Chapter 11 - DOCSIS Analyzer
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11.4.3
Downstream and upstream analysis using DOCSIS-3.0 analyzer
The DOCSIS 3.0 analyzer can be used to draw a conclusion about whether the communication
between a modem and the CMTS at the site of the measurement works in principle. Furthermore,
the analyzer can be used as an instrument for levelling return path amplifiers.
The boot time of the DOCSIS analyzer is around 18 seconds. When the DOCSIS analyzer is
activated, a home screen initially appears in the graphic display on which the boot progress is
displayed in percent. The actual graphics interface of the analyzer is then displayed.
The instrument uses the DOCSIS 3.0 analyzer to provide a graphical overview of all bundled
downstream and upstream channels with their level ratios and channel bandwidths.
Figure 11-5 DOCSIS typical measurement display
The following measurement parameters are available on the graphic display when there is a
functioning DOCSIS connection:
•
DOCSIS standard (e.g..: DOCSIS1.1, DOCSIS2.0)
•
Display of the encryption system used (e.g. BPI+)
•
Stack State of synchronization to CMTS
•
Number of bundled DS channels
•
Number of bundled US channels
The uppermost line provides information about the DOCSIS system currently being measured.
Here you can see if the system is a pure 1.1, 2.0 or 3.0 system, or if mixed-mode using different
systems has been activated to enable modems to communicate with the head end according to
different specifications.
The “Stack-Status” parameter provides information about how far the analyzer can synchronize or
logon to the CMTS. At the beginning of a measurement, the modem searches for information about
how it should transmit data upstream. If this data is found, the stack-status changes to
“UsParameters Acquired”. Once ranging has been completed successfully, the status changes to
“Ranging Complete”. The status is “DHCP Complete” if the modem is able to obtain an IP address
from the DHCP. The status changes to “Operational” if it has been possible to completely log on to
the head end.
The graphical overview provides an overview of all existing downstream and upstream ratios. For
the downstream, a distinction is made between primary and secondary channels.
