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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
Using a Cable Modem at the Headend to Verify Downstream Signals
Managing Cable Modems on the HFC Network
Configuring Sync Message Interval
Verifying Sync Message Interval
Activating Cable Modem Authentication
Verifying Cable Modem Authentication
Activating Cable Modem Upstream Address Verification
Verifying Cable Modem Upstream Address Verification
Configuring Dynamic Contention Algorithms (Cable Insertion Interval, Range, and Data Backoffs)
Configuring the Dynamic Map Advance Algorithm
Configuring the Maximum Number of Hosts Attached to a Cable Modem
Configuring Cable Modem Registration Timeout
Verifying Clear Cable Modem Reset
Verifying Clear Cable Modem Counters
Configuring Downstream Rate Limiting and Shaping
Configuring Upstream Rate Limiting and Shaping
Configuring Spectrum Management
Combining Blind Strategies and Time Scheduled Spectrum Management
Spectrum Management Debug and Test Commands
Configuring Remote Modem Monitoring
Monitoring and Maintaining Remote Querying
Understanding Show Command Responses
show cable modem maintenance Command
Enhanced show interface upstream output Command
show interface cable sid Command
show cable qos profile Command
Troubleshooting Cable Flap Lists
Troubleshooting with the Flap List
Verifying Cable Flap List Aging
Setting Cable Flap List Insertion Time
Verifying Cable Flap List Insertion Time
Setting Cable Flap List Power Adjustment Threshold
Verifying Cable Flap List Power Adjustment Threshold
Setting Cable Flap List Miss Threshold
Verifying Cable Flap List Miss Threshold
Verifying Cable Flap List Size
Customizing Other Flap List Values and Related Commands
Performing Amplitude Averaging
Enabling or Disabling Power Adjustment
Setting Frequency Threshold to Affect Power Adjustment
Setting Downstream Test Signals
Configuring Unmodulated Test Signals
Pinging Unresponsive Cable Modems
Using the Cable Monitor Feature
Using Cable Interface debug Commands
debug cable envm Command (Environmental Monitor Messages)
debug cable err Command (MAC Protocol Errors)
debug cable privacy Command (Baseline Privacy)
debug cable keyman Command (Baseline Privacy Activity)
debug cable mac-messages Command
debug cable phy Command (Messages)
debug cable range Command (Ranging Messages)
debug cable receive Command (Upstream Messages)
debug cable reg Command (Modem Registration Requests)
debug cable reset Command (Messages)
debug cable specmgmt Command (Spectrum Management)
debug cable startalloc Command (Channel Allocations)
debug cable transmit Command (CMTS Transmissions)
debug cable ucc Command (Upstream Channel Change Messages)
debug cable ucd Command (Upstream Channel Description Messages)
Troubleshooting the System
This chapter contains troubleshooting information for various functions of your Cisco uBR7100 series CMTS, and includes the following sections:
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"Using a Cable Modem at the Headend to Verify Downstream Signals" section
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Using a Cable Modem at the Headend to Verify Downstream Signals
You can use a Cisco uBR924 cable access router to verify the downstream signal originating from a Cisco uBR7100 series universal broadband router. Be sure you configure the Cisco uBR924 according to DOCSIS cable modem practices. To verify the downstream signal from a Cisco uBR7100 series universal broadband router using a Cisco uBR924, follow the procedure below:
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Managing Cable Modems on the HFC Network
To manage cable modems connected to the network, perform the following tasks as appropriate:
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Configuring Sync Message Interval
To specify the sync message interval between successive sync message transmissions from the Cisco uBR7100 series CMTS, use the following command in cable interface configuration mode.
Verifying Sync Message Interval
To determine if a sync message interval is configured, enter the show running-config command and look for the cable interface configuration information. If the sync message interval is deactivated or reset to its default value, the no sync interval command line appears in the output.
Activating Cable Modem Authentication
The Cisco uBR7100 series CMTS can be configured to require all cable modems to return a known text string to register with the CMTS and gain access to the network. The text string can be from 1 to 80 characters in length. To activate cable modem authentication, use the following command in cable interface configuration mode.
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Verifying Cable Modem Authentication
To determine if cable modem authentication is activated or deactivated, enter the more system:running-config command and look for the cable interface configuration information. If cable modem authentication is deactivated, it appears in this output as no cable secret-shared.
Activating Cable Modem Upstream Address Verification
Cable modem upstream address verification ensures that only cable modems that have received DHCP leases through the Cisco uBR7100 series CMTS can access the HFC network. The Cisco uBR7100 series CMTS discards all packets received from or for hosts that have not received DHCP-assigned addresses.
To activate cable modem upstream address verification, use the following cable interface configuration command.
Verifying Cable Modem Upstream Address Verification
To determine if cable modem upstream verification is activated or deactivated, enter the more system:running-config command and look for the no cable source-verify notation in the cable interface configuration information.
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Configuring Dynamic Contention Algorithms (Cable Insertion Interval, Range, and Data Backoffs)
The Cisco uBR7100 series software includes:
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These algorithms control the capacity of the contention subchannel and how efficiently a given contention subchannel capacity is utilized.
In high contention mode, the Cisco uBR7100 series MAC scheduler uses collision statistics and sustains a high frequency of initial ranging slots until it detects a steady ranging state. The CMTS dynamically varies the frequency of initial ranging slots using the data grant utilization on the upstream channels. The CMTS trades upstream bandwidth between data grants and initial ranging slots. The CMTS autodetects a high collision state and switches to low insertion interval mode after a steady state is achieved where few collisions occur.
The CMTS is careful when monitoring the ranging channel health to revert to a steady state. In steady state mode, data grants—grant utilization—receive preference over initial ranging slots.
Although the binary exponential backoff algorithm operates in a distributed fashion at different CMs, the CMTS provides centralized control for the backoff algorithm. To achieve this, it remotely monitors traffic load—the backlog developing on the contention channel—and then varies the backoff start and end specified in the MAPs for that upstream channel. This ensures colliding CMs are properly randomized in time.
The following cable interface commands are available to configure the dynamic contention algorithms:
[no] cable insertion-interval [automatic [Imin [Imax]]] | [msecs]
[no] cable upstream port num range-backoff [automatic] | [start end]
[no] cable upstream port num data-backoff [automatic] | [start end]
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The default automatic insertion interval setting enables the Cisco automatic initial ranging period algorithm where lower and upper default values of 50 msecs and 2 secs are used. The default automatic range-backoff enables the dynamic backoff algorithm.
To deviate from system defaults when modifying the dynamic contention algorithm, use one of the following commands in cable interface configuration mode.
Configuring the Dynamic Map Advance Algorithm
A CMTS administrator can enhance the upstream throughput from a cable modem connected to the Cisco uBR7100 series CMTS. The system employs a new algorithm that automatically tunes the lookahead time in MAPs based on several input parameters for the corresponding upstream channel. The use of dynamic/optimal lookahead time in MAPs significantly improves the per-modem upstream throughput.
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To configure the dynamic map advance algorithm, use the following command in cable interface configuration mode.
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Configuring Per Modem Filters
You can configure the Cisco uBR7100 series router to filter incoming packets from individual hosts or cable modems based on the source Media Access Controller (MAC) or Internet Protocol (IP) address. Definition of filters follows standard Cisco IOS configuration practices for access lists and groups.
To configure per modem filters, use the following commands in cable interface configuration mode.
Caution
The software supports traps to alert CMTS administrators on CMs going offline or back online. This is a typical registration and login procedure:
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Configuring the Maximum Number of Hosts Attached to a Cable Modem
To specify the maximum number of hosts that can be attached to a subscriber's cable modem, use the following command in cable interface configuration mode.
Configuring Cable Modem Registration Timeout
By default, registered cable modems that have no upstream activity for three minutes are timed out and disconnected from the Cisco uBR7100 series CMTS. This timeout interval can be decreased to 2 minutes or increased up to 60 minutes.
