Technical information

Cuda 12000 IP Access Switch CudaView Administration Guide
Monitoring Quality of Service 587
Monitoring Quality of Service
The Quality of Service (QoS) feature defines the transmission ordering and
scheduling on the Radio Frequency Interface. It provides for both upstream
and downstream traffic through the cable modem and CMTS. QoS classifies
packets traversing the RF MAC interface into a Service Flow. The Cuda
12000 and cable modems provide this QoS by shaping, policing, and
prioritizing traffic according to a parameter set defined for the Service Flow.
Service Flows
A Service Flow is unidirectional flow of packets transmitted either upstream
by the cable modem or downstream by the CMTS. There are three types of
services flows:
■ Provisioned Service Flows
■ Admitted Service Flows
■ Active Service Flows
A Service Flow is characterized by the Service Flow ID, the service ID, the
provisioned QoS parameter set, the admitted QoS parameter set, and the
active QoS parameter set. It serves as the principal identifier in the cable
modem and CMTS for the Service Flow.
Every Service Flow has a Service Flow Identifier (SFID) that the CMTS assigns.
Active and admitted upstream Service Flows also have a service identifier
(SID).
Classifiers
A classifier is a set of matching criteria that applies to each packet entering
the cable network. It consists of some packet matching criteria, such as the
destination IP address, a priority, and a reference to a Service Flow. Also,
several classifiers may refer to the same Service Flow.
Incoming packets attempt to match to a classifier. If the packet matches one
of the classifiers, it is forwarded to the Service Flow indicated by the SFID
parameter in the classifier. If the packet does not match any of the classifiers,
it is forwarded to the primary Service Flow.