Zyxel IES-5112 [211/1156] Configured versus actual rate

Zyxel IES-5106 [211/1156] Configured versus actual rate
Chapter 10 Subscriber Port Setup Screens
Management Switch Card User’s Guide
211
10.2.5 Configured Versus Actual Rate
You configure the maximum rate of an individual VDSL port by modifying its profile (see the VDSL
Profile Setup screen) or assigning the port to a different profile (see the Port Setup screen).
However, the actual rate varies depending on factors such as transmission range and interference.
10.2.6 Impulse Noise Protection (INP)
Short impulses from external sources may cause bursts of errors which could impact the
multimedia (ex. voice, video, or picture) quality. VDSL2 supports impulse noise protection (INP)
which provides the ability to correct errors regardless of the number of errors in an errored DMT
(Discrete Multi-Tone) symbol.
10.2.7 UPBO
In a network with varying telephone wiring lengths, the PSD on each line is different. This causes
crosstalk between the lines. Enable UPBO (Upstream Power Back Off) to allow the device to adjust
the transmit PSD of all lines based on a reference line length. This mitigates the upstream crosstalk
on shorter loops to longer loops. It allows the switch to provide better service in a network
environment with telephone wiring of varying lengths.
An example is shown below. Line 1 and Line 2 are in the same cable binder. Crosstalk occurs when
the signal flows and is near to CPE (A)s location. Besides, higher Line 1 PSD causes higher
interference to the Line 2. CO receives signal with higher attenuation. With UPBO enabled on the
CPE (A), it decreases the PSD level and reduces the crosstalk impact on long loops.
Figure 129 UPBO Resolves Upstream Far-End Crosstalk
10.2.8 DPBO
VDSL signals may interfere with other services (such as ISDN, ADSL or ADSL2 provided by other
devices) on the same bundle of lines due to downstream far-end crosstalk. DPBO (Downstream
Power Back Off) can reduce performance degradation by changing the PSD level on the VDSL
switch(es) at street cabinet level.
Central
CPE (A)
CPE (B)
Site (CO)
Line1 (150m)
Line2 (600m)
No-UPBO
UPBO

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