C H A P T E R 3 Spectrum Management for the Cisco Cable Modem Termination System This chapter describes the spectrum management features supported by the Cisco Cable Modem Termination System (CMTS) universal broadband routers.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Feature Overview Spectrum management is a software and hardware feature provided in the Cisco Cable Modem Termination System (CMTS) so that the CMTS may sense both downstream and upstream plant impairments, report them to a management entity, and automatically mitigate them where possible. The CMTS directly senses upstream transmission errors.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Upstream Signal Channel Overview The upstream channel is characterized by many cable modems transmitting to the CMTS. These signals operate in a burst mode of transmission. Time in the upstream channel is slotted. The CMTS provides time slots and controls the usage for each upstream interval. The CMTS periodically broadcasts Upstream Channel Descriptor (UCD) messages to all cable modems.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Upstream Segments and Combiner Groups The Cisco routers divide a cable plant into downstream channels. Downstream channels contain upstream segments. Each upstream segment typically serves more than one fiber node. Upstream segments can be defined as one of the following: Note • Sparse segment—Containing one upstream channel per upstream segment.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Frequency Management Policy Spectrum management applies a common frequency-management policy to a set of upstream ports to ensure that data is delivered reliably over the cable plant. Cable plant operators must make noise measurements and determine the cable plant’s spectrum management policy.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview The cable interface does not operate until you either create and configure a spectrum group or set a fixed upstream frequency. Configuring a spectrum group disables the fixed upstream frequency setting. From the interface configuration prompt, an interface is assigned membership in a spectrum group.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Table 3-1 Spectrum Management Phases Intelligent Spectrum Management Using uBR-MC16S Card Guided and Scheduled Spectrum Management Advanced Spectrum Management Using uBR-MC16S Card Cisco IOS release supported 11.3(9)NA, 12.0(5)T1, 12.1(2)EC and later, 12.0(6)SC, 12.1(1), 12.2(8)BC21 12.1(1)T, 12.1(2)EC, 12.2(2)XF, 12.2(4)BC1b, and later. See Table 3-2 on page 3-8 for more detailed information. 12.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview See Table 3-2 on page 3-8 for a summary of the Guided and Scheduled spectrum management features and the Cisco IOS release in which it was introduced and subsequently supported. Table 3-2 Summary of Guided and Scheduled Spectrum Management Features by Release Feature Traffic Shaping, page 3-8 Upstream Traffic Shaping, page 3-9 Downstream Traffic Shaping, page 3-10 Cisco IOS Release Supported 11.3(6)NA, 11.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Each time a packet belonging to a flow is transmitted on an output channel, the token-bucket policer function checks the rate limit status of the flow, passing the following parameters: • Token bucket peak rate in bits/msec. • Token bucket depth (maximum transmit burst) in bits. • Length of current packet to be sent in bits. • Pointer to the flow’s token bucket.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Downstream Traffic Shaping The CMTS supports basic downstream traffic shaping by effecting data rate limiting on a per-modem basis. A downstream traffic shaping feature called downstream rate limiting with type-of-service (ToS) bits extends that capability by allowing the CMTS administrator to configure the ToS byte to calculate the data rate for a specified flow.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Time-scheduled and guided hopping techniques are independent concepts: • The spectrum is controlled by a script, not a frequency table. • The available spectrum is time-scheduled as an option. • A guided hopping frequency is selected from the available spectrum at the current time. You can configure and activate frequency hopping by using spectrum groups.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Time-Scheduled Frequency Hopping You can specify upstream channel frequency reassignment based on a configured time of every day or of a specific day of the week. If your cable plant has an upstream noise characteristic on a weekly cycle, use time-scheduled spectrum allocation. With a time-scheduled policy, a single frequency becomes valid at any given time.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview The criteria for modulation profile 1 to switch to modulation profile 2 (more robust modulation scheme) includes one of the following: • The upstream SNR goes below 25dB (SNR < 25dB) OR • The number of correctable FEC errors is more than 3 percent of the packets received in a 15-second time period OR • The number of uncorrectable FEC errors is more than 1 percent of the packets received in a 15-second time per
