The ability to quickly create a simple and informative diagram is a handy skill that will help you train or troubleshoot complex systems with your teams. My two favorite browser based tools are Creately and DrawIO. I use them constantly to create training aids or to spice up my own academic papers. Below is a quick run down on both.
Creately is my go-to tool for building network diagrams. They have a massive clip-art gallery to choose from and a handful of great templates to help get you started. The UI is intuitive and isn’t too resource intensive. There are premium account packages but as long as you aren’t working on more than 5 different diagrams at the same time you will be able to get by with their free basic user account.
draw.io is another free, easy to use tool and they also have an impressive selection of clip art for network and component diagrams. I tend to use draw.io more when I need to model data flow diagrams. draw.io + this Crow’s Foot cheat sheet is a winning combination.