Filter
Top Products
Appendix L - Media Traffic Shaping
Polycom, Inc. 1068
● Delays due to traffic shaping, if any, are limited to 10ms.
● This feature is not applied on audio, since the encoder output audio rate is constant.
● When LPR is enabled, traffic shaping is applied following packets repair and prior to packets sending.
System Flags
Traffic shaping usage is controlled by Collaboration Server configuration system flags (for the entire bridge):
● ENABLE_RTP_TRAFFIC_SHAPING - Controls traffic shaping. When set to YES, traffic shaping is
applied to all ports, resulting in some port capacity reduction in MCUs with MPMx/MPMRx cards (see
Capacity Reduction in MPMx and MPMRx MCUs). When set to NO (default), traffic shaping is
disabled.
● VIDEO_BIT_RATE_REDUCTION_PERCENT - Indicates the percentage of actual reduction in bit
rate sent from the MCU to the endpoint (negotiated bit rate is not reduced). This flag is applicable
only when traffic shaping is enabled (ENABLE_RTP_TRAFFIC_SHAPING set to YES).
Range: 0-60; Default value: 15
● TRAFFIC_SHAPING_MTU_FACTOR - Used for the MTU (Maximum transmitting Unit - the size of
transmitted packets) dynamic calculation:
New MTU = video bit rate / TRAFFIC_SHAPING_MTU_FACTOR
where the new MTU value is guaranteed to be a minimum of 410, and a maximum of 1460
(MAX_MTU). The purpose of this calculation is to match video rate in outgoing video to call rate, yet
force lower encoder bit rates to avoid overflow.
This flag is applicable only when traffic shaping is enabled.
Range: 0-5000, where 0 signifies no change in MTU; Default value: 800
To modify any of these flags, manually add them into the MCMS user parameters section of the system
configuration flags, and then modify their value (see Manually Adding and Deleting System Flags).
Capacity Reduction During Traffic Shaping
The table below describes the maximum capacity left after reduction due to traffic shaping in Collaboration
Servers 1500/2000/4000. There is no capacity reduction in Collaboration Server 1800.
Capacity Reduction in MPMx and MPMRx MCUs
Resolution
MPMx MPMRx
Non-mixed Mode Mixed Mode Non-mixed Mode Mixed Mode
CIF 70 40 150 * 100 *
SD 50 40 150 * 100 *
HD720p 30 20 100 66
HD1080p 15 10 50 40
Audio Only 70/360 40/360 300 150
* Assuming conference bit rate ≤ 1024 Kbps