Chapter 26: Connection Admission Control
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
799
Bandwidth for a new bonded multicast flow is distributed across the least loaded channels of the modem’s bonding
group based on the total allocated bandwidth for each channel. Redistribution or rebalancing is not done when the
bonded flow is destroyed.
An IGMP "join" results in creation of a multicast flow which requests bandwidth from multicast CAC. The amount of
bandwidth allocated is the minimum reserve rate (Tmin) of the Service Class Name (SCN) associated with the IGMP
join.
Guidelines for CAC Thresholds in Non-converged System
Threshold values are expressed in percentages of channel bandwidths, where the data throughput is a function of channel
width and compression technique. Allowed-total-voice should be equal to allowed-emergency-voice. Voice traffic is not
recommended on 320 or 640 Kbps upstream channels.
Note: In non-converged systems, voice channels are separate from multicast channels. (See
(page 776) for more information.)
The following table provides recommendations for setting allowed-normal-voice and allowed-emergency-voice thresholds
for a non-converged system:
Upstream
Channel BW
allowed-normal-voice allowed-emergency-voice
1.28 Mbps
55%
75%
2.56 Mbps
75%
85%
5.12 Mbps
85%
90%
10.24 Mbps & greater 90%
90%
Downstream
Channel BW
allowed-normal-voice allowed-emergency-voice
30 Mbps
83%
83%
42 Mbps
85%
85%
Downstream (for multicast only)
Channel BW
Multicast
30 Mbps
70%
42 Mbps
75%