Specifications

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Cisco Cable Modem Termination System Feature Guide
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Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System
Configuration Tasks
Configuring Proactive Channel Management
To optimize the spectrum management behavior for your plant’s specific characteristics, you can
customize the following parameters:
• Optionally specify the priority of the corrective actions to be taken when noise on an upstream
exceeds the threshold for its modulation profile.
• Optionally configure the CNR threshold and FEC values for the upstream and its two modulation
profiles.
• Optionally specify the allowable range of channel widths that can be used if frequency hopping or
modulation switching cannot avoid the upstream problems.
Command Purpose
Step 1
Router(config)# configure terminal
Enters configuration mode.
Step 2
Router(config)# interface cable slot/port
Enters interface configuration mode for the cable interface
where:
slot = slot number in chassis (slot numbers begin with a 0)
port = port number on cable modem slot (port numbers begin
with a 0)
Step 3
Router(config-if)# cable upstream n
hop-priority frequency modulation
channel-width
or
cable upstream n hop-priority modulation
frequency channel-width
or
cable upstream n hop-priority frequency
channel-width modulation
(Optional) Configures the priority of corrective actions to be
taken when ingress noise occurs on a downstream.
n = upstream number on cable modem slot (on the
Cisco uBR-MC16S, upstream port numbers are 0 to 5).
frequency, modulation, channel-width = Specifies the order
of corrective actions to be taken. The default order is
frequency, modulation, and channel-width. The
channel-width option must come after the frequency option,
either immediately or after the modulation option, as shown in
the above examples.
Step 4
Router(config-if)# cable upstream n
channel-width first-choice-width
[ last-choice-width ]
(Optional) Specifies the range of channel widths to scan when
ingress noise conditions require changing the channel width.
first-choice-width = Specifies upstream channel width in hertz
(Hz). Valid values are: 200,000 (160,000 symbols/sec), 400,000
(320,000 symbols/sec), 800,000 (640,000 symbols/sec),
1600,000 (1,280,000 symbols/sec), and 3,200,000 (2,560,000
symbols/sec).
last-choice-width = (Optional) The upstream channel width in
hertz. The valid values are the same as those for the
first-choice-width parameter. Use this parameter with the
Cisco uBR-MC16S cable interface line card to enable symbol
rate management algorithms. The symbol rate automatically
steps up from the first-choice-width value to the highest
value until a stable channel is established.