Juniper G10 CMTS, Hardware Manual

Page: 168 / 210

Ideal HFC Plant Configuration Issues
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JUNOSg 3.0 G10 CMTS Hardware Guide 152
!
The cable modem received a configuration file, but the contents of the file are not valid.
Ensure the configuration settings are valid and are consistent with the DOCSIS
specifications.
!
The cable modem timed out waiting for the time of day (TOD) server to respond. Newer
cable modems continue the registration process while continuing to retry the TOD
request. However, some older cable modems do not attempt to register if they time out
while waiting for a TOD response. The TOD timeout might occur if the TOD server IP
address provided in the DHCP response was incorrect.
A high IM value in the flap list can be an indication of TFTP, configuration file, or registration
issues.
Cable Modem Throughput is Slow
If the throughput of a cable modem seems slow, the cause might be one or more of the
following:
!
The DOCSIS 1.0 Class of Service Configuration Setting (for DOCSIS 1.0) or the
Upstream Service Flow Configuration Setting and the Downstream Service Flow
Configuration Setting fields (DOCSIS 1.1) of the configuration file are limiting the
maximum upstream and downstream bandwidth of the cable modem. If necessary,
increase the parameters within these fields in the configuration file to increase the cable
modem’s throughput.
To determine the maximum bandwidth settings for a cable modem, issue the show
cable modem command to determine the QoS profile for a cable modem:
user@host> show cable modem
Interface Us Prim Online Timing Rec QoS BPI IP-Address MAC-Address
Reg Modul
Sid State Offset Power
ca-0/2/0 0 36 init(rc) 585 0.0 1 Off 10.27.1.101
00:40:36:09:44:EB 1.0 TDMA
In this example, the cable modem uses QoS profile 1. Then issue the show cable
qos-profile command to display the characteristics of QoS profile 1:
user@host> show cable qos-profile 1
Service Prio Max Guarantee Max Max tx Create Baseline
class upstream upstream downstream burst by privacy
bandwidth bandwidth bandwidth enable
1 0 1000000 0 10000000 0 cmts no
The cable modem’s maximum upstream bandwidth is 1 Mbps and its maximum
downstream bandwidth is 10 Mbps.