To specify the registration timeout interval for cable modems connected to the Cisco uBR7100 series CMTS, use the following command in cable interface configuration mode.
Clearing Cable Modem Reset
To remove a single cable modem (or all cable modems) from the station maintenance list and reset the cable modem (or all cable modems) on the network, use one of the following commands in cable interface configuration mode.
Verifying Clear Cable Modem Reset
To determine if the clear cable modem reset command has removed a cable modem from the station maintenance list and forced it to start a reset sequence, enter the show cable modem command.
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Clearing Cable Modem Counters
To clear the counters for the cable modem(s) in the station maintenance list, use one of the following commands in cable interface configuration mode.
Verifying Clear Cable Modem Counters
To determine if the counters in the station maintenance list are cleared, enter one of the following commands. The station maintenance list counter is 0.
Configuring Traffic Shaping
Configuring Downstream Rate Limiting and Shaping
To configure downstream rate limiting or shape downstream traffic, use the following command in cable interface configuration mode.
You can use this command in the following ways:
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cable downstream rate-limit token-bucket shaping granularity 8 command.
Acceptable values are 1, 2, 4, 8, or 16 msecs.•
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Configuring Upstream Rate Limiting and Shaping
You can rate limit and shape traffic on a DOCSIS upstream channel. This delays the scheduling of the upstream packet, which in turn causes the packet to be buffered on the cable CPE device, instead of being dropped. This allows the user's TCP/IP stack to pace the application traffic appropriately and approach throughput commensurate with the subscriber's defined QoS levels.
To configure upstream rate limiting and shaping, use the following command in cable interface configuration mode.
The software supports:
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CMTS01# show interface c1/0 sid 1 countersSid Inpackets Inoctets Outpackets Outoctets Ratelimit RatelimitBWReqDrop DSPktDrop1 67859 99158800 67570 98734862 2579 0Configuring Spectrum Management
Combining Blind Strategies and Time Scheduled Spectrum Management
Cisco uBR7100 series software supports combined blind and time scheduled spectrum management:
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With combined blind and time scheduled strategies, blind hop tables are given the capability for time-variant configuration. The frequency or subband list can change with time. Blind frequency hop is performed within the spectrum specified to be currently available. An example follows:
uBR(config)# cable spectrum-group 2 time Mon 09:00:00 frequency 10000000uBR(config)# cable spectrum-group 2 time Tue 09:05:00 delete frequency 10000000uBR(config)# cable spectrum-group 2 time Tue 09:00:00 frequency 5000000uBR(config)# cable spectrum-group 4 time Fri 09:00:00 band 15000000 25000000uBR(config)# cable spectrum-group 4 time Sat 09:00:00 delete band 15000000 25000000Using Guided Frequency Hop
Using guided frequency hop, the upstream channel frequency is reassigned if a threshold number or percentage of CMs suddenly go offline. You can adjust the thresholds and assign explicit frequencies or frequency subbands and associated input power levels in the unified spectrum group table. The Cisco uBR7100 series CMTS locates the defined channel or a suitable channel and moves all CMs on the upstream port.
The following example shows that the Cisco uBR7100 series can force the CTMS to change the upstream to another frequency before the CMTS sends a message to increase output power levels. You can configure the frequency hop table so that the next entry has the same frequency, but a different power level:
uBR(config)# cable spectrum-group 2 frequency 20000000uBR(config)# cable spectrum-group 2 frequency 20000000 2uBR(config)# cable spectrum-group 2 frequency 20000000 -2uBR(config)# cable spectrum-group 2 frequency 22000000uBR(config)# cable spectrum-group 2 frequency 22000000 2uBR(config)# cable spectrum-group 2 frequency 22000000 3The order of the configuration commands defines the order which frequency or power level is changed. There is always a single allocation set per spectrum group, listing the currently available bands. In the case of a shared spectrum group, there is also a single free set and "in-use" set because there is a single RF domain. Otherwise, there are free and in-use sets for each upstream port because each upstream port has its own RF domain.
Sample output:
noisy1# show cable specGroup Frequency Upstream Weekly Scheduled Power SharedNo. Band Port Availability Level Spectrum(Mhz) From Time: To Time: (dBmV)1 10.000- 0.000 1 No1 11.000- 0.000 1 No1 12.000- 0.000 1 No1 13.000- 0.000 1 No1 14.000- 0.000 1 No2 10.000-15.000 2 No2 10.208 [0.40] Cable1/0 U1 23 20.000- 0.000 3 Yes3 21.000- 0.000 3 Yes3 22.000- 0.000 3 Yes3 23.000- 0.000 3 Yes3 24.000- 0.000 3 Yes3 0.400 [0.80] Cable1/0 U2 34 20.000-25.000 4 Yes4 20.800 [1.60] Cable1/0 U3 45 10.000- 0.000 5 No5 11.000- 0.000 5 No5 12.000- 0.000 5 No5 13.000- 0.000 Mon 17:06:00 --- --:--:-- 5 No5 14.000- 0.000 Mon 17:08:00 --- --:--:-- 5 No5 13.000- 0.000 Mon 17:10:00 --- --:--:-- 5 NoTo display information about a specific interface or upstream port, enter the
show cable hop cable-if [upstream portnum] command. Information lines describe the frequency hop status of an upstream port.
Sample output:
noisy1# show cable hopUpstream Port Poll Missed Min Missed Hop Hop Corr UncorrPort Status Rate Poll Poll Poll Thres Period FEC FEC(ms) Count Sample Pcnt Pcnt (sec) Errors ErrorsCable1/0/U0 down 1000 * * * frequency not set * * * 0 0Cable1/0/U1 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U2 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U3 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0Cable1/0/U0 down 1000 * * * frequency not set * * * 0 0Spectrum Management Debug and Test Commands
To enable display of frequency hopping debugging messages, enter:
debug cable freqhopTo enable display of spectrum management debugging messages, enter:
debug cable specmgmtThis command also enables display of channel width list and offer list for the
show cable spectrum-group command.To force a frequency hop decision on the port or ports, enter:
test cable hop cable-if [upstream portnum]show cable hop Command
You can use the following command to obtain specific upstream interface information:
show cable hop cable-if [upstream portnum]
noisy1# show cable hopUpstream Port Poll Missed Min Missed Hop Hop Corr UncorrPort Status Rate Poll Poll Poll Thres Period FEC FEC(ms) Count Sample Pcnt Pcnt (sec) Errors ErrorsCable1/0/U0 down 1000 * * * frequency not set * * * 0 0Cable1/0/U1 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U2 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U3 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0Cable1/0/U0 down 1000 * * * frequency not set * * * 0 0You can use the following command to obtain specific upstream interface information:
show cable hop cable-if [upstream portnum]
Sample output:
noisy1# show cable hopUpstream Port Poll Missed Min Missed Hop Hop Corr UncorrPort Status Rate Poll Poll Poll Thres Period FEC FEC(ms) Count Sample Pcnt Pcnt (sec) Errors ErrorsCable1/0/U0 down 1000 * * * frequency not set * * * 0 0Cable1/0/U1 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U2 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U3 admindown 1000 * * * interface is down * * * 0 0Cable1/0/U0 10.800 Mhz 1000 0 0 ----- 100% 300 0 0Cable1/0/U0 down 1000 * * * frequency not set * * * 0 0Debug and Test Commands
To enable display of frequency hopping debugging messages, enter:
debug cable freqhopTo enable display of spectrum management debugging messages, enter:
debug cable specmgmtTo force a frequency hop decision on the port or ports, enter:
test cable hop cable-if I portnumPolling Cable Modems
You can obtain operating statistics and determine the state of CMs on the network. The Cisco uBR7100 series CMTS supports polling of CMs to obtain parameter and status information on an ongoing basis. The following Cisco IOS commands have been added to support the feature:
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The Cisco uBR7100 series CMTS polls CMs on the network and caches the state information on the CMTS, allowing administrators to use SNMP to manage the system.
