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Cisco Systems uBR7200 Series Troubleshooting

1. Cable modem registered enabled for data online d Cable modem registered but network access for the cable modem is disabled online pk Cable modem registered BPI enabled and KEK assigned online pt Cable modem registered BPI enabled and TEK assigned reject m Cable modem did attempt to register registration was refused due to bad MIC reject c Cable modem did attempt to register registration was refused due to bad COS reject pk KEK modem key assignment rejected reject pt TEK modem key assignment rejected The Rec Power column contains the nominal receive power in decibels for this SID Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses E D Note means the noise power adjustment method is active for this modem means the modem has reached its maximum transmit power The QoS column contains the service class assigned to the modem The CPE column identifies the number of devices behind the modem The Max CPE column identifies the maximum number of devices configured for the modem The IP address reveals the modem s IP address The MAC address reveals the modem s MAC address The Concatenation column reveals if concatenation is enabled yes or disabled no The Rx SNR column reveals the SNR ratio level in dBmV as perceived by the cable modem amp Note This param
2. PCB Serial Number RMA Test History RMA Number RMA History EEPROM format version EEPROM contents hex 0x00 04 FF 40 01 AC 0x10 42 31 31 80 00 0x20 34 30 34 36 4E th T1 controller dware discovery sl Al 800 05867 02 sat 0 0 702 CAB04046NXV 00 0 0 0 0 00 41 01 01 CO 46 03 20 00 16 EB 02 00 00 00 02 02 C1 8B 43 41 42 30 58 56 03 00 81 00 00 00 00 04 00 Table 4 33 describes the fields shown in the show diag display Table 4 33 Show Diag Parameter Descriptions Field Description National clock card with T1 controller The system has identified the cable clock card EEPROM contents at hardware discovery EEPROM programmed data present when the system identified the clock card Hardware Revision Version number of the card Part Number The part number of the card Board Revision Revision number signifying a minor revision of the card Deviation Number Revision number signifying a minor deviation of the card Fab Version Manufacturing fabrication version number PCB Serial Number Serial number of the printed circuit board RMA Test History Counter indicating how many times diagnostics have been performed on this card RMA Number Return material authorization number which is an administrative number assigned if the card needs to be returned for repair RMA History Counter indicating how many times the card has been return
3. 0 209 165 200 4 0090 8330 020f Cable3 0 U0 8 offline 2266 0 50 2 0 209 165 200 5 0090 8330 0211 Cable3 0 U0 9 init rc 4662 1 00 2 0 209 165 200 0 00d0 bad3 c459 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pa B 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses E See the following sample output of unregistered modems connected on upstream channel 0 for cable interface 3 port 0 router show cable modem cable 3 0 upstream 0 unregistered Interface Prim Online Timing Rec QoS CPE IP address MAC address Sid State Offset Power Cable3 0 U0 1 offline 2264 0450 lt 2 0 209 165 200 2 0090 8330 0214 Cable3 0 U0 2 offline A37 1 3 50 2 0 209 165 200 9 0050 7366 17d3 Cable3 0 U0 3 init d A136 S2 95 2 0 209 165 20020 0050 7366 17ab Cable3 0 U0 4 init d 4137 1 3 25 2 0 209 165 200 0 0050 7366 1803 Cable3 0 U0 5 init d Ala Yo2 75 2 0 209 165 200 0 0050 7366 180 Cable3 0 U0 6 offline Zeal Qy2S 2 0 209 165 200 3 0090 8330 0213 Cable3 0 U0 7 offline 2254 1 00 lt 2 0 209 165 200 4 0090 8330 020f Cable3 0 U0 8 offline 2248 0 00 2 0 209 165 200 5 0090 8330 021 Cable3 0 U0 9 init rc 4665 O50 2 0 209 T65 20 00 00d0 bad3 c459 See the following sample output of offline modems connected on upstream channel 0 for cable interface 3 port 0 router show cable modem cable 3 0 upstream 0 offline Interface MAC address Prim Previous Offline Rx Rx SM Sid
4. State Time Power SNR Exhaust Count Cable3 0 U0 0050 7366 17d3 2 init o Jan 16 20230726 3 50 gt gt 1 Cable3 0 U0 0090 8330 0213 6 init o Jan 16 20730255 0 25 181 Cable3 0 U0 0090 8330 020f 7 init o dan 10 2081207 LL00 s 181 Cable3 0 U0 0090 8330 0211 8 init o Jan 16 20 31 23 0 00 181 Show Cable Modem Maintenance 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 e The SM Exhausted Count value refers to the number of times a cable modem was dropped because it did not reply to station maintenance requests A CM is removed from the station maintenance list after 16 times of periodic ranging opportunity without seeing the RNG_REQ from the modem The SM Aborted Count value refers to the number of times the CM was dropped because its operational parameters were unacceptable This includes such reasons as the power level is outside the acceptable range or the timing offset keeps changing The respective times in the command output indicate when this happened 78 5897 01 Cisco uBR7200 Series Universal Broadband Router S
