Cisco DNCS System Release 2.7 3.7 4.2 설치 가이드
Chapter 1 Installation Process Overview
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The CVT Method
The CVT is a table that contains information about download channel and
information to map application platform software versions to specific devices.
The DNCS sends the CVT to all QAMs in the network. The QAMs then send the
The DNCS sends the CVT to all QAMs in the network. The QAMs then send the
CVT to the devices once every second. The DNCS also sends CVT through the
DAVIC (QPSK) or DOCSIS out-of-band forward data channel once every 10
minutes.
The CVT method is the only download method available for newer DHCTs and for
The CVT method is the only download method available for newer DHCTs and for
all CableCARD modules.
In systems using harmonically related carrier (HRC) frequencies, certain DHCTs can
In systems using harmonically related carrier (HRC) frequencies, certain DHCTs can
only be staged using the OSM method. See What to Consider When Choosing a
Download Method (on page 7) for more information.
The OSM Method
In the OSM staging method, the DHCT receives System Information (SI) and a type-
specific user-to-network configuration (Unconfig) message, which includes a table of
contents (TOC) file, from the DNCS.
The DHCT reads the contents of the TOC file and compares the checksums of the
The DHCT reads the contents of the TOC file and compares the checksums of the
currently installed image files against the file information in the TOC file. If the
checksum of either file does not match, the DHCT installs the new software as
needed.
In systems using harmonically related carrier (HRC) frequencies, certain DHCTs can
In systems using harmonically related carrier (HRC) frequencies, certain DHCTs can
only be staged using the OSM method. See What to Consider When Choosing a
Download Method (on page 7) for more information.
Determining DHCT Models Supported on Your System
Cisco provides the listCVT and listOSM scripts that let you quickly determine which
DHCT models are supported on your network and which download method the
DHCT currently uses.
Distributed BFS
If the BFS data is carried on more than one QAM, then you must configure your
DNCS and the network to carry the OSM data carousel (or the bootloader in newer
system releases) out to the various BFS QAMs. Refer to Distributed Broadcast File
System Configuration Guide for System Releases 2.2 and 3.2 for further information.
Note: Even if you use the CVT method, the software files are sent to the DHCT on
Note: Even if you use the CVT method, the software files are sent to the DHCT on
the OSM data carousel or bootloader.