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I'm planning a network design "upgrade" so to speak to utilise VLANs across the campus, and as such trying to figure out and research the best VLAN solution for our network of around 300 machines.

The current layout looks a bit like this (simplified) - every machine and switch is on VLAN1, the default:

Servers ----> Core Switch (3Com 5500G-EI 24-port) <---- Edge switches (all 3Com 4200G and 4500s) <---- Workstations & Printers

Every edge switch is in a unique building on the campus, and they won't move around at all.

I would think the simplest solution would be to have a single VLAN per building (and additional ones for wireless or security cameras as we build that infrastructure). The only traffic needed on the network is from clients to servers - there is no need for machines in one building to communicate with machines in another building. Without a router though this might be difficult.

What would be the best solution for VLAN-ing with the infrastructure I have? It would be preferable to avoid purchasing additional switches or new routers where possible, and avoiding IP reconfiguration across the network would be nice too (although I realise that's very much wishful thinking!).

Update: Our network at this stage runs on a single subnet; there is little segregation between workstations, servers, switches, and printers.

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What are your specific goals for implementing VLAN's? Do you have a specific problem that VLAN's will help you resolve? Are you implementing VLAN's just because everyone says you should? – joeqwerty Sep 13 '10 at 12:06
@joeqwerty: A valid question. I'm looking at implementing VLANs to reduce the broadcast domain on the network as a primary goal at this stage. Security is also a potential outcome - especially on the wireless rollout we're doing in the next year or so. – Matthew Iselin Sep 13 '10 at 23:03
up vote 1 down vote accepted

I'm assuming your switches are fully vlan capable, which I haven't checked. Also I'm assuming all links between buildings can transport large enough packets.

If you've made any segregation based on IP addresses, that's an easy line to draw the vlan borders on, in terms of implementation.

Try thinking of vlans along the lines of your security zones. Servers are seperate, wireless, ip-cams and 'clients'. I see little use in using physical structures like buildings (unless you have other management concerns like bandwidth).

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Just what I needed - thanks! – Matthew Iselin Sep 15 '10 at 4:12

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