5. The r in the Create by column means the first two classes of service the CMTS creates are reserved for CMs that are not online Displays upstream packet discards errors error free packets correctable and uncorrectable errors noise and microreflection statistics show interface slot downstream port upstream Troubleshooting Using Cable Flap Lists The Cisco uBR7200 series universal broadband routers maintain a database of flapping cable modems to assist in locating cable plant problems The flapping cable modem 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 modem flap Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Zn 78 5897 01 Chapter 4 Troubleshooting the System Troubleshooting Using Cable Flap Lists E list keeps track of the cable modem MAC address up and down transitions registration events missed periodic ranging packets upstream power adjustments and the physical interface on the Cisco uBR7200 series gt Note Although this is a Cisco proprietary CMTS feature it is compatible with all DOCSIS compliant cable modems Unlike SNMP the flap list uses zero bandwidth The flap list collects the following station maintenance statistics e Detects interface up down flap the reinsertion counter counts
6. 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 uBR7200 series console The format for the command follows CMTSO1 debug cable modems To deactivate debugging of cable MAC messages use the following command CMTSO1 no debug cable modems Debug Cable PHY Messages This command activates debugging of messages generated in the cable PHY the physical layer where upstream and downstream activity between the Cisco uBR7200 series and the HFC network is controlled When this command is activated messages generated in the cable PHY are displayed on the Cisco uBR7200 series console The format for the command follows CMTSO1 debug cable phy To deactivate debugging of the cable PHY use the following command CMTSO1 no debug cable phy Activate QoS Debug This command activates debugging of QoS When this command is activated messages related to QoS parameters are displayed on the Cisco uBR7200 series console The format for the command follows CMTSO1 debug cable qos To deactivate debugging of QoS use the following command CMTSO1 no debug cable qos 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Using Cable Interface Debug Commands Debug Cable Modem Ranging Messages This command activates debugging of ranging messages fr
7. Users enable admission control by using the admission control CLI Default MAC scheduler Indicates the status of the MAC scheduler as being in default mode as opposed to Automated Test Procedure ATP Queue Rng Polls The MAC scheduler queue showing the number of ranging polls Queue Cont Mslos The MAC scheduler queue showing the number of forced contention request slots in MAPS Queue CIR Grants The MAC scheduler queue showing the number of CIR grants pending Queue BE Grants The MAC scheduler queue showing the number of BE grants pending Queue Grant Shpr The MAC scheduler queue showing the number of grants that have been buffered for traffic shaping drops Number of packets dropped Reserved slot table currently has O CBR entries Number of CBR sessions active on an upstream channel at any given time Req IEs The running counter of request IEs sent in MAPS Req Data IEs The counter of request data IEs sent in MAPS Init Mtn IEs The counter of Initial Maintenance IEs Stn Mtn IEs Number of station maintenance ranging poll IEs Long Grant IEs Number of long grant IEs Short Grant IEs Number of short grant IEs Avg upstream channel utilization Indicates on average what percent of the upstream channel bandwidth is being used Avg percent contention slots Indicates on average what percent of slots are in contention state Avg percent initial
8. approximately every 25 seconds When the CMTS receives a response from the modem the event is counted as a Hit If the CMTS does not receive a response from the cable modem the event is counted as a Miss A cable modem will fail to respond either because of noise or if it is down Modems which only log Misses and zero Hits are assumed to be powered off Misses are not desirable since this is usually an indication of a return path problem however having a small number of misses is normal The flap count is incremented if there are M consecutive misses where M is configured in the cable flap miss threshold parameter The parameter value ranges from 1 to 12 with a default of 6 Ideally the HIT count should be much greater than the Miss counts If a modem has a HIT count much less than its MISS count then registration is failing Noisy links cause the MISS HIT ratio to deviate from a nominal 1 or less High Miss counts can indicate Intermittent upstream possibly due to noise e Laser clipping e Common path distortion Ingress or interference Too much or too little upstream attenuation This statistic tracks the CRC error counter per modem CRC errors are usually an indication of noise on a plant A low count can be always be expected but a high CRC number calls for some the plant troubleshooting The CRC counter indicates Intermittent upstream e Laser clipping e Common path distortion e Impulsive noise or interference T
