What is your business need for the network? What content are you shuffling around? What kind of performance do you need?
Like you say, it’s not a home network you’re building. Here are some buzzwords used in IT, that may be helpful when planning the network (they’re really aimed more at service development/SLA, but I get alot of help from them with whatever):
People - Who are the users and who will be resources in setting this up? How will the users adapt to any visible changes and is any training required?
Products - What equipment and technology do we need to complete the task?
Processes - (This ties in with ITIL stuff, but basically documenting, evaluating how it relates to and impacts other things in the organization, and planning the work so that it’s easy to fit into existing processes and to manage)
Partners - What external partners and suppliers are required or affected? Is there any reliance on a third party supplier?
- Performance - what can you do to gain maximum performance, while…
- Constraints - trying to minimize or mitigate limiting factors.
Warranty: (in your case, “reliability and robustness”)
- Security - This one you should get plenty of tips from others. What I’d like to advise on, is making an IT Security Policy early on.
Continuity - planning for failures and minimizing downtime, but also looking at future needs (from a business/strategic standpoint).
- Capacity - What are your needs? How do you scale if need increases? Map out bottlenecks and potential future tuning needs contra costs
Availability - Make your own mind based on the video. Closely tied in with continuity above.
Finally, you should use these words when going through the keywords: Value - Outcome - Costs - Risks
Try hard to think of them from your business’s standpoint, and not your own, technical one. Use the five W’s for each : )
I’m basing my advice on the following quote:
Start off by checking with your boss/whoever gave you the assignment how much he’s actually willing to put out, and what he’s really expecting the result (outcome/value) to be. You don’t want to under or over shoot too much with the first proposal - try instead to make your first estimate on his budget (even if it’s just on a hunch on his part), and then lay out any risks you see with that budget, as well as proposals for improvement (from a business perspective)
You won’t give him what he wants, if you’re not speaking the same language. (and yes, that means you have to adapt to his level of knowledge and insight if he’s the boss)
$10k is alot of money for 50 people, including work hours to set things up, unless you also need to install new cabling. You should begin by creating an inventory of the assets you have today, how they’re all connected, and if they can be reused.
Do you have an SBS or AD server in the office today? Those have alot of uses you can offload from the rest of the IT infrastructure (such as authentication and log/file storage), and may let you instead focus on building a stable and expandable network.
Depending on what you do at you office, your requirements will different capacity. If you shuffle around alot of big files, having a sling topology for the switches, or stacking them if they’re in the same cabinet, you can have a single/dual 10 GE link(s) between them, and let most traffic go over IP in the office. Connections to the router can then be 1GE (or less) without sacrificing much performance during file transfers in such a scenario.
I would advise against building a pfsense router, and instead going with something more ready-made. If you are transitioning into an IT management role and don’t have years of experience, building an entire network from scratch will be extremely time-consuming and unfulfilling because of all the gaps in knowledge, if you also have to manage configuration in detail. 10 GE routers are not cheap though, but using hosts and having the router primarily work as a gateway/firewall (all equipment connected via underlying managed switches), you can definitely make do with 1 GE, or even FastEthernet on the router, internally. Remember that there are direct-attach cables if you don’t have large distances between the switches (alot cheaper than optical transceivers).
For $10k, you could consider taking in a consultant design and configure the network. A decent prestudy shouldn’t take more than a couple of hours, and would give you alot of valuable information to build on - maybe enough to build the network on your own.
I would definitely consider taking in some expert advise (paid consultant), so you don’t make any changes that threaten your business.
My final advise is based on IT security: Be careful of what you share about the project outside the organization. Yes, that means even here. Try to scrub any descriptive questions from identifying your employer and your environment, so you don’t put yourself in a legal dilemma.