ZyXEL Communications MSC1000G Series, Руководство пользователя

Страница: 934 / 1168

Chapter 32 show Commands
Management Switch Card User’s Guide
934
32.3.1 show adsl Commands
Use the
show adsl
commands to display the line information for an active ADSL line.
32.3.1.1 show adsl linedata Command
Syntax:
show adsl linedata < slot-port >
This command displays a ADSL port's line bit allocation.
Discrete Multi-Tone (DMT) modulation divides up a line’s bandwidth into tones. This command
displays the number of bits transmitted for each tone. This can be used to determine the quality of
the connection, whether a given sub-carrier loop has sufficient margins to support ADSL
transmission rates, and possibly to determine whether certain specific types of interference or line
attenuation exist. Refer to the ITU-T G.992.1 recommendation for more information on DMT.
The better (or shorter) the line, the higher the number of bits transmitted for a DMT tone. The
maximum number of bits that can be transmitted per DMT tone is 15.
“usBit table” displays the number (in hexadecimal format) of bits transmitted per DMT tone for the
upstream channel (from the subscriber’s DSL modem or router to the DSL line card).
“dsBit table” displays the number (in hexadecimal format) of bits received per DMT tone for the
downstream channel (from the DSL line card) to the subscriber’s DSL modem or router).
“usSnr Table” displays the upstream (from the subscriber’s DSL modem or router to the DSL line
card) Signal to Noise Ratio. The higher the number, the better the line quality for that tone.
The bit allocation contents are only valid when the link is up.
The following example displays the line bit allocation for DSL port 5 on the line card in slot 7. In the
following example, the upstream channel is carried on tones 8 to 17 and the downstream channel is
carried on tones 34 to 497 (space is left between the channels to avoid interference).