Cisco Headend System Release 2.5 User Guide

1-6 

DHCT Status Reporting Utility 

78-738186-01 Rev B 

This section summarizes some actions that system operators can take to reduce the 

non-responding condition on their network. 

Often, an examination of your basic network configuration can eliminate some 

conditions that cause DHCTs to become non-responders. Consider these points as 

you examine your network: 
• 

Review your existing network topology. Verify that you have separately 

partitioned each hub. You do not want noise or interference on one hub to affect 

another hub. 

• 

Review the concentration of DHCTs assigned to your system’s QPSK modulators. 

Verify that DHCTs are assigned as evenly as possible to your system’s modulators. 

Be certain that you never have more than 16,000 DHCTs assigned to any one 

modulator. 

• 

Verify the integrity of all network elements. Examine your routers and switches 

for proper throughput. Examine your power supplies, amplifiers, nodes, and taps, 

elements that are frequently overlooked during an examination of a network. 

• 

Examine and correct any laser calibration issues present on your network. A laser 

that is incorrectly calibrated may produce a distorted signal. 

DHCTs lose the contents of their volatile memory when they reboot. After they 

reboot, DHCTs sign back on to the network and their network configuration data is 

then reloaded. Too many sign-on attempts by DHCTs contribute to network 

congestion and could cause DHCTs to become non-responders. 
The signonCount utility can help the system operator monitor the following DHCT 

network sign-on activities: 
• 

DAVIC connections and UN-Config requests on a minute-by-minute basis 

• 

Excessive DHCT sign-on requests 

• 

QPSK modulator reboots 

• 

DHCTs signing on with an incorrect type, revision, or OUI 

• 

Successful sign-on statistics 

Note:  Refer to Chapter 2 of this guide for instructions on running and interpreting 

the signonCount Utility.