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Cisco uBR7100 Series Software Configuration Guide
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Preface
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Chapter 1: Overview of Cisco uBR7100 Series Software
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Chapter 2: Configuring the CMTS for the First Time
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Chapter 3: Configuring the Cisco Cable Modem Card
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Chapter 4: Configuring Basic Broadband Internet Access
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Chapter 5: Troubleshooting the System
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Appendix A: Configuration Register Information for the Cisco uBR7100 Series Universal Broadband Router
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Table Of Contents
Configuring the Cisco Cable Interface
Configuring the Downstream Cable Interface
Activating the Downstream Carrier
Verifying the Downstream Carrier
Setting the Integrated Upconverter
Verifying the Integrated Upconverter Configuration
Setting the Downstream Channel ID
Verifying the Downstream Channel ID
Setting the MPEG Framing Format
Verifying the Downstream MPEG Framing Format
Setting the Downstream Modulation
Verifying the Downstream Modulation
Setting the Downstream Interleave Depth
Verifying the Downstream Interleave Depth
Setting the Downstream Helper Address
Verifying the Downstream Helper Address
Setting Downstream Rate Limiting
Verifying Downstream Rate Limiting
Configuring the Upstream Cable Interface
Setting the Upstream Frequency
Verifying the Upstream Frequency
Setting the Upstream Channel Width
Verifying Upstream Channel Width
Setting the Upstream Input Power Level
Verifying the Upstream Input Power Level
Activating Upstream Admission Control
Verifying Upstream Admission Control
Activating Upstream Forward Error Correction (FEC)
Specifying Upstream Minislot Size
Verifying Upstream Minislot Size
Activating the Upstream Scrambler
Verifying the Upstream Scrambler
Activating Upstream Differential Encoding
Verifying Upstream Differential Encoding
Activating Upstream Rate Limiting
Verifying Upstream Rate Limiting
Activating Upstream Frequency Adjustment
Verifying Upstream Frequency Adjustment
Activating Upstream Power Adjustment
Verifying Upstream Power Adjustment
Activating Upstream Timing Adjustment
Verifying Upstream Timing Adjustment
Setting Upstream Backoff Values
Verifying Upstream Data Backoff Automatic
Enabling and Configuring Baseline Privacy
Introduction to the Baseline Privacy Interface (BPI)
Differentiating Traffic Streams
Configuring Key Encryption Key (KEK) Privacy
Configuring Traffic Encryption Key (TEK) Privacy
Configuring and Activating Frequency Agility
Configuring and Activating Spectrum Groups
Verifying Spectrum Group Configuration
Configuring Spectrum Group Characteristics
Verifying Spectrum Group Characteristics
Assigning the Spectrum Group and the Upstream Ports
Verifying Spectrum Group and Upstream Port Assignments
Activating Cable Address Resolution Protocol Requests
Activating Cable Address Resolution Protocol (ARP) Requests
Activating Host-to-Host Communication (Proxy ARP)
Activating Cable Proxy ARP Requests
Verifying Cable Proxy ARP Requests
Verifying DHCP giaddr Activation
Configuring Time-of-Day Service
Activating Time-of-Day Service
Setting Optional IP Parameters
Activating Packet Intercept Capabilities
Configuring Cable Modulation Profiles
Configuring Cable Modulation Profiles
Verifying Cable Modulation Profiles
Enforcing a QoS Profile Assignment
Verifying a QoS Profile Assignment
Setting Quality of Service (QoS) for Higher Priority Traffic
Configuring a QoS Profile for Higher Priority Traffic
Monitoring and Maintaining QoS for Higher Priority Traffic
Setting and Viewing Concatenation
Configuring the Cisco Cable Interface
The Cisco IOS software command-line interface (CLI) can be used to configure the Cisco cable modem interface for correct operation on the hybrid fiber coax cable (HFC) network. This chapter describes the following tasks required to configure the Cisco cable modem card.
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For tasks marked optional below, default settings are typically adequate to configure the system. Change default settings only with careful prior analysis.
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Configuring the Downstream Cable Interface
The first step in configuring the Cisco CM interface is to configure the downstream cable interface, which generally entails the downstream frequency, symbol rate, compression, and modulation. Configuring the downstream cable interface consists of the following specific tasks:
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For information on other configuration options, see the "Cisco Cable Modem Termination System Commands" chapter in the Broadband Command Consolidation Guide, available on Cisco.com and the Documentation CD-ROM.
Activating the Downstream Carrier
To activate a downstream port on a Cisco uBR7100 series cable interface card for digital data transmissions over the HFC network, complete the steps in the following table.
Verifying the Downstream Carrier
To determine if the downstream carrier is active (up), enter the show controllers cable command for the downstream port that you just configured. For NTSC 6 MHz operations, see the following example:
CMTS01# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Setting the Integrated Upconverter
The Cisco uBR7100 series router supports an integrated upconverter that outputs a DOCSIS RF signal on the DS0 RF downstream port. To enable the integrated upconverter, you must do the following:
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To configure the integrated upconverter, use the following commands in cable interface configuration mode.
Verifying the Integrated Upconverter Configuration
To verify the configuration for the integrated upconverter, enter the show controllers cable downstream command. The following is a typical display with a correctly configured center frequency:
router# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=525000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 0Then enter the show controllers cable command, which also displays the center frequency, along with the power levels and whether the integrated upconverter is enabled. The following is a typical display when these values have been correctly configured:
ubr7100# show controllers cable1/0Interface Cable1/0Hardware is IMC11BCM3210 revision=0x56B2Cable1/0 Upconverter is Enabled Output is EnabledModel: 74-2094-01 Serial Number: 0WAV04480010 CLEI Code: CLEI#HW Rev: PC2D0107 SW Rev: 007, NVRAM Rev: 006 ECI number 123456Downstream Frequency 525.0000 MHzIF Power 0.3 dBmv RF Power 51.0 dBmv...If the center frequency has not been configured, the frequency is shown as "not set" as shown in the following example:
ubr7100# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency is not set. Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 0If you are having trouble, make sure the cable connections are not loose or disconnected, and that you have calculated and entered the center frequency for your router accurately.
Setting the Downstream Channel ID
To assign a numeric channel ID to the downstream port on the Cisco cable modem card, use the following command in cable interface configuration mode. Acceptable range is 0 to 255.
CMTS01(config-if)# cable downstream channel-id id
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cable downstream frequency 54000000-1000000000 broadcast frequency - hThe commands are used in instances where you want to send multiple downstream frequencies to a single region that contains CMs that can only connect to upstream ports on the same cable modem card. You must configure unique channel IDs for each downstream that any CM is capable of receiving. The downstream frequency setting must match the setting on the upconverter.
Caution
Verifying the Downstream Channel ID
To verify the downstream channel ID, enter the show controllers cable command for the downstream port you have just configured. See the following example:
Router# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 1For EuroDOCSIS operations, a sample appears below:
Router# show controllers cable 1/0 downstreamCable1/0 Downstream is upFrequency 669.0000MHz, Channel Width 8MHz, 64-QAM, Symbol Rate6.952000 MspsFEC ITU-T J.83 Annex A, R/S Interleave I=12, J=17Downstream channel ID: 1Setting the MPEG Framing Format
The MPEG framing format must be compatible with DOCSIS or EuroDOCSIS specifications and your local cable plant operations.
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The following command appears in the Cisco uBR7100 series router configuration file to designate Annex B or Annex A operation. This command sets the downstream MPEG framing format.