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Advanced Hardware-Based Spectrum Management The Cisco uBR-MC16S cable interface line card is a card with a DOCSIS-based cable interface that supports one downstream and six upstreams. It incorporates a daughter board with hardware-based spectrum management features that provide enhancements to the basic features supported by the other Cisco cable interface line cards.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Feature Overview Advanced Spectrum Management Features The Advanced spectrum management features for the Cisco uBR-MC16S cable interface line card are available in 12.2(8)BC2 and later 12.2 BC releases as a software-only upgrade. These enhancements provide the following additional features. • Supports proactive channel management, to avoid the impacts of ingress and keep subscribers online and connected.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Benefits Note The Dynamic Upstream Modulation feature was introduced in Cisco IOS Release 12.1(3a)EC1. The above enhancements to this feature exist only in Cisco IOS Release 12.2(8)BC2 and later 12.2 BC releases; they are not supported in any Cisco IOS 12.1 EC Release. • When using a Cisco uBR-MC16S line card on a Cisco CMTS router running Cisco IOS Release 12.2(8)BC2 and later 12.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Benefits Table 3-3 Benefits of Guided and Scheduled Spectrum Management Features Guided and Scheduled Spectrum Management Feature Benefits Upstream Traffic Shaping • The CMTS can buffer the grants for rate-exceeded modems. This grant buffering at the CMTS avoids TCP-related timeouts and retransmits, resulting in an improved TCP throughput performance for the rate-exceeded modems.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Benefits Table 3-4 Benefits of Advanced Spectrum Management Features (Cisco uBR-MC16S Card) (continued) Advanced Spectrum Management Feature Intelligent Frequency Hopping Dynamic Upstream Modulation SNMP Interface Benefits1 • Proactively changes upstream frequency for an interface before noise conditions become severe enough to force cable modems offline.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Restrictions and Limitations Restrictions and Limitations Dynamic Upstream Modulation • The Cisco router has one preconfigured (primary) modulation profile that defines a typical profile for QPSK modulation. To use the Dynamic Upstream Modulation feature, you must create a second modulation profile that has a higher modulation scheme than the preconfigured profile.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Restrictions and Limitations Note • This default is being tracked by caveat CSCdx35070. When using Cisco IOS Release 12.2(8)BC2, in rare situations, using CLI commands to configure the Cisco uBR-LCP2-MC16 card could result in the error message "Resources are busy with other msg requests. Try later." The workaround is to repeat the same configuration command again until the error disappears.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Prerequisites Constant use of the DCMTA tool could result in excessive volumes of SNMP traffic that affects network bandwidth and performance on the Cisco uBR7200 series CMTS. For this reason, Cisco recommends against running the DCMTA software continuously. Instead, start the software when needed and exit it after the problem has been resolved.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Related Documents • For Intelligent and Advanced spectrum management features (hardware-based, CNR frequency hopping), Cisco uBR-MC16S cable interface line card (Cisco uBR7200 series routers) or Cisco uBR-LCP2-MC16S cable interface line card (Cisco uBR10012 routers). • Ensure that your network is designed to support reliable broadband data transmission.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Related Documents • Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide • Cisco uBR7200 Series Universal Broadband Router Cable Modem Card Installation and Configuration publication • Cisco uBR7200 Series Universal Broadband Router Port Adapter Installation and Configuration publication • Cisco uBR7200 Series Universal Broadband Router 550-Watt DC-Input Power Supply Replacement Instructions • Cisco
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Supported Platforms Supported Platforms Table 3-6 Spectrum Management Features and Supported Platforms Feature Upstream Traffic Shaping Supported Platform • Cisco uBR7100 series • Cisco uBR7223, Cisco uBR7246, and Cisco uBR7246 VXR • Cisco uBR10012 router • Cisco uBR7100 series • Cisco uBR7223, Cisco uBR7246, and Cisco uBR7246 VXR • Cisco uBR10012 router • Cisco uBR7100 series • Cisco uBR7223, Cisco uBR7246, and
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Supported Standards, MIBS, and RFCs Supported Standards, MIBS, and RFCs Standard DOCSIS 1.0 (SP-RFI-I05-991105) DOCSIS 1.1 (SP-RFIv1.1-I06-001215) MIBs • These features support the standard MIBs supported by the Cisco uBR7100 series, Cisco uBR7200 series, and the Cisco uBR10012 router, including the DOCSIS 1.0 and 1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks • Configuring Dynamic Upstream Modulation, page 3-32 • Setting Input Power Level, page 3-34 • Verifying Frequency Hopping, page 3-35 Setting 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.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks 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.