9. following configuration tasks Enable SNMP required e Configure Remote Modem Monitoring required Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pais E 78 5897 01 Chapter 4 Troubleshooting the System Polling Cable Modems E Enable SNMP Command Purpose Router config snmp server manager Opens the SNMP manager Router config snmp server community Community String Defines user permissions Permissions Configure Remote Modem Monitoring Command Purpose Router config cable modem remote query polling interval Specifies how often SNMP polls the modem and Community string 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 sh cable modem remote query IP address MAC address S N US DS Tx Time Micro dB Modem Ratio Power Power Offset Reflection State 5 108 1 2 0010 4bd7 ccf2 0 0 0 0 0 0 O 0O offline Bis Osa oe 0000 0000 0022 0 0 0 0 0 0 0 0 offline So 10 2 0000 0000 0023 0 0 0 0 0 0 O 0O offline Ea Logela 0000 0000 0026 0 0 0 0 0 0 O 0 offline 5106 1 4 0000 0000 0024 0 0 0 0 0 0 O 0O offline 5 108 1 3 0000 0000 0025 0 00 0 0 0 0 O 0O offline Tips To display debugging information enter the debug cable remote query command See the following for an example debug message of a successful poll of a cable modem router de
10. packets discarded because there was no buffer space in the main system Received broadcast Total number of broadcast or multicast packets received by the interface runts Number of packets that are discarded because they are smaller than the medium s minimum packet size giants Number of packets that are discarded because they exceed the medium s maximum packet size input errors Includes runts giants no buffers CRC frame overrun and ignored counts CRC Indicates the number of times the cyclic redundancy checksum generated by the originating LAN station or far end device does not match the checksum calculated from the data received frame Number of packets received incorrectly with a CRC error and a non integer number of octets overrun Number of times the receiver hardware was unable to forward received data to a hardware buffer because the input rate exceeded the receiver s ability to handle the data ignored Number of received packets ignored by the interface because the interface hardware ran low on internal buffers packets output Total number of messages transmitted by the system bytes Total number of bytes including data and MAC encapsulation transmitted by the system underruns Number of times the transmitter ran faster than the receiving device could handle output errors Sum of all errors that prevented the final transmission of packets out of the int
11. the dynamic contention algorithms no cable insertion interval automatic lt Imin Imax gt lt msecs gt no cable upstream lt port num gt range backoff automatic lt start gt lt end gt no cable upstream lt port num gt data backoff automatic lt start gt lt end gt Tips System defaults are to have dynamic ranging interval enabled dynamic ranging backoff enabled and fixed data backoffs for each upstream of a cable interface 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 use one of the following commands in cable interface configuration mode Table 4 4 Instructions to Modify Dynamic Contention Algorithm Defaults Command Purpose CMTSO1 config if automatic CMTSO1 config if lt 25 2000 gt CMTSO1 config if lt 500 2000 gt CMTSO1 config if CMTSO1 config if no cable insertion interval Disable or enable the dynamic ranging interval algorithm If lower and upper bounds for varying the period are not specified the system uses default values of 50 msecs and 2 secs respectively cable insertion interval automatic min Set the lower bound on the initial ranging period for the auto ranging algorithm cable insertion int
