Cisco Broadband Cable Command Reference Guide

Cisco CMTS Feature Summary
Table 2-2 Principle Software Features (continued)
Feature Category Item
Quality of Service
DOCSIS 1.0 extensions:
(QoS)—DOCSIS 1.0 Extensions
Multiple service identifiers (SIDs).
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Cisco Broadband Cable Command Reference Guide
Chapter 2 Cisco Cable Modem Termination System Commands
CM-initiated dynamic MAC messages such as Dynamic Service Addition (DSA)
and Dynamic Service Deletion (DSD) that allow dynamic SIDs to be created at run
time on a per-VoIP call basis.
Unsolicited grant service (for example, constant bit rate (CBR) scheduling on the
upstream to provide a higher quality of service (QoS) for VoIP packets from an
Integrated Telephony Cable Modem (ITCM).
Ability to provide separate downstream rates for any given ITCM, based on the
IP-precedence value in the packet.
Dynamic map advance to improve the upstream throughput for a CM or an STB,
enables the map advance to be dynamic and self-adjusting to propagation delay,
even for the furthest CM on the cable plant.
Quality of Service—Generic Committed Access Rate (CAR).
Cisco Express Forwarding (CEF).
Weighted random early detection (WRED).
TAG/NetFlow Switching including type of service (ToS) support.
Weighted fair queuing (WFQ).
Weighted fair drop (WFD) enhancements to associate a maximum bandwidth in kbps
with a particular setting of IP ToS bits; can be used to ensure that basic data traffic does
not exceed preset rate limit and thereby interfere with higher-priority traffic such as
voice.
Common Open Policy Service (COPS) for Resource Reservation Protocol (RSVP) to
support admission control, bandwidth guarantee, media-independent reservation, data
classification, and data policing.
Rate Limiting and
Shaping—DOCSIS
Limiting the data rate to and from a CM or STB, and shaping traffic per DOCSIS such
that TCP behavior is not adversely impacted by downstream and upstream rate limiting
or shaping; MAC scheduler supports traffic shaping of upstream traffic to ensure a that
single CM or STB does not consume all the channel bandwidth and allow the CMTS
administrator to configure different maximum data rates for different subscribers; traffic
shaping feature delays the scheduling of upstream packets, which allows the TCP/IP
stack to pace application traffic appropriately and approach throughput commensurate
with the subscriber’s defined QoS levels. The downstream packets rate shaping is done
by the DOCSIS driver in the Cisco IOS software.
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