This section describes how you can enable this. See the following configuration tasks:
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Enabling SNMP
Opens the SNMP manager.
Defines user permissions.
Configuring Remote Modem Monitoring
Router(config)# cable modem remote-query [polling interval] [Community string]Specifies how often SNMP polls the modem and allows you to configure access.
Verifying Remote Query Information
To display information from a queried modem, enter the show cable modem remote-query command.
R7732-01-uBR7246# show cable modem remote-queryIP address MAC address S/N US DS Tx Time Micro (dB) ModemRatio Power Power Offset Reflection State5.108.1.2 0010.4bd7.ccf2 0.0 0.0 0.0 0 0 offline5.109.1.2 0000.0000.0022 0.0 0.0 0.0 0 0 offline5.110.1.2 0000.0000.0023 0.0 0.0 0.0 0 0 offline5.108.1.5 0000.0000.0026 0.0 0.0 0.0 0 0 offline5.108.1.4 0000.0000.0024 0.0 0.0 0.0 0 0 offline5.108.1.3 0000.0000.0025 0.0 0.0 0.0 0 0 offline
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See the following for an example debug message of a successful poll of a CM:
Router# debug cable remote-queryremote-query debugging is on.For IP address 209.165.200.223Nov 10 15:56:50.241: docsIfSignalQualityEntry.5.4 = 380Nov 10 15:56:50.241: docsIfMibObjects.2.2.1.3.2 = 360Nov 10 15:56:50.245: docsIfDownstreamChannelEntry.6.4 = -30Nov 10 15:56:50.245: docsIfUpstreamChannelEntry.6.3 = 12422Nov 10 15:56:50.249: docsIfSignalQualityEntry.6.4 = 0Nov 10 15:56:50.477:See the following for an example debug message when the waiting queue at the CMTS is empty:
SNMP proxy exec got event, but queue is emptySee the following for an example debug message when you try to modify the polling interval or community string while polling in is progress:
Community string if modified will not be reflected
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Monitoring and Maintaining Remote Querying
Use the following show commands to gather status information about the specified modems.
Understanding Show Command Responses
General show Commands
Key show commands include:
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Additional or changed show commands include the following:
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You can also limit your search for modem status to specific cable interfaces.
show cable modem Command
The show cable modem command includes all DOCSIS states, and other useful troubleshooting information such as last received upstream RF power level and maximum number of provisioned customer premises equipment.
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Specific added information includes the downstream receive power ratio, downstream SNR, upstream and downstream power levels, transmit timing offset, and micro reflections in decibels.
For each upstream channel, you can obtain the following information:
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Sample show cable modem command output follows:
Router# show cable modemInterface Prim Online Timing Rec QoS CPE IP address MAC addressSid State Offset PowerCable1/0/U0 1 online 2257 0.00 3 0 10.30.128.142 0090.8330.0217Cable1/0/U0 2 online 2262 *-0.50 3 0 10.30.128.145 0090.8330.020fCable1/0/U0 3 online 2260 0.25 3 0 10.30.128.146 0090.8330.0211Cable1/0/U0 4 online 2256 *0.75 3 0 10.30.128.143 0090.8330.0216Cable1/0/U0 5 online 2265 *0.50 3 0 10.30.128.140 0090.8330.0214Cable1/0/U0 6 online 2256 0.00 3 0 10.30.128.141 0090.8330.0215Cable1/0/U0 7 online 4138 !-1.00 3 1 10.30.128.182 0050.7366.124dCable1/0/U0 8 online 4142 !-3.25 3 1 10.30.128.164 0050.7366.1245Cable1/0/U0 9 online 4141 !-3.00 3 1 10.30.128.185 0050.7366.17e3Cable1/0/U0 10 online 4142 !-2.75 3 0 10.30.128.181 0050.7366.17abCable1/0/U0 11 online 4142 !-3.25 3 1 10.30.128.169 0050.7366.17efThe output from the show cable modem command indicates when the Cisco uBR7100 series CMTS has detected an unstable return path for a particular CM and has compensated with a power adjustment. An asterisk (*) in the power adjustment field for a CM indicates that a power adjustment has been made. An exclamation point (!) indicates that the CM has reached its maximum power transmit level and cannot increase its power level any further.
Columns are described below:
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See the following sample for detailed output of the show cable modem command:
Router# show cable modem detailInterface SID MAC address Max CPE Concatenation Rx SNRCable1/0/U0 1 0090.8330.0215 3 yesCable1/0/U0 2 0090.8330.0213 3 yesCable1/0/U0 3 0090.8330.0214 3 yesCable1/0/U0 4 0090.8330.0217 3 yesCable1/0/U0 5 0090.8330.020f 3 yesCable1/0/U0 6 0050.7366.17e3 3 noCable1/0/U0 7 0090.8330.0211 3 yesCable1/0/U0 8 0050.7366.17af 3 noCable1/0/U0 9 0090.8330.0216 3 yesCable1/0/U0 10 0050.7366.1801 3 noCable1/0/U0 11 0050.7366.124d 3 noCable1/0/U0 12 0050.7366.1241 3 noCable1/0/U0 13 0050.7366.17db 3 noCable1/0/U0 14 0050.7366.1239 3 noCable1/0/U0 15 0050.7366.17ab 3 noCable1/0/U0 1 0050.7366.1db1 3 no 26.50Cable1/0/U1 2 0050.7318.e97f 3 no 23.87Cable1/0/U1 3 0050.7318.e965 3 no 23.85Cable1/0/U0 4 0050.7318.e931 3 no 26.72Cable1/0/U1 5 0050.7318.e92d 3 no 23.31Cable1/0/U1 6 0050.7318.e97b 3 no 23.85Cable1/0/U0 7 0050.7366.1d8d 3 no 26.88Cable1/0/U0 8 0050.7318.e953 3 no 26.54Cable1/0/U1 9 0050.7366.1d9d 3 no 23.72Cable1/0/U1 10 0050.7318.e96b 3 no 23.79Cable1/0/U1 11 0050.7366.1d95 3 no 23.82Cable1/0/U0 12 0050.7318.e93f 3 no 26.26Cable1/0/U1 13 0050.7318.e96d 3 no 23.51Cable1/0/U0 14 0050.7318.e941 3 no 26.69Cable1/0/U0 15 0050.7366.1dcd 3 no 26.94Cable1/0/U1 16 0050.7318.e939 3 no 23.98Cable1/0/U0 17 0050.7366.1d8f 3 no 27.13Cable1/0/U0 18 0050.7302.3da3 3 no 26.58Cable1/0/U0 19 0050.7318.e93b 3 no 26.49Cable1/0/U0 20 0050.7318.e901 3 no 26.68Cable1/0/U1 21 0050.7366.1dbb 3 no 23.45Cable1/0/U0 22 0050.7318.e957 3 no 26.35Cable1/0/U0 23 0050.7318.e985 3 no 26.40Cable1/0/U0 24 0050.7366.1dbd 3 no 26.69Router# show cable modem cable 1/0 upstream 0Interface Prim Online Timing Rec QoS CPE IP address MAC addressSid State Offset PowerCable1/0/U0 1 offline 2264 -0.50 2 0 209.165.200.2 0090.8330.0214Cable1/0/U0 2 offline 4137 !-3.50 2 0 209.165.200.9 0050.7366.17d3Cable1/0/U0 3 init(d) 4136 !-2.50 2 0 209.165.200.0 0050.7366.17abCable1/0/U0 4 init(d) 4138 !-4.75 2 0 209.165.200.0 0050.7366.1803Cable1/0/U0 5 init(d) 4137 !