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Creating Spectrum Groups To create a spectrum group with either a specific frequency or a band of frequencies, use one of the following commands in global configuration mode: Command Purpose CMTS01(config)# cable spectrum-group group-number [time day hh:mm:ss [delete]] frequency up-freq-Hz [power-level-dBmV] Creates a spectrum group with a specific frequency.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks You can use the command to configure all the characteristics at once or enter the parts of the command separately to configure a separate characteristic. Use the no form of the command to remove a spectrum group. Note For more information on the cable spectrum-group command and for syntax descriptions, see the Cisco Broadband Cable Command Reference Guide on Cisco.com and on the Documentation CD-ROM.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Note You must repeat the command described above for each frequency or power level that you want to add to a spectrum group’s list of valid values.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Command Purpose CMTS01(config)# cable spectrum-group group-number hop threshold percent Sets the percentage of all cable modems losing keepalive messages that will cause a frequency hop. Hop threshold is the threshold value (expressed as a percentage) of the number of offline modems identified before the CMTS initiates an automatic frequency hop.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Assigning the Spectrum Group and the Upstream Ports After you have added upstream frequencies (hop tables) and you have determined which upstream ports you want assigned to a combiner group, you want to assign the upstream ports to the frequency hop tables for an interface.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Step 2 Command Purpose Router(config)# cable modulation-profile profile [ mix | qam-16 | qpsk ] Creates a modulation profile. A modulation profile is a collection of six burst profiles sent out in a UCD message to configure modem transmit parameters for the upstream message types: request, reqdata, initial maintenance, station maintenance, short grant, and long grant.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Setting Input Power Level When you set the frequency, you may also set the input power level. To set upstream input power levels, use one of the following commands in global configuration mode.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Verifying Frequency Hopping You can verify frequency hopping on the CMTS either by using command-line interface (CLI) commands or by using an RF tone generator. Verifying Frequency Hopping Using CLI Commands To verify frequency hopping using CLI commands, use the following procedure: Step 1 Verify that the interface being tested is up, using the show interface cable command in privileged EXEC mode.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Verifying Frequency Hopping Using an RF Tone Generator To verify frequency hopping using an RF tone generator, first verify that the upstream is performing properly. Then inject a tone to the upstream port at the current upstream frequency and cable modem power level. For example, if the upstream frequency is 22.4-MHz, inject a 22.4 MHz tone at approximately the same power level as the modem.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Configuring Spectrum Groups Frequency hopping cannot be done without first creating one or more spectrum groups, which define the specific frequencies that are available to an upstream. A spectrum group can contain a range of frequencies as well as a list of specific frequencies.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks To configure a spectrum group with multiple fixed frequencies, use the following procedure: Command Purpose Step 1 Router(config)# configure terminal Enters configuration mode. Step 2 Router(config)# cable spectrum-group group-number [day time hh:mm:ss] frequency up-freq-hz [power-level-dbmv] Creates a spectrum group and specifies the frequency (or frequencies) that belong to the group.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Configuring Dynamic Upstream Modulation To enable the Dynamic Upstream Modulation feature for the Cisco uBR-MC16S cable interface line card, create at least two modulation profiles then assign them to the appropriate upstream. Command Purpose Step 1 Router(config)# configure terminal Enters configuration mode.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Step 5 Command Purpose Router(config-if)# cable upstream n modulation-profile primary-profile-number secondary-profile-number Adds the modulation profile to an upstream on the cable interface. n = upstream number on cable modem slot (on the Cisco uBR-MC16S, upstream port numbers are 0–5) primary-profile-number = the primary modulation profile added to the interface.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Step 4 Command Purpose Router(config-if)# cable upstream n threshold cnr-profile1 threshold1-in-dB cnr-profile2 threshold2-in-dB corr-fec fec-corrected uncorr-fec fec-uncorrected (Optional) Specifies the CNR threshold and FEC values for the upstream and its two modulation profiles.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Step 2 To display modulation profile group information, use the show cable modulation-profile command in privileged EXEC mode: Router# show cable modulation-profile [profile] [iuc-code] profile—(Optional) Profile number (1–8). iuc-code—(Optional) Internal usage code (IUC).
