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Table Of Contents
CM Steering on the Cisco CMTS Routers
How to Configure CM Steering on Cisco CMTS Routers
Configuring a Channel Redirection
Verifying a Channel Redirection
Clearing a Channel Redirection
Configuring a Channel Restriction
Verifying a Channel Restriction
Configuration Examples for CM Steering
Configuring Channel Redirection: Example
Configuring Channel Restriction: Example
Feature Information for CM Steering
CM Steering on the Cisco CMTS Routers
Revised: November 16, 2009First Published: December 18, 2008The cable modem (CM) steering feature helps to redirect or steer CMs to multiple Cable Modem Termination Systems (CMTS) using downstream frequency overrides. A configurable string is used to bond the CM to the proper CMTS. Once the bonding is done, the CMTS can move the CM within itself for load balancing.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for CM Steering" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS, Catalyst OS, and Cisco IOS XE software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Prerequisites for CM Steering
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Prerequisites for CM Steering
DOCSIS 3.0-defined Type-Length-Values (TLVs) are required to aid channel selection. All TLVs encoded as general extension information in CM configuration files are backward compatible with DOCSIS 1.1 and DOCSIS 2.0 CMs.
Table 1 shows the Cisco Cable Modem Termination System (CMTS) hardware compatibility prerequisites for this feature.
Table 1
CM Steering Hardware Compatibility Matrix
Restrictions for CM Steering
The CM steering feature has the following general restrictions:
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Information About CM Steering
CM steering allows you to redirect or steer the CMs to one or more CMTS using downstream frequency overrides. Once a CM registers on a downstream on the proper CMTS, the CMTS can move the CM to any location for load balancing.
The DOCSIS 3.0-compliant Service Type Identifier used as the configurable string in the CM configuration file is backward-compatible with DOCSIS 1.1 and DOCSIS 2.0 CMs.
The CMTS can also impose restrictions on the number of channels a CM can use. DOCSIS 3.0 defines several TLVs to aid the channel selection.
The following TLVs are used in CM steering:
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The following TLVs are supported in CM Steering:
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CM steering contains three small featurettes: Channel Redirection, Channel Restriction, and Load Balancing. The Load Balancing feature is covered in the Configuring Load Balancing and Dynamic Channel Change (DCC) on the Cisco CMTS document.
Channel Redirection
The service type identifier-based channel redirection allows you to redirect or steer the CMs to one or more CMTS using downstream frequency overrides. A configurable string in the CM configuration file is used to bond the CM to the correct CMTS. A global CLI ties the string to the downstream frequency, which is configured on the CMTS.
Once a CM registers on a downstream of a CMTS, the CMTS can move the CM to any location within the CMTS for load balancing.
A DOCSIS 3.0-compliant TLV (TLV 43.11) service identifier is used as the configurable string in the CM configuration file. It is backward-compatible with DOCSIS 1.1 and DOCSIS 2.0 CMs. This TLV is used as the tag of the CM to decide whether to redirect or not. The method used to redirect is downstream frequency override in the ranging phase.
Channel Restriction
The CMTS can impose restrictions on the channels a CM uses based on the CMs configuration file or its capabilities. For example, Advanced Time Division Multiple Access (ATDMA) capable CMs should not use Time Division Multiple Access (TDMA) upstream channels.
DOCSIS 3.0 provides guidelines on how a CMTS can choose a pair of channels for a CM at both registration time and during autonomous load balancing. DOCSIS 3.0 defines several TLVs to aid channel selection, including the service type identifier, load balancing group ID, and CM attribute masks and service flow attribute masks.
Except for the service flow attribute masks, the TLVs are encoded as general extension information in the CM configuration file, which are backward compatible with DOCSIS 1.1 and DOCSIS 2.0 CMs.
Channel restriction looks only for upstream CM attribute masks, and is therefore compatible with DOCSIS 1.1, DOCSIS 2.0 and DOCSIS 3.0 CMs in non-Multiple Transmit Channel (MTC) mode.
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How to Configure CM Steering on Cisco CMTS Routers
This section describes the following required and optional procedures:
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Configuring a Channel Redirection
To configure a channel redirection that allows you to redirect or steer the CMs to one or more CMTS using the downstream frequency override in the ranging phase, use the cable service type ds-frequency command.
Restrictions
You can redirect CMs matching the service type identifier to a downstream frequency. However, one service type identifier cannot be redirected to multiple downstream frequencies.
During registration, the CM service type identifier is stored in the CMTS to redirect target downstream frequency during ranging time. If you want to clear the stored service type identifier, you must manually execute the clear cable modem service-type command.
To restrict the CM on the exact downstream on the target CMTS, the redirection must be configured on the target CMTS. If the CMs are redirected to the source CMTS, the dynamic load balance may not work properly and the CM may drop offline during load balancing. For the CMs to be redirected it must reach the target frequency.
