Chapter 38: Per-Subscriber Throughput
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
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Class and Quality of Service
Current DOCSIS modems rely on a reservation scheme wherein the modems request a time to transmit and the C4/c CMTS
grants time slots based on availability. Cable Modems (CMs) are assigned a Service ID (SID) that is mapped to Class of
Service (CoS)/Quality of Service (QoS) parameters.
Determining Throughput
Determining data throughput begins with the calculation of a theoretical maximum of throughput, and then concludes
with the determination of the effective throughput. This is because effective throughput that is available to subscribers of
a service will always be less than the theoretical maximum.
Configuration File
Once effective throughput is determined, the appropriate parameters can be entered in the CM’s configuration (config) file
settings to optimize throughput.
Displaying Throughput
To display the current throughput settings assigned for the upstream or downstream flows of a CM, the C4/c CMTS Per-
Subscriber Throughput feature provides specific outputs to the
show cable modem qos
Two Display Formats
The primary purpose of the show cable modem qos command is to display the cable modem QoS parameters for the
specified CM MAC address, CM IP address, CPE-MAC address, or CPE IP address.
Depending on whether the verbose parameter is entered, the QoS parameters associated with a specific CM MAC address,
CM IP address, CPE MAC address, or CPE IP address is output in two different formats, by the following command:
show cable modem qos [<cm-mac address>|<cm-ip address>|cm-ipv6 address|<cpe-mac address>|<cpe-ip
address>] [verbose]