ZyXEL Communications SBG5500-A, User Manual

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Chapter 5 WAN/Internet
SBG5500 Series User’s Guide
54
The following table describes the labels in this screen.
Table 7 Configuration > WAN / Internet > WAN Status > xDSL Statistics
LABEL DESCRIPTION
Refresh Click this to refresh the statistics.
xDSL Training Status This displays the current state of setting up the DSL connection.
Mode This displays the ITU standard used for this connection.
Traffic Type This displays the type of traffic the DSL port is sending and receiving. Inactive displays
if the DSL port is not currently sending or receiving traffic.
Link Uptime This displays how long the port has been running (or connected) since the last time it
was started.
xDSL Port Details
Upstream These are the statistics for the traffic direction going out from the port to the service
provider.
Downstream These are the statistics for the traffic direction coming into the port from the service
provider.
Line Rate These are the data transfer rates at which the port is sending and receiving data.
Actual Net Data Rate These are the rates at which the port is sending and receiving the payload data
without transport layer protocol headers and traffic.
Trellis Coding This displays whether or not the port is using Trellis coding for traffic it is sending and
receiving. Trellis coding helps to reduce the noise in ADSL transmissions. Trellis may
reduce throughput but it makes the connection more stable.
SNR Margin This is the upstream and downstream Signal-to-Noise Ratio margin (in dB). A DMT sub-
carrier’s SNR is the ratio between the received signal power and the received noise
power. The signal-to-noise ratio margin is the maximum that the received noise
power could increase with the system still being able to meet its transmission targets.
Actual Delay This is the upstream and downstream interleave delay. It is the wait (in milliseconds)
that determines the size of a single block of data to be interleaved (assembled) and
then transmitted. Interleave delay is used when transmission error correction (Reed-
Solomon) is necessary due to a less than ideal telephone line. The bigger the delay,
the bigger the data block size, allowing better error correction to be performed.
Transmit Power This is the upstream and downstream far end actual aggregate transmit power (in
dBm).
Upstream is how much power the port is using to transmit to the service provider.
Downstream is how much port the service provider is using to transmit to the port.
Receive Power Upstream is how much power the service provider is receiving from the port.
Downstream is how much power the port is receiving from the service provider.
Actual INP Sudden spikes in the line’s level of external noise (impulse noise) can cause errors
and result in lost packets. This could especially impact the quality of multimedia
traffic such as voice or video. Impulse noise protection (INP) provides a buffer to
allow for correction of errors caused by error correction to deal with this. The number
of DMT (Discrete Multi-Tone) symbols shows the level of impulse noise protection for
the upstream and downstream traffic. A higher symbol value provides higher error
correction capability, but it causes overhead and higher delay which may increase
error rates in received multimedia data.
Attainable Net Data Rate These are the highest theoretically possible transfer rates at which the port could
send and receive payload data without transport layer protocol headers and traffic.
xDSL Counters
Downstream These are the statistics for the traffic direction coming into the port from the service
provider.
Upstream These are the statistics for the traffic direction going out from the port to the service
provider.