ZyXEL Communications MSC1000G Series, Руководство пользователя

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Chapter 11 Profile Screens
Management Switch Card User’s Guide
342
Bitswap 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 rates on a high SNR VDSL2 line.
Select Off to disable it.
Max Rx Power Enter the maximum receiving power in dBm for UpStream traffic. Select noLimit if
there is no limit.
Max Tx Power Enter the maximum transmission power in dBm the system uses for DownStream
traffic. Enter the maximum transmission power the CPE uses for UpStream traffic.
Min Overhead Rate Enter the minimum transmission rate (4~248 kbps) reserved for a line’s overhead
channel. Both the system and CPE device use the overhead channel of a line to get
transmission statistics with each other.
Limit PSD Mask 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.
Transmission
Mode
This is the transmission standard for this profile. At the time of writing G.993.2 Annex
A mode is supported (for countries which follow the North American VDSL2 standard).
Class Mask A class mask is a combination of several PSD masks according to the PSD mask types.
The available options vary depending on the selection in the
Transmission Mode field.
At the time of writing, 998 is supported.
Limit Mask Select a downstream limit mask you want the system to use.
US0 Mask Select a limit mask you want the system to use for the upstream band 0.
UPBO UPBO (Upstream Power Back-Off) mitigates far-end crosstalk (FEXT) caused by
upstream transmission on shorter loops to longer loops. See
Section 9.2.7 on page 207 .
Select Auto to enable UPBO and CPE devices’ PSD adjustment based on the negotiation
result with the MSC.
Select Override to force CPE devices to use the electrical length defined by the MSC (in
the UPBOKL field below) to compute their UPBO. See Section 9.2.9 on page 208 .
Select Disable to turn UPBO off.
Enter variable A and B values of upstream band 1 and band 2 for UPBO PSD mask
calculation.
UPBOKL Specify the electrical length (0~128 dB) of the cable between the system and CPE
devices. See
Section 9.2.9 on page 208 .
UpStream Band
1 ~ 4
Specify 4000~8095 (0.01dBm/Hz) for parameter A which defines the original band
shape. Specify 0~4095 (0.01dBm/Hz) for parameter B which defines the power back-
off degree.
US0 Specify whether you want the system to automatically activate the upstream band
(
enable ) or not ( disable ) when necessary. Select Allow to have CPE and the system
use the upstream band 0 for upstream traffic over long distances. If you select disable ,
the CPE may not able to transmit data over long distances.
Table 160
Profile > VDSL2 > LineProfile (continued)
LABEL DESCRIPTION