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Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide
OL-2239-03
Chapter3 Configuring Cable Modem Interface Features
Configuring the Upstream Cable Modem Interface
Activating Upstream Admission Control
Upstream admission control tallies up the total amount of guaranteed minimum upstream throughput
reserved by CMs on an upstream interface. Once the total exceeds an allowable level, no more CMs
requiring a guaranteed minimum upstream rate are allowed online on that upstream port.
“Activating Upstream Power
Adjustment” section on page3-16
Provides instructions to enable upstream power adjustment.
This feature sets the minimum power adjustment in dB that will
allow continued ranging status.
“Activating the Upstream
Scrambler” section on page3-17
Provides instructions to activate the upstream scrambler on the
upstream RF carrier, which enables CMs on the HFC network
to use built-in scrambler circuitry for upstream data
transmissions.
“Activating Upstream Timing
Adjustment” section on page3-17
Provides instructions to activate upstream timing adjustment on
the specified interface. This feature sets the minimum timing
adjustment that allows continued ranging status.
“Configuring Upstream Rate
Limiting and Traffic Shaping”
section on page3-18
Provides instructions to configure upstream rate limiting and
traffic shaping, which delays the scheduling of the upstream
packet. In turn, this causes the packet to be buffered on the
cable CPE device, instead of being dropped.
“Setting Upstream Backoff Values”
section on page3-19
Provides DOCSIS-compliant instructions that define
contention resolution for CMs wanting to transmit data or
requests on the upstream channel. Contention resolution is
achieved with a truncated binary exponential backoff value.
“Setting the Upstream Channel
Width” section on page3-21
Provides instructions to enter the upstream channel width in
hertz (Hz). Also describes NTSC spectrum parameters and
spectrum management processes.
“Setting the Upstream Frequency”
section on page3-22
Provides instructions to set upstream channel frequency for the
RF output that complies with the expected input frequency of
the Cisco cable interface line card.
“Setting the Upstream Input Power
Level” section on page3-24
Provides instructions to set the upstream input power level in
decibels per millivolt (dBmV), and provides additional
information about the Cisco uBR7200 series controls the output
power levels of CMs
“Setting Upstream Traffic Shaping”
section on page3-26
Provides instructions to activate traffic shaping on the
upstream. Upstream traffic shaping, available on the DOCSIS
upstream channel, delays the scheduling of the upstream
packet, which in turn causes the packet to be buffered on the
cable customer premises equipment (CPE) device, instead of
being dropped.
“Specifying Upstream Minislot
Size” section on page3-25
Provides instructions to specify the minislot size (in ticks) for
specific upstream cable interfaces. The minislot size and the
channel width are related to certain degree but not tightly
coupled.
Task Description