12. the number of times a cable modem comes up and inserts into the network This helps identify potential problems in the downstream because improperly provisioned cable modems tend to try to reestablish a link repeatedly e Detects intermittent upstream the keepalive hits versus misses is the number of times cable modems don t respond or don t respond to the MAC layer keepalive messages If there are a number of misses this points to a potential problem in the upstream e Lists cable modem MAC addresses sorted by flap rate or most recent flap time e Shows power adjustment statistics during station maintenance polling this represents the number of times the CMTS tells a cable modem to adjust the transmit power more than 3 dB If constant power adjustments are detected this usually indicates a problem with an amplifier By looking at the cable modems in front and behind various amplifiers you can find the source of failure The cable system administrator typically e Sets up a script to periodically poll the flap list for example every 15 minutes e Uses the resulting data to perform trend analysis to identify the cable modems that are consistently in the flap list e Queries the billing and administrative database for cable modem MAC address to street address translation and generates a report These reports can be given to the Customer Service Department or the cable plant s Operations and Maintenance Department Using these reports mainte
13. transmitted and received were last reset to zero Queueing strategy Displays the type of queueing configured for this interface In the example output the type of queueing configured is First In First Out FIFO Output queue Number of packets in the output queue The format of this number is A B where A indicates the number of packets in the queue and B indicates the maximum number of packets allowed in the queue drops Indicates the number of packets dropped due to a full queue input queue drops Number of packets in the input queue The format of this number is A B where A indicates the number of packets in the queue and B indicates the maximum number of packets allowed in the queue 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Understanding Show Command Responses Table 4 16 Show Interface Cable Command Field Descriptions continued Field Description drops Indicates the number of packets dropped due to a full queue Five minute input rate Five minute output rate Average number of bits and packets transmitted per second in the last five minutes packets input Total number of error free packets received by the system bytes input Total number of bytes including data and MAC encapsulation in the error free packets received by the system no buffer Number of received
14. 0 from the show interface cable upstream command router show interface cable 3 0 upstream 0 Cable3 0 Upstream 0 is up Received 16873 broadcasts 0 multicasts 73310 unicasts 0 discards 89053 errors 0 unknown protocol 90183 packets input 1 uncorrectable 89042 noise 0 microreflections Total Modems On This Upstream Channel 8 4 active Default MAC scheduler Queue Rng Polls 0 20 fifo queueing 0 drops Queue Cont Mslots 0 104 fifo queueing 0 drops Queue CIR Grants 0 20 fair queueing 0 drops Queue BE Grants 0 30 fair queueing 0 drops Queue Grant Shpr 0 30 calendar queueing 0 drops Reserved slot table currently has 0 CBR entries Req IEs 134469315 Req Data IEs 0 Init Mtn IEs 385879 Stn Mtn IEs 131059 Long Grant IEs 10766 Short Grant IEs 15895 Avg 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 bps CIR admission control not enforced Current minislot count 6676390 Flag 0 Scheduled minislot count 6676545 Flag 0 Table 4 18 describes the fields shown in the show interface cable upstream display 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 E Understanding Show Command Responses Table 4 18 Show Interface Cable Upstream Command Field Descriptions Field Cable Description Indicates the location of th
15. 00 0 000 1 4 000 0 000 2 0 000 15 000 2 0 208 0 40 3 20 000 0 000 3 21 000 0 000 3 22 000 0 000 3 23 000 0 000 3 24 000 0 000 3 0 400 0 80 4 20 000 25 000 4 20 800 1 60 5 0 000 0 000 5 1 000 0 000 5 2 000 0 000 5 3 000 0 000 5 4 000 0 000 5 3 000 0 000 5 1 600 3 20 6 0 000 13 000 6 3 000 15 000 6 0 800 1 60 Managing Cable Modems on the HFC Network E Upstream Weekly Scheduled Power Shared Port Availability Level Spectrum From Time To Time dBmvV No No No No No 2 No Cable3 0 U1 2 3 Yes 3 Yes 3 Yes 3 Yes 3 Yes Cable3 0 U2 3 4 Yes Cable3 0 U3 4 5 o 5 o 5 o Mon 17 06 00 5 o Mon 17 08 00 5 o Mom 17220200 e7 Anr E G o Cable3 0 U4 5 6 o Mon 17 11 00 Mon 17 12 00 6 Cable3 0 U5 0 To display information about a specific interface or upstream port enter the following command show cable hop cable if upstream portnum Information lines describe the frequency hop status of an upstream port Table 4 13 Show Cable Hop Parameter Descriptions Field Description Upstream Port The upstream port for this information line Port Status Show down if frequency is unassigned admindown if the port is shutdown or the center frequency of the channel if the port is up Poll Rate The rate station maintenance polls are generated msec Missed Poll Count The number of missing polls Min Poll Sample The number of polls in
