mdnsnsp.dll is a Bonjour Namespace Provider
from Apple Computer, Inc.
belonging to Bonjour
mdnsnsp.dll is a file which is usually associated with Itunes.
Non-system processes like mdnsnsp.dll originate from software you installed on your system. Since most applications store data in your system's registry, it is likely that over time your registry suffers fragmentation and accumulates invalid entries which can affect your PC's performance. It is recommended that you check your registry to identify slowdown issues