Guided Frequency Hopping

Guided frequency hopping is called “guided” because the frequency hopping uses the frequencies that are specified in the spectrum group, which can be either a set of discrete frequencies or a band. The cable interface line cards that support guided frequency hopping do not have a “look-ahead” mechanism that would allow them to determine the quality of the new frequency or band ahead of time, which is why previous documents referred to this as blind hopping. Because of this, though, the cable interface does not need to perform any search on the new potential frequencies, so the switching time between frequencies is only approximately 20 milliseconds.

You can specify some rules the system uses when hopping to another frequency when the frequency band in use is not clean. You can assign explicit frequency subbands and associated input power levels in a spectrum group. All cable modems then on the upstream port migrate to the next frequency with an assigned input power level. The number of lost station management messages exceeding a configured threshold can initiate an upstream channel frequency reassignment. For example, you can specify a frequency hop based on lost station management messages that exceed a threshold. The default threshold may be 10 to 20 percent depending on the Cisco IOS release. The frequency change occurs rapidly without data loss and with minimal latency.

Take care to reduce the spectrum allocation when it is 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. Guided 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.

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.

Input Power Levels

Allows the cable plant operator to perform minor power level equalization as a function of frequency.

Frequency Hopping Capabilities

Proactively countermeasures upstream noise impairments by assigning a new upstream channel to the cable modem. MSOs can take advantage of this feature especially when they have less than an optimal carrier-to-noise ratio in the upstream frequencies or when their cable plants exhibit random bursts of ingress noise that affect reliability.

Dynamic Upstream Modulation

• Reduces the risk associated with transitioning to QAM-16 modulation in the return path and provides assurance that subscribers remain online and connected during return path impairments.

• Checks that the active upstream signal quality can support the configured modulation scheme and proactively adjusts to the more robust modulation scheme when necessary.

• Eliminates the necessity to hop channels for cable modems to stay online by automatically switching from the primary modulation profile to the secondary modulation profile.

Dynamic Channel Width Change

• Improves the DOCSIS upstream channel availability by finding the maximum possible channel width for an upstream when noise conditions make the current channel width unusable.

• Provides the maximum RF spectrum utilization efficiency for current plant conditions.

• Customizable range of channel widths that can be used to respond to noise problems.

Intelligent Frequency Hopping

• Proactively changes upstream frequency for an interface before noise conditions become severe enough to force cable modems offline.

• Dedicated hardware intelligent frequency hopping performs “look-ahead” to choose new upstream frequency to find a stable channel.

• Flexible priority configuration allows hopping decision criteria to be tailored to the individual cable plant environment.

• Improves responsiveness to ingress impairments, by matching the hopping decision criteria to the fluctuating plant conditions.

• Pinpoints CNR (CNiR) variations with per-modem accuracy to isolate problematic cable modems.

• Sustains or even improves subscriber online percentages through user-programmable proactive channel management techniques.

Dynamic Upstream Modulation

• Reduces the risk associated with switching between QPSK and QAM-16 modulation in the upstream to respond to ingress noise, so that subscribers remain online and connected.

• Checks the current upstream signal to ensure that it can support the configured modulation scheme, and proactively adjusts to the secondary more robust modulation scheme when necessary.

• Improves DOCSIS upstream channel availability and provides maximum RF spectrum utilization efficiency.

• Eliminates unnecessary frequency hopping by switching modulation profiles to one that allows cable modems to remain online while using the currently assigned upstream.

• Provides assurance that subscribers remain online and connected during periods of return path impairments.

SNMP Interface

• Provides a way to remotely obtain the current status of noise on an upstream. This information can then be inserted into third-party or custom reporting and graphing applications.

• Provides visibility to ingress and impulse noise under the carrier frequency on a per-port basis.

• Provides an easy-to-use, distributed method to remotely gather real-time display of the DOCSIS upstream spectrum for individual cable modems and set-top boxes (STBs).

• Reduces the reliance on costly spectrum analyzers at every headend or hub.

• Quickly provides spectrum views through an intuitive interface, without the complicated setup time of a spectrum analyzer.

• Allows the technician to troubleshoot the network remotely, as opposed to having to be physically present to connect and use a spectrum analyzer.

