CAC bandwidth allocation

Unanswered Question
Aug 23rd, 2009
User Badges:


Can someone please summerize the bandwidth allocation done by ccm and gatekeeper?

[assume we are using latest versions/spec.]

Is it true that both CCM(CAC) and Gatekeeper allocate twice the amount of codec bit rate for admission request?

For example ccm/gk reserves 128kbps bw for a G.711 call request to accomodate bi-directional voice stream. And without reserving bw for overheads. Is that true?


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 4.5 (2 ratings)
Jaime Valencia Sun, 08/23/2009 - 11:39
User Badges:
  • Cisco Employee,
  • Hall of Fame,


No, CUCM considers (RTP + overhead)x2. GK only RTP x 2

Location Configuration

For purposes of location bandwidth calculations only, assume that each call stream consumes the following amount of bandwidth:

•G.711 call uses 80 kb/s.

•G.722 call uses 80 kb/s.

•G.723 call uses 24 kb/s.

•G.728 call uses 16 kb/s.

•G.729 call uses 24 kb/s.

•GSM call uses 29 kb/s.

•Wideband call uses 272 kb/s.

Note Each call comprises two call streams.

IE with G711 for 1 call

CUCM = 160

GK = 128


CUCM = 48

GK = 16



if this helps, please rate


This Discussion