SUMMARY STEPS
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Verifying a Channel Redirection
To verify configuration of channel redirection, use the show cable modem verbose command as shown in the following example:
Router# show cable modem verbose
MAC Address : 0014.bfbe.81e3IP Address : 30.0.52.15IPv6 Address : ---Dual IP : NPrim Sid : 15Host Interface : C1/0/U0MD-DS-SG : N/AWideband Capable : YRCP Index : 0sysDescr :Upstream Power : 0.00 dBmV (SNR = 36.12 dB)Downstream Power : 0.00 dBmV (SNR = ----- dB)Timing Offset : 1874Initial Timing Offset : 1874Curr US Timing Adjust : 0Prev US Timing Adjust : 0Received Power : 0.00 dBmVMAC Version : DOC2.0QoS Provisioned Mode : DOC1.1Enable DOCSIS2.0 Mode : YPhy Operating Mode : tdmaModem Status : {Modem=online(pt), Security=assign(tek)}Capabilities : {Frag=Y, Concat=Y, PHS=Y}Security Capabilities : {Priv=BPI+, EAE=N}L2VPN Capabilities : {L2VPN=N, eSAFE=N}Sid/Said Limit : {Max US Sids=16, Max DS Saids=15}Optional Filtering Support : {802.1P=N, 802.1Q=N, DUT=N}Transmit Equalizer Support : {Taps/Symbol= 1, Num of Taps= 24}Number of CPE IPs : 0(Max CPE IPs = 16)CFG Max-CPE : 10Flaps : 0()Errors : 0 CRCs, 0 HCSesStn Mtn Failures : 0 aborts, 0 exhaustedTotal US Flows : 1(1 active)Total DS Flows : 1(1 active)Total US Data : 1 packets, 401 bytesTotal US Throughput : 0 bits/sec, 0 packets/secTotal DS Data : 0 packets, 0 bytesTotal DS Throughput : 0 bits/sec, 0 packets/secLB group index : 0x0LB reg_group_id : 0x0LB policy id : 0LB reg_policy_id : 0LB priority : 0Required DS Attribute Mask : 0x0Forbidden DS Attribute Mask : 0x0Required US Attribute Mask : 0x0Forbidden US Attribute Mask : 0x0Service Type ID : commercialActive Classifiers : 0 (Max = NO LIMIT)DSA/DSX messages : permit allNumber of Multicast DSIDs Support : 15MDF Capability Mode : 0FCType10 Forwarding Support : NFeatures Bitmask : 0x0Total Time Online : 00:59To view the modems having the service type identifier, use the show cable modem service-type-id command as shown in the following example:
Router# show cable modem service-type-id
B DMAC Address IP Address I/F MAC Prim Service-type-id P IState Sid I P0018.6812.29ae 41.42.2.212 C6/1/4/U2 offline 3838 commercial N N0018.6811.f9f8 41.42.0.140 C6/1/4/U2 offline 3225 commercial N N0018.6811.fba6 41.42.5.169 C6/1/4/U2 offline 3439 commercial N N0018.6812.225a 41.42.3.210 C6/1/4/U2 offline 3355 commercial N N0018.6811.fa8c 41.42.1.133 C6/1/4/U2 offline 3091 commercial N N0018.6812.37e8 41.42.0.136 C6/1/4/U2 offline 7439 commercial N N0018.6811.fbca 41.42.2.255 C6/1/4/U2 offline 6263 commercial N N0018.6811.fb44 41.42.2.17 C6/1/4/U2 offline 2996 commercial N N0018.6812.2f20 41.42.0.100 C6/1/4/U2 offline 3544 commercial N NClearing a Channel Redirection
To clear the cable modem attributes, use the clear cable modem command as shown in the following examples:
Router# clear cable modem all
Router# clear cable modem oui string
Router# clear cable modem cable slot/subslot/port offline
To clear the cable modem service type identifiers, use the clear cable modem service-type command as shown in the following examples:
Router# clear cable modem all service-type-id
Router# clear cable modem oui string service-type-id
Router# clear cable modem slot/subslot/port offline service-type-id
Configuring a Channel Restriction
To impose restrictions on the channels a CM can use based on its configuration file or capabilities, use the cable upstream attribute-mask command.
Prerequisites
Advanced Time Division Multiple Access (ATDMA) capable cable modems should be restricted from using Time Division Multiple Access (TDMA) upstream channels.