-2.25 2 0 209.165.200.0 0050.7366.1801Cable1/0/U0 6 init(o) 2251 -0.25 2 0 209.165.200.3 0090.8330.0213Cable1/0/U0 7 offline 2264 0.75 2 0 209.165.200.4 0090.8330.020fCable1/0/U0 8 offline 2266 -0.50 2 0 209.165.200.5 0090.8330.0211Cable1/0/U0 9 init(rc) 4662 1.00 2 0 209.165.200.0 00d0.bad3.c459Router# show cable modem cable 1/0 upstream 0 unregisteredInterface Prim Online Timing Rec QoS CPE IP address MAC addressSid State Offset PowerCable1/0/U0 1 offline 2264 -0.50 2 0 209.165.200.2 0090.8330.0214Cable1/0/U0 2 offline 4137 !-3.50 2 0 209.165.200.9 0050.7366.17d3Cable1/0/U0 3 init(d) 4136 !-2.75 2 0 209.165.200.0 0050.7366.17abCable1/0/U0 4 init(d) 4137 !-3.25 2 0 209.165.200.0 0050.7366.1803Cable1/0/U0 5 init(d) 4141 !-2.75 2 0 209.165.200.0 0050.7366.1801Cable1/0/U0 6 offline 2251 -0.25 2 0 209.165.200.3 0090.8330.0213Cable1/0/U0 7 offline 2254 -1.00 2 0 209.165.200.4 0090.8330.020fCable1/0/U0 8 offline 2248 0.00 2 0 209.165.200.5 0090.8330.0211Cable1/0/U0 9 init(rc) 4665 -0.50 2 0 209.165.200.0 00d0.bad3.c459Router# show cable modem cable 1/0 upstream 0 offlineInterface MAC address Prim Previous Offline Rx Rx SMSid State Time Power SNR ExhaustCountCable1/0/U0 0050.7366.17d3 2 init(o) Jan 16 20:30:26 !-3.50 ----- 1Cable1/0/U0 0090.8330.0213 6 init(o) Jan 16 20:30:55 -0.25 ----- 181Cable1/0/U0 0090.8330.020f 7 init(o) Jan 16 20:31:07 -1.00 ----- 181Cable1/0/U0 0090.8330.0211 8 init(o) Jan 16 20:31:23 0.00 ----- 181show cable modem maintenance Command
When a cable modem is detected to be offline by the CMTS—no reply after 16 retries of station maintenance requests—the cable modem is marked offline. Besides marking the cable modem and SID state offline, the SID is removed immediately from the CMTS ranging list, and an aging timer is started to cleanup the SID completely if the cable modem does not attempt to come online within the next 24 hours.
Output fields are described below:
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Following is a response to the show cable modem maintenance command:
uBR7100# show cable modem maintenanceInterface SID MAC Address SM Exhausted SM AbortedCount Time Count TimeCable1/0/U1 1 0010.7b6b.5e27 4 Apr 29 19:33:19 0Cable1/0/U0 2 0010.7b6b.5e15 8 Apr 29 19:34:55 0Cable1/0/U2 11 0050.731c.b025 1 Apr 29 16:43:39 0Cable1/0/U0 13 0050.731c.b021 1 Apr 29 15:58:43 0Cable1/0/U0 16 0050.731c.b009 1 Apr 29 15:58:28 0Cable1/0/U0 20 0050.731c.bfed 1 Apr 28 14:36:22 0Cable1/0/U2 24 0050.731c.b023 1 Apr 27 10:30:36 0Cable1/0/U1 27 0050.731c.bfeb 1 Apr 28 14:54:53 0Cable1/0/U2 28 0050.731c.bfdf 1 Apr 28 14:50:55 0Cable1/0/U1 30 0050.7366.1a71 2 Apr 29 17:49:00 0Cable1/0/U1 31 0050.7366.1bab 3 Apr 29 16:21:47 0Cable1/0/U1 32 0050.731c.bfe7 0 2 Jan 1 09:00:00Cable1/0/U1 33 0050.731c.bfd3 4 Apr 29 15:09:28 0Cable1/0/U2 35 0050.731c.b041 1 Apr 29 16:17:41 0Cable1/0/U1 36 0050.7366.1ab9 2 Apr 29 16:53:26 0show interface cable Command
To display cable interface information, use the show interface cable privileged EXEC command:
show interface cable slot/port [downstream | upstream]
See the following sample show interface cable command output for a cable modem located in slot 1/port 0:
Router# show interface cable 1/0Cable1/0 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 4d07h, 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/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec10908 packets input, 855000 bytes, 0 no bufferReceived 3699 broadcasts, 0 runts, 0 giants, 0 throttles3 input errors, 3 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort5412 packets output, 646488 bytes, 0 underruns0 output errors, 0 collisions, 13082 interface resets0 output buffer failures, 0 output buffers swapped out
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See the following sample output for the downstream cable interface from the
show interface cable downstream command:Router# show interface cable 1/0 downstreamCable1/0: Downstream is up111947771 packets output, 1579682655 bytes, 0 discarded0 output errors
See the following sample output for the upstream cable interface for upstream cable interface 0 from the
show interface cable upstream command:Router# show interface cable 1/0 upstream 0Cable1/0: Upstream 0 is upReceived 16873 broadcasts, 0 multicasts, 73310 unicasts0 discards, 89053 errors, 0 unknown protocol90183 packets input, 1 uncorrectable89042 noise, 0 microreflectionsTotal Modems On This Upstream Channel : 8 (4 active)Default MAC schedulerQueue[Rng Polls] 0/20, fifo queuing, 0 dropsQueue[Cont Mslots] 0/104, 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 0 CBR entriesReq IEs 134469315, Req/Data IEs 0Init Mtn IEs 385879, Stn Mtn IEs 131059Long Grant IEs 10766, Short Grant IEs 15895Avg upstream channel utilization : 1%Avg percent contention slots : 97%Avg percent initial ranging slots : 0%Avg percent minislots lost on late MAPs : 0%Total channel bw reserved 0 bpsCIR admission control not enforcedCurrent minislot count : 6676390 Flag: 0Scheduled minislot count : 6676545 Flag: 0Table 5-6 describes the fields shown in the show interface cable upstream display.
Enhanced show interface upstream output Command
The show interface cable upstream command displays detailed MAC scheduler state information for the upstream port. The example below illustrates the new display:
cmts# show interface cable 1/0 upstream 0Cable1/0:Upstream 0 is upReceived 13 broadcasts, 0 multicasts, 110 unicasts0 discards, 106 errors, 0 unknown protocol123 packets input, 0 uncorrectable106 noise, 0 microreflectionsTotal Modems On This Upstream Channel :3 (3 active)Default MAC schedulerQueue[Rng Polls] 0/20, fifo queuing, 0 dropsQueue[Cont Mslots] 0/104, 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 2 CBR entriesReq IEs 280185, Req/Data IEs 0Init Mtn IEs 800, Stn Mtn IEs 49Long Grant IEs 26, Short Grant IEs 15Avg upstream channel utilization :1%Avg percent contention slots :97%Avg percent initial ranging slots :1%Avg percent minislots lost on late MAPs :0%Total channel bw reserved 192000 bpsCIR admission control not enforcedCurrent minislot count :1165412 Flag:1Scheduled minislot count :1176227 Flag:1New items in the display include:
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show interface cable sid Command
To display per-SID counters for bandwidth requests, use the show interface cable privileged EXEC command:
show interface cable interface sid [sid] counters verbose
Data transport over the RF link uses the registered SID address, rather than the Ethernet address. This allows multiple hosts to access the network by using a single cable modem.