Default Hop Priority

For Intelligent and Advanced Spectrum Management feature, the default hop priority is as given below:

• Frequency, modulation, and channel width (when using spectrum groups on spectrum cards).

• Modulation, guided frequency hop, and channel width (when using analyzer cards with spectrum groups).

• Modulation only (when not using spectrum groups [fixed frequency]).

A spectrum group defines the frequencies that an upstream is allowed to use when frequency hopping is done, as well as other parameters that control the frequency hops. When creating and configuring spectrum groups, you can specify the following parameters:

• Frequencies that are assigned to the group. The cable interface uses these frequencies to determine what frequencies are available to use when frequency hopping is needed. You can specify either a list of fixed frequencies or a band of frequencies, or both. The Cisco CMTS uses the following rules when adding frequencies to a spectrum group:

  • When specifying a fixed frequency, the Cisco CMTS assumes it is a center frequency with a 6.4-MHz channel width to allow that frequency to operate at all possible channel widths. For example, specifying a frequency of 17,700,000 Hz is equivalent to specifying a frequency band from 14,500,000 Hz to 20,900,000 Hz (a band that is 6.4 MHz wide).

  • If you configure multiple fixed frequencies or bands of frequencies that overlap, the spectrum group combines them into one band. For example, if you specify a fixed frequency of 17,700,000 Hz and a band from 15,800,000 Hz to 25,200,000 Hz, the spectrum group is configured with one band from 14,500,000 Hz to 25,200,00 Hz.

  • If you want more control over a spectrum group’s frequencies, configure bands of frequencies with the same width as the desired channel width. For example, if you want to use a center frequency of 17,700,000 Hz with a 3.2-MHz channel width, specify a band that ranges from 16,100,000 Hz to 19,300,000 Hz. To ensure you configure non-overlapping bands, separate the bands by a minimum of 20 KHz.

• Upstream input power level—(Optional) Power level, in dBmV, that the upstream should use when hopping to a new frequency. (Some cable plants might want to change only the input power level, and not the frequency, on a daily time schedule.)

• Hop threshold—(Optional) Percentage of cable modems that start missing station maintenance messages before a frequency hop can occur. Configure the hop threshold percentage as needed to prevent a single failing cable interface from affecting service to other good cable interfaces. This ensures that the system does not hop endlessly because one cable modem is generating 90 percent of the errors and 90 percent of the traffic.

• Hop period—(Optional) Minimum time period that must elapse between frequency hops. This allows you to specify a time period long enough to allow an upstream to stabilize before another frequency hop can be performed.

• Scheduled hop time—(Optional) Time of day at which a frequency hop should be scheduled.

• Shared—(Optional) Specifies that all the upstream ports using a spectrum group should use a unique frequency.

Tip	Before adding a list of upstream frequencies (or frequency hop tables), start by determining which upstream ports are assigned to a combiner group. Refer to the Example: Determining the Upstream Ports Assigned to a Combiner Group for an example.

To create and configure a spectrum group, use the following procedure.

After a spectrum group has been created and configured, you must assign it to one or more upstream ports before the group’s frequency spectrum is used for frequency hopping. You can assign a spectrum group to an upstream in the following ways:

• Use the cable spectrum-group interface configuration command to assign a spectrum group to all of the upstreams on a cable interface.

• Use the cable upstream spectrum-group interface configuration command to assign a spectrum group to one individual upstream. This command overrides a group that might have been assigned to all of the upstreams on the interface by the cable spectrum-group command.

To assign a spectrum group to one or all upstream ports on an interface, use the following procedure.

Cisco IOS Release 12.3(21)BC, and later releases, support shared spectrum groups, otherwise known as fiber node groups, for DOCSIS 3.0 on the Cisco uBR10012 router.

This feature supports shared spectrum groups that cross multiple cable interface line cards on the Cisco CMTS router, and shared spectrum groups within a single cable interface line card.

