ZyXEL Communications eircom D1000 User Manual Download

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207

eircom D1000

modem User’s Guide

Chapter 25 Diagnostic

The following table describes the fields in this screen.

Table 88

Maintenance > Diagnostic > DSL Line

LABEL

DESCRIPTION

ATM Status

Click this to view your DSL connection’s Asynchronous Transfer Mode (ATM) statistics.
ATM is a networking technology that provides high-speed data transfer. ATM uses fixed-
size packets of information called cells. With ATM, a high QoS (Quality of Service) can be
guaranteed.

The (Segmentation and Reassembly) SAR driver translates packets into ATM cells. It also
receives ATM cells and reassembles them into packets.

These counters are set back to zero whenever the device starts up.

inPkts

is the number of good ATM cells that have been received.

inDiscards

is the number of received ATM cells that were rejected.

inF4Pkts

is the number of ATM Operations, Administration, and Management (OAM) F4

cells that have been received. See ITU recommendation I.610 for more on OAM for ATM.

inF5Pkts

is the number of ATM OAM F5 cells that have been received.

outPkts

is the number of ATM cells that have been sent.

outDiscards

is the number of ATM cells sent that were rejected.

outF4Pkts

is the number of ATM OAM F4 cells that have been sent.

outF5Pkts

is the number of ATM OAM F5 cells that have been sent.

ATM Loopback
Test

Click this to start the ATM loopback test. Make sure you have configured at least one PVC
with proper VPIs/VCIs before you begin this test. The Device sends an OAM F5 packet to
the DSLAM/ATM switch and then returns it (loops it back) to the Device. The ATM
loopback test is useful for troubleshooting problems with the DSLAM and ATM network.

DSL Line Status

Click this to view statistics about the DSL connections.

noise margin downstream

is the signal to noise ratio for the downstream part of the

connection (coming into the Device from the ISP). It is measured in decibels. The higher
the number the more signal and less noise there is.

output power upstream

is the amount of power (in decibels) that the Device is using to

transmit to the ISP.

attenuation downstream

is the reduction in amplitude (in decibels) of the DSL signal

coming into the Device from the ISP.

Discrete Multi-Tone (DMT) modulation divides up a line’s bandwidth into sub-carriers
(sub-channels) of 4.3125 KHz each called tones. The rest of the display is the line’s bit
allocation. This is displayed as the number (in hexadecimal format) 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 certain ADSL transmission rates, and
possibly to determine whether particular 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. There will be
some tones without any bits as there has to be space between the upstream and
downstream channels.

Reset ADSL Line

Click this to reinitialize the ADSL line. The large text box above then displays the progress
and results of this operation, for example:

"Start to reset ADSL
Loading ADSL modem F/W...
Reset ADSL Line Successfully!"

WAN Connection
Test

Click this to check your WAN connection status of DSL, ATM, Ethernet PPPoE, IP, and
Pinging.