Westermo RedFox Series - Manual (Page 207)

Westermo OS Management Guide
Version 4.17.0-0
The operator can either specify a fixed data rate to be used, or let the CO
and CPE discover the achievable data rate automatically.
Using Auto mode will optimise the data rate for the current SNR conditions.
❼ Noise margin: The noise margin is the difference between the required SNR
for a certain bit rate, and the actual SNR.
When the SHDSL connection data rate is set to auto-negotiation mode, the
operator can configure an administrative noise margin (also referred to as
target noise margin or target SNR margin). A large administrative noise
margin gives robustness against SNR fluctuations. But as the required SNR
increases with data rate, specifying a a large administrative noise margin
may imply that a low data rate is negotiated.
Thus, when configuring the administrative noise margin the operator can op-
timise the connection for reliability (noise margin 10dB), high speed (noise
margin 3dB) or as a tradeoff thereof (normal mode, i.e., noise margin 6dB).
To monitor the quality of the connection, WeOS enables the operator to read
the current noise margin.
❼ G.HS Threshold: The G.HS threshold setting is only needed if the units are
located in a noisy environment with SHDSL line cables of good quality, and
where a connection can not even be established at SHDSL rate 192kbit/s.
The setting configures a higher threshold of the G.HS idle parameter in or-
der to detect idle. The SHDSL line length capability will be affected, since
the G.HS idle threshold and the G.HS signals meet earlier when the G.HS
Threshold is raised.
When enabling GHS threshold, possible settings include ’low(750)’, ’medium
(1500)’, ’high(3000)’ and a custom configured value.
Corresponding values to the fixed value settings are [low-750; medium-
1500; high-3000]. The custom configured value could be set in the range
[0-32767] in steps of 1.
❼ PAF - PME Aggregation Function: PAF functionality is used to aggregate the 2
SHDSL ports on DDW-142 (and DDW-142-485) to achieve higher bandwidth.
The 2 "bonded" ports can reach rates from 64 kbit/s to 30,6 Mbit/s.
❼ Low Jitter function: Low Jitter is a SHDSL port specific function that can be
used in applications where high accuracy of the Ethernet packet jitter is
needed. If enabled the jitter of the latency over the SHDSL link will be mini-
mized.
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