For additional information about configuring fiber node groups on the Cisco CMTS, see:

• Creating and Configuring Spectrum Groups

• Assigning a Spectrum Group to One or More Upstream Ports

• Cisco uBR10012 Universal Broadband Router SIP and SPA Software Configuration Guide

To use the Dynamic Upstream Modulation feature on cable interface line cards that support only the MER (SNR) version of this feature, you must do the following:

1. Create a primary modulation profile. This typically is a more bandwidth-efficient but a less robust profile.

2. Optionally create a secondary modulation profile. This typically is a less bandwidth-efficient but a moderately robust profile.

3. Optionally create a tertiary modulation profile. This typically is a less bandwidth-efficient but a more robust profile.

4. Assign the profiles to the desired cable interfaces and upstreams.

Tip	When creating the modulation profiles, we recommend that you use the predefined modulation profiles, as opposed to manually specifying each burst parameter for each modulation profile.

You can verify frequency hopping on the CMTS by using the command-line interface (CLI).

Verifying Frequency Hopping Using CLI Commands

To verify frequency hopping using CLI commands, use the following procedure:

You must create and configure a spectrum group before you can use the intelligent and advanced spectrum management features. These procedures are the same as those used for guided and scheduled spectrum management, which are given in the following sections:

• Creating and Configuring Spectrum Groups

• Assigning a Spectrum Group to One or More Upstream Ports

After the spectrum groups have been configured and assigned to upstreams, the Cisco IOS software automatically uses the advanced frequency hopping algorithms on the cable interface line cards that support it.

Note

For efficient use of the intelligent and advanced spectrum management features, we recommend configuring only frequency bands, and not fixed frequencies, when creating spectrum groups. A spectrum group must contain a frequency band that is wide enough for the cable interface to find at least two center frequencies at the configured channel width, before frequency hopping can occur.

Configuring the CNR-based version of the Dynamic Upstream Modulation feature is similar to configuring the MER (SNR)-version of this feature:

1. Create a primary modulation profile. This typically is a more bandwidth-efficient but a less robust profile.

2. Create a secondary modulation profile. This typically is a less bandwidth-efficient but a more robust profile.

   Tip	When creating the modulation profiles, we recommend that you use the predefined modulation profiles, as opposed to manually specifying each burst parameter for each modulation profile.

3. Assign the profiles to the desired cable interfaces and upstreams.

After the modulation profiles have been created and assigned to upstreams, the Cisco IOS software automatically uses the advanced CNR-based version of the Dynamic Upstream Modulation feature on the cable interface line cards that support it.

The cable interface line cards that support the advanced spectrum management features can be configured with the following parameters to fine-tune the operation of proactive channel management on the upstreams of the cards:

• Priority of the corrective actions to be taken when noise on an upstream exceeds the threshold for its modulation profile.

• CNR (CNiR) and MER (SNR) threshold and FEC values for the upstream and its two modulation profiles.

• Allowable range of channel widths that can be used if frequency hopping or modulation switching cannot avoid the upstream problems.

These parameters all have default settings, so you do not need to perform this procedure unless you want to change these parameters to better match the characteristics of your physical plant.

A major exception to this is if you are using only one modulation profile and are using a software release prior to Cisco IOS Release 12.2(8)BC2. In these releases, a frequency hop would occur if just one of the measured values (CNR [CNiR] value, correctable FEC counter, or uncorrectable FEC counter) crosses the configured threshold value. Because of this, if you are using only one modulation profile (QPSK) with one of these software releases, you might need to reduce the CNR (CNiR) threshold value and increase the correctable FEC error value to prevent undesired frequency hopping.

Note	This situation no longer occurs in Cisco IOS Release 12.2(8)BC2 and later releases, because a frequency hop can occur only when both the CNR (CNiR) value and one of the FEC counters falls below the threshold value.

To configure the parameters, use the following procedure.

Note	Starting with Cisco IOS Release 12.3(13a)BC, the cable upstream n threshold command was changed to provide more functionality.

Follow the steps given below to verify the spectrum management configuration.

The table below lists the attributes in the ccsSNRRequestTable table, which contains the CNR (CNiR) measurements that are made for individual cable modems on an upstream.

The table below lists the attributes for each entry in the ccsSpectrumRequestTable table, which is used to obtain the spectrum profile for a particular cable modem or to obtain the background MER (SNR) for an entire upstream.