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See the following display output for the verbose keyword extension for SID 1:
Router# show interface c1/0 sid 1 counters verboseSid : 1Input packets : 39Input octets : 15964Output packets : 30Output octets : 8796BW requests received : 40Grants issued : 40Rate exceeded BW request drops : 0Rate exceeded DS packet drops : 0See the following display output for the verbose keyword extension for all SIDs on the specified interface:
Router# show interface c1/0 sid counters verboseSid : 1Input packets : 39Input octets : 15964Output packets : 30Output octets : 8796BW requests received : 40Grants issued : 40Rate exceeded BW request drops : 0Rate exceeded DS packet drops : 0Sid : 2Input packets : 0Input octets : 0Output packets : 0Output octets : 0BW requests received : 0Grants issued : 0Rate exceeded BW request drops : 0Rate exceeded DS packet drops : 0Sid : 3Input packets : 0Input octets : 0Output packets : 0Output octets : 0BW requests received : 0Grants issued : 0Rate exceeded BW request drops : 0Rate exceeded DS packet drops : 0See the following display for the SIDs connected to the specified interface:
Lab-CMTS# show inter cab 1/0 sidSid Prim Type Online Admin QoS Create IP Address MAC AddressSid State Status Time23 stat init(d) enable 2 04:00:54 209.165.200.0 0050.7366.17ab24 stat init(d) enable 2 04:00:58 209.165.200.0 0050.7366.180325 stat init(rc) enable 2 04:01:05 209.165.200.0 00d0.bad3.c45926 stat init(d) enable 2 04:01:10 209.165.200.0 0050.7366.180127 stat offline enable 2 04:01:31 209.165.200.225 0090.8330.021328 stat offline enable 2 04:01:59 209.165.200.226 0090.8330.021129 stat offline enable 2 04:02:07 209.165.200.227 0090.8330.021430 dyn init(o) enable 2 04:03:09 209.165.200.228 0090.833See the following connection information for all SIDs on the specified interface:
Router# show interface c1/0 sid connectivitySid 1st time Times %online Online time Offline timeonline Online min avg max min avg max1 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:172 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:173 15:37:24 1 99.73 00:00 1h45m 1h45m 00:17 00:17 00:17See the following connection information for SID 1 on the specified interface:
Router# show interface c1/0 sid 1 connectivitySid 1st time Times %online Online time Offline timeonline Online min avg max min avg max1 15:37:24 1 99.72 00:00 1h41m 1h41m 00:17 00:17 00:17See the following display for the counters of the SIDs connected to the specified interface:
Router# show interface c1/0 sid countersSid Inpackets Inoctets Outpackets Outoctets Ratelimit RatelimitBWReqDrop DSPktDrop1 40 16586 31 9160 0 02 0 0 0 0 0 03 0 0 0 0 0 0See the following display for the counters of SID 1 on the specified interface:
Router# show interface c1/0 sid 1 countersSid Inpackets Inoctets Outpackets Outoctets Ratelimit RatelimitBWReqDrop DSPktDrop1 39 15964 30 8796 0 0Table 5-7 describes the fields shown in the output for the show interface cable sid displays.
show cable qos profile Command
Following is a response to the show cable qos profile command. The display shows ToS specifications:
uBR7100# show cable qos profileService Prio Max Guarantee Max Max tx TOS TOS Create Bclass upstream upstream downstream burst mask value by priv> bandwidth bandwidth bandwidth enab1 0 0 0 0 0 0x0 0x0 cmts(r) no2 0 64000 0 1000000 0 0x0 0x0 cmts (r) no3 0 1000 0 1000 0 0x0 0x0 cmts no4 3 256000 0 512000 0 0x0 0x0 cm no5 5 1000000 0 10000000 0 0x0 0x0 cm no6 3 256000 0 512000 0 0x0 0x0 cm yes
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Displays upstream packet discards, errors, error-free packets, correctable and uncorrectable errors, noise and micro-reflection statistics:
show interface slot/downstream-port upstreamTroubleshooting Cable Flap Lists
The Cisco uBR7100 series maintains a database of flapping cable modems to assist in locating cable plant problems. The flapping cable interface detector tracks the upstream and downstream performance of all cable modems on the network, without impacting throughput and performance, or creating additional packet overhead on the broadband network. The cable interface flap list keeps track of:
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The flap list collects the following station maintenance statistics:
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The cable system administrator typically:
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These reports can be given to the Customer Service Department or the cable plant's Operations and Maintenance Department. Using these reports, maintenance personnel can quickly discern how characteristic patterns of flapping cable modems, street addresses, and flap statistics can indicate which amplifier or feeder lines are faulty. The reports also help you quickly discern whether problems exist in your downstream or upstream path, and whether the problem is ingress noise or equipment related.
Default values for the following flap-list configuration commands are:
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Tip
The following tips and scenarios allow you to use the flap list in the most effective way:
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Following is a sample response to the show cable flap command:
uBR7100# show cable flapMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.9500.461f C1/0 U1 56 18857 887 0 1 116 Jun 1 14:09:120010.9500.446e C1/0 U1 38 18686 2935 0 1 80 Jun 2 19:03:570010.9500.38ec C1/0 U2 63 18932 1040 0 8 138 Jun 2 23:50:530010.9500.4474 C1/0 U2 65 18913 1053 0 3 137 Jun 2 09:30:090010.9500.4672 C1/0 U2 56 18990 2327 0 6 124 Jun 2 10:44:140010.9500.38f0 C1/0 U2 50 18964 2083 0 5 111 Jun 2 20:46:560010.9500.e8cb C1/0 U2 0 6537 183 0 1 5 Jun 2 22:35:480010.9500.38f6 C1/0 U3 50 19016 2511 0 2 104 Jun 2 07:46:310010.9500.4671 C1/0 U3 43 18755 3212 1 1 89 Jun 1 19:36:200010.9500.38eb C1/0 U0 57 36133 1608 0 6 126 Jun 2 20:04:580010.9500.3ce2 C1/0 U0 44 35315 1907 0 4 99 Jun 2 16:42:470010.9500.e8d0 C1/0 U2 0 13213 246 0 1 5 Jun 3 04:15:300010.9500.4674 C1/0 U2 56 36037 2379 0 4 121 Jun 3 00:34:120010.9500.4677 C1/0 U2 40 35781 2381 0 4 91 Jun 2 12:14:380010.9500.4614 C1/0 U2 40 21810 2362 0 502 586 Jun 2 21:43:020010.9500.3be9 C1/0 U2 63 22862 969 0 0 128 Jun 1 14:09:030010.9500.4609 C1/0 U2 55 22723 2127 0 0 112 Jun 1 14:08:020010.9500.3cb8 C1/0 U2 49 22607 1378 0 0 102 Jun 1 14:08:580010.9500.460d C1/0 U3 46 22477 2967 0 2 96 Jun 2 17:03:480010.9500.3cba C1/0 U3 39 22343 3058 0 0 81 Jun 1 14:13:160010.9500.3cb4 C1/0 U3 38 22238 2936 0 0 79 Jun 1 14:09:260010.9500.4612 C1/0 U3 38 22306 2928 0 0 79 Jun 1 14:09:29The command line with an arrow next to it reveals a cable interface that is continuously flapping. A high flap rate indicates that the cable interface is power adjusting frequently. This can indicate a problem with an amplifier. The number reveals the number of times the CMTS instructed the cable interface to adjust the transmit power more than 3 dB.
Cable modems are automatically added to the flap list when any of the following conditions are detected:
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Displaying the Flap List
The flap list can be queried either using the standard Simple Network Management (SNMP) API or the CLI. Using any third party SNMP Management Information Base (MIB) browser, you can query the ccsFlapTable in the CISCO-CABLE-SPECTRUM-MIB, a proprietary extension to the DOCSIS MIBs.
