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Cisco uBR10012 Universal Broadband Router Software Configuration Guide
OL-1520-05
Chapter 4 Managing Cable Modems on the Hybrid Fiber-Coaxial Network
Configuring the Dynamic Map Advance Algorithm
The following cable interface commands are available to configure the dynamic contention algorithms:
[
no
]
cable insertion-interval
[
automatic
[
Imin
[
Imax
]]] | [
msecs
]
[
no
]
cable upstream
port num
range-backoff
[
automatic
] | [
start
end
]
[
no
]
cable upstream
port num
data-backoff
[
automatic
] | [
start
end
]
cable insertion-interval Command Examples
To deviate from system defaults when modifying the dynamic contention algorithm, use one of the
following commands in cable interface configuration mode.
Tip
System defaults are to have dynamic ranging interval enabled, dynamic ranging backoff enabled, and
fixed data backoffs for each upstream of a cable interface.
The default
automatic
insertion interval setting enables the Cisco automatic initial ranging period
algorithm, where lower and upper default values of 60 msecs and 480 msecs are used. The default
automatic range-backoff
setting
enables the dynamic backoff algorithm.
Configuring the Dynamic Map Advance Algorithm
A CMTS administrator can enhance the upstream throughput from a CM connected to the
Cisco uBR10000 series CMTS. The system employs a new algorithm that automatically tunes the
lookahead time in MAPs, based on several input parameters for the corresponding upstream channel.
The use of dynamic and optimal lookahead time in MAPs significantly improves the per-modem
upstream throughput.
Caution
Only a trained CMTS administrator should adjust these values.
Command
Purpose
[
no
]
cable
insertion-interval
[
automatic
[
Imin
[
Imax
]]] |
[
msecs
]
cable insertion-interval
automatic
min 25-2000
cable insertion-interval
max 500-2000
no cable insertion-interval
cable insertion-interval
100-2000
Enables or disables the dynamic ranging interval algorithm. If lower
and upper bounds for varying the period are not specified, the
system uses default frequency values of initial ranging upstream
slots between 60 milliseconds to 480 milliseconds, respectively.
Sets the lower bound on the initial ranging period for the automatic
ranging algorithm.
Sets the upper bound on initial ranging period for the automatic
ranging algorithm.
Resets fixed initial ranging period to default value of 500 msecs.
Also invokes fixed initial ranging algorithm.
Enables fixed initial ranging period algorithm with specified fixed
period (msecs).