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Range Load Reg Size=0x58 Request Load Reg Size=0x0E Minislot Size in number of Timebase Ticks is = 8 Minislot Size in Symbols = 64 Bandwidth Requests = 0x12 Piggyback Requests = 0x5 Invalid BW Requests= 0x0 Minislots Requested= 0xFA Minislots Granted = 0xFA Minislot Size in Bytes = 32 Map Advance (Dynamic) : 2454 usecs UCD Count = 230 DES Ctrl Reg#0 = C000C043, Reg#1 = 0 Dynamic Services Stats: DSA: 0 REQs 0 RSP
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks 1 1 1 1 1 1 1 1 1 1 Step 6 23.120 22.832 22.896 23.024 23.152 22.896 22.896 20.784 22.928 22.960 [1.60] [1.60] [1.60] [1.60] [1.60] [1.60] [1.60] [1.60] [1.60] [1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks To configure a spectrum group with a range of frequencies, use the following procedure: Command Purpose Step 1 Router(config)# configure terminal Enters configuration mode. Step 2 Router(config)# cable spectrum-group group-number [day time hh:mm:ss] band up-freq-hz up-freq2-hz [power-level-dbmv] Creates a spectrum group and specifies a range of frequencies that belong to the group.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Configuring Upstream Modulation To create and configure the module profile for the Cisco uBR-LCP2-MC16S cable interface line card on the Cisco uBR10012 router, and then to assign it to the appropriate upstreams, use the following procedure: Command Purpose Step 1 Router(config)# configure terminal Enters configuration mode.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Configuring Proactive Channel Management To optimize the spectrum management behavior for your plant’s specific characteristics, you can customize the following parameters: Optionally specify the priority of the corrective actions to be taken when noise on an upstream exceeds the threshold for its modulation profile.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Step 5 Command Purpose Router(config-if)# cable upstream n threshold cnr-profile1 threshold1-in-dB cnr-profile2 threshold2-in-dB corr-fec fec-corrected uncorr-fec fec-uncorrected (Optional) Specifies the CNR threshold and FEC values for the upstream and its two modulation profiles.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Tasks Frequency 15.792 MHz, Channel Width 1.600 MHz, QPSK Symbol Rate 1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management 12 13 14 14 14 15 16 17 17 19 19 19 20 22 22 22 22 22 22 CMTS# Step 6 15.000-20.000 15.000-20.000 15.000-20.000 24.000-29.000 15.792 [1.60] 15.000-20.000 20.000-21.600 30.000-33.000 30.000-33.200 30.000-34.000 20.000-24.000 10.000-14.000 20.000-24.000 20.000-30.000 25.936 [1.60] 26.192 [1.60] 26.480 [1.60] 20.784 [1.60] 23.984 [1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management Using CLI Commands The following commands provide information on the spectrum condition of an upstream: Command Purpose Router# show cable hop [cx/y] [upstream usport] Displays the hop period and hop threshold values, as well as the FEC error counters, for all upstreams in the router, all upstreams on one cable interface line card, or a single upstream.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management The CISCO-CABLE-SPECTRUM-MIB has been enhanced to provide this SNMP support using the following MIB attributes: • ccsSNRRequestTable, page 3-52 • ccsSpectrumRequestTable, page 3-52 • ccsSpectrumDataTable, page 3-53 • ccsUpSpecMgmtTable, page 3-54 • ccsHoppingNotification, page 3-55 ccsSNRRequestTable Table 3-7 lists the attributes in the ccsSNRRequestTable, which contains the CNR measuremen
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management Table 3-8 ccsSpectrumRequestTable Attributes Attribute Type Description ccsSpectrumRequestIndex Integer32 Arbitrary index to uniquely identify each table entry. ccsSpectrumRequestIfIndex InterfaceIndex OrZero Interface identifying the upstream. ccsSpectrumRequestMacAddr MacAddress MAC address to specify an SNR value for a particular cable modem, or 0000.0000.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management ccsUpSpecMgmtTable Table 3-10 lists the attributes in the ccsUpSpecMgmtTable table, which provides an entry describing each frequency hop: Table 3-10 ccsUpSpecMgmtEntry Attributes Attribute Type Description ccsUpSpecMgmtHopPriority INTEGER Specifies the priority of frequency, modulation profile, and channel width in determining corrective action for excessive noise on the upstream (default is f
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Monitoring Spectrum Management ccsHoppingNotification Table 3-11 describes the attributes contained in the notification that is sent after each frequency hop: Table 3-11 ccsHoppingNotification Attributes Attribute Type Description ccsUpSpecMgmtHopCondition INTEGER Reports the condition that triggers a frequency hop (SNR value or percentage of modems going offline) ccsUpSpecMgmtFromCenterFreq CCSFrequency Provides the cente
