Octal-Port DMT ATU-C Line Card
Feature Overview
2
Cisco IOS Release 12.1(6)DA
Benefits
G.hs Support (ITU G.994.1)
G.hs support is provided through both the MIB and the CLI. Features from G.hs that are
supported include:
•
Enabling/disabling all or one of the following modes.
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G.dmt
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T1.413 Issue 2
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G.lite
•
Setting auto mode defers the mode selection to the ATU-R.
•
Displaying current mode/capability.
Bit Swapping
Bit swapping is a mechanism that allows DMT transceivers to reallocate bits between carriers and adjust
gain scaling based on the carrier SNR margin.
Fast or Interleaved Path Selection
The fast path feature allows you to configure either the fast or the interleave path via DSL profile
configuration commands provided that the CPE also supports fast path. You can use either the interleave
or fast path with the 8xDMT line card provided that the CPE also supports fast path. The fast path
provides improved latency characteristics for applications that cannot tolerate latency (for
example, voice).
The parameters for either path are configurable using the DSL profile configuration commands. Note that
although you can configure both paths, only one path will actually be enabled (dual latency is not
supported at this time). Thus the maximum bit rates for the unused path must be zero. For example, to
configure and use the fast path, you must specify nonzero maximum bit rates for the fast path. Once you
configure the maximum bit rates for the fast path, the rates for the interleave path must be zero. The IOS
software ensures that only one path is enabled at a given time.
Trellis Encoding
Trellis encoding is a method of providing better performance in a noisy environment. The end result of
using Trellis encoding is that you can transmit at faster line rates with lower error rates, thus providing
a faster overall throughput in a moderately noisy environment. You can enable or disable trellis encoding
for a specific DSL profile.
Enhanced Line Quality Monitoring and Management
The 8xDMT improves the manageability of DMT ports on supported DSLAMs. The following
commands are used to configure this functionality:
•
dmt minrate-blocking
DMT minrate-blocking customizes the DMT port reaction to lines that train below configured
minimum bit rates. Formerly, if a line trained below the configured minimum bit rate threshold, it
would generate a minor alarm, but the DMT port remained active. The dmt minrate-blocking
prevents DMT ports from training when bit rates fall below the configured minimum threshold
specified in the dmt bitrate minimum command.