The table below lists the attributes in each entry of the ccsSpectrumDataTable table, which contains the results for a spectrum request.

Note	The ccsSpectrumRequestTable and ccsSpectrumDataTable tables provide the same information as that provided by the show controllers cable upstream spectrum command. This command is obsolete in Cisco IOS Release 12.3(21)BC.

The table below lists the attributes in the ccsUpSpecMgmtTable table, which provides an entry describing each frequency hop.

The table below describes the attributes contained in the notification that is sent after each frequency hop.

To verify that a spectrum group has been created, enter the show cable spectrum-group command:

Router# show cable spectrum-group 
spectrum-group 1
spectrum-group 2
spectrum-group 3

If your cable plant has an upstream noise characteristic on a weekly cycle, use time-scheduled spectrum allocation.

Router(config)# cable spectrum-group 1 time Mon 08:00:00 frequency 21600000

Deletion is performed using the delete keyword:

Router(config)# cable spectrum-group 1 time Mon 18:00:00 delete frequency 21600000

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.

Router# show cable spectrum-group 

22:07:46: %SYS-5-CONFIG_I: Configured from console by console
Group  Frequency      Upstream     Weekly Scheduled            Power   Shared
No.    Band           Port         Availability                Level   Spectrum
       (Mhz)                       From Time:    To Time:      (dBmV)
1       5.000-15.000                                           0       Yes
1      12.000                                                  0       Yes
1      22.000         Cable6/0 U5                              7       Yes
2      29.000         Cable6/0 U4                              6       No
2      26.000                                                  0       No
3      35.000-41.000                                           0       No
3      16.000-19.000  Cable6/0 U3                              5       No
5*      5.000-10.000               Thu 21:50:00  Thu 21:45:00  0       Yes 

Following is a sample topology for a CMTS with combiner groups designated A through J. Combiner groups C and E have multiple upstream ports that should be configured in a shared spectrum group. The other upstreams should be configured in a nonshared spectrum group.

In this example, ten combiner groups are served with frequency hop tables from three spectrum groups:

Cable3/0
DS +-----+ Upconverter +----- laser group 1
U0 +----- combiner group A
U1 +----- combiner group B
U2 +------combiner group C
U3 +------combiner group C
U4 +----- combiner group D
U5 +------combiner group E
Cable4/0
DS +-----+ Upconverter +----- laser group 2
U0 +------combiner group E
U1 +----- combiner group F
U2 +----- combiner group G
U3 +----- combiner group H
U4 +----- combiner group I
U5 +----- combiner group J

The laser group term refers to the set of fiber nodes that share the same downstream signal. An optical splitter is often used to create individual feeds per node.

In the downstream direction, two 6-MHz channel slots are assigned. All fiber nodes in combiner groups A through E should have a channel slot containing the downstream signal from Cable3/0. Combiner groups A through E are said to belong to laser group 1.

All fiber nodes in combiner groups E through J should have a channel slot containing the downstream signal from Cable4/0. Combiner groups E through J are said to belong to laser group 2.

Because combiner group E belongs to two laser groups, there should be two different downstream channel slots for Cable3/0 and Cable4/0.

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-group 3 band 20000000 26000000
CMTS01(config)# interface Cable3/0
CMTS01(config-if)# cable spectrum-group 1
CMTS01(config-if)# cable upstream 2 spectrum-group 2
CMTS01(config-if)# cable upstream 3 spectrum-group 2
CMTS01(config-if)# cable upstream 5 spectrum-group 3
CMTS01(config-if)# exit
CMTS01(config)# interface Cable4/0
CMTS01(config-if)# cable spectrum-group 1
CMTS01(config-if)# cable upstream 0 spectrum-group 3

A description of the spectrum groups 1 through 3 follows:

• Spectrum group 1—This group is nonshared. Upstream RF domains exist for each member upstream port.

  Upstream Port   RF Domain
  Cable3/0 U0     combiner group A
  Cable3/0 U1     combiner group B
  Cable3/0 U4     combiner group D
  Cable4/0 U1     combiner group F
  Cable4/0 U2     combiner group G
  Cable4/0 U3     combiner group H
  Cable4/0 U4     combiner group I
  Cable4/0 U5     combiner group J
  
  

• Spectrum group 2—This group is shared. A single upstream RF domain exists.

