Cisco Systems uBR7200 Activating Upstream Admission Control, Verifying Upstream Admission Control

Configuring Headend Broadband Access Router Features

Configuring the Upstream Cable Interface

Verifying the Upstream Input Power Level

To verify the current value of the upstream input power level, 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 0.800 MHz, QPSK Symbol Rate 0.640 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

Troubleshooting Tips

To troubleshoot the configuration, perform the following tasks:

•Verify that the upstream amplitude of an optimal RF carrier injected at the fiber node reference input point reaches the MC16C input point at a consistent level (node-to-node and port-to-port), and that this absolute level as installed matches both the design and software settings on the Cisco uBR7200 series.

•Software adjustments of 1 to 3 dB can be used to adjust for minor variations in measurement or setup and port-to-port calibration differences. These adjustments can significantly improve cable modem performance, especially in marginal situations. Larger adjustments should be made in conjunction with spectrum analyzer-support in the headend.

Activating Upstream Admission Control

The admission control is set as a percentage of the specified upstream channel capacity. The acceptable range is from 10 to 1000 percent. Admission control is disabled by default.

To set the upstream admission control, use the following command in cable interface configuration mode:

Command	Purpose
CMTS01(config-if)#cable upstream usport admission-control	Sets the admission control as a percentage of the
percentage	upstream channel capacity. Valid range is from 10 to
	1000 percent.

Verifying Upstream Admission Control

To verify whether or not upstream admission control has been configured and activated, enter the show running-configcommand in privileged EXEC mode and look for the cable interface configuration information. If upstream admission control has been configured and enabled, an admission control entry will be displayed in the show running-configoutput, indicating the user-defined percentage of upstream channel capacity allowable. If upstream admission control is disabled, no admission control entry will be displayed in the output.

CMTS01# show running-config

Cisco IOS Multiservice Applications Configuration Guide

MC-548