Cisco Network Topology Icons
The full Cisco Icon Library PDF as an Omnigraffle Stencil. 291 icons spanning the full set of Cisco products plus miscellaneous icons useful in network diagramming.
Given the amount of vectors in this Stencil, when searching for icons it is suggested to right-click on the stencil and Edit it, search for what you are looking for, and copy-paste in your document.
NOTE: All images are freely available from Cisco and are likely copyrighted by or trademarks of Cisco.