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 Upstream Modulation
To create and configure the module profile for the Cisco uBR-LCP2-MC16S cable interface line card on
the Cisco uBR10012 router, and then to assign it to the appropriate upstreams, use the following
procedure:
Command Purpose
Step 1
Router(config)# configure terminal
Enters configuration mode.
Step 2
Router(config)# cable modulation-profile
profile {qpsk | mix | qam-16}
Creates a modulation profile using the predefined profile for
QPSK modulation.
profile = Modulation profile number (1–8).
qpsk = Creates a default QPSK modulation profile, where all
bursts are sent using QPSK.
mix = Creates a default QPSK/16-QAM mix modulation profile
where short and long grant bursts are sent using 16-QAM, while
request, initial ranging, and station maintenance bursts are sent
using QPSK.
qam-16 = Creates a default 16-QAM modulation profile, where
all bursts are sent using 16-QAM.
Note The cable modulation-profile command also supports setting the individual parameters for the initial, long
grant, request/data, request, short grant, and station ranging bursts. These parameters, however, should not
be modified unless you are thoroughly familiar with how changing each parameter affects the DOCSIS
MAC layer.
Step 3
Router(config)# interface cable slot/port
Enters interface configuration mode for the cable interface
where:
slot = slot number in chassis for the Cisco uBR-LCP2-MC16S
line card (slot numbers begin with a 0)
port = port number on cable modem slot (port numbers begin
with a 0)
Step 4
Router(config-int)# cable upstream n
modulation-profile profile
[ secondary-profile-number ]
Adds the modulation profile to an upstream on the cable
interface.
n = upstream number on cable modem slot (on the
Cisco uBR-MC16S, upstream port numbers are 0–5)
profile = the modulation profile to be assigned to the upstream.
(Specify the profile number created with the cable
modulation-profile command in Step 2 above.)
secondary-profile-number = (Optional) Secondary modulation
profile for the upstream port, which is used when noise on the
upstream increases to the point that the primary modulation
profile can no longer be used.
Note The secondary modulation profile should specify a
more robust performance profile (in terms of coping
with noise) than the primary profile.
Step 5
Router(config-int)# cable upstream n
modulation-profile profile
Repeat this command as needed to configure the six upstreams
on the Cisco uBR-LCP2-MC16S line card.
Step 6
Router(config-int)# exit
Exits back to the configuration mode.