Cisco Systems uBR7200 manual Headend Broadband Access Router Configuration Prerequisites, MC-533

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Configuring Headend Broadband Access Router Features

Headend Broadband Access Router Configuration Prerequisites

data. The DOCSIS specification sets the minimum value for both of these parameters to 25 dB in the 5-MHz to 42-MHz frequency range. If the CNR drops below this value on a particular channel due to noise, the cable modem on that channel will drop off of the HFC network.

We recommend that system administrators use upstream frequency hopping as a countermeasure to long-term narrowband noise. To provide this capability, Cisco uBR7200 series routers contain a spectrum manager that continuously monitors the noise in unused upstream channels. If the CNR reaches an unacceptable level on a particular channel, the spectrum manager will automatically assign a new upstream channel to the cable modem using that channel. This is referred to as frequency agility.

Cisco uBR7200 series routers support the following techniques for upstream frequency hopping when no clean frequency band is available:

Blind frequency hopping—The spectrum manager automatically assigns a new upstream channel frequency when station maintenance (keepalive) messages fail for approximately 2.5 minutes. This represents a complete impairment of the upstream due to noise, plant, or equipment failure.

Time scheduled frequency hopping—Frequency reassignment is based on the time of day or week.

Combined blind and time scheduled reassignment.

Guided frequency hopping—Explicit frequency subbands and associated input power levels are assigned in a spectrum group.

Note Frequency hopping is not effective against broadband noise phenomena such as impulse noise.

The Cisco uBR7200 series allows you to create up to 32 cable spectrum groups, each containing multiple upstream ports. The configured channel width is used for each upstream. In addition, the router maintains a flap list containing the MAC address for each cable modem having problems maintaining its connection. (A “flapping modem” is a cable modem that rapidly disconnects and reconnects to the CMTS.)

Note Because spectrum management capabilities focus on the upstream path over an HFC network, this feature is not applicable to one-way (telco return) systems.

Headend Broadband Access Router Configuration Prerequisites

Before you can configure Cisco uBR7200 series universal broadband router features, you must first perform the following tasks:

Make sure that your current network is designed to support broadband transmission. At the very least, your network must include the following:

Computer on the WAN side of your Cisco uBR7200 series configured as a DHCP server to assign IP addresses to cable modems on the HFC network.

Cisco uBR7200 series-compatible IF-to-RF upconverter installed in the downstream data path at your headend site. The upconverter is installed between the Cisco uBR7200 series and the combiner.

Note The combiner refers to all cables, amplifiers, and taps at the headend or cable distribution center that connect the Cisco uBR7200 series to the HFC network.