16. 0090 8330 0215 Cable3 0 U0 7 online 4138 1 00 3 1 0 30 128 182 0050 7366 124d Cable3 0 U0 8 online 4142 3 25 3 1 0 30 128 164 0050 7366 1245 Cable3 0 U0 9 online 4141 3 00 3 1 0 30 128 185 0050 7366 17e3 Cable3 0 U0 10 online 4142 2 75 3 0 0 30 128 181 0050 7366 17ab Cable3 0 U0 11 online 4142 3 25 3 1 0 30 128 169 0050 7366 17ef Similar 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 cable upstream power adjust noise cable upstream frequency adjust averaging Enable or Disable 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 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Performing Amplitude Averaging Table 4 27 Cable Upstream Power Adjust Syntax Descriptions Syntax Valid Values n Specifies the upstream port number threshold Specifies the power adjustment threshold The threshold range is from 0 through 10 dB The default is 1 dB tolerable value Determines if the st
17. 10 2362 0 502 586 Jun 2 21 43 02 0010 9500 3be9 C6 0 U5 63 22862 969 0 0 28 Jun 1 4 09 03 0010 9500 4609 C6 0 U5 55 22725 2127 0 0 12 Jun 1 4 08 02 0010 9500 3cb8 C6 0 U5 49 22607 1378 0 0 02 Jun 1 4 08 58 0010 9500 460d C6 0 U5 46 22477 2967 0 2 96 Jun 2 7 03 48 0010 9500 3cba C6 0 U5 39 22343 3058 0 0 81 Jun 1 4 13 16 0010 9500 3cb4 C6 0 U5 38 22238 2936 0 0 79 Jun 1 4 09 26 0010 9500 4612 C 6 0 U5 38 22306 2928 0 0 79 Jun 1 4 09 29 The command line with an arrow next to it reveals a cable modem that is continuously flapping A high flap rate indicates that the cable modem is power adjusting frequently This can indicate a problem with an amplifier The number reveals the number of times the CMTS instructed the cable modem 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 e When the cable modem re registers more frequently than the user specified insertion time e When intermittent keepalive messages are detected between the CMTS and the cable modem e When the cable modem s upstream transmit power is adjusted beyond the user specified power threshold Display 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 ext
18. 3 09 209 165 200 228 0090 833 See the following connection information for all SIDs on the specified interface router show interface c3 0 sid connectivity Sid lst time Times f online Online time Offline time online Online min avg max min avg max 1 153 3324 T 99 13 00 00 1h45m 1h45m 00 17 00 17 00 17 15 37 24 1 99 73 00 00 1h45m 1h45m 00 17 00 17 00 17 3 15 37 24 1 oo 73 00 00 1h45m 1h45m 00 17 00 17 00 17 See the following connection information for SID 1 on the specified interface router show interface c3 0 sid 1 connectivity Sid lst time Times f online Online time Offline time online Online min avg max min avg max 1 15 37 24 1 99 72 00 00 1h41m 1h41m 00 17 00 17 00 17 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pa B 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses See the following display for the counters of the SIDs connected to the specified interface router show interface c3 0 sid counters Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit BWReqDrop DSPktDrop 1 40 16586 SA 9160 0 0 0 0 0 0 0 3 0 0 0 0 0 0 See the following display for the counters of SID 1 on the specified interface router show interface c3 0 sid 1 counters Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit BWReqDrop DSPktDrop 1 39 15964 30 8796 0 0 Table 4 19 describes the fields shown in the output for the show interface cable sid di
19. 8 8 8 0050 7302 0050 73 0050 73 0050 73 0050 73 8 8 8 8 02 02 02 02 020 02 oO NM MB ON N a AO w 10 PAarFPAMrRPwWwWMHA BW N u w Q oo Jab dbl 1d8d 1d9d 1d95 3da3 e93b e901 0050 7366 e957 2985 0050 7366 dbd Max CPE WWWWWWWWwWwWwwwwWwwwwwwwwwwwwwwwwwwwwwwww ww Ww Concatenation Rx SNR yes yes yes yes yes no yes no yes no no no no no no no no no no no no no no no no no no no no no no no no no no no no no no 26 23 23 26 23 23 26 26 23 23 23 26 28 26 26 23 2 Lie 26 26 26 23 26 26 26 50 87 85 72 sod 85 88 54 72 79 82 26 ot 69 94 98 13 58 49 68 45 s35 40 69 See the following sample output of modems connected on upstream channel 0 for cable interface slot 3 port 0 router show cable modem cable 3 0 upstream 0 Interface Prim Online Timing Rec QoS CPE IP address MAC address Sid State Offset Power Cable3 0 U0 1 offline 2264 0 50 2 0 209 165 200 2 0090 8330 0214 Cable3 0 U0 2 offline 4137 A 2 0 209 165 200 9 0050 7366 17d3 Cable3 0 U0 3 init d 4136 1 2 50 2 0 209 165 200 0 0050 7366 17ab Cable3 0 U0 4 init d 4138 4 75 2 0 209 165 200 0 0050 7366 1803 Cable3 0 U0 5 init d AFIT 2 2 25 32 0 209 165 200 0 0050 7366 1801 Cable3 0 U0 6 init 0 2251 0 25 2 0 209 165 200 3 0090 8330 0213 Cable3 0 U0 7 offline 2264 0575 2