  Upstream Port   RF Domain
  Cable3/0 U2     combiner group C
  Cable3/0 U3     combiner group C
  
  

• Spectrum group 3—This group is shared. A single upstream RF domain exists.

  Upstream Port   RF Domain
  Cable3/0 U5     combiner group E
  Cable4/0 U0     combiner group E
  
  

For 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 Cable3/0 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

Note	Channels 2 and 3 are not available when channel 1 is in use.

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  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  27.4

Try to reduce the spectrum allocation when it is used with small channel widths. Otherwise, there will be a large number of upstream channel slots, and the frequency hopping may require several minutes to find a clean slot.

In Cisco IOS Release 12.1(3a)EC1 and later, the Cisco CMTS has one preconfigured modulation profile resident in memory, which defines a typical profile for QPSK modulation. To use the Dynamic Upstream Modulation feature, a second profile must be created that is unique from the first profile, and typically provides a higher, more robust modulation scheme.

The following example is a modulation profile for QAM-16, in which the initial, request, and station maintenance messages are sent as QPSK, and the short and long data packets are sent as QAM-16. The QAM-16 modulation is more bandwidth-efficient than QPSK, but QPSK is more robust than QAM-16.

Note

The upstream request and station maintenance messages use less time on the cable network when configured in QPSK for symbol rates of 640K, 1280K, and 2560K symbols/sec. Thus, these messages are actually more efficient when used in QPSK mode and they ensure a more reliable modem connection. The upstream initial maintenance message takes exactly the same amount of time on the cable network, no matter how it is configured. Modems connect more quickly and experience fewer cycles of power adjustment during initial maintenance if the system is set for QPSK.

Router# configure terminal
Router(config)# cable modulation-profile 2 request 0 16 1 8 qpsk scrambler 152 no-diff 64 fixed uw16
Router(config)# cable modulation-profile 2 initial 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
Router(config)# cable modulation-profile 2 station 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
Router(config)# cable modulation-profile 2 short 6 75 6 8 16qam scrambler 152 no-diff 72 fixed uw16
Router(config)# cable modulation-profile 2 long 8 220 0 8 16qam scrambler 152 no-diff 160 fixed uw16

In the following example, all message types are carried with QAM-16 modulation. Although QAM-16 modulation offers a consistent modulation scheme for all five types of messages, the added length of the QAM-16 preamble offsets the increased bandwidth efficiency of the MAC data message for the station maintenance messages and bandwidth request messages.

Router# configure terminal
Router(config)# cable modulation-profile 2 request 0 16 1 8 16qam scrambler 152 no-diff 128 fixed uw16
Router(config)# cable modulation-profile 2 initial 5 34 0 48 16qam scrambler 152 no-diff 256 fixed uw16
Router(config)# cable modulation-profile 2 station 5 34 0 48 16qam scrambler 152 no-diff 256 fixed uw16
Router(config)# cable modulation-profile 2 short 5 75 6 8 16qam scrambler 152 no-diff 144 fixed uw16
Router(config)# cable modulation-profile 2 long 8 220 0 8 16qam scrambler 152 no-diff 160 fixed uw16

Note	When using DOCSIS concatenation with a 16-QAM or mixed symbol rate, configure the CMTS for Unique Word 16 (“uw16”) in the preamble for both short and long data burst profiles.

Add the cable upstream port-number modulation-profile primary profile-number secondary profile-number command to the appropriate interfaces. In this example, modulation profile 2 is for QAM-16 modulation and profile 1 is for QPSK modulation.

Router# configure terminal
Router(config)# interface Cable6/0
Router(config-if)# cable upstream 0 modulation-profile 2 1

 

This section provides a typical configuration example for a Cisco uBR7200 series router using the Cisco uBR-MC16U cable interface line card. This configuration does the following:

• Creates three spectrum groups with different frequency bands, hop periods, and hop thresholds.

• Creates two upstream modulation profiles, one for QPSK operation and one for QAM-16 operation, by specifying the parameters for each burst type.