Using the show cable flap list command, the flap list statistics are accessed. Refer to the following example. Each of the columns in the display are described in Table 5-8:
MAC ID___ CableIF Ins _Hit__ Miss CRC P-Adj Flap ___Time____0010.7b6b.60ad C1/0 U0 0 14386 1390 1 38 41 Nov 24 21:34:240010.7b6b.65a3 C1/0 U0 0 14503 1264 1 33 37 Nov 24 21:28:090010.7b6b.6b9d C1/0 U0 0 14060 1726 3 40 43 Nov 24 21:18:36
Troubleshooting with the Flap List
This section includes suggestions on how to interpret different network conditions based on the flap list statistics:
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Analysis: This exhibits an optimal network situation.•
Analysis: Hit/miss analysis should be done after the "Ins" count stops incrementing. In general, if the hit and miss counts are about the same order of magnitude, the upstream can be experiencing noise. If the miss count is greater, then the modem is probably dropping out frequently and not completing registration. The upstream or downstream might not be stable enough for reliable link establishment. Very low hits and miss counters and high insertion counters indicate provisioning problems.•
Analysis: Indicates the power adjustment threshold is probably set at default value of 2 dB adjustment. The modem transmitter step size is 1.5 dB, but the headend can command 0.25 dB step sizes. Tuning your power threshold to 6 dB is recommended to decrease irrelevant entries in the flap list. The power adjustment threshold can be set using cable flap power threshold <0-10 dB> from the Cisco IOS global configuration mode. A properly operating HFC network with short amplifier cascades can use a 2 to 3 dB threshold.•
Analysis: This condition can indicate that the fiber node is clipping the upstream return laser. Evaluate the modems with the highest CRC count first. If the modems are not going offline
(Ins = 0), this will not be noticed by subscribers. However, they could receive slower service due to dropped IP packets in the upstream. This condition also results in input errors on the Cisco uBR7100 series router cable interface.•
Analysis: If link re-establishment happens too frequently, the modem is usually having a registration problem. This is indicated by a high Ins counter which tracks the Flap counter.Setting Cable Flap List Aging
You can specify the number of days to record and retain flapping activity on cable interfaces currently in the flap list table. This value is known as the age of the flap list. The valid range is from 1 to 60 days.
To set the age of the cable flap list, use the following command in global configuration mode.
CMTS01(config)# cable flap-list aging daysSpecifies the number of days to record and retain flapping activity for the cable modems connected to this Cisco uBR7100 series CMTS.
Verifying Cable Flap List Aging
To verify that cable flap list aging is set, enter the show cable flap list command:
CMTS01# show cable flap listMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.7b6b.5d1d C1/0 U0 0 688 169 0 0 3 Nov 5 12:28:500010.7b6b.5e15 C1/0 U0 1 707 185 0 0 5 Nov 5 12:29:520010.7b6b.5e27 C1/0 U0 1 707 198 0 0 5 Nov 5 12:29:550010.7b6b.5d29 C1/0 U0 1 709 205 0 0 5 Nov 5 12:29:520010.7b6b.5e2b C1/0 U0 1 710 204 0 0 7 Nov 5 12:30:16Setting Cable Flap List Insertion Time
You can set the cable flap list insertion time. When a cable interface makes an insertion request more frequently than the amount of insertion time defined by this command, the cable interface is placed in the flap list for activity recording. The valid range is from 60 to 86400 seconds.
To set the cable flap list insertion time, use the following command in global configuration mode.
Verifying Cable Flap List Insertion Time
To verify cable flap list insertion time, enter the show cable flap list command:
CMTS01# show cable flap listMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.7b6b.5d1d C1/0 U0 0 688 169 0 0 3 Nov 5 12:28:500010.7b6b.5e15 C1/0 U0 1 707 185 0 0 5 Nov 5 12:29:520010.7b6b.5e27 C1/0 U0 1 707 198 0 0 5 Nov 5 12:29:550010.7b6b.5d29 C1/0 U0 1 709 205 0 0 5 Nov 5 12:29:520010.7b6b.5e2b C1/0 U0 1 710 204 0 0 7 Nov 5 12:30:16Setting Cable Flap List Power Adjustment Threshold
You can specify the power adjustment threshold that will cause a flap list event to be recorded. When the power adjustment of a cable interface meets or exceeds the threshold, the cable interface is placed in the flap list. The valid range is from 1 to 10 dBmV.
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To set the power adjustment threshold for flap-list events, use the following command in global configuration mode.
CMTS01(config)# cable flap-list power-adjust threshold dbmvSpecifies the minimum power adjustment that will constitute a flap-list event.
Verifying Cable Flap List Power Adjustment Threshold
To verify the cable flap list power adjustment threshold, enter the show cable flap list command:
CMTS01# show cable flap listMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.7b6b.5d1d C1/0 U0 0 688 169 0 0 3 Nov 5 12:28:500010.7b6b.5e15 C1/0 U0 1 707 185 0 0 5 Nov 5 12:29:520010.7b6b.5e27 C1/0 U0 1 707 198 0 0 5 Nov 5 12:29:550010.7b6b.5d29 C1/0 U0 1 709 205 0 0 5 Nov 5 12:29:520010.7b6b.5e2b C1/0 U0 1 710 204 0 0 7 Nov 5 12:30:16Setting Cable Flap List Miss Threshold
You can specify the miss threshold for recording a flap-list event. A miss is the number of times a cable modem does not acknowledge a MAC layer keepalive message from a cable interface card. An 8% miss rate is normal for the Cisco cable interface cards. When the number of misses exceeds the threshold, the cable interface is placed in the flap list.
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To set the miss threshold for recording a flap-list event, use the following command in global configuration mode.
CMTS01(config)# cable flap-list miss-threshold missesSpecifies the number of MAC layer keepalive misses that will result in the cable modems being place in the flap list.
Verifying Cable Flap List Miss Threshold
To verify the cable flap list miss threshold, enter the show cable flap list command:
CMTS01# show cable flap listMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.7b6b.5d1d C1/0 U0 0 688 169 0 0 3 Nov 5 12:28:500010.7b6b.5e15 C1/0 U0 1 707 185 0 0 5 Nov 5 12:29:520010.7b6b.5e27 C1/0 U0 1 707 198 0 0 5 Nov 5 12:29:550010.7b6b.5d29 C1/0 U0 1 709 205 0 0 5 Nov 5 12:29:520010.7b6b.5e2b C1/0 U0 1 710 204 0 0 7 Nov 5 12:30:16Setting Cable Flap List Size
You can specify the maximum number of cable interfaces that can be listed in the cable flap list tables. The valid range is from 1 to 8192 cable interfaces. The default is 8192 cable interfaces.
To specify the maximum number of cable modems that can be recorded in the flap list, use the following command in global configuration mode.
CMTS01(config)# cable flap-list size numberSpecifies the maximum size of the flap list.
Verifying Cable Flap List Size
To verify the cable flap list size, enter the show cable flap list command:
CMTS01# show cable flap listMac Addr CableIF Ins Hit Miss CRC P-Adj Flap Time0010.7b6b.5d1d C1/0 U0 0 688 169 0 0 3 Nov 5 12:28:500010.7b6b.5e15 C1/0 U0 1 707 185 0 0 5 Nov 5 12:29:520010.7b6b.5e27 C1/0 U0 1 707 198 0 0 5 Nov 5 12:29:550010.7b6b.5d29 C1/0 U0 1 709 205 0 0 5 Nov 5 12:29:520010.7b6b.5e2b C1/0 U0 1 710 204 0 0 7 Nov 5 12:30:16Clearing Cable Flap List
To remove a single cable modem from the flap list or to remove all cable modems from the flap list, use one of the following commands in global configuration mode.
