This is Video #2 of our CUCM video series, which is designed to help viewers understand how to configure the features and functionalities of Cisco Unified Communications Manager, or CUCM. The tutorials will be fast paced and it is recommended to repeat the videos several times along with actual practice of the concepts described. This series will be helpful for aspiring CCNA/CCNP Collaboration candidates to prepare for their certification.


In this video, we will discuss how to configure Region which is one of the key elements of the IP phone configuration.


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Related Links:


Region Configuration


Voice over IP – Per Call Bandwidth Consumption


Understanding Codecs





CUCM Region


  • Defines the maximum bit rate between group of IP Phones.
  • Codecs that have higher bit rate than the value set in Region will not be used between IP Phones.
  • Region is used to for bandwidth sizing.
  • Codecs will determine how many calls are possible for a given bandwidth.




  • The word CODEC is taken from the words COder and DECoder.
  • Codecs are used for compression and decompression of audio signals.
  • Not all audio codecs can be used for telephony.
  • IP Phones need to have the same Codec to play the audio stream both ways. If IP Phones don’t have the same type of codec a Transcoder is required.
    • Traditional Transcoding: G.711 <-> Other
    • Universal Transcoding : Other <-> Other
  • Some codecs are not free to use.
  • Most common codecs for telephony are already available in the Cisco IP Phones.





  • ITU-T standard. Used in the PSTN (Public Switched Telephony Network and most IP PBX implementations.
  • Comes in two variants – u-law and a-law.
  • U-law is commonly used in the United States, North America and Japan. A-law is used anywhere else.
  • Medium complexity codec – uses less computational resources.





  • Mostly used in VOIP applications due to low bandwidth requirements.
  • Commonly used for calls outside the IP LAN environment.
  • Good for Latin Based language but not fit for music on hold.
  • Has several two main variants of the original – G.729a and G.729b.
  • G.729a, medium complexity
  • G.729b, added VAD (Voice Activity Detection).




  • Internet Low Bitrate Codec – released in 2004.
  • Was used in Yahoo Messenger, Gtalk and older versions of Skype.
  • Royalty free – no need to pay to use.



Region Configuration


  1. Specify Region Name.
  2. Modify Relationship to Other Regions.
  3. Set Max Audio Bit Rate
  4. Set Max Video Call Bit Rate
  5. Set Link Loss Type
  6. “Use System Default” will follow the values set in Service Parameter Configuration -> Cisco Call Manager.