CMTS01(config-if)# cable downstream annex {B}Verifying the Downstream MPEG Framing Format
To verify the downstream MPEG framing format setting, enter the show controllers cable command for the downstream port you have just configured. See the following example:
router# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 0A sample output appears below for EuroDOCSIS operations:
Router# show controllers cable 1/0 downstreamCable3/0 Downstream is upFrequency 669.0000MHz, Channel Width 8MHz, 64-QAM, Symbol Rate6.952000 MspsFEC ITU-T J.83 Annex A, R/S Interleave I=12, J=17Downstream channel ID: 0Setting the Downstream Modulation
To set the downstream modulation, define the speed in symbols per second at which data travels downstream to the subscriber's CM. A symbol is the basic unit of modulation. QPSK encodes 2 bits per symbol, QAM-16 encodes 4 bits per symbol, QAM-64 encodes 6 bits per symbol, and QAM-256 encodes 8 bits per symbol.
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Use the following command in cable interface configuration mode to set the downstream modulation. The standard DOCSIS modulation rate (and the Cisco default) is QAM-64.
CMTS01(config-if)# cable downstream modulation 64qamVerifying the Downstream Modulation
To verify the downstream modulation setting, enter the show controllers cable command for the downstream port you have just configured. See the following example:
Router# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Perform these steps if you are having difficulty with verification:
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Setting the Downstream Interleave Depth
Set the interleave depth for the downstream port on the Cisco cable modem card. A higher interleave depth provides more protection from bursts of noise on the HFC network; however, it will increase downstream latency.
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To set the downstream interleave depth in milliseconds, use the following command in cable interface configuration mode:
CMTS01(config-if)# cable downstream interleave-depth {8|16|32 |64|128}Verifying the Downstream Interleave Depth
To verify the downstream interleave depth setting, enter the show controllers cable command for the downstream port you have just configured:
Router# show controllers cable1/0 downstreamCable1/0 Downstream is upFrequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Perform these steps if you are having difficulty with verification:
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Setting the Downstream Helper Address
Specify an IP address of a DHCP server where UDP broadcast (DHCP) packets will be sent. You can specify a DHCP server for UDP broadcast packets from cable interfaces, and a DHCP server for UDP broadcast packets from hosts.
To set a downstream helper address, use the following commands in cable interface configuration mode.
Verifying the Downstream Helper Address
To verify the downstream helper address setting, enter the show running-config command and look for cable helper-address in the cable interface configuration information:
CMTS01# show running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 10.254.254.254 255.0.0.0no ip directed-broadcastcable helper-address 192.168.1.1no keepalivePerform these steps if you are having difficulty with verification:
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Setting Downstream Rate Limiting
Downstream rate limiting enables you to use the token bucket policing algorithm with traffic shaping options or the weighted discard policing algorithm to buffer, shape, or discard packets that exceed a set bandwidth. Downstream rate limiting is disabled by default.
To enable downstream rate limiting for a downstream port on a Cisco cable modem card, use one of the following commands in cable interface configuration mode.
Verifying Downstream Rate Limiting
To determine if downstream rate limiting is configured and activated, enter the show running-config command and look for the cable interface configuration information. If downstream rate limiting is configured and enabled, a rate limiting entry displays in the output. If downstream rate limiting is disabled, no rate limiting entry displays.
CMTS01# show running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 10.254.254.254 255.0.0.0no ip directed-broadcastcable helper-address 192.168.1.1no keepalivecable downstream rate-limit token-bucket shapingcable downstream annex Bcable downstream modulation 64qamPerform these steps if you are having difficulty with verification:
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Configuring the Upstream Cable Interface
Upstream cable interface commands configure the frequency and input power level of the upstream signal, in addition to error detection and correction of the upstream signal. The configuration of the upstream cable interface depends on the characteristics of your cable plant.
Perform the following tasks to configure the upstream cable interface.
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Setting the Upstream Frequency
The upstream channel frequency of your RF output must be set to comply with the expected input frequency of your Cisco cable modem card. To configure upstream channel frequencies, perform one of the following tasks:
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A modulation profile consists of a table of physical layer characteristics for the different types of upstream bursts; for example, initial maintenance, long grant, request/data, request, short grant, and station maintenance.
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If you are setting a fixed upstream frequency, make sure that the frequency selected does not interfere with the frequencies used for any other upstream applications running on the cable plant.To set a fixed upstream frequency, use the following commands in cable interface configuration mode.
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Verifying the Upstream Frequency
To verify the current value of the upstream frequency, enter the show controllers cable command for the upstream port you have just configured:
CMTS01# show controllers cable1/0 u0Cable1/0 Upstream 0 is upFrequency 24.016 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 MspsSpectrum Group is overriddenSNR 33.2560 dBNominal Input Power Level 0 dBmV, Tx Timing Offset 2288Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1
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Perform these steps if you are having difficulty with verification:
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Setting the Upstream Channel Width
Enter the channel width in hertz (Hz). For NTSC operations, valid values are 200000 Hz (160 kilosymbols per second [ksps]), 400000 Hz (320 ksps), 800000 Hz (640 ksps), 1600000 Hz (1280 ksps), and 3200000 Hz (2560 ksps). The default is 1600000 Hz.
If no acceptable channels of the specified width are found, the spectrum management card automatically begins to scan the upstream spectrum for the next largest available channel width; for example, if the spectrum management card is unable to find a usable 1.6 MHz upstream channel, it automatically begins searching for usable 800 kHz channels.
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Verifying Upstream Channel Width
To verify the current value of the upstream channel width, enter the show controllers cable command for the upstream port you just configured. A sample appears below:
CMTS01# show controllers cable1/0 u0Cable1/0 Upstream 0 is upFrequency 24.016 MHz, Channel Width 0.800 MHz, QPSK Symbol Rate 0.640 MspsSpectrum Group is overriddenSNR 33.2560 dBNominal Input Power Level 0 dBmV, Tx Timing Offset 2288Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1Perform these steps if you are having difficulty with verification:
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Setting the Upstream Input Power Level
The Cisco uBR7100 series CMTS controls the output power levels of CMs to meet the desired upstream input power level. The nominal input power level for the upstream RF carrier is specified in decibels per millivolt (dBmV). The default setting of 0 dBmV is the optimal setting for the upstream power level.
The valid range for the input power level depends on the data rate. At 1.6 MHz, the valid range is -10 to 25 dBmV. If your power levels operate at greater than the maximum valid level, use an inline attenuator to bring the power level to within the valid range.
Caution
You should not adjust your input power level by more than 5 dB in a 30-second interval. If you increase the power level by more than 5 dB within 30 seconds, cable interface service on your network is disrupted. If you decrease the power level by more than 5 dB within 30 seconds, cable interfaces on your network are forced offline.
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To set the upstream input power level in dBmV, use the following command in cable interface configuration mode. Default = 0 dBmV.
CMTS01(config-if)# cable upstream usport power-level dbmvVerifying the Upstream Input Power Level
To verify the current value of the upstream input power level, enter the show controllers cable command for the upstream port you have just configured:
CMTS01# show controllers cable1/0 u0Cable1/0 Upstream 0 is upFrequency 24.016 MHz, Channel Width 0.800 MHz, QPSK Symbol Rate 0.640 MspsSpectrum Group is overriddenSNR 33.2560 dBNominal Input Power Level 0 dBmV, Tx Timing Offset 2288Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1Perform these steps if you are having difficulty with verification:
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Activating Upstream Admission Control
The admission control is set as a percentage of the specified upstream channel capacity. The acceptable range is from 10 to 1000 percent. Admission control is disabled by default.
To set the upstream admission control as a percentage of the upstream channel capacity, use the following command in cable interface configuration mode. Valid range is from 10 to 1000 percent.
CMTS01(config-if)# cable upstream usport admission-control percentageVerifying Upstream Admission Control
To determine if upstream admission control is configured and activated, enter the show running-config command in privileged EXEC mode and look for the cable interface configuration information. If upstream admission control is configured and enabled, an admission control entry displays in the show running-config output, indicating the user-defined percentage of upstream channel capacity allowable. If upstream admission control is disabled, no admission control entry displays in the output.