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples • Configure matching SNMP community strings on the Cisco CMTS and DCMTA software tool so that the DCMTA software can obtain the spectrum management data using SNMP requests.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Step 1 Configure a low-peak upstream rate limit for the cable modem in its QoS profile. Either use the command-line interface (CLI) to modify the modem’s QoS profile, or edit the modem’s TFTP configuration file. Use a regular rate-limiting algorithm on the upstream without rate shaping and note the drops of the excess bandwidth requests from this cable modem when it exceeds its peak upstream rate.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Applying the Rate-Limiting Algorithm Without Rate Limiting Example Router(config-if)# cable upstream 0 rate-limit Router# ping ip Target IP address:1.11.53.100 Repeat count [5]:100000 Datagram size [100]:10000 Timeout in seconds [2]: Extended commands [n]: Sweep range of sizes [n]: Type escape sequence to abort. Sending 100000, 10000-byte ICMP Echos to 1.11.53.100, timeout is 2 seconds: !.!.!!!.!!.!.!!!.!!.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Type escape sequence to abort. Sending 1000000, 10000-byte ICMP Echos to 1.11.53.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Verifying Downstream Rate Limiting Example 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 appears in the output. If downstream rate limiting is disabled, no rate limiting entry appears.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Verifying Spectrum Group Configuration Example To verify if spectrum groups have been configured and activated, enter the show cable spectrum-group command. This command displays each spectrum group, the frequencies assigned to it, the upstream port to which it has been assigned, whether a schedule exists for it, the currently measured power level, and whether it is a shared spectrum group.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Combiner Group Example The following example enables spectrum management for all upstream ports, where all combiner groups use the frequency band from 20 to 26 MHz: CMTS01(config)# cable spectrum-group 1 band 20000000 26000000 CMTS01(config)# cable spectrum-group 2 shared CMTS01(config)# cable spectrum-group 2 band 20000000 26000000 CMTS01(config)# cable spectrum-group 3 shared CMTS01(config)# cable spectrum
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Because the group is shared, ports U2 and U3 will be assigned channels 1 and 4, respectively, to prevent overlap. Note There are no alternate frequency assignments for either port, and bandwidth is wasted from 24.8 to 26.0 MHz. To create alternate channels, increase the upper boundary from 26.0 to 28.0 MHz. > Channel > > 1 > 2 > 3 > 4 > 5 > 6 > 7 Width Start Stop Center (Mhz) (Mhz) (Mhz) (Mhz) 3.2 20.0 23.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples • Use the following example to configure a continuous band between 5,000,004 and 40,000,000 Hz for scheduled spectrum group 4 with a default power level of 0 dBmV. The band is available to the spectrum group starting at 12:00 p.m.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Step 2 To display modulation profile group information, use the show cable modulation-profile command in privileged EXEC mode: Router# show cable modulation-profile [profile] [iuc-code] profile—(Optional) Profile number. Valid values are from 1 to 8. iuc-code—(Optional) Internal usage code.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Router(config)# cable scrambler 152 no-diff Router(config)# cable scrambler 152 no-diff Router(config)# cable 152 no-diff 144 fixed Router(config)# cable 152 no-diff 160 fixed Note modulation-profile 256 fixed uw16 modulation-profile 256 fixed uw16 modulation-profile uw16 modulation-profile uw16 2 initial 5 34 0 48 16qam 2 station 5 34 0 48 16qam 2 short 5 75 6 8 16qam scrambler 2 long 8 220 0 8 16qam scr
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples • Configures the upstream so that when its noise threshold is reached, it first attempts to change the frequency, then the channel-width, and finally to switch the modulation profile (using the Dynamic Upstream Modulation feature). ! version 12.1 no service pad no service password-encryption service udp-small-servers service tcp-small-servers ! hostname ubr7200 ! ! ! Define a frequency band for a 1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples cable downstream modulation 64qam cable downstream interleave-depth 32 cable downstream frequency 687000000 ! Assign upstream to spectrum group cable upstream 0 spectrum-group 1 ! Set channel-width to be fixed at 1.
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples cable upstream 1 hop-priority frequency channel-width modulation cable upstream 1 threshold cnr-profile1 23 cnr-profile2 15 Corr-Fec cable upstream 1 modulation-profile 5 1 no cable upstream 1 concatenation no cable upstream 1 shutdown cable upstream 2 spectrum-group 1 cable upstream 2 channel-width 1600000 1600000 cable upstream 2 hop-priority frequency channel-width modulation cable upstream 2 threshold cnr
Chapter 3 Spectrum Management for the Cisco Cable Modem Termination System Configuration Examples Assigns a spectrum group to each of the four upstreams. • Configures each upstream for the default CNR and FEC thresholds. • Current configuration : 4899 bytes ! version 12.
