Chapter 37: Service Class Names
STANDARD Revision 1.0
C4® CMTS Release 8.3 User Guide
© 2016 ARRIS Enterprises LLC. All Rights Reserved.
1001
Integrated Service Class Agility (ISCA)
At times certain heavy users consume so much of the available bandwidth of their service groups that other cable
customers become dissatisfied with their cable broadband service. This problem is exacerbated by file sharing and
streaming video, especially during peak usage times. MSOs are seeking a way to monitor usage and to restrain or penalize
those users who preempt an excessive amount of the shared bandwidth. ISCA permits MSOs to do this in a way that is not
perceived as heavy-handed by the cable users.
The ISCA feature consists primarily of usage monitoring and assignment of Service Classes. Normally the assigned Service
Class (SC) is permissive. However, heavy users who have exceeded a user-defined threshold of average kbps averaged over
two or more sampling intervals are reassigned to a more restrictive Service Class. If ISCA is enabled, the C4/c CMTS
continually monitors the usage of US and DS Service Flows (SFs). Those cable modems whose SFs have exceeded the
threshold of acceptable average usage are assigned to a penalty list. The penalty consists of the application of a new
Service Class with a reduced Quality of Service (QoS) for a certain period of time. For more information on QoS
parameters, see Appendix C of the DOCSIS 3.0 MULPI Specification.
Operational Considerations for ISCA
MSOs and operators of the C4/c CMTS should be aware of the following when using this feature:
Service Flows (SFs) can be monitored by this feature only if the cable modems (CMs) using those flows have
configuration files that use Service Class Names (SCNs) and do not have configuration file overwrites of the four
parameters listed in the next bullet point.
The Enforce SC replaces all of the following four parameters of the Reference SC. One or more of these parameters will
have lower values in the Enforce SC than they do in the Reference SC:
priority
max-tr-rate
max-tr-burst
peak-tr-rate
MSOs can define 1-50 Enforce Rules. Each such rule consists of a Reference Service Class (SC) and an Enforce (penalty)
SC which replaces the Reference SC under certain triggering conditions. A trigger or bandwidth threshold is defined for
each rule. A penalty period must also be defined for each rule.