Perform these steps if you are having difficulty with verification:
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Activating Upstream Forward Error Correction (FEC)
The Cisco uBR7100 series CMTS uses forward error correction (FEC) to attempt to correct any upstream data that might have been corrupted. FEC is activated by default and should not be disabled. When FEC is activated, all cable modems on the network also activate FEC.
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To activate the upstream forward error correction and to enable FEC, use the following command in cable interface configuration mode. FEC is enabled by default.
CMTS01(config-if)# cable upstream usport fecVerifying Upstream FEC
To verify if FEC is activated or deactivated, enter the more system:running-config command and look for the cable interface configuration information. If FEC is enabled, an FEC entry displays in the show running-config output. If FEC is disabled, no FEC entry displays in the output.
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Specifying Upstream Minislot Size
To specify the minislot size (in ticks) for specific upstream cable interfaces, use the following command in cable interface configuration mode. Acceptable values are 2, 4, 8, 16, 32, 64, and 128. Default = 8.
CMTS01(config-if)# cable upstream usport minislot-size sizeVerifying Upstream Minislot Size
To verify upstream minislot size, enter the show controllers cable command for the upstream port you have just configured:
CMTS01# show controllers cable1/0 u0Cable1/0 Upstream 0 is upFrequency 24.016 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 MspsSpectrum Group is overriddenSNR 33.2560 dBNominal Input Power Level 0 dBmV, Tx Timing Offset 2288Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1part_id=0xFFFF, rev_id=0xFF, rev2_id=0xFFnb_agc_thr=0x0000, nb_agc_nom=0x0000Range Load Reg Size=0x58Request Load Reg Size=0x0EMinislot Size in number of Timebase Ticks is = 8Minislot Size in Symbols = 64Bandwidth Requests = 0xFEPiggyback Requests = 0xDInvalid BW Requests= 0x2Minislots Requested= 0x2963Minislots Granted = 0x2963Minislot Size in Bytes = 16Map Advance = 4000 usecsUCD Count = 32964DES Ctrl Reg#0 = C000C043, Reg#1 = 0Perform these steps if you are having difficulty with verification:
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Activating the Upstream Scrambler
The scrambler on the upstream RF carrier enables cable modems on the HFC network to use built-in scrambler circuitry for upstream data transmissions. The scrambler circuitry improves reliability of the upstream receiver on the cable modem card.
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To activate the upstream scrambler, use the following command in cable interface configuration mode. The upstream scrambler is enabled by default.
CMTS01(config-if)# cable upstream usport scramblerVerifying the Upstream Scrambler
To determine if the upstream scrambler is activated, enter the more system:running-config command and look for the cable interface configuration information.
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Activating Upstream Differential Encoding
To enable differential encoding on upstream traffic to a specified cable interface, use the following command in cable interface configuration mode. Upstream differential encoding is enabled by default.
CMTS01(config-if)# cable upstream usport differential-encodingVerifying Upstream Differential Encoding
To determine if upstream differential encoding is activated, enter the show running-config command and look for the cable interface configuration information. If upstream differential encoding is enabled, a differential encoding entry displays in the show running-config output. If upstream differential encoding is disabled, no differential encoding entry displays in the output.
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Activating Upstream Rate Limiting
Upstream rate limiting allows upstream bandwidth requests from rate-exceeding cable modems to be buffered without incurring TCP-related timeouts and retransmits. This enables the CMTS to enforce the peak upstream rate for each cable modem without degrading overall TCP performance for the subscriber CPEs. Upstream grant shaping is per cable interface (SID).
Token bucket policing with shaping is the per-upstream default rate-limiting setting at the CMTS. Shaping can be enabled or disabled for the token-bucket algorithm.
To enable upstream rate limiting for an upstream port on a Cisco cable modem card, use one of the following commands in cable interface configuration mode.
To disable upstream traffic shaping for an upstream port, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport rate-limitVerifying Upstream Rate Limiting
To determine if upstream rate limiting is configured and activated, enter the show running-config command and look for the cable interface configuration information. If upstream rate limiting is configured and enabled, a rate limiting entry displays in the show running-config output. If upstream rate limiting is disabled, no cable upstream rate-limit displays in the output.
You can also perform the following tasks to verify that rate limiting is enabled on the upstream channel:
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Use the show interface cx/y sid counters command to see the bandwidth request drops. Verify that the upstream rate received by that modem is less than its configured peak rate due to the timeouts and backoffs produced by the drop in bandwidth requests. Enter the show interface cx/y sid command to see the input rate at CMTS in bps.Step 3
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Let the pings run for a period to let averages at the CMTS settle; then view the upstream rate received by this single modem. Use the show interface cx/y command and see the input rate in bps. This value should be close to the modem's peak upstream rate. Also note the drop counts for the modem's SID by using the show interface sid counters command and verify that the CMTS no longer drops the bandwidth requests from the cable modem.
The bandwidth request drop count (from previous non-shaping test) remains unchanged when upstream rate shaping is used, indicating that the CMTS is actually shaping (buffering) the grants for the modem. Verify that the input rate at the CMTS (from the single rate-exceeded CM) stabilizes close to the configured peak rate of 128 Kbps.
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Activating Upstream Frequency Adjustment
To enable automatic upstream frequency adjustment for a specified cable interface, use the following commands in cable interface configuration mode.
To return the automatic upstream frequency adjustment percentage to the default value of 30 percent, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport frequency-adjust averagingVerifying Upstream Frequency Adjustment
To determine if upstream frequency adjustment is configured and activated, enter the show running-config command and look for the cable interface configuration information. If upstream frequency adjustment is enabled, frequency adjustment entries are displayed in the show running-config output. If frequency adjustments are disabled, no frequency adjustment entry displays in the output.
Perform these steps if you are having difficulty with verification:
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Activating Upstream Power Adjustment
To enable upstream power adjustment for a specified cable interface, use one of the following commands in cable interface configuration mode.
To return the automatic upstream power adjustment ranging value to the default of 2 dB, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport power-adjust continueTo return the automatic upstream power adjustment noise value to the default of 30 percent, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport power-adjust noiseTo return the upstream power adjustment threshold value to the default of 1 dB, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport power-adjust thresholdVerifying Upstream Power Adjustment
To determine if upstream power adjustment is configured and activated, enter the show running-config command and look for the cable interface configuration information. If upstream power adjustment is enabled, any or all three of the continue, noise, and threshold power adjustment entries are displayed in the show running-config output. If all three continue, noise, and threshold upstream power adjustments are disabled, no power adjustment entry displays in the show running-config output.
Activating Upstream Timing Adjustment
To enable upstream timing adjustment for a specified cable interface, use one of the following commands in cable interface configuration mode.
To return the upstream time adjustment ranging value to the default of 2 seconds, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport time-adjust continueTo return the upstream time adjustment threshold value to the default of 1 second, enter the following command in cable interface configuration mode:
CMTS01(config-if)# no cable upstream usport time-adjust thresholdVerifying Upstream Timing Adjustment
To determine if upstream timing adjustment is configured and activated, enter the show running-config command and look for the cable interface configuration information. If upstream timing adjustment is enabled, either or both of the continue and threshold timing adjustment entries are displayed in the show running-config output. If both the continue and threshold upstream timing adjustments are disabled, no timing adjustment entry displays in the show running-config output.
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Activating the Upstream Ports
Each upstream port must be activated to enable upstream data transmission from the cable modems on the HFC network to the Cisco uBR7100 series CMTS.
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To activate the upstream ports, use the following commands in global configuration mode.
