ZyXEL Communications VES1724-56 User Manual page 107

Table 34 VDSL Line Profile Setup (continued)
LABEL
Max SNR Margin
Target SNR Margin
Min SNR Margin
Bitswap
Max Rx Power
Max Tx Power
Min Overhead Rate
Limit PSD Mask
Transmission
Mode
ADSL/VDSL
Protocol
Class Mask
Limit Mask
US0 Mask
UPBO
UPBOKL
UpStream Band
1 ~ 4
PM Mode
VES1724-56 User's Guide
DESCRIPTION
Enter the maximum SNR (Signal to Noise Ratio) margin allowed on the line. When the
actual SNR margin is going to reach this specified value, this mechanism forces
connected CPE device(s) to lower its transmission power level and maintains the actual
SNR margin equal to or less than this value. Select noLimit to turn this mechanism off.
Enter the target upstream and downstream SNR (Signal to Noise Ratio) margin.
Enter the minimum upstream and downstream SNR margin accepted on the line to
which this profile applies.
Select On to allow on-line bits and power (for example, margin) reallocation among the
allowed sub-carriers without service interruption or errors. This helps to keep
transmission data rate on a high SNR VDSL line.
Select Off to disable it.
Enter the maximum receiving power in dBm for UpStream traffic. Select noLimit if
there is no limit.
Enter the maximum transmission power in dBm the Switch uses for DownStream
traffic. Enter the maximum transmission power the CPE uses for UpStream traffic.
Enter the minimum transmission rate (4~248 kbps) reserved for a line's overhead
channel. Both the Switch and CPE device use the overhead channel of a line to get VDSL
transmission statistics with each other.
To reduce the impact of interference and attenuation, ITU-T G.993.2 specifies a limit
PSD mask that limits the VDSL2 transmitters PSD at both downstream and upstream.
Select an appropriate transmission standard (according to your territory) you want to
apply for this profile. At the time of writing, the Switch supports G.993.2 Annex A
mode for countries which follow the North American VDSL2 standard.
Select the ADSL (G.992.1, G.992.2, G.992.3, G.992.5, ANSI, and ETSI) and VDSL
(G.993.2) protocols this profile uses.
A class mask is a combination of several PSD masks according to the PSD mask types.
The available options vary depending on your selection in the Transmission Mode
field. At the time of writing, 998 is the only option in this field when you select G.993.2
Annex A in the Transmission Mode field.
Select a downstream limit mask you want the Switch to use.
Select a limit mask you want the Switch to use for the upstream band 0.
UPBO (Upstream Power Back-Off) mitigates far-end crosstalk (FEXT) caused by
upstream transmission on shorter loops to longer loops. See
Select Auto to enable UPBO and CPE devices' PSD adjustment based on the negotiation
result with the Switch.
Select Override to force CPE devices to use the electrical length defined by the Switch
(in the UPBOKL field below) to compute their UPBO. See
on page 100.
Select Disable to turn UPBO off.
Enter variable A and B values of upstream band 1 and band 2 for UPBO PSD mask
calculation.
Specify the electrical length (0~128 dB) of the cable between the Switch and CPE
devices. See UPBO/DPBO Electrical Length
Specify 40~80.95 (dBm/Hz) for parameter A which defines the original band shape.
Specify 0~40.95 for parameter B which defines the power back-off degree.
Select allowTransitionsToIdle to have the Switch or CPE devices autonomously enter
an idle state for power management (PM).
Chapter 9 VDSL Setup
UPBO on
UPBO/DPBO Electrical Length
on page 100.
page 98.
107