Installation guide

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Release Notes for Cisco uBR7200 Series for Cisco IOS Release 12.1 T
78-10643-04 Rev. B0
Caveats
• CSCdr52543
The upstream port of a line card might be poorly initialized and not receive upstream bursts from
the cable modems. In that case, the modems are not able to complete the initial ranging and
continue to power-cycle infinitely.
This situation only occurs if the upstream port has non default physical-layer configuration
parameters stored in the startup configuration.
Workaround: Configure the following sequence of cable interface configuration commands so
that the upstream port can start receiving data while allowing non default physical-layer
configuration parameters:
cable upstream {port} shutdown
no cable upstream {port} shutdown
Alternative workaround: Use default physical-layer configuration parameters for the upstream port.
This is resolved in Cisco IOS Release 12.1(3)T.
Open Caveats for Release 12.1(2)T
There are no open caveats specific to the Cisco uBR7200 series router that require documentation in the
Cisco IOS Release 12.1(2)T release notes. For a list of open caveats for Release 12.1 T, refer to Caveats
for Cisco IOS Release 12.1 T.
Closed and Resolved Caveats for Release 12.1(2)T
All the caveats listed in this section are closed or resolved in Cisco IOS Release 12.1(2)T.
• CSCdm62122 and CSCdm90388
When an MC16C or MC16S Cable Modem Card is configured for a mixed burst profile (station
maintenance packets are using QPSK modulation and data packets are using 16-QAM modulation),
the MC16S does not hop to a new frequency band when noise interferes with data packets but only
at much higher noise levels when station maintenance packets are dropped. Workaround: Use
16-QAM modulation for all modes (request, initial, station, and data).
This is resolved in Cisco IOS Release 12.1(2)T.
• CSCdp66700
The following new object is now supported to meet DOCSIS OSSI compliance:
“ifCounterDiscontinuityTime”. This will cause a discontinuity on CMTS if you reset interface
counters using CLI commands clear counters or clear counters cable 5/0.
This is resolved in Cisco IOS Release 12.1(2)T.
• CSCdp73335
Modem calls over BRI do not work correctly.
This is resolved in Cisco IOS Release 12.1(2)T.
• CSCdr05920
Prior to this fix, CMs will fail to complete initial ranging when minislot size is set to 128 ticks and
channel width is set to 200000 Hz.