Anybody with who is involved in datacenter designing has to use multiple tools everyday and most of the times these tools are very expensive and not very user friendly. While working for a low budget project, I came across number of tools provided by various vendors. These tools are awesome to work with and free of cost. Apart from that I would also share some design guides, which I personally found wonderful. So, lets get started with the guides first.

Everything which is considered while planning a datacenter like -

Virtual Local Area Networks - VLANs - these are ways in which to create broadcast domains (subnets) across Cisco devices