6100-Gfast Multifunction Network Analyzer Operation Manual
188
© 2020 Radiodetection Ltd
Performance Counters - Local/Remote
o
G.INP RTX_TX
is the number of
frames retransmitted by the transmitter.
The
Local
number is what is
retransmitted from the CPE to the
DSLAM. The
Remote
value is what is
retransmitted from the DSLAM to the
CPE.
Note:
The RTX_TX number may contain retransmits
not requested by the receiver (that is, the
retransmission request channel got corrupted
and a retransmission was sent automatically)
resulting in an incremental value even though the
same frame ID was retransmitted multiple times.
o
G.INP RTX_C
is a counter that is
increased each time a frame is
detected in error and has successfully
been
corrected
by a retransmission.
The
Local
number is received by the
CPE, the
Remote
value received by
the DSLAM.
o
G.INP RTX_UC
is a counter that is
increased each time a frame is
detected in error and has
not been
corrected
by one or more
retransmissions within the maximum
delay period. The
Local
number is
received by the CPE, the
Remote
value received by the DSLAM.
Note:
The RTX_TX may not equal RTX_C + RTX_UC
because of the infrequent reboot nature of the
DSLAM and the double-counting that the
RTX_TX counter might do.
Vector Err. Samples Sent
is the total number
of error samples the CPE has sent to the
DSLAM during the test. A high number can
indicate a network that is unstable (CPEs
joining / leaving, causing the VCE to
continuously recalculate the best solution).
Vector Err. Samples Dis.
is the total number
of error samples discarded. A high number can
indicate a network that is unstable (CPEs
joining / leaving, causing the VCE to
continuously recalculate the best solution).
17.6 Band Information
The
Band Information
tab allows you to view a list of
individual upstream or downstream band parameter
details. The test results display
Bits per Tone
in
graphical format. For G.fast, the
Frequency
is shown
in MHz.
When the
Test Interface
for
Auto
or
Manual Test
is set to ADSL2+ or VDSL2 bonding mode, there
will be 2 pages of results, one for each DSL line-
pair.
To access the second-pair results, press the
Pair 1
/
2
function key at the bottom-right of the
screen.
The tab
contains
Upstream
and
Downstream
parameters. Press to toggle
between bands.
o
ADSL lists only 1 of each.
o
VDSL lists US0 to US3, and DS1 to
DS4 possible bands, depending on the
band plan.
Parameter - Downstream/Upstream
o
SNR Margin
is the measured current
signal-to-noise ratio margin across all
active sub-carriers, as an amount of
increased noise relative to the
measured noise power that the system
would be able to tolerate. Only a value
of 6 or above is able to support a bit
error rate of 10
-7
.
o
Loop Atten
(VDSL) is the current
quality of the line and is measured only
once during testing.