Verifying the Upstream Ports
To determine if the upstream ports are activated or deactivated, enter the show interface cable command for the upstream port just configured:
router# show interface cable1/0Cable1/0 is up, line protocol is upHardware is BCM3210 FPGA, address is 00e0.1e5f.7a60 (bia 00e0.1e5f.7a60)Internet address is 1.1.1.3/24MTU 1500 bytes, BW 27000 Kbit, DLY 1000 usec, rely 255/255, load 1/255Encapsulation, loopback not set, keepalive not setARP type: ARPA, ARP Timeout 04:00:00Last input 00:00:25, output 00:00:00, output hang neverLast clearing of "show interface" counters neverQueuing strategy: fifoOutput queue 0/40, 0 drops; input queue 0/75, 0 drops5 minute input rate 0 bits/sea, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec10878 packets input, 853740 bytes, 0 no bufferReceived 3679 broadcasts, 0 runts, 0 giants, 0 throttles3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort5401 packets output, 645885 bytes, 0 underruns0 output errors, 0 collisions, 9 interface resets0 output buffer failures, 0 output buffers swapped outSetting Upstream Backoff Values
The DOCSIS-specified method of contention resolution for cable modems wanting to transmit data or requests on the upstream channel is a truncated binary exponential backoff, with the initial backoff window and the maximum backoff window controlled by the CMTS. The Cisco uBR7100 series CMTS specifies backoff window values for both data and initial ranging, and sends these values downstream as part of the Bandwidth Allocation Map (MAP) MAC message.
The values are configurable on the Cisco uBR7100 series software and are power-of-two values. For example, a value of 4 indicates a window between 0 and 15; a value of 10 indicates a window between 0 and 1023. You can set fixed start and end values for data backoff on the upstream ports, or you can set the upstream ports for automatic data backoff. You have the same options for ranging backoff. For both backoff windows, the default start value is 0; the default end value is 4. Valid values are from 0 to 15.
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To set data or ranging backoff values for an upstream port, use one or more of the following commands, in cable interface configuration mode.
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Verifying Upstream Data Backoff Automatic
To verify backoff window settings, enter the show controllers cable command for the upstream port you have just configured:
CMTS01# show controllers cable1/0 u0Cable1/0 Upstream 0 is upFrequency 24.016 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 MspsSpectrum Group is overriddenSNR 33.2560 dBNominal Input Power Level 0 dBmV, Tx Timing Offset 2288Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1part_id=0x3137, rev_id=0x03, rev2_id=0xFFnb_agc_thr=0x0000, nb_agc_nom=0x0000Range Load Reg Size=0x58Request Load Reg Size=0x0EMinislot Size in number of Timebase Ticks is = 8Minislot Size in Symbols = 64Bandwidth Requests = 0xFEPiggyback Requests = 0xDInvalid BW Requests= 0x2Minislots Requested= 0x2963Minislots Granted = 0x2963Minislot Size in Bytes = 16Map Advance = 4000 usecsUCD Count = 32964DES Ctrl Reg#0 = C000C043, Reg#1 = 0Enabling and Configuring Baseline Privacy
Introduction to the Baseline Privacy Interface (BPI)
BPI gives subscribers data privacy across the RF network, encrypting traffic flows between the CMTS and CM. The level of data privacy is roughly equivalent to that provided by dedicated line network access services such as analog modems or digital subscriber lines (DSL). BPI provides basic protection of service, ensuring that a CM, uniquely identified by its MAC address, can obtain keying material for services only it is authorized to access.
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BPI is defined as a set of extended services within the DOCSIS MAC sublayer. Refer to the DOCSIS Baseline Privacy Interface Specification for detailed requirements.
BPI extends the definition of the MAC sublayer's SID. The DOCSIS RF Interface Specification defines a SID as a mapping between CMTS and CM to allocate upstream bandwidth and class of service management. When BPI is activated, the SID also identifies a particular security association and has upstream and downstream significance. When BPI is operational, downstream multicast traffic flow that typically does not have a SID associated with it, now has a SID. The Privacy Extended Header Element includes the SID associated with the MAC Packet Data Physical Data Unit (PDU). The SID and other components of the extended header element identify to a CM the keying material required to decrypt the MAC PDU's packet data field.
BPI's key management protocol runs between the CMTS and the CM. CMs use the protocol to obtain authorization and traffic keying material relevant to a particular SID from the CMTS, and to support periodic reauthorization and key refresh.
The key management protocol uses RSA—a public key encryption algorithm—and the electronic codebook (ECB) mode of DES to secure key exchanges between the CMTS and a CM. Privacy is in the form of 56-bit (the default) or 40-bit encryption between the CMTS and CM. Since BPI is part of DOCSIS, all DOCSIS-certified CMs and qualified CMTS are fully interoperable. Figure 3-1 shows a BPI architecture.
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A SID's keying material has a limited life span. When the CMTS delivers SID keying material to a CM, it also provides the CM with the lifetime value.
Figure 3-1 BPI Network Example
BPI Key Management
BPI initialization begins with the CM sending the CMTS an authorization request, containing data identifying:
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At that time, BPI provides basic protection against theft of service by ensuring the CM, identified by its MAC address, can obtain keying materials only it is authorized to access. The CMTS replies with a list of SIDs on which to run BPI. The reply also includes an authorization key from which the CM and CMTS derive the keys needed to secure a CM's subsequent requests for additional encryption keys. After obtaining the traffic encryption key, the CMs begin to transmit encrypted data.
Differentiating Traffic Streams
BPI only encrypts data on the cable network and only encrypts the user data itself, not cable MAC headers. BPI also does not encrypt MAC management messages.
After BPI is enabled, however, and encryption has been negotiated for a given SID, all user data sent using that SID is encrypted. BPI differentiates traffic, based on the SID alone.
CM Communication with BPI
Figure 3-2 illustrates BPI communications. When user A sends packets to user B, the CM encrypts those packets using special keys specific to the user's CM. Packets are then transmitted to the CMTS where they are decrypted.
If user B is attached to the cable TV network, the CMTS then re-encrypts the information using a key specific to user B, and the encrypted data is passed to user B's CM where it is decrypted and sent to user B. In this manner, an unauthorized user is not able to see unencrypted traffic between user A and user B.
Caution
Figure 3-2 BPI Encrypted Data on the Cable TV Network
Enabling BPI
To enable BPI, choose software images at both the CMTS and CM that support the mode of operation. For the Cisco uBR7100 series software, choose an image with "k1" in its file name or BPI in the feature set description. For Cisco uBR924 cable access routers, all CM images from Cisco IOS Release 12.0(5)T1 or later support this by default. For earlier Cisco IOS release CM images, choose an image with "k1" in its file name or BPI in the feature set description.
Note
When baseline privacy is enabled, the Cisco uBR7100 series router generates traffic encryption keys (TEKs) for each applicable SID; 56-bit encryption/decryption is the default for Cisco uBR7100 series equipment.
The router uses the keys to encrypt downstream data and decrypt upstream traffic from two-way cable interfaces. The Cisco uBR7100 series router generates keys for unicast, broadcast, and multicast operation as appropriate. Keys are refreshed periodically and have a default lifetime of 12 hours.
Configuring Baseline Privacy
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To configure baseline privacy (deviating from default values), follow procedures in this section:
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Configuring Key Encryption Key (KEK) Privacy
A gracetime KEK can be set from 300 to 1800 seconds. A lifetime KEK can be set from 86400 to 6048000 seconds. If you do not set a KEK value, the default values are used.
To configure KEK data privacy on the HFC network, enter one of the following commands in cable interface configuration mode.
Verifying KEK Privacy
To verify the KEK lifetime or gracetime values that are set, enter the show cable privacy kek command:
CMTS01# show cable privacy kekConfigured KEK life time value = 750000Configured KEK grace time value = 800
Tip
Configuring Traffic Encryption Key (TEK) Privacy
A gracetime TEK can be set from 300 to 1800 seconds. A lifetime TEK can be set from 1800 to 604800 seconds. If you do not set a TEK value, the defaults are used.
