Cisco Systems uBR7200 Series manual Configure Per Modem Filters

Chapter 4 Troubleshooting the System

Managing Cable Modems on the HFC Network

Caution Only a trained CMTS administrator should adjust these values.

To configure the dynamic map advance algorithm, use the following command in cable interface configuration mode.

Table 4-5	Instructions to Configure the Dynamic Map Advance Algorithm
Command		Purpose
CMTS01(config-if)#cable map-advance dynamic [<n>] static		Specify a value to enhance the upstream
		throughput from a cable modem connected to the
		Cisco uBR7200 series. The <n> parameter
		provides the safety factor for the dynamic map
		advance algorithm. This parameter is specified in
		usecs and controls the amount of extra lookahead
		time in MAPs to account for inaccuracies of the
		measurement system and software latencies. The
		default value is 1000 usecs.
		You can vary this between 500 to 1500 usecs. This
		parameter is a delta value added to the dynamic
		map-advance that the algorithm computes. Using
		larger safety factors increases the run time
		lookahead in MAPs, but reduces the upstream
		performance.
		Use the static keyword for the map advance
		command. The Cisco uBR7200 series will use a
		fixed lookahead time in MAPs, regardless of the
		real propagation delay of the farthest cable modem
		on the network. This fixed lookahead time is
		computed based on the worst case parameters such
		as farthest DOCSIS propagation delay for the
		CMs.

Caution Cisco recommends if you are adjusting the dynamic map advance algorithm that you do not reduce the safety factor below the default value of 1000 usecs in a production network until you are confident that the reduced safety factor suffices for your deployment. The default value is chosen to be a safe operating point for the algorithm.

Configure Per Modem Filters

You can configure the Cisco uBR7200 series to filter incoming packets from individual hosts or cable modems based on the source Media Access Controller (MAC) or Internet Protocol (IP) address. Definition of filters follows standard Cisco IOS configuration practices for access lists and groups.

Note Configuring per modem or host filters is supported in Cisco IOS Release 12.0(5)T1 or higher, as well as in Cisco IOS Release 12.0(6)SC or higher.

Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide

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