Customizing Other Flap List Values and Related Commands
The following displays flap list with different sorting options:
show cable modem flap-list [cable n | sort-flap | sort-time | sort-interface]The following sets the threshold value for link establishment:
[no] cable flap-list insertion-time sec
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The following sets the number of consecutive missed station maintenance (RNG-RSP) messages that must be missed for a flap event to occur. Value ranges from 1 to 2 with a default of 6 seconds. The hits and miss counters are not affected:
[no] cable flap-list miss-threshold miss-threshold
The following clears the counters for a cable modem (or all cable modems) in the station maintenance list:
clear cable modem {mac-addr | ip-addr | all} counters
The following displays the QoS, modem status, In and Out octets, IP and MAC addresses per SID:
show int cable slot/port sid
The following drops the modem's RF link by removing a modem from the keep-alive polling list. This forces the modem to reset:
clear cable-modem {mac-addr | ip-addr | all} reset
The following uses a MAC layer ping to determine if the cable modem is online. It uses smaller data units on the wire than a standard IP ping, resulting in lower overhead. This command works even if the IP layer in the modem is down or has not completed registration:
ping DOCSIS cable-modem mac-addr | IP address
The following displays the timing offset, receive power, and QoS values by cable interface, SID, and MAC address:
show cable modem [ip-address | MAC-address]
The following displays the current allocation table and frequency assignments:
show cable spectrum-group [spectrum group number]
The following displays maximum, average, and minimum% online time and offline times for a given SID on a given Cisco uBR7100 series router interface:
show int slot/port sid connectivity
The following command displays input and output rates, input errors, CRC, frames, overruns, underruns, collisions, interface resets. High input errors in the CMTS retrieved from this query suggests noisy upstream. In older versions of the chassis, loose midplane and line card screws caused a similar problem:
show interface slot/downstream-port
Performing Amplitude Averaging
The Cisco uBR7100 series CMTS uses an averaging algorithm to determine the optimum power level for a cable modem with low carrier-to-noise ratio that is making excessive power adjustments—known as flapping. To avoid dropping flapping cable modems, the Cisco uBR7100 series CMTS averages a configurable number of RNG-REQ messages before it makes power adjustments. By compensating for a potentially unstable return path, the Cisco uBR7100 series CMTS maintains connectivity with affected cable modems. You can interpret these power adjustments, however, as indicating unstable return path connections.
The show cable flap-list and show cable modem commands are expanded to indicate which paths the Cisco uBR7100 series CMTS is making power adjustments and which modems have reached maximum transmit power settings. These conditions indicate unstable paths that should be serviced.
The following example shows the output of the show cable flap-list command:
Router# show cable flap-listMAC Address Upstream Ins Hit Miss CRC P-Adj Flap Time0010.7bb3.fd19 Cable1/0/U1 0 2792 281 0 *45 58 Jul 27 16:54:500010.7bb3.fcfc Cable1/0/U1 0 19 4 0 !43 43 Jul 27 16:55:010010.7bb3.fcdd Cable1/0/U1 0 19 4 0 *3 3 Jul 27 16:55:01The asterisk (*) indicates that the CMTS is using the power adjustment method on this modem. An exclamation point (!) indicates that the modem has reached maximum transmit power.
Output of the show cable modem command appears below:
Router# show cable modemInterface Prim Online Timing Rec QoS CPE IP address MAC addressSid State Offset PowerCable1/0/U0 1 online 2257 0.00 3 0 10.30.128.142 0090.8330.0217Cable1/0/U0 2 online 2262 *-0.50 3 0 10.30.128.145 0090.8330.020fCable1/0/U0 3 online 2260 0.25 3 0 10.30.128.146 0090.8330.0211Cable1/0/U0 4 online 2256 *0.75 3 0 10.30.128.143 0090.8330.0216Cable1/0/U0 5 online 2265 *0.50 3 0 10.30.128.140 0090.8330.0214Cable1/0/U0 6 online 2256 0.00 3 0 10.30.128.141 0090.8330.0215Cable1/0/U0 7 online 4138 !-1.00 3 1 10.30.128.182 0050.7366.124dCable1/0/U0 8 online 4142 !-3.25 3 1 10.30.128.164 0050.7366.1245Cable1/0/U0 9 online 4141 !-3.00 3 1 10.30.128.185 0050.7366.17e3Cable1/0/U0 10 online 4142 !-2.75 3 0 10.30.128.181 0050.7366.17abCable1/0/U0 11 online 4142 !-3.25 3 1 10.30.128.169 0050.7366.17efSimilar to the show cable flap-list display, the * symbol in the show cable modem output indicates that the CMTS is using the power adjustment method on this CM. The ! symbol indicates that the CM has reached maximum transmit power.
This section documents the commands pertaining to amplitude averaging:
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Enabling or Disabling Power Adjustment
To enable or disable the power adjustment capability, use the following commands:
cable upstream n power-adjust {threshold [threshold #] | continue [tolerable value] | noise [% of power adjustment]}
no cable upstream power-adjust
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Caution
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If CMs cannot complete ranging because they have reached maximum power levels, you might try to set the tolerable value CONTINUE field to a larger value than the default of 2 dB. Values larger than 10 dB on "C" versions of cable modem cards, or 5 dB on FPGA versions, are not recommended.
If the flap list shows CMs with a large number of power adjustments, but the CMs are not detected as "noisy," you might try to decrease the percentage for "noisy." If you think too many CMs are unnecessarily detected as "noisy," you might try to increase it.
Setting Frequency Threshold to Affect Power Adjustment
To control power adjustment methods by setting the frequency threshold, use the
cable upstream freq-adj averaging interface configuration command. To disable power adjustments, use the no form of this command.cable upstream n freq-adj averaging % of frequency adjustment
no cable upstream freq-adj averaging
The following example shows how to change the power adjustment method when the frequency adjustment packet count reaches 50 percent:
Router(config-if)# cable upstream 0 freq-adj averaging 50Setting Downstream Test Signals
This feature provides configuration commands that allow you to create downstream test signals. Both Pseudo Random Bit Stream (PRBS) and unmodulated carrier test signals are now supported.
A PRBS test signal is a random data pattern that has been modulated to look like a real data stream. An unmodulated test signal is a continuous sine wave that looks like a carrier wave on the downstream transmission.
See the following required tasks to create PRBS and unmodulated carrier test signals:
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Configuring Unmodulated Test Signals
Configuring PRBS Test Signals
Verifying Test Signal Output
To verify the output of a continuous wave test signal or the output of a PRBS test signal, use a spectrum analyzer on the downstream channel. The downstream carrier is enabled as a default.
The standard mode of operation is modulated signal output and the interface is active. For PRBS and continuous wave output, the selected interface is shut down.
The functioning of the no cable downstream if-output command has not changed. The interface is shut down.
Pinging Unresponsive Cable Modems
Pinging a Cable Modem
Ping DOCSIS is a Cisco patent-pending feature that allows a cable system administrator to quickly diagnose the health of a channel between the Cisco uBR7100 series and the cable interface. The technology uses 1/64—the bandwidth of IP ping—and works with cable modems that do not have an IP address. This allows cable operators to ping cable modems that are unable to complete registration, have internal bugs, or that are unresponsive due to a crash.
The Ping DOCSIS feature includes a real time view and plot of requested power adjustments, and a measure of optimal headend reception power. This gives the cable operator the ability to solicit a configurable number of periodic ranging requests from a cable interface.
To ping a specific cable interface to determine if it is online, use the following command in EXEC mode.
Table 5-13 Instructions to Ping a Cable Modem
Pings the cable modem with a specific MAC address or IP address to see if it is online.
Verifying the Ping
The ping docsis command returns a verification from a cable modem that is pinged:
Queuing 5 MAC-layer station maintenance intervals, timeout is 25 msec:!!!!!Success rate is 100 percent (5/5)
Tip
Using the Cable Monitor Feature
Note
Router(config-if)# cable monitor [outbound | incoming] [timestamp] interface interface {access-list <name | number> | sid <n> | mac-addr <address> | upstream <n>}[packet-type {mac [type {map-req | map-grant | dsa | dsc | dsd ... }] | data packet-header {ethernet | docsis}}]Enter configuration commands, one per line. Then press ctrl+z.