To configure TEK data privacy on the HFC network, use the following commands in cable interface configuration mode.
Verifying TEK Privacy
To verify the TEK lifetime or gracetime values that are set, enter the show cable privacy tek command:
CMTS01# show cable privacy tekConfigured TEK life time value = 56000Configured TEK grace time value = 900Activating Baseline Privacy
BPI is activated by default when using an image that supports baseline privacy. Commands in the cable interface configuration mode are as follows:
Verifying Baseline Privacy
To determine if baseline privacy is activated, enter the show interface privacy command. When using a Cisco uBR7100 series "k1" image, cable privacy is enabled by default and can only be disabled with the no cable privacy command. The cable modem must also be configured to support baseline privacy.
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Configuring and Activating Frequency Agility
Set upstream port frequency to a fixed value during system installation and testing. Choose this value from your frequency allocation plan for the RF plant segment connected to the upstream.
When the system has reached sufficient stability, the RF domain topology can be entered into the configuration file to enable spectrum management. Spectrum management or frequency agility is configured and activated using spectrum groups.
Frequency-hopping policies supported on all Cisco cable modem cards include combined blind and scheduled specifications, as well as guided frequency hops.
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To configure and activate frequency agility, perform the following tasks:
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Creating Spectrum Groups
To create a spectrum group, use one of the following general commands in global configuration mode.
Frequency agility is configured and activated using spectrum groups. You can create from 1 to 32 spectrum groups for each cable interface card upstream port.
To create spectrum groups, specify a list of upstream frequencies and nominal power levels that each spectrum group can use when an upstream frequency change is necessary. Each spectrum group should have its own list of upstream frequencies.
After you have created one or more spectrum groups, you can add characteristics to them, providing more definitive control over frequency usage and frequency hopping. See the "Configuring and Activating Spectrum Groups" section.
Verifying Spectrum Groups
To verify that a spectrum group is created, enter the show cable spectrum-group command:
CMTS01# show cable spectrum-groupspectrum-group 1spectrum-group 2spectrum-group 3
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Configuring and Activating Spectrum Groups
After you create a spectrum group, configure a list of upstream frequencies and optional nominal power levels that each spectrum group can use when an upstream frequency change is necessary. Each spectrum group should have its own list of upstream frequencies.
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To configure and activate a spectrum group, use the following commands in global configuration mode.
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If your cable plant has an upstream noise characteristic on a weekly cycle, use time-scheduled spectrum allocation:
CMTS01(config)# cable spectrum-group 1 time Mon 08:00:00 frequency 21600000Deletion is performed using the delete keyword:
CMTS01(config)# cable spectrum-group 1 time Mon 18:00:00 delete frequency 21600000The following example displays a spectrum group configuration that is designed to perform minor equalization as a function of frequency.
CMTS01(config)# cable spectrum-group 1 frequency 21600000CMTS01(config)# cable spectrum-group 1 frequency 24800000 1CMTS01(config)# cable spectrum-group 1 frequency 28000000 2In the previous example, the upstream port nominal receive power at 21.6 MHz is 0 dBmV, at 24.8 MHz is 1 dBmV, and at 28.0 MHz is 2 dBmV. At any time, the power level set in the interface configuration overrides the spectrum group power level.
The following example enables spectrum management for all upstream ports, assuming that all combiner groups use the frequency band from 20 to 26 MHz:
CMTS01(config)# cable spectrum-group 1 band 20000000 26000000CMTS01(config)# cable spectrum-group 2 sharedCMTS01(config)# cable spectrum-group 2 band 20000000 26000000CMTS01(config)# cable spectrum-group 3 sharedCMTS01(config)# cable spectrum-group 3 band 20000000 26000000CMTS01(config)# interface Cable1/0CMTS01(config-if)# cable spectrum-group 1CMTS01(config-if)# cable upstream 2 spectrum-group 2CMTS01(config-if)# cable upstream 3 spectrum-group 2CMTS01(config-if)# exitFor the 20 to 26 MHz band of each RF domain, the spectrum is channelized according to the channel width settings of each member port. For example, if the ports U2 and U3 of Cable1/0 are set to 3.2 MHz and 1.6 MHz channel widths, respectively, then spectrum group 2 uses the following channelization:
> Channel Width Start Stop Center> (Mhz) (Mhz) (Mhz) (Mhz)> 1 3.2 20.0 23.2 21.6> 2* 1.6 20.0 21.6 20.8> 3* 1.6 21.6 23.2 22.4> 4 1.6 23.2 24.8 24.0
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Because the group is shared, ports U2 and U3 will be assigned channels 1 and 4, respectively, to prevent overlap.
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> Channel Width Start Stop Center> (Mhz) (Mhz) (Mhz) (Mhz)> 1 3.2 20.0 23.2 21.6> 2 3.2 23.2 26.4 24.8> 3 1.6 20.0 21.6 20.8> 4 1.6 21.6 23.2 22.4> 5 1.6 23.2 24.8 24.0> 6 1.6 24.8 26.4 25.6> 7 1.6 26.4 28.0 27.4Care should be taken to reduce the spectrum allocation when used with small channel widths. Otherwise, there will be a large number of upstream channel slots.
For example, if the allocation is from 20.0-to-28.0 MHz and an upstream port has its channel width set to 0.2 MHz, there are 40 possible slots for that channel width. Blind frequency hopping can require a long time to find the clean slot, because it tries each available slot, one at a time for several seconds during each try.
Verifying Spectrum Group Configuration
To verify if spectrum groups are configured and activated, enter the show cable spectrum-group command:
CMTS01# show cable spectrum-group22:07:46: %SYS-5-CONFIG_I: Configured from console by consoleGroup Frequency Upstream Weekly Scheduled Power SharedNo. Band Port Availability Level Spectrum(Mhz) From Time: To Time: (dBmV)1 5.000-15.000 0 Yes1 12.000 0 Yes1 22.000 7 Yes2 29.000 6 No2 26.000 0 No3 35.000-41.000 0 No3 16.000-19.000 5 No5* 5.000-10.000 Thu 21:50:00 Thu 21:45:00 0 YesVerifying Frequency Hopping
To verify frequency hopping on the Cisco uBR7100 series CMTS, note the following:
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After you have established basic operation, inject a tone to the upstream port. For example, if the upstream frequency is currently 22.4 MHz, inject a 22.4 MHz tone at approximately the same power level as the modem. If the power level at the modem is 40 dBmV, set the tone power to 40 dBmV. The interfering carrier should shut down the channel and cause the frequency to change to the next configured value. In this example, it would be 24.0 MHz.
If you do not have an RF tone generator, use another cable modem card and modem that carries traffic. Connect the upstream to the same combiner group, and use the data carrier as an interfering signal by setting it to the same frequency. For example, to test frequency hopping on c1/0, install c1/0 and connect both upstreams together using a combiner. If the upstream frequency of c1/0 is currently 22.4 Mhz, set c1/0 to 22.4 MHz while c1/0 is carrying traffic. This should force c1/0 to change the frequency to the next configured value.
Tip
When defining your spectrum, avoid frequencies with known ingress problems such as amateur radio bands or short-wave bands and spectrum below 20 MHz; allow extra bands for frequency hopping; place upstream ports in the same combiner group in a shared spectrum group; use the receive power level setting to perform slight equalization adjustments.
Configuring Spectrum Group Characteristics
After you have created one or more spectrum groups, add characteristics to them. As stated in the DOCSIS RFI specification, RF channel migration occurs by broadcasting a change in the upstream channel descriptor (UCD) message to all cable interfaces. The UCD message contains the upstream frequency and transmission parameters associated with an upstream channel.
The speed of channel migration via the UCD message is typically less than 20 milliseconds (ms). During this time, upstream transmission is interrupted until the cable interface transmitter adjusts to its new frequency. Data is stored in the cable interface's buffers during this time and is sent when the frequency hop is complete.