Restrictions
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Verifying a Channel Restriction
To verify the service type identifier and CM attribute masks configured for a CM, use the show cable modem verbose command as shown in the following example:
Router# show cable modem 0019.474d.e291 verbose
MAC Address : 0019.474d.e291IP Address : 40.3.100.16IPv6 Address : ---Dual IP : NPrim Sid : 35Host Interface : C5/0/4/U0MD-DS-SG : 1MD-CM-SG : 0x40100Primary Downstream : Mo1/0/0:0 (RfId : 0)Wideband Capable : NRCP Index : 0sysDescr :Upstream Power : 0.00 dBmV (SNR = 36.12 dB)Downstream Power : 0.00 dBmV (SNR = ----- dB)Timing Offset : 1573Initial Timing Offset : 1573Curr US Timing Adjust : 0Prev US Timing Adjust : 0Received Power : -0.50 dBmVMAC Version : DOC2.0QoS Provisioned Mode : DOC1.1Enable DOCSIS2.0 Mode : YPhy Operating Mode : tdmaModem Status : {Modem=online, Security=disabled}Capabilities : {Frag=Y, Concat=Y, PHS=Y}Security Capabilities : {Priv=, EAE=N}L2VPN Capabilities : {L2VPN=N, eSAFE=N}Sid/Said Limit : {Max US Sids=16, Max DS Saids=15}Optional Filtering Support : {802.1P=N, 802.1Q=N, DUT=N}Transmit Equalizer Support : {Taps/Symbol= 1, Num of Taps= 24}Number of CPE IPs : 0(Max CPE IPs = 16)CFG Max-CPE : 16Flaps : 0()Errors : 0 CRCs, 0 HCSesStn Mtn Failures : 0 aborts, 0 exhaustedTotal US Flows : 1(1 active)Total DS Flows : 1(1 active)Total US Data : 7 packets, 619 bytesTotal US Throughput : 0 bits/sec, 0 packets/secTotal DS Data : 2 packets, 148 bytesTotal DS Throughput : 4 bits/sec, 0 packets/secLB group index : 0x0LB reg_group_id : 0x0LB policy id : 2LB reg_policy_id : 2LB priority : 0Required DS Attribute Mask : 0x0Forbidden DS Attribute Mask : 0x0Required US Attribute Mask : 0x1111Forbidden US Attribute Mask : 0x0Service Type ID : commercialActive Classifiers : 0 (Max = NO LIMIT)DSA/DSX messages : permit allVoice Enabled : NODS Change Times : 0Boolean Services : 0Number of Multicast DSIDs Support : 0MDF Capability Mode : 0FCType10 Forwarding Support : NFeatures Bitmask : 0x0Total Time Online : 00:19Clearing Attribute Masks
If the CM fails to come online after configuring attribute masks in the CM configuration file, you can use the following procedure to verify the contents of the CM configuration file and clear its contents if the attribute masks are configured differently.
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Debugging Channel Redirection
Use the following steps to debug channel redirection:
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Troubleshooting Tips
This section provides tips and commands you can use to troubleshoot your CM Steering configuration.
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Configuration Examples for CM Steering
This section provides the following configuration examples:
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Configuring Channel Redirection: Example
In the following example, CMs matching a particular service type identifier are redirected to a particular downstream frequency.
Router(config)# cable service type commercial ds-frequency 519000000Configuring Channel Restriction: Example
The following example sets an upstream's attribute mask in hexadecimal format for channel restriction.
Router# configure terminalRouter(config)# interface Cable 5/0/4Router(config-if)# cable upstream 0 attribute-mask ffffRouter(config-if)# endTo verify the channel restriction configuration, use the following command:Router# show cable modem service-type-id
B DMAC Address IP Address I/F MAC Prim Service-type-id P IState Sid I P0018.6812.29ae 41.42.2.212 C6/1/4/U2 offline 3838 commercial N N0018.6811.f9f8 41.42.0.140 C6/1/4/U2 offline 3225 commercial N N0018.6811.fba6 41.42.5.169 C6/1/4/U2 offline 3439 commercial N N0018.6812.225a 41.42.3.210 C6/1/4/U2 offline 3355 commercial N N0018.6811.fa8c 41.42.1.133 C6/1/4/U2 offline 3091 commercial N N0018.6812.37e8 41.42.0.136 C6/1/4/U2 offline 7439 commercial N N0018.6811.fbca 41.42.2.255 C6/1/4/U2 offline 6263 commercial N N0018.6811.fb44 41.42.2.17 C6/1/4/U2 offline 2996 commercial N N0018.6812.2f20 41.42.0.100 C6/1/4/U2 offline 3544 commercial N NAdditional References
The following sections provide references related to the CM Steering feature.
Related Documents
CMTS cable commands
DOCSIS 1.1 as it relates to Cisco CMTS
Load Balancing and Dynamic Channel Change (DCC)
Load Balancing and Dynamic Channel Change on the Cisco CMTS Routers
N+1 Redundancy
Standards
MIBs
RFCs
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
Technical Assistance
Feature Information for CM Steering
Table 2 lists the features in this module and provides links to specific configuration information. Only features that were introduced or modified in Cisco IOS Release 12.2(33)SCB or a later release appear in the table.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Table 2 Feature Information for CM Steering on the Cisco CMTS Routers
Channel Redirection
12.2(33)SCB
Channel redirection allows you to redirect or steer the CMs to one or more CMTS using downstream overrides.
The following sections provide information about this feature:
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The following commands were introduced or modified: cable service type, cable service type ds-frequency, clear cable modem attribute-masks, clear cable modem service-type, show cable modem service-type-id.
Channel Restriction
12.2(33)SCB
The CMTS can impose restrictions on the channels a CM can use based on the CM configuration file or its capabilities.
The following sections provide information about this feature:
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The following command is introduced: cable upstream attribute-mask.
Channel Restriction
12.2(33)SCB4
When the CMTS cannot find an appropriate US channel in the same legacy LB group, the CM steering checking is skipped and CMs come online.
The following sections provide information about this feature:
RLBG/GLBG Support and NB DBS Interact with DLB Support
12.2(33)SCC
The following sections have been updated with information about this feature:
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