CUCM Features: Understanding Media Resources

There are many features that just “happen” on the VoIP network that we take for granted: hold, transfer, conference, music on hold…the list goes on. ALL of these features require resources to support them: Media Termination Points (MTP), Conference Bridges (CFB), Music on Hold (MOH), Transcoding (XCODE), and Annunciator (ANN). This Nugget provides an over view of each service detailing is function and placement in the VoIP network.


Media Resources Defined…. “Hardware or Software that support the function of the VoIP network”

  • Conference Bridge: Handles Conference Calls – (G.711 Only with CUCM – Software based resource)
  • Media Termination Point: Hold Calls On Hold! (CUCM)
  • Annunciator: Plays recorded announcements (CUCM) (Accessed via TFTP as below)
  • Transcoder: Converts one CODEC to another (DSPs needed and not performed in CUCM – VG for example. Can also be done between phones as DSP chips installed locally into the phone itself!)
  • MoH Server: Plays Music on Hold (CUCM)

To access Annunciator messages/wav files:
Cisco OS Admin -> Software Upgrades -> TFTP File Management
All files in the TFTP server

How does CUCM do all of this…….?
Serviceability-> ‘Cisco IP Voice Media Streaming App’ -> Enables all of the above!
System>Service Parameters>Cisco IP Voice Media Streaming App -> You can decide what roles each CUCM server has.

Voice Termination (DSP required) Unable to do with CUCM. Call from PSTN, converted to another CODEC, not possible with CUCM. VG can do this for us as it has a foot in the PSTN and IP world.