Also, per the DOCSIS RFI, station maintenance intervals are used to perform per-modem keepalive polling. The Cisco uBR7100 series poll each cable interface. When ingress noise causes loss of keepalive messages from a configurable percentage of all cable interfaces, resulting in those cable modems going offline, a new frequency is selected from the allocation table and a UCD update is performed.
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The migration time is 10 seconds (maximum) for the decision and 20 ms for the frequency hop. The percentage threshold method prevents a single failing cable interface from affecting service to other good cable interfaces. The system will not hop endlessly because one cable interface is generating 90% of the errors and 90% of the traffic.
The minimum period between frequency hops is also configurable, with a default setting of 300 seconds. If the destination channel is expected to be impaired, the minimum period between frequency hops can be reduced to a small value such as 10 seconds. This allows the frequency hop to continue more rapidly until a clear channel is found. If excessive frequency hop is an issue, the minimum period between hops can be increased.
To adjust the frequency hop threshold percentage or the minimum period between frequency hops, use the following commands in global configuration mode.
To specify that a particular spectrum group is a shared RF spectrum group, use the following command in global configuration mode.
Table 3-1 describes the spectrum-group parameters.
Examples are provided to configure differing spectrum groups:
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Router(config)# cable spectrum-group 1 frequency 6500000•
Router(config)# cable spectrum-group 1 frequency 7000000•
Router(config)# cable spectrum-group 2 frequency 7500000 5•
Router(config)# cable spectrum-group 3 band 12000000 18000000•
Router(config)# cable spectrum-group 3 band 20000000 24000000 13•
Router(config)# cable spectrum-group 4 time Monday 12:00:00 band 5000004 40000000•
Router(config)# cable spectrum-group 3 time 02:00:00 frequency 9500000 5•
Router(config)# cable spectrum-group 3 hop period 800•
Router(config)# cable spectrum-group 3 hop threshold 40•
Router(config)# cable spectrum-group 3 shared•
Router(config)# no cable spectrum-group 3Verifying Spectrum Group Characteristics
To verify spectrum group characteristics and to determine if a spectrum group is shared, use the
show cable spectrum-group command:CMTS01# show cable spectrum-group22:07:46: %SYS-5-CONFIG_I: Configured from console by consoleGroup Frequency Upstream Weekly Scheduled Power SharedNo. Band Port Availability Level Spectrum(Mhz) From Time: To Time: (dBmV)1 5.000-15.000 0 Yes1 12.000 0 Yes1 22.000 7 Yes2 29.000 6 No2 26.000 0 No3 35.000-41.000 0 No3 16.000-19.000 5 No5* 5.000-10.000 Thu 21:50:00 Thu 21:45:00 0 Yes
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Assigning the Spectrum Group and the Upstream Ports
After determining which upstream ports you want assigned to a combiner group, perform the following steps to configure a frequency hop table.
Verifying Spectrum Group and Upstream Port Assignments
Use the show cable spectrum-group command to display the current allocation table and frequency assignments.
Activating Cable Address Resolution Protocol Requests
Address Resolution Protocol (ARP) is an Internet protocol used to map IP addresses to MAC addresses on computers and other equipment installed in a network. You need to activate ARP requests on the cable interface so that the Cisco uBR7100 series CMTS can perform IP address resolution on the downstream path.
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Activating Cable Address Resolution Protocol (ARP) Requests
To activate ARP requests, use the following command in cable interface configuration mode:
Verifying ARP Requests
To verify if cable ARP is activated, enter the more system:running-config and look for the cable interface configuration information. If ARP is activated, it does not appear in this output. If ARP is deactivated, it appears in the output as no cable arp.
CMTS01# more system:running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 1.1.1.1 255.255.255.0no keepaliveno cable arpcable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable downstream symbol-rate 5056941cable upstream 0 frequency 15008000no cable upstream 0 shutdown
Tip
show interface cable command.
Activating Host-to-Host Communication (Proxy ARP)
Cable proxy ARP allows the Cisco uBR7100 series CMTS to issue cable ARP requests on behalf of cable modems on the same cable network subnet.
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Activating Cable Proxy ARP Requests
To activate cable proxy ARP for host-to-host communications, use the following command in cable interface configuration mode.
Table 3-2 Instructions to Activate Cable Proxy ARP Requests
Enable proxy ARP on the cable interface. This is the default.
Verifying Cable Proxy ARP Requests
To verify if cable proxy ARP has been activated or deactivated, enter the more system:running-config and look for the cable interface configuration information. If cable proxy ARP has been activated, it does not appear in the output. If cable proxy ARP has been deactivated, it appears in the output as no cable proxy-arp.
CMTS01# more system:running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 1.1.1.1 255.255.255.0no keepaliveno cable proxy-arpcable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable downstream symbol-rate 5056941cable upstream 0 frequency 15008000no cable upstream 0 shutdown
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Configuring DHCP Options
Activating Cable Relay Agent
The cable relay agent is for use with DOCSIS-based DHCP servers that utilize option 82 to automatically map the Ethernet MAC address of a host (subscriber PC) with the cable interface to which it is connected.
With the cable relay agent activated, the Cisco uBR7100 series CMTS inserts the cable interface MAC address into a DHCP packet when the packet is received from a cable interface or another host. The Cisco uBR7100 series CMTS then forwards the packet to the DHCP server.
To activate the cable relay agent, use the following command in cable interface configuration mode.
CMTS01(config)# cable relay-agent-optionActivate the cable relay agent. This is the default.
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Activating DHCP giaddr
Configure the Cisco uBR7100 series CMTS so it will either assign primary addresses to cable modems and remote hosts, or assign primary addresses to cable modems and secondary addresses to remote hosts.
To configure cable DHCP giaddr functionality, use one of the following commands in cable interface configuration mode.
To disable cable DHCP giaddr functionality (the default) after it has been enabled, enter the no cable dhcp-giaddr command in cable interface configuration mode.
Verifying DHCP giaddr Activation
To determine if DHCP giaddr is activated, enter the show running-config command and look for the cable interface configuration information. If DHCP giaddr is activated, a notation appears in this output. If DHCP giaddr is deactivated, no entry appears in this output.
Configuring Time-of-Day Service
Activating Time-of-Day Service
To activate Time-of-Day (ToD) service for the Cisco uBR7100 series CMTS, use the following command in global configuration mode.
CMTS01(config)# cable time-server enableEnable Time-of-Day (ToD) service for the Cisco uBR7100 series CMTS
To disable ToD service (the default) after it has been enabled, enter the no cable time-server command or the cable time-server disable command in global configuration mode.
Verifying Time-of-Day Service
To determine if ToD service is activated, enter the show running-config command and look for the global cable configuration information. If ToD service is activated, an entry appears in this output. If ToD service is deactivated, no entry appears in this output.
Setting Optional IP Parameters
You can set additional IP parameters to enable downstream echoing of upstream data. To configure these optional IP parameters, perform the following tasks:
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Activating IP Multicast Echo
The Cisco uBR7100 series CMTS echos IP multicast packets by default. To activate IP multicast echo if it has been previously disabled, use the following command in cable interface configuration mode.
Enable IP multicast echo. This is the default.
To disable IP multicast echo, enter the no cable ip-multicast-echo command in cable interface configuration mode.
Verifying IP Multicast Echo
To determine if IP multicast echo is activated or deactivated, enter the more system:running-config command and look for the cable interface configuration information. If IP multicast echo is activated, there is no notation in the output, because this is the default setting. If IP multicast echo is deactivated, a notation appears in the output:
CMTS01# more system:running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 1.1.1.1 255.255.255.0no keepaliveno cable ip-multicast-echocable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable upstream 0 frequency 15008000no cable upstream 0 shutdown
Tip
Activating IP Broadcast Echo
By default, the Cisco uBR7100 series CMTS does not echo IP broadcast packets. To activate IP broadcast echo, use the following command in cable interface configuration mode.
