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9.1 VDSL Overview
Very High Bit Rate DSL is an asymmetric version of DSL that is used as the final drop from a fiber
optic junction point to nearby customers. VDSL lets an apartment or office complex obtain high-
bandwidth services using existing copper wires without having to replace the infrastructure with
optical fiber. Like ADSL, VDSL can share the line with the telephone.
Your Switch supports VDSL2 (Very High Speed Digital Subscriber Line 2) which is the second
generation of the VDSL standard (which is currently denoted VDSL1). VDSL2 allows a frequency
band of up to 30MHz and transmission rates of up to 100 Mbps in each direction. VDSL2 is defined
in G.993.2.
VDSL Parameters
The following sections describe the VDSL parameters you configure in the following screens:
•VDSL Template Setup
•VDSL Alarm Template Setup
PSD
PSD (Power Spectral Density) defines the distribution of a VDSL line's power in the frequency
domain. A PSD mask is a template that specifies the maximum allowable PSD for a line.
Frequency Band Plan
Each VDSL mode operates in a different frequency band allocation, resulting in different upstream
and downstream speeds. Your VES switch automatically changes the band plan based on the loop
condition and loop length.
Band plans include an optional band (between 25 kHz and 276 kHz) controlled by "limit PSD mask".
The optional band is used for upstream transmission which is to be negotiated during line initiation.
A sample of limit PSD mask and associated frequency band is shown next.
Table 26 Limit PSD Mask
TRANSMISSION MODE
G.993.2 Annex A
G.993.2 Annex A
G.993.2 Annex A
G.993.2 Annex A
VES1724-56 User's Guide
C
(see
Section 9.3 on page
(see
Section 9.4 on page
CLASS MASK US0 MASK
998
EU-32
998
EU-36
998
EU-40
998
....
H A PT ER
VDSL Setup
104).
121).
LIMIT MASK
FREQUENCY BAND
D-32
= 25 ~ 138 kHz
D-48
= 25 ~ 155.25 kHz
D-48
= 25 ~ 172.5 kHz
...
= ...
9
97
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