ZyXEL Communications MSC1000G Series, Руководство пользователя

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Chapter 12 Statistics Screens
Management Switch Card User’s Guide
439
Ds/Us
Attenuation(0.1dB
)
This field displays the downstream/upstream loss of power (in dB) for traveling along the
line.
Ds/Us Line
Attenuation(0.1dB
)
This field displays the upstream/downstream line attenuation the system detects
according to the line length, frequency and the line wire diameter.
Line attenuation increases with line length and frequency. Thicker wires reduce
attenuation.
Profile This field displays the VDSL2 profile this line uses. The possible values are none, 8a, 8b,
8c, 8d, 12a, 12b, 17a, and 30a.
Note: Only the VLC1424G supports the 30a VDSL2 profile.
Limitmask To reduce the impact of interference and attenuation, ITU-T 993.2 specifies a limit PSD
(Power Spectrum Density) mask that limits the VDSL2 transmitters’ PSD for both
downstream and upstream traffic.
This field displays a standard-defined limit PSD mask that the line is currently using.
Us0mask This field displays the PSD mask used for upstream band 0.
The possible masks are shown next. (See ITU-T G.993.2 Annex A for more information.)
eu32 , eu36 , eu40 , eu44 , eu48 , eu52 , eu56 , eu60 , eu64 , eu128
Electrical
Length(0.1dB) This field displays the final electrical length of the cable negotiated by the IES and the
connected CPE device.
Electric length (kl0) computed by the CO (in units of 0.1 dB). This is the attenuation at
1MHz.
Cyclic
Extension(1/32
samples) Cyclic extension is a method that adds redundant data into each DMT symbol. This helps
to reduce interference on a line.
This field displays the length of the redundant data used on the line.
Channel Info
This section displays current VDSL performance measured from downstream ( XTUC ) and upstream ( XTUR )
for the line.
Actual Rate(kbps) This field displays the current data rate.
Previous Actual
Rate(kbps) This field displays the data rate the line was running when the last connection was up.
Delay(ms) This field displays the downstream/upstream interleave delay (in milliseconds) on the
line.
Inp(0.1 symbols) This field displays the actual impulse noise protection in units of 0.1 DMT symbols.
Inp Report This field displays the method used to compute the actual INP above.
Formula the actual INP value was computed according to the INP_no_erasure formula
defined in the ITU-T G.993.2 standard.
estimated : The actual INP value was estimated by the VTU-R receiver.
Codeword
Size(bytes) This field displays the actual size of Reed-Solomon codeword used in this line. Reed-
Solomon (RS) Code is an error-correction code (refer to G.993.2).
RFEC(bytes) RFEC refers to Redundancy Forward Error Correction (FEC). This field displays the actual
number of Reed-Solomon redundancy bytes. The Reed-Solomon code has the capability
to correct errors by adding redundancy bytes. The longer the Reed-Solomon redundancy
bytes the higher the error correction capability.
LSYMB(bits) LSYMB refers to Latency SYMbol Bit. This field displays the actual number of bits per
symbol for the line.
Table 210
Port Statistics: DSL Line Card: Line Detail (VLC14XX) (continued)
LABEL DESCRIPTION