from vlan 2 to vlan 3 and to vlan 4 ?

Regards,

Benedict

[benny]

Example:

Your PC1 is connected in vlan 2. The IP address of the client is 192.168.2.100. On that client you set the GW IP as 192.168.2.1 (the IP address of the switch).

Your PC2 is connected in vlan 3. The IP address of the client is 192.168.3.100. On that client you set the GW IP as 192.168.3.1 (the IP address of the switch in that vlan).

Now you can communicate between PC1 and PC2.

-benny

[benedictp]

Thank you sir for your reply.

I have other questions too.
Since OS6850 doesn't support NAT.
What is the best solution to have several VLAN accessing the internet ?
Does this mean if we have 3 VLAN, we must have 3 Public IP and 3 line from routers, or are there any solutions for this ?
Our customer wish to use Metro Ethernet and they will have 15 Public IP Address, they wish to implement several VLAN while our OS6850 as Core Switch are unable to implement NAT. Are there any ways we can implement this ?

Best Regards,

Benedict P.

[benny]

I would use a firewall and/or proxy for that. Its never a good idea to simply NAT the workstations to the internet.

That's good enough for home users, but not a good idea for enterprises/companies.

Your proxy server must have a public IP and an internal IP. The computers contact the internal IP and the proxy will use its public IP to communicate with the external web server. The proxy will then forward the web pages to the client using the internal IP.

Squid is a good open-source proxy server -> http://www.squid-cache.org/

-benny

[benedictp]

I have been told from my friends that are Cisco network admin, why don't u use VLAN Trunking for configuring the VLAN in the switch and if you have 3VLAN, you can have one connection to the Cisco router and apply "encapsulation dot1q" from the router, to have different gateway for each VLAN.

Are there any command for VLAN Trunking in Alcatel ?
Are VLAN Trunking simillar to Link Aggregation in Alcatel, because i didn't found vlan trunking explanation in the configuration guide ?
Does this work using Alcatel 6850 and Cisco Router 2600 ?

Best Regards,

Benedict P.

[benny]

You did not mention that you have such a router in your network.

I can't simply guess how your network looks like....

You can use "vlan trunking" or "tagging" with OmniSwitch -> 802.1Q

vlan x 802.1q 1/1
vlan y 802.1q 1/1
vlan z 802.1q 1/1

This way you have a default vlan + three tagged vlans on the port.

On the other side (Cisco) you have to configure the same tags and IP interfaces per vlan as well (those should act as your gateway then).

-benny