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cable downstream interleave-depth
cable downstream interleave-depth
To set the downstream interleave depth, use the cable downstream interleave-depth command in cable
interface configuration mode. To restore the default setting, use the no form of this command.
Syntax Description
8 | 16 | 32 | 64 | 128
Defaults
32
Command Modes
Interface configuration (cable interface only)
Command History
Release
11.3 XA
12.0(7)XR2,
12.(0)SC,12.1(2)EC1
This command is not supported on the Cisco uBR-MC16E cable interface line card or on the
Note
Cisco uBR7111E and Cisco uBR7114E universal broadband routers, because the interleave on the
EuroDOCSIS downstream is fixed.
Usage Guidelines
This command sets the minimum latency of the system. A higher interleave depth provides more
protection from bursts of noise on the HFC network by spreading out the bits for each codeword over a
greater transmission time.
Interleave transmissions do not transmit each codeword by itself, but instead send bits from multiple
codewords at the same time, so that a noise burst affects the minimum number of bits per codeword,
which allows the Forward Error Correction (FEC) algorithm a greater chance of detecting and correcting
any transmission errors.
A higher interleave depth transmits bits from a greater number of codewords, increasing the efficacy of
the FEC algorithm. However, a higher depth also increases downstream latency, which might slow
TCP/IP throughput for some configurations, so you need to choose an interleave depth that is appropriate
both for your plant's noise levels and application needs.
If your cable plant is experiencing high noise levels, consider increasing the interleave from the default
of 32 to 64. For plants with exceptionally high noise levels, increase the interleave to 128 to provide the
maximum protection from noise bursts.
Cisco Broadband Cable Command Reference Guide
2-54
cable downstream interleave-depth {8 | 16 | 32 | 64 | 128}
no cable downstream interleave-depth
Indicates the downstream interleave depth in number of rows of
codewords.
Modification
This command was introduced.
This command was modified to support Annex A operation (which uses a
fixed interleave).
Chapter 2
Cisco CMTS Configuration Commands
OL-1581-08
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