Cisco is a major provider of switches and routers to most medium and large companies. Cisco devices often run IOS or NX-OS. This is a generic tag to be used when no more specific tags are available. See the partial list of tags in the full Tag Wiki.
Since Cisco acquired Linksys, the consumer line of switches and routers (which do NOT run IOS) have been rebranded to the Cisco name.
This tag is a generic tag - Wherever possible a more specific tag related to the product you are using should be used instead. For example: