There is an attractive set of images produced by VRT for constructing network diagrams. These are packaged into a set of gallery groups for Apache Open Office.
To test the use of the gallery, I created a version of an existing Apache Cloudstack diagram that shows a server configuration using separate storage services
The following diagram was exported from an OpenOffice Draw file.
The source OpenOffice file is available as SeparateStorageNetwork.odg
The appearance is a bit different but more modern-looking, in my opinion. The icons are reasonably easy to work with.
OpenOffice images can be easily modified and have connection points which makes it easy to add connecting lines.
In the new diagram I changed the connecting lines to indicate the type of network by the color of the lines. I also had to change the placement and organization of the servers to better fit the available server icons for storage and computing.
Apache OpenOffice is an open source software. The images have been contributed by VRT to the OpenOffice catalog so they can easily be installed in OpenOffice.