20. CHAPTER Troubleshooting the System This chapter contains troubleshooting information The chapter includes the following sections Using a Cable Modem at the Headend to Verify Downstream Signals Managing Cable Modems on the HFC Network Polling Cable Modems Understanding Show Command Responses Troubleshooting Using Cable Flap Lists Performing Amplitude Averaging Setting Downstream Test Signals Pinging Unresponsive Cable Modems Using Cable Interface Debug Commands Managing the Cisco uBR7246 VXR Clock Card Using a Cable Modem at the Headend to Verify Downstream Signals Step 1 Step 2 You can use a Cisco uBR924 cable access router to verify the downstream signal originating from a Cisco uBR7200 series universal broadband router Be sure you configure the Cisco uBR924 according to DOCSIS cable modem practises To verify the downstream signal from a Cisco uBR7200 series universal router using a Cisco uBR924 follow the procedure below After the Cisco uBR924 is operational and you have an input signal between 0 and 5 dBmV enter the show controller c0 tuner command Scan the output for the value corresponding to the signal to noise SNR estimate variable If this value is at least 35 dB then you have an optimized signal If the value is less than 34 dB adjust the upconverter at the cable headend 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide n Chapter 4 Troubleshooting
21. O 0 Cable3 0 U5 admindown 000 interface is down xk 0 0 Cable4 0 U0 10 800 Mhz 1000 0 0a 2 SSeS 100 300 0 0 Cable6 0 U0 down 0007 see frequency not set BORER 0 0 Debug and Test Commands To enable display of frequency hopping debugging messages enter debug cable freqhop To enable display of spectrum management debugging messages enter debug cable specmgmt To force a frequency hop decision on the port or ports enter test cable hop cable if I portnum Polling Cable Modems Cisco IOS Release 12 0 7 XR2 Cisco IOS Release 12 1 1a T1 or higher CMTS images contain modem status enhancements You can obtain operating statistics and determine the state of cable modems on the network The Cisco uBR7200 series supports polling of cable modems to obtain parameter and status information on an ongoing basis Two new Cisco IOS commands are added to support the feature The cable modem remote command configures the router for the polling interval the no version of this command disables the status polling The show cable modem remote query command displays the collected information downstream receive power level downstream signal to noise ratio upstream power level micro reflection in dB The Cisco uBR7200 series polls cable modems 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
22. Ping the cable modem with a specific MAC address or IP address to see if it is online Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Using Cable Interface Debug Commands E Verify the Ping The ping docsis command returns a verification from a cable modem that is pinged Queueing 5 MAC layer station maintenance intervals timeout is 25 msec Success rate is 100 percent 5 5 Tips If you are having trouble make sure you are using a valid MAC or IP address for the cable modem you want to ping Using Cable Interface Debug Commands To troubleshoot cable interfaces use the following debug commands in enable privileged EXEC mode Table 4 32 Instructions to Use Debug Command Command Purpose CMTS01 debug cable View all debug cable commands that are available CMTS01 undebug all Turn off all debugging information to the console and choose a more selective debug command s Note Refer to the debug commands that follow A Caution The following commands can generate large amounts of output as the number of cable modems grows On heavily loaded systems with thousands of cable modems these commands can dramatically affect router performance Debug Cable ARP Requests This command activates debugging of arp requests on the cable interfaces When this command is activated all cable arp r
23. The Flap counter is incremented when N consecutive Misses are detected after a Hit where N can be user configurable with a default value of 6 Unusual power adjustment The Flap and P adj counters are incremented when the modem s upstream power is adjusted beyond a user configurable power level Time Time is the timestamp indicating the last time the modem flapped The value is based on the clock configured on the local Cisco uBR7200 series If no time is configured this value is based on the current uptime of the Cisco uBR7200 series When a modem meets one of the three flap list criteria the Flap counter is incremented and Time is set to the current time Troubleshoot with the Flap List Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide This section includes suggestions on how to interpret different network conditions based on the flap list statistics Condition 1 Low miss hit ratio lt 10 for MC11 card lt 2 for MC16 card low insertion low P adj low flap counter and old timestamp Analysis This exhibits an optimal network situation Condition 2 High ratio of misses over hits gt 10 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 then the upstream may be experiencing noise If the miss count is greater then the modem is probably dropping out frequently and not com