• Creates two upstream modulation profiles, one for QPSK operation and one for mixed QPSK/QAM-16 operation, using the default profile options (qpsk and mix).

• Configures one upstream (port 5) on cable interface 3/0 to use spectrum group 3.

• Configures the upstreams with the primary modulation profile set to mixed QPSK/QAM-16 operation and the secondary modulation profile set for QPSK operation.

• 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 12.3
no service pad
no service password-encryption
service udp-small-servers
service tcp-small-servers
!
hostname ubr7200
!
!
! Define a frequency band for a 1.6 MHz channel around center frequency of 20.800 MHz
cable spectrum-group 1 band 19750000 21850000 0
! Define a frequency band for a 1.6 MHz channel around center frequency of 23.200 MHz
cable spectrum-group 1 band 22150000 24250000 0
! Hop period set to 30 sec to avoid modems going offline before initiating a hop priority
cable spectrum-group 1 hop period 30
! Percentage of missed station maintenance from modems
cable spectrum-group 1 hop threshold 20
!
cable modulation-profile 1 initial 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 1 station 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
! Create second modulation profile numbered 4
cable modulation-profile 4 request 0 16 0 8 qpsk scrambler 152 no-diff 64 fixed uw16
cable modulation-profile 4 initial 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 4 station 5 34 0 48 qpsk scrambler 152 no-diff 128 fixed uw16
cable modulation-profile 4 short 6 75 6 8 16qam scrambler 152 no-diff 144 shortened uw16
cable modulation-profile 4 long 8 220 0 8 16qam scrambler 152 no-diff 160 shortened uw16
! Create two modulation profiles using the default QPSK and QPSK/16-QAM profiles 
cable modulation-profile 3 qpsk
cable modulation-profile 5 mix
!
no cable qos permission create
no cable qos permission update
cable qos permission modems
cable time-server
clock calendar-valid
no ip subnet-zero
no ip domain-lookup
!
!
!
interface FastEthernet0/0
 no ip address
 no ip mroute-cache
 shutdown
 media-type MII
 full-duplex
!
interface Ethernet1/0
 ip address 10.11.10.1 255.0.0.0
 no ip mroute-cache
 half-duplex
!
interface Cable3/0
 ip address  255.255.255.0 secondary
 ip address  255.255.255.0
 no keepalive
 cable map-advance static
 cable bundle 1 master
 cable downstream annex B
 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 1.6 MHz
 cable upstream 0 channel-width 1600000 1600000  
! Set priority of corrective actions
 cable upstream 0 hop-priority frequency channel-width modulation
! Set the thresholds for corrective action
cable upstream 0 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
! Assign modulation profiles to upstream port in order of preference
 cable upstream 0 modulation-profile 5 1
 no cable upstream 0 concatenation
 no cable upstream 0 shutdown
 cable upstream 1 spectrum-group 1
 cable upstream 1 channel-width 1600000 1600000  
 cable upstream 1 hop-priority frequency channel-width modulation
cable upstream 1 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 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-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 2 modulation-profile 5 1
 no cable upstream 2 concatenation
 no cable upstream 2 shutdown
 cable upstream 3 spectrum-group 1
 cable upstream 3 channel-width 1600000 1600000  
 cable upstream 3 hop-priority frequency channel-width modulation
cable upstream 3 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 3 modulation-profile 5 1
 no cable upstream 3 concatenation
 no cable upstream 3 shutdown
 cable upstream 4 spectrum-group 1
 cable upstream 4 channel-width 1600000 1600000  
 cable upstream 4 hop-priority frequency channel-width modulation
cable upstream 4 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 4 modulation-profile 5 1
 no cable upstream 4 concatenation
 no cable upstream 4 shutdown
 cable upstream 5 spectrum-group 1
 cable upstream 5 channel-width 1600000 1600000  
 cable upstream 5 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 5 modulation-profile 5 1
 no cable upstream 5 concatenation
 no cable upstream 5 shutdown
 no cable dci-response
 cable dhcp-giaddr policy
!
interface Cable4/0
 no ip address
 no keepalive
 cable map-advance static
 cable bundle 1
 cable downstream annex B
 cable downstream modulation 64qam
 cable downstream interleave-depth 32
 cable downstream frequency 687000000
 cable upstream 0 spectrum-group 1
 cable upstream 0 channel-width 1600000 1600000  
 cable upstream 0 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 0 modulation-profile 5 1
 no cable upstream 0 concatenation
 no cable upstream 0 shutdown
 cable upstream 1 spectrum-group 1
 cable upstream 1 channel-width 1600000 1600000  
 cable upstream 1 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 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 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 2 modulation-profile 5 1
 no cable upstream 2 concatenation
 no cable upstream 2 shutdown
 cable upstream 3 spectrum-group 1
 cable upstream 3 channel-width 1600000 1600000  
 cable upstream 3 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 3 modulation-profile 5 1
 no cable upstream 3 concatenation
 no cable upstream 3 shutdown
 cable upstream 4 spectrum-group 1
 cable upstream 4 channel-width 1600000 1600000 
 cable upstream 4 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 4 threshold Uncorr-Fec 2
 cable upstream 4 modulation-profile 5 1
 no cable upstream 4 concatenation
 no cable upstream 4 shutdown
 cable upstream 5 spectrum-group 1
 cable upstream 5 channel-width 1600000 1600000 
 cable upstream 5 hop-priority frequency channel-width modulation
cable upstream 5 threshold cnr-profiles 23 15
cable upstream 0 threshold Corr-Fec 5
cable upstream 0 threshold Uncorr-Fec 2
 cable upstream 5 modulation-profile 5 1
 no cable upstream 5 concatenation
 no cable upstream 5 shutdown
 no cable dci-response
 cable dhcp-giaddr primary
!
ip default-gateway 10.11.0.1
ip classless
ip route 10.11.254.254 255.255.255.255 10.11.0.1
no ip http server
!!
snmp-server engineID local 00000009020000D0CAA7BB00
snmp-server community private RW  
snmp-server trap-source FastEthernet0/0
snmp-server packetsize 2048
snmp-server system-shutdown
snmp-server enable traps cable hopping
snmp-server manager
!
line con 0
 exec-timeout 0 0
 transport input none
line aux 0
line vty 0 4
 no login
!
end

