user manual

Configuring Headend Broadband Access Router Features
Configuring the Upstream Cable Interface
MC-545
Cisco IOS Multiservice Applications Configuration Guide
To set a fixed upstream frequency, use the following commands in cable interface configuration mode:
To configure the default upstream frequency (which is no fixed frequency), enter the cable upstream
usport frequency command without specifying a center frequency.
Verifying the Upstream Frequency
To verify the current value of the upstream frequency, enter the show controllers cable command for
the upstream port you have just configured:
CMTS01# show controllers cable 6/0 u0
Cable6/0 Upstream 0 is up
Frequency 24.016 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 Msps
Spectrum Group is overridden
SNR 33.2560 dB
Nominal Input Power Level 0 dBmV, Tx Timing Offset 2288
Ranging Backoff automatic (Start 0, End 3)
Ranging Insertion Interval automatic (60 ms)
Tx Backoff Start 0, Tx Backoff End 4
Modulation Profile Group 1
Note The upstream frequency displayed in the show controllers cable command output might
not match the frequency that you entered when you set the upstream frequency. The
Cisco uBR7200 series might select an upstream frequency close to the frequency you
entered that offers better performance. The minimum upstream frequency step size on the
MC16C is 32 kHz. The Cisco uBR7200 series selects the closest frequency available.
Troubleshooting Tips
To troubleshoot the configuration, perform the following tasks:
• Make sure the cable connections are not loose or disconnected.
• Make sure the Cisco cable modem card is firmly seated in its chassis slot and the captive installation
screws are tight.
• Make sure you entered the correct slot and port numbers when you typed the command.
• Make sure you entered the correct upstream port number:
– On the MC16C cable modem card, this can be u0 to u5.
– On the MC14C cable modem cards, this can be u0 to u3.
– On the MC12C cable modem cards, this can be u0 or u1.
– On the MC11C cable modem cards, this can be u0 only.
• Make sure you selected a valid frequency for your headend.
Command Purpose
Step 1
CMTS01(config-if)# cable upstream usport frequency
up-freq-hz
Sets a fixed upstream frequency when you enter the
fixed center frequency for your upstream RF carrier
in Hz. Valid range for usport is from 0 to 5 if you are
using the MC16 cable modem card.
Step 2
CMTS01(config-if)# no cable upstream usport +
Places the upstream port in the “admin up” state.