Cisco SR2016T-NA Reference Manual page 330

cable upstream hop-priority
2.
3.
To use the Dynamic Upstream Modulation feature, you must first create two modulation profiles (using
the
modulation-profile
Examples The following example shows that when ingress noise on the upstream exceeds the threshold allowed for
the primary modulation profile, the Cisco uBR-MC16S line card should first switch to the secondary
modulation profile, then try frequency hopping, and if that fails to correct problem, to finally try
narrowing the channel width:
Router(config)# interface cable 3/0
Router(config-if)# cable upstream 0 hop-priority modulation frequency channel-width
Router(config-if)# exit
Router(config)#
Related Commands Command
cable modulation-profile
cable upstream channel-
width
cable upstream
modulation-profile
show cable hop
show cable modulation-
profile
Cisco Broadband Cable Command Reference Guide
2-318
If no clean frequency is available, the Cisco uBR-MC16S uses the Dynamic Upstream Modulation
feature to switch the upstream to the secondary modulation profile.
If the noise levels still exceed the CNR threshold value for the secondary modulation profile, and if
the upstream has been configured for a range of channel widths, the Cisco uBR-MC16S narrows the
channel width of the upstream by half. If the noise levels are still excessive, the channel width is
again cut in half, and this process continues until a clean upstream is found or the bandwidth is
reduced to the minimum channel width that has been configured using the
width command.
Allowable DOCSIS channel widths are 3.2 MHz, 1.6 MHz, 800 KHz, 400 KHz, and 200 KHz. If the
channel width drops to 200 KHz, but the noise still exceeds the SNR threshold, the CMs go offline.
The default specifies only a single channel width of 1.6 MHz. If this is not changed to
Note
specify a range of allowable channel widths (using the cable upstream channel-width
command), the Cisco uBR-MC16S does not attempt to change the channel width.
cable modulation-profile
command).
Description
Creates a cable modulation profile.
Configures an upstream for a range of allowable channel widths.
Configures an upstream for one modulation profile (static profile) or two
modulation profiles (Dynamic Upstream Modulation).
Displays the current hop period and threshold for an upstream, along with
other statistics.
Displays the cable modulation profiles that have been created.
command) and assign them to the upstream (using the
Chapter 2 Cisco CMTS Configuration Commands
cable upstream channel-
cable upstream
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