Installation guide

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Cisco uBR7100 Series Universal Broadband Router Software Configuration Guide
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Chapter 5 Troubleshooting the System
Troubleshooting Cable Flap Lists
Clearing Cable Flap List
To remove a single cable modem from the flap list or to remove all cable modems from the flap list, use
one of the following commands in global configuration mode.
Customizing Other Flap List Values and Related Commands
The following displays flap list with different sorting options:
show cable modem flap-list [cable n | sort-flap | sort-time | sort-interface]
The following sets the threshold value for link establishment:
[no] cable flap-list insertion-time sec
Note A modem is tagged as flapping if the insertion time exceeds this value. Its value can be set from 60 to
86400 seconds with a default of 180 seconds.
The following sets the number of consecutive missed station maintenance (RNG-RSP) messages that
must be missed for a flap event to occur. Value ranges from 1 to 2 with a default of 6 seconds. The hits
and miss counters are not affected:
[no] cable flap-list miss-threshold miss-threshold
The following clears the counters for a cable modem (or all cable modems) in the station maintenance
list:
clear cable modem {mac-addr | ip-addr | all} counters
The following displays the QoS, modem status, In and Out octets, IP and MAC addresses per SID:
show int cable slot/port sid
The following drops the modem’s RF link by removing a modem from the keep-alive polling list. This
forces the modem to reset:
clear cable-modem {mac-addr | ip-addr | all} reset
The following uses a MAC layer ping to determine if the cable modem is online. It uses smaller data
units on the wire than a standard IP ping, resulting in lower overhead. This command works even if the
IP layer in the modem is down or has not completed registration:
ping DOCSIS cable-modem mac-addr | IP address
The following displays the timing offset, receive power, and QoS values by cable interface, SID, and
MAC address:
show cable modem [ip-address | MAC-address]
Command Purpose
CMTS01(config)# clear cable flap-list
mac-addr
CMTS01(config)# clear cable flap-list all
Clears the entries in the cable flap list for the cable
modem with this MAC address.
Clears the entries for all cable modems in the flap
list.