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How to subnet and add VLANS into my network

10 years 4 months ago #38489 by Chris

Network diagrams always help :)

The last diagram you posted would certainly work, however I'd like to make a few comments if I could:

1) There is no gain placing L3 switches all over the place. You could use one L3 switch at the top where all three networks/VLANs connect to and from there below, use L2 switches, so that all Red switches are L2, all Green switches are L2 and all blue switches are L2.

Since the switch at the top is a L3 switch, you would only need one single cable to the Firewall. This link can either be a trunk link (that carries all 3 vlans) or a single access link with a completely different VLAN - e.g VLAN4.

Of course you can also connect the L3 switch the same way you show in your diagram and you would require 3 Ethernet ports on your Firewall.

Closing, if you decided to perform the VLAN routing through the Firewall, then you could also replace the top switch with a standard L2 switch.

As you can see, there are quite a few alternatives here. It all has to do with your budget, physical setup of your network and requirements.

If you asked me how would I set this network up, then this is what i'd do:

I'd connect one link from the Firewall to the Top Switch, in access-link mode (a single VLAN) and I'd make sure the Top switch is a L3 switch. From there on all switches below would be L2 switches e.g 2960.

From there on, depending on the physical setup of the network, I'd certainly create multiple rings to ensure redundancy and even connect the three VLANs between them if I can. Of course, this type of a setup would require good knowledge of Spanning Tree, to ensure traffic is spread out amongst the switches in the best possible way.

Please let us know if you require any additional information.


Chris Partsenidis.
Founder & Editor-in-Chief
10 years 3 months ago #38500 by AdminOmid
Hey Chris - thanks for all you help with this. As it turns out the company is adding a lab and will need another network in addition to what I have talked about.

I do have another question. You mentioned setting up multiple rings and connecting the three VLANs between them. That it requires knowledge of spanning tree. I haven't any what that is. Can you explain?

Also cant I setup the VLANS without rings and communicate between them and later setup the rings?

Thanks Again!
10 years 3 months ago #38502 by Chris
Hi Omid -

I wouldn't worry about creating connecting the switches between each other at this point - it does indeed require knowledge on the Spanning Tree protocol, and its something that can be done later.

You can also setup a small lab to being becoming familair with STP. When you're ready, you can then implement it on your network topology as well.

Good luck!

Chris Partsenidis.
Founder & Editor-in-Chief
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