A media resource is a
software-based or hardware-based entity that performs media processing
functions on the data streams to which it is connected. Media processing
functions include mixing multiple streams to create one output stream
(conferencing), passing the stream from one connection to another (media
termination point), converting the data stream from one compression type to
another (transcoding), streaming music to callers on hold (music on hold), echo
cancellation, signaling, voice termination from a TDM circuit
(coding/decoding), packetization of a stream, streaming audio (annunciation),
and so forth. The software-based resources are provided by the Cisco Unified Communications
Manager (Unified CM) IP Voice Media Streaming Service (IP VMS). Digital signal processor
(DSP) cards provide both software and hardware based resources.