To disable IP broadcast echo when it is enabled, enter the no cable ip-broadcast-echo command in cable interface configuration mode.
Verifying IP Broadcast Echo
To determine if IP broadcast echo is activated or deactivated, enter the more system:running-config command, and look for a notation in the cable interface configuration information:
CMTS01# more system:running-configBuilding configuration...Current configuration:!interface Cable1/0ip address 1.1.1.1 255.255.255.0no keepalivecable ip-broadcast-echocable downstream annex Bcable downstream modulation 64qamcable downstream interleave-depth 32cable upstream 0 frequency 15008000no cable upstream 0 shutdownActivating Packet Intercept Capabilities
To activate packet intercept functionality, use the following commands in cable interface configuration mode.
Configuring Cable Modulation Profiles
To configure cable profiles (deviating from defaults), perform the following as necessary:
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Configuring Cable Modulation Profiles
In this step, you are defining the elements used in a cable modulation profile. The Cisco uBR7100 series CMTS supports as many as 8 cable modulation profiles. Profile 1 is the default.
Caution
The following modulation profile values are configurable:
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To create or change a cable modulation profile, use the following command in global configuration mode.
In the following example, the request burst for cable modulation profile 2 is defined to have 0 fec-tbytes, 16 kbytes fec-len, a burst-len of 1, a guard time of 8, a mod value of qpsk, scrambler enabled with a seed value of 152, differential encoding disabled, a preamble length of 64 bits, a fixed code word length, and 8-bit unique words for upstream unique word length.
CMTS01(config)# cable modulation-profile 2 request 0 16 1 8 qpsk scrambler 152 no-diff 64 fixed uw8To remove a cable modulation profile, use the no cable modulation-profile profile command in global configuration mode. You can use this command to remove all modulation profiles except for modulation profile 1.
Tip
Verifying Cable Modulation Profiles
To determine if a cable modulation profile is created, enter the show cable modulation-profile command.
A sample output is shown in the following example:
CMTS01# show cable modulation-profileMo IUC Type Preamb Diff FEC err FEC Scrambl Max Guard Last Scrambl Preamb length enco correct T seed B time CW offset bytes size size short1 request qpsk 64 no 0x0 0x10 0x152 1 8 no yes 56 1 initial qpsk 128 no 0x5 0x22 0x152 0 48 no yes 0 1 station qpsk 128 no 0x5 0x22 0x152 0 48 no yes 0 1 short qpsk 72 no 0x5 0x4B 0x152 0 8 no yes 48
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Tip
The preamble offset is calculated from the modulation profile entries. The preamble offset is the distance the CMTS looks into the preamble to determine where the preamble starts. The CMTS does not need to look at the entire preamble in all instances. A shorter preamble has less overhead and time associated with that type of burst request. In general, you should use an offset of "0" for initial/station maintenance because you need to separate these packets as distinctly as possible.
The offset for QPSK is shorter because of the way DOCSIS specifies the preamble. For QPSK, it only takes a preamble length of 256 bits to separate frames, whereas with QAM-16, the date rate is much higher. Utilization of a larger preamble is necessary.
Configuring QoS Profiles
The Cisco uBR7100 series CMTS supports multiple QoS profiles. QoS profile 1 is used during cable interface registration and QoS profile 2 is the default QoS profile. Both of these profiles are preconfigured and cannot be removed. However, you can modify these profiles and create additional Q0S profiles for various traffic flows.
To create or change a QoS profile, use the first command below, plus as many of the additional commands as are necessary to make the changes you require. All of the QoS profile commands are global configuration commands.
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Verifying QoS Profiles
To determine if a QoS profile has been created, and to see how it is configured, enter the
show cable qos profile command:CMTS01# show cable qos profileService Prio Max Guarantee Max Max tx TOS TOS Create B IPclass upstream upstream downstream burst mask value by priv precbandwidth bandwidth bandwidth enab enab1 0 0 0 0 0 0x0 0x0 cmts no no2 0 64000 0 1000000 0 0x0 0x0 cmts no no3 0 3120 31200 0 0 0x0 0x0 cmts yes no4 7 87200 87200 0 0 0x0 0x0 cmts yes yes5 0 256000 128000 1000000 0 0x0 0x0 cm no yes
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Caution
Setting QoS Permission
The Cisco uBR7100 series CMTS supports the creation of QoS table entries by SNMP or by CM registration requests. You can also configure a Cisco uBR7100 series CMTS to dynamically update QoS table entries via SNMP.
To set QoS table access, use one or more of the following commands in global configuration mode.
Verifying QoS Permission
To verify QoS permissions, enter the show cable qos permission command:
CMTS01# show cable qos permissionCreate by SNMP Update by SNMP Create by modemsno no yes
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Enforcing a QoS Profile Assignment
To override the provisioned QoS profile of a CM and enforce a CMTS-specified QoS profile, use the following command in global configuration mode.
Assigns the QoS profile, specified by the index number, to all CMs attempting to connect to theCisco uBR7100 series CMTS.
Verifying a QoS Profile Assignment
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Notice that the CMs are getting their provisioned class of service as indicated by the
show cable modem and show cable qos profile commands.Step 2
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Notice that the CMs are assigned temporarily the CMTS-defined PRE_REGISTRATION QoS profile with index 2 until the CMs register with the CMTS.
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Setting Quality of Service (QoS) for Higher Priority Traffic
This feature describes the software enhancements and procedures that support QoS for higher priority traffic. These enhancements include improved support for:
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Refer to the following procedures for setting QoS for higher priority traffic:
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Configuring a QoS Profile for Higher Priority Traffic
Perform these steps to configure a QoS modulation profile:
Monitoring and Maintaining QoS for Higher Priority Traffic
Use the following commands to monitor and maintain QoS for higher priority traffic.
The following example shows how the cable router (mgmt) creates a CM with a QoS profile 30:
Router(config)# cable qos profile 30 name qostestRouter(config)# cable qos profile 30 grant-int 55Router(config)# cable qos profile 30 grant-size 100Router(config)# cable qos profile 30 guaranteed 60000Router(config)# cable qos profile 30 ip-prec 7Router(config)# cable qos profile 30 max-bur 256Router(config)# cable qos profile 30 max-down 3000Router(config)# cable qos profile 30 max-up 6000Router(config)# cable qos profile 30 prior 7Router(config)# cable qos profile 30 privacyrouter# show cable qos profile 30ID Prio Max Guarantee Max Max ToS ToS Create B IP prec.upstream upstream downstream tx mask value by priv ratebandwidth bandwidth bandwidth burst enab enab30 7 6000000 60000000 100000000 256 0x0 0x0 mgmt yes noTo configure a QoS profile, enter the cable qos profile global configuration command. To set default values for profile group numbers 1 or 2, or to remove the QoS profile if no specific parameters remain, enter the no form of this command.
cable qos profile {groupnum | grant-interval {interval}| grant-size {size} | guaranteed-upstream {rate} | ip-precedence {value} | max-burst {rate} | max-downstream {rate} | max-upstream {rate} | name {string} | priority {value} | privacy | ToS-overwrite {value}}
no cable qos profile {groupnum | grant-interval {interval} | grant-size {size} | guaranteed-upstream {rate} | ip-precedence {value} | max-burst {rate} | max-downstream {rate} | max-upstream {rate} | name {string} | priority {value} | privacy | ToS-overwrite {value}}
The following table describes the syntax and values for these commands.
