[cisco-voip] Ad-Hoc Video Conference not working with more than 3 parties with 3545 MCU in SCCP

[Daniele Visaggio]

Hi all,

my scenario: CUCM 6.1.4 - 3545 MCU in SCCP (software version 5.5.3.0.14)
- SCCP Phones with VT Advantage. The MCU is seen from CUCM as a video
conference bridge, inserted in a MRG and in a MRGL, then applied to the
phones device pool.

The problem is that we can't do an ad-hoc video conferences with more
than 3 parties, because the fourth party does not display video stream
or display it in an intermittent/corrupted way.

My suspect is the "max call rate" field in the MCU configuration ( MCU >
Services > Default SCCP Video Service). This parameter cannot be set
over 768 kbps. From the Cisco MCU Administrator Guide, the max call rate
is the "maximum bit rate available for this service. This value
represents the total bit rate of the voice, video and data streams
combined, up to a maximum of 2 Mbps per call". BTW the 768 kbps limit is
right for the sccp service (always from the cisco guide).

IMHO, 768 kbps are not sufficient for a video conference with more than
3 parties, considering the total video/audio bandwith usage. I already
checked the regions configuration, in order to exclude that the regions
limit the bandwith. Anyway all the phone for the videoconference test
stay in the same region.


How can I fix this?


Thank you in advance - Daniele