Cisco IOS Multiservice Applications Configuration Guide

MC-533

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Contents MC-519 Configuring Headend Broadband Access Router FeaturesMC-520 Headend OverviewTopology of a Typical Broadband Network Voice over IP Services MC-523 Telco ReturnTOD MC-524MC-525 QoS FeaturesService Class Profiles Multiple Service IDsTAG/NetFlow Switching QoS Profile EnforcementMC-526 Tag Switching Netflow SwitchingMC-527 Committed Access Rate CAR Security FeaturesWeighted Random Early Detection Weighted Fair QueueingMC-529 Cable Modem and Multicast Authentication Using RadiusDocsis Baseline Privacy Upstream Address VerificationMC-530 Traffic Shaping FeaturesOperations and Provisioning Features Dynamic RangingCPE Limitation Downstream Channel ID ConfigurationBurst Profile Configuration Downstream Frequency OverrideSpectrum Management MC-533 Headend Broadband Access Router Configuration PrerequisitesMC-534 Headend Broadband Access Router Configuration TasksActivating the Downstream Carrier Configuring the Downstream Cable InterfaceCMTS01# configure terminal CMTS01config# interface cable 6/0MC-536 Setting the Downstream Center FrequencyTroubleshooting Tips Verifying the Downstream CarrierCMTS01config-if#cable downstream frequency Verifying the Downstream Center FrequencyMC-537 MC-538 Setting the Downstream Channel IDSetting the Downstream Mpeg Framing Format Annex B Verifying the Downstream Channel IDMC-539 Setting the Downstream ModulationVerifying the Downstream Mpeg Framing Format Verifying the Downstream ModulationMC-540 Setting the Downstream Interleave DepthCMTS01config-if#cable downstream interleave-depth Verifying the Downstream Interleave DepthSetting the Downstream Helper Address Verifying the Downstream Helper AddressMC-541 MC-542 Setting Downstream Rate LimitingConfiguring the Upstream Cable Interface Verifying Downstream Rate LimitingMC-543 MC-544 Setting the Upstream FrequencyVerifying the Upstream Frequency MC-545CMTS01# show controllers cable 6/0 u0 Channel-width width Setting the Upstream Channel WidthVerifying Upstream Channel Width MC-546MC-547 Setting the Upstream Input Power LevelMC-548 Verifying the Upstream Input Power LevelActivating Upstream Admission Control Verifying Upstream Admission ControlMC-549 Activating Upstream FECMC-550 Router# more systemrunning-configSpecifying Upstream Minislot Size Verifying Upstream FECActivating the Upstream Scrambler Verifying Upstream Minislot SizeMC-551 MC-552 CMTS01config-if#cable upstream usport scramblerCMTS01# more systemrunning-config Verifying the Upstream ScramblerMC-553 Activating Upstream Differential EncodingActivating Upstream Rate Limiting Verifying Upstream Differential EncodingCMTS01config-if#no cable upstream usport rate-limit Verifying Upstream Rate LimitingMC-554 Activating Upstream Frequency Adjustment Frequency-adjust averaging percentageMC-555 Activating Upstream Power Adjustment Verifying Upstream Frequency AdjustmentMC-556 Continue seconds Activating Upstream Timing AdjustmentVerifying Upstream Power Adjustment MC-557Verifying Upstream Timing Adjustment Activating the Upstream PortsMC-558 Setting Upstream Backoff Values Verifying the Upstream PortsMC-559 Data-backoff automatic CMTS01config-if#cable upstream usport rangeMC-560 Data-backoff start endConfiguring and Activating Baseline Privacy Verifying Upstream Data Backoff AutomaticMC-561 Configuring KEK Privacy CMTS01config-if#cable privacy kek grace-timeMC-562 MC-563 Configuring TEK PrivacyVerifying KEK Privacy Verifying TEK PrivacyMC-564 Configuring and Activating Frequency AgilityActivating Baseline Privacy Verifying Baseline PrivacyMC-565 Combiner GroupsMC-566 Frequency Management PolicyMC-567 Determining the Upstream Ports Assigned to a Combiner GroupMC-568 Configuring and Activating Spectrum GroupsCreating Spectrum Groups Verifying Spectrum GroupsMC-569 Command PurposeMC-570 Verifying Spectrum Group Configuration Verifying Frequency HoppingMC-571 MC-572 Configuring Spectrum Group CharacteristicsThreshold percent Verifying Spectrum Group CharacteristicsCMTS01config# cable spectrum-group groupnum hop MC-573Verifying Spectrum Group and Upstream Port Assignments Activating IP Address Resolution ProtocolAssigning the Spectrum Group and the Upstream Ports Activating Cable ARP RequestsActivating Host-to-Host Communication Proxy ARP Verifying ARP RequestsMC-575 Verifying Cable Proxy ARP Requests Configuring Dhcp OptionsActivating Cable Proxy ARP Requests Activating Cable Relay AgentActivating Dhcp giaddr Verifying Dhcp giaddr ActivationMC-577 Verifying ToD Service Setting Service OptionsSetting Optional IP Parameters Configuring ToD ServiceMC-579 Activating IP Multicast EchoActivating IP Broadcast Echo Verifying IP Multicast EchoMC-580 Configuring Cable ProfilesConfiguring Cable Modulation Profiles Verifying IP Broadcast EchoMC-581 Number profileConfiguring QoS Profiles Verifying Cable Modulation ProfilesMC-582 MC-583 Verifying QoS ProfilesMC-584 Setting QoS PermissionEnforcing a QoS Profile Assignment Verifying QoS PermissionManaging Cable Modems on the HFC Network Verifying a QoS Profile AssignmentMC-585 Verifying Sync Message Interval Configuring Sync Message IntervalConfiguring Telco Return Activating Cable Modem AuthenticationVerifying Cable Modem Authentication Activating Cable Modem Upstream Address VerificationMC-587 MC-588 CMTS01config-if#cable source-verify dhcpActivating Cable Modem Insertion Interval Verifying Cable Modem Upstream Address VerificationCMTS01config-if#cable insertion-interval automatic Verifying Cable Modem Insertion IntervalMC-589 Configuring Cable Modem Registration Timeout Verifying the Maximum Number of HostsMC-590 Clearing and Resetting Cable Modems Verifying Registration TimeoutMC-591 Verifying Cable Modem Clearing and Resetting Clearing Cable Modem CountersMC-592 MC-593 Using Ping DocsisVerifying that Cable Modem Counters are Cleared Verifying Ping DocsisMC-594 Spectrum Management Configuration ExampleMC-595 Virtual Private Network Configuration ExampleMC-596 MC-597 Ip http server Ip http authentication local No cdp runMC-598 VoIP Configuration ExampleIp subnet-zero No ip domain-lookup MC-599MC-600 Telco Return Configuration ExampleMC-601 Cable telco-return enableCable Reg QoS Profile Enforcement Configuration ExampleCable Modem all reset MC-602MC-603 Troubleshooting Using Cable Flap ListsSetting Cable Flap List Aging CMTS01config# cable flap-list aging daysVerifying Cable Flap List Insertion Time Setting Cable Flap List Insertion TimeSetting Cable Flap List Power Adjustment Threshold Verifying Cable Flap List AgingVerifying Cable Flap List Miss Threshold Setting Cable Flap List Miss ThresholdVerifying Cable Flap List Power Adjustment Threshold CMTS01config# cable flap-list miss-threshold missesMC-606 Setting Cable Flap List SizeClearing Cable Flap List Verifying Cable Flap List Size
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