Refer to the following example to configure QoS profile 4 with guaranteed upstream of 2 kbps, maximum transmission burst of 2, an IP precedence of 7, a maximum downstream rate of 300 kbps, with a priority of 4, cable baseline privacy set, and a ToS-overwrite mask and value byte (in hex) of 0x7:
Router(config)# cable qos profile 4 name MondayqosRouter(config)# cable qos profile 4 guaranteed-upstream 2Router(config)# cable qos profile 4 max-burst 2Router(config)# cable qos profile 4 ip-precedence 7 max-downstream 300Router(config)# cable qos profile 4 priority 4Router(config)# cable qos profile 4 ToS-overwrite 0x7To display QoS profiles, use the show cable qos profile privileged EXEC configuration command.
Note
show cable qos profile qos profile index verbose
The qos profile index option displays the index of the specified QoS profile. The verbose option displays all details for the specified QoS profile index.The following example shows the full QoS table for profile 30:
router# show cable qos profile 30 verboseProfile Index 30Name testUpstream Traffic Priority 7Upstream Maximum Rate (bps) 6000000Upstream Guaranteed Rate (bps) 60000000Unsolicited Grant Size (bytes) 100Unsolicited Grant Interval (usecs) 55000Upstream Maximum Transmit Burst (bytes) 256IP Type of Service Overwrite Mask 0x0IP Type of Service Overwrite Value 0x0Downstream Maximum Rate (bps) 100000000Created By mgmtBaseline Privacy Enabled yesIP precedence rate limitsIP precedence 2Rate Limit 100000Table 3-2 describes the fields shown in the show cable qos profile displays.
Table 3-3 Related Commands
In the sample show cable qos profile output response, note the added IP precedence column:
CMTS01# show cable qos profileService Prio Max Guarantee Max Max tx TOS TOS Create B IPclass upstream upstream downstream burst mask value by priv precbandwidth bandwidth bandwidth enab enab1 0 0 0 0 0 0x0 0x0 cmts no no2 0 64000 0 1000000 0 0x0 0x0 cmts no no3 0 3120 31200 0 0 0x0 0x0 cmts yes no4 7 87200 87200 0 0 0x0 0x0 cmts yes yes5 0 256000 128000 1000000 0 0x0 0x0 cm no yesThe software provides QoS based on the CM SID. Every QoS profile carries a parameter maximum downstream rate which is used to provide peak rate limiting and traffic shaping on the downstream. When the particular CM supports combined high priority and data traffic, rate exceeded data packets might shut out or delay higher priority packets, degrading quality. As a solution, IP precedence bits are used as a basic differentiator to provide independent rate limits for different traffic streams as desired.
The show interface cable x/y upstream port # command is also enhanced to reflect the current state of the new MAC scheduler for the specified upstream port as shown in the following example:
cmts# show interface cable 1/0 upstream 0Cable1/0: Upstream 0 is upReceived 68 broadcasts, 0 multicasts, 20811 unicasts0 discards, 99 errors, 0 unknown protocol20879 packets input, 0 corrected, 0 uncorrectable99 noise, 0 microreflectionsTotal Modems On This Upstream Channel : 2 (2 active)Default MAC schedulerQueue[Cont Mslots] 1/104, fifo queuing, 0 dropsQueue[Rng Polls] 0/20, fifo queuing, 0 dropsQueue[CIR Grants] 0/20, fair queuing, 0 dropsQueue[BE Grants] 0/30, fair queuing, 0 dropsQueue[Grant Shpr] 0/30, calendar queuing, 0 dropsReserved slot table currently has 5 CBR entriesReq IEs 176103, Req/Data IEs 0Init Mtn IEs 540, Stn Mtn IEs 101Long Grant IEs 10042, Short Grant IEs 405Total channel bw reserved 200000 bpsCIR admission control not enforcedCurrent minislot count : 2099853 Flag: 1Scheduled minislot count : 2100020 Flag: 1The show interface sid command is also enhanced to display the type of SID—whether it is "Static" versus "Dynamic".
cmts# show interface cable x/y sid
Sid
Prim Sid
Type
Online State
Admin Status
QoS
Create Time
IP Address
MAC Address
2
stat
online
enable
4
12:10:25
1.11.51.37
0010.7b6b.722d
4
2
dyn
online
enable
5
12:10:30
1.11.51.37
0010.7b6b.722d
You can optimize the physical layer parameters on an upstream channel. An example is provided for physical layer parameters that can be used on the CMTS for upstream channels expected to support high priority traffic density. These parameters minimize the physical layer overhead encountered for each fixed sized (89 bytes) packet. The resulting fine tuning gives a direct improvement in the number of CBR high priority connections that can be admitted on a single upstream channel.
Configure the following settings for the upstream channel to maximize the number of CBR
connections:•
•
•
•
•
•
•
•
To configure the above modulation profile at the CMTS, use the following commands:
Create a new qpsk modulation profile template m with all default parameters, except the "short grant" profile which has special parameters as given below:
cmts(config)# cable modulation-profile m qpskcmts(config)# cable modulation-profile m short 2 52 16 8 qpsk scrambler 152 diff 72 shortened uw8Configure upstream port n on a given interface to use minislot size of 8 ticks and above modulation profile template m:
cmts(config-if)# cable upstream n minislot-size 8cmts(config-if)# cable upstream n modulation-profile mSetting and Viewing Concatenation
To turn concatenation off or on from the CMTS, use the cable upstream concatenation interface configuration command. To turn off concatenation from the default state of on, use the no form of this command.
cable upstream n concatenation
no cable upstream n concatenation
Note
Setting Concatenation
Tip
Caution
Viewing Concatenation Status
Use the following command to monitor concatenation:
Displays the current status of concatenation for the specified slot and port.
The following display indicates that concatenation is turned off.
Lab-CMTS# show controller cab 1/0Interface Cable1/0Hardware is BCM3210 FPGAidb 0x6182BE18 MAC regs 0x3D900000 PLX regs 0x3D800000rx ring entries 1024 tx ring entries 128 MAP tx ring entries 128Rx ring 0x4B09A400 shadow 0x61849408 head 359Tx ring 0x4B09C440 shadow 0x6184A478 head 85 tail 85 count 0MAP Tx ring 0x4B09C880 shadow 0x6184A8E8 head 7 tail 7 count 0MAP timer sourced from slot 4throttled 0 enabled 0 disabled 0Rx: spurious 341 framing_err 0 hcs_err 2 no_buffer 0 short_pkt 2no_enqueue 0 no_enp 1 miss_count 0 latency 16invalid_sid 0 invalid_mac 0 bad_ext_hdr_pdu 0 concat 0 bad-concat 0Tx: full 0 drop 0 stuck 0 latency 1MTx: full 0 drop 0 stuck 0 latency 9Slots 68056 NoUWCollNoEngy 15 FECorHCS 2 HCS 0Req 1803579865 ReqColl 1 ReqNoise 276120 ReqNoEnergy 0ReqData 0 ReqDataColl 0 ReqDataNoise 0 ReqDataNoEnergy 0Rng 143099 RngColl 0 RngNoise 3891FECBlks 0 UnCorFECBlks 0 CorFECBlks 0MAP FIFO overflow 0, Rx FIFO overflow 0, No rx buf 0DS FIFO overflow 0, US FIFO overflow 0, US stuck 0Bandwidth Requests= 0xFFC9Piggyback Requests= 0xA1DRanging Requests= 0x22039Timing Offset = 0x0Bad bandwidth Requests= 0x31BCNo MAP buffer= 0x0Cable1/0 Downstream is upFrequency not set, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 MspsFEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4Downstream channel ID: 0Cable1/0 Upstream 0 is upFrequency 20.208 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.280 MspsSpectrum Group is overriddenSNR - UnknownNominal Input Power Level 0 dBmV, Tx Timing Offset 4667Ranging Backoff automatic (Start 0, End 3)Ranging Insertion Interval automatic (60 ms)Tx Backoff Start 0, Tx Backoff End 4Modulation Profile Group 1concatenation is disabled