This section provides an excerpt from a typical configuration example for a Cisco uBR10012 router using the Cisco uBR10-MC5X20S/U/H cable interface line card. This configuration does the following:

• Configures four spectrum groups with a hop period of 30 seconds.

• Creates a QPSK modulation profile and assigns it to four upstreams on the Cisco uBR-MC5X20S/U/H cable interface line card in slot 6/1/0.

• Assigns a spectrum group to each of the four upstreams.

• Configures each upstream for the default CNR (CNiR) and FEC thresholds.

cable modulation-profile 21 qpsk
interface Cable6/1/0
cable bundle 1
cable downstream annex B
cable downstream modulation 256qam
cable downstream interleave-depth 32
! upstream 0
cable upstream 0 spectrum-group 1
cable upstream 0 modulation-profile 21
cable upstream 0 threshold cnr-profiles 16 0 
cable upstream 0 threshold Corr-Fec 3 
cable upstream 0 threshold Uncorr-Fec 1 
no cable upstream 0 shutdown ! upstream 1 
cable upstream 1 spectrum-group 2 
cable upstream 1 modulation-profile 21 
cable upstream 1 threshold cnr-profiles 16 0 
cable upstream 1 threshold Corr-Fec 3 
cable upstream 1 threshold Uncorr-Fec 1 
no cable upstream 1 shutdown ! upstream 2 
cable upstream 2 spectrum-group 3 
cable upstream 2 modulation-profile 21 
cable upstream 2 threshold cnr-profiles 16 0 
cable upstream 2 threshold Corr-Fec 3 
cable upstream 2 threshold Uncorr-Fec 1 
no cable upstream 2 shutdown ! upstream 3 
cable upstream 3 spectrum-group 4 
cable upstream 3 modulation-profile 21 
cable upstream 3 threshold cnr-profiles 16 0 
cable upstream 3 threshold Corr-Fec 3 
cable upstream 3 threshold Uncorr-Fec 1 
no cable upstream 3 shutdown