Router# conf tRouter(config)# int c1/0Router(config-if)# cable monitor ?incoming Monitor incoming packetsoutbound Monitor outbound packetstimestamp Enable packet timestampinginterface Interface to forward monitored packetsRouter(config-if)# cable monitor incoming ?timestamp Enable packet timestampinginterface Interface to forward monitored packetsRouter(config-if)# cable monitor incoming timestamp ?interface Interface to forward monitored packetsRouter(config-if)# cable monitor incoming timestamp interface e1/0 ?access-list IP access list namemac-addr MAC address of the device monitoredsid Service ID to be monitoredupstream Upstream port to monitorRouter(config-if)# cable monitor incoming timestamp interface e1/0 sid 2 packet-type ?mac Monitor mac packetsdata Monitor data packets<cr>Router(config-if)# cable monitor incoming timestamp interface e1/0 sid 2 packet-type mac ?type Monitor selected mac packets<cr>Router(config-if)# cable monitor incoming timestamp interface e1/0 sid 2 packet-type mac type ?map-req Monitor Requestsmap-grant Monitor Grantsdsa Monitor dynamic service additiondsc Monitor dynamic service changedsd Monitor dynamic service deletionRouter(config-if)# cable monitor incoming timestamp interface e1/0 sid 2 packet-type mac type map-reqShow CLI :Router# show interface cable 1/0 monitorUS/ Time Outbound Flow Flow Type Flow Packet MAC MAC EncapDS Stmp Interface Type Identifier Extn. Type Extn. Type Typeall yes Et1/0 mac-addr 0050.5462.008c yes data no - Ethernetus yes Et1/0 acc-list 300 no - no - -us no Et1/0 sid 2 yes mac yes map-grant -all no Et1/0 acc-list rrr no - no - -all no Et1/0 mac-addr 0042.b013.008c yes data no - Ethernetall no Et1/0 upstream 0 yes data no - docsis
Note
Using Cable Interface debug Commands
To troubleshoot cable interfaces, use the following debug commands in enable (privileged EXEC) mode.
Caution
debug cable arp Command
This command activates debugging of arp requests on the cable interfaces. When this command is activated, all cable arp request messages are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable arpTo deactivate debugging of arp requests, use the following command:
CMTS01# no debug cable arpdebug cable envm Command (Environmental Monitor Messages)
This command activates debugging of the Cisco uBR7100 series environmental monitor. When this command is activated, all environmental monitor messages are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable envmTo deactivate debugging of the environmental monitor, use the following command:
CMTS01# no debug cable envmdebug cable err Command (MAC Protocol Errors)
This command activates debugging of cable MAC protocol errors. When this command is activated, any errors that occur in the cable MAC protocol are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable errTo deactivate debugging of MAC protocol errors, use the following command:
CMTS01# no debug cable errdebug cable privacy Command (Baseline Privacy)
This command activates debugging of baseline privacy. The format for the command follows:
CMTS01# debug cable privacyTo deactivate debugging of baseline privacy, use the following command:
CMTS01# no debug cable privacydebug cable keyman Command (Baseline Privacy Activity)
This command activates debugging of the TEK and KEK baseline privacy key activity. When this command is activated, all activity related to KEK and TEK keys displays on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable keymanTo deactivate debugging of the keys, use the following command:
CMTS01# no debug cable keymandebug cable mac-messages Command
This command activates debugging of messages generated in the cable MAC that frames and encrypts downstream RF signals. When this command is activated, messages generated by the cable MAC are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable mac-messagesTo deactivate debugging of cable MAC messages, use the following command:
CMTS01# no debug cable mac-messagesdebug cable map Command
This command activates debugging of cable maps that identify data on cable interfaces. When this command is activated, messages related to cable maps are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable mapTo deactivate debugging of cable maps, use the following command:
CMTS01# no debug cable mapdebug cable modems Command
This command activates debugging of cable modems. When this command is activated, messages from cable modems on the HFC network are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable modemsTo deactivate debugging of cable MAC messages, use the following command:
CMTS01# no debug cable modemsdebug cable phy Command (Messages)
This command activates debugging of messages generated in the cable PHY—the physical layer where upstream and downstream activity between the Cisco uBR7100 series router and the HFC network is controlled. When this command is activated, messages generated in the cable PHY are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable phyTo deactivate debugging of the cable PHY, use the following command:
CMTS01# no debug cable phydebug cable qos Command
This command activates debugging of QoS. When this command is activated, messages related to QoS parameters are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable qosTo deactivate debugging of QoS, use the following command:
CMTS01# no debug cable qosdebug cable range Command (Ranging Messages)
This command activates debugging of ranging messages from cable interfaces on the HFC network. When this command is activated, ranging messages generated when cable interfaces request or change their upstream frequencies are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable rangeTo deactivate debugging of cable interface ranging, use the following command:
CMTS01# no debug cable rangedebug cable receive Command (Upstream Messages)
This command activates debugging of upstream messages from cable interfaces. When this command is activated, any messages generated by cable interfaces and sent to the Cisco uBR7100 series router will be displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable receiveTo deactivate debugging of upstream messages, use the following command:
CMTS01# no debug cable receivedebug cable reg Command (Modem Registration Requests)
This command activates debugging of registration requests from cable interfaces on the HFC network. When this command is activated, messages generated by cable interfaces as they make requests to connect to the network are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable regTo deactivate debugging of cable registration, use the following command:
CMTS01# no debug cable regdebug cable reset Command (Messages)
This command activates debugging of reset messages from cable interfaces on the HFC network. When this command is activated, reset messages generated by cable interfaces are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable resetTo deactivate debugging of cable reset messages, use the following command:
CMTS01# no debug cable resetdebug cable specmgmt Command (Spectrum Management)
This command activates debugging of spectrum management (frequency agility) on the HFC network. When this command is activated, messages generated because of spectrum group activity are displayed on the Cisco uBR7100 series router console. Spectrum group activity can be additions or changes to spectrum groups, or frequency and power level changes controlled by spectrum groups. The format for the command follows:
CMTS01# debug cable specmgmtTo deactivate debugging of cable spectrum management, use the following command:
CMTS01# no debug cable specmgmtdebug cable startalloc Command (Channel Allocations)
This command activates debugging of channel allocations on the HFC network. When this command is activated, messages generated when channels are allocated to cable interfaces on the HFC network are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable startallocTo deactivate debugging of cable channel allocations, use the following command:
CMTS01# no debug cable startallocdebug cable transmit Command (CMTS Transmissions)
This command activates debugging of transmissions from the Cisco uBR7100 series router across the HFC network. When this command is activated, messages generated at the headend are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable transmitTo deactivate debugging of cable transmissions, use the following command:
CMTS01# no debug cable transmitdebug cable ucc Command (Upstream Channel Change Messages)
This command activates debugging of upstream channel change (UCC) messages generated when cable interfaces request or are assigned a new channel. When this command is activated, messages related to upstream channel changes are displayed on the Cisco uBR7100 series router console. The format for the command follows:
CMTS01# debug cable uccTo deactivate debugging of cable upstream channel changes, use the following command:
CMTS01# no debug cable uccdebug cable ucd Command (Upstream Channel Description Messages)
This command activates debugging of upstream channel descriptor (UCD) messages. UCD messages contain information about upstream channel characteristics and are sent to the cable modems on the HFC network. Cable modems that are configured to use enhanced upstream channels use these UCD messages to identify and select an enhanced upstream channel to use. When this command is activated, messages related to upstream channel descriptors are displayed on the Cisco uBR7100 series router console. The format for the command is as follows:
CMTS01# debug cable ucdTo deactivate debugging of cable upstream channel descriptor, use the following command:
CMTS01# no debug cable ucd
