There is a problem with drawing network diagrams in Microsoft Visio that has been bugging me for years. Earlier this week, I finally set about finding a solution for it, and I'm happy to report I was successful.
The problem occurs when attaching connectors to a shape, such as a router or switch icon. By default, connectors are terminated when they reach the target shape's rectangular border, not the edge of the shape itself. This is especially problematic with round shapes like our beloved router icon. (The icon below is from a set produced by VSDfx.)
So how do we fix it? Theoretically, modifying the glue settings in Visio so that connectors attach to a shape's geometry should work, but that hasn't been my experience. Instead, we're going to do a bit of a hack.
First, select the target shape and open its ShapeSheet. In Visio 2010, the ShapeSheet button can be found in the Shape Design section of the Developer toolbar (which is not shown by default). If the ShapeSheet button is disabled, make sure you have selected the shape first.
Next, scroll to the bottom of the ShapeSheet to the Shape Layout table. Change the value of the ShapeFixedCode parameter to 128 (visSLOFixedNoFoldToShape). Hit enter to apply the change and close the ShapeSheet.
Now, redraw one of the connectors to reattach it to the shape. It and any other connectors attached to the shape should now all meet at the center of the shape. Vertical and horizontal lines may need to be redrawn separately.
Finally, move the shape to the foreground. In Visio 2010, this can be done by right-clicking on the shape and selecting Bring to Front. Now you have some very smooth-looking connectors which will follow the shape as it is moved.