24. a power adjustment An asterisk appears in the power adjustment field for a modem when a power adjustment has been made an exclamation point appears when the modem has reached its maximum power transmit level and cannot increase its power level any further The following tips and scenarios allow you to use the flap list in the most effective way If a subscriber s cable modem shows a lot of flap list activity it is having communication problems If a subscriber s cable modem shows little or no flap list activity it is communicating reliably the problem is probably in the subscriber s computer equipment or in the connection to the cable modem The top 10 most active cable modems in the flap list are most likely to have difficulties communicating with the headend Cable modems with more than 50 power adjustments per day have a suspect upstream path Cable modems with approximately the same number of hits and misses and with a lot of insertions have a suspect downstream path for example low level into the cable modem All cable modems incrementing the insertion at the same time indicates a provisioning server failure Cable modems with high CRC errors have bad upstream paths or in home wiring problems Correlating cable modems on the same physical upstream port with similar flap list statistics can quickly resolve outside plant problems to a particular node or geography Monitoring the flap list cannot affect cable modem communic
25. able to all modems that do not have any reserved rate on the upstream Total Modems On This Upstream Channel Number of cable modems currently sharing this upstream channel This field also shows how many of these modems are active Current Total Bandwidth Reserved Total amount of bandwidth reserved by all modems sharing this upstream channel that require bandwidth reservation The Class of Service for these modems specifies some non zero value for the guaranteed upstream rate When one of these modems is admitted on the upstream this field value is incremented by this guaranteed upstream rate value Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Troubleshooting the System 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses Table 4 18 Show Interface Cable Upstream Command Field Descriptions continued Field Description CIR admission control formerly Current Admission Control Status Indicates the status of admission control on the upstream channel ENFORCED status allows users to enable admission control on a per port basis This controls how limited bandwidth is allocated NOT ENFORCED status indicates that there is no admission control Every modem that registers with a class of service specifying a minimum upstream rate will be admitted by the CMTS regardless of how much aggregate bandwidth is actually available
26. ain an IP address or respond to SNMP messages Clear Cable Modem Counters To clear the counters for a cable modem or for all cable modems in the station maintenance list use one of the following commands in cable interface configuration mode Table 4 10 Instructions to Clear Cable Modem Counters Command Purpose CMTSO1 config if clear cable modem mac addr counters CMTSO1 config if clear cable modem ip addr counters CMTSO1 config if clear cable modem all counters Clear the counters in the station maintenance list for the cable modem with a specific MAC address Clear the counters in the station maintenance list for the cable modem with a specific IP address Clear the counters in the station maintenance list for all cable modems 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 5 Chapter 4 Troubleshooting the System E Managing Cable Modems on the HFC Network Verify Clear Cable Modem Counters To verify whether or not the counters in the Station Maintenance List are cleared enter the following command The station maintenance list counter will be 0 Configure Traffic Shaping Configure Downstream Rate Limiting and Shaping To configure downstream rate limiting or shape downstream traffic use the following command in cable interface configuration mode Table 4 11 Instructions to Configure Downstream Shaping Command Purpose CMTSO1 config i
27. andard Cisco IOS configuration practices for access lists and groups amp Note Configuring per modem or host filters is supported in Cisco IOS Release 12 0 5 T1 or higher as well as in Cisco IOS Release 12 0 6 SC or higher Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Managing Cable Modems on the HFC Network E To configure per modem filters use the following commands in cable interface configuration mode Table 4 6 Instructions to Configure Per Modem Filters Command Purpose CMTSO1 config if cable modem host device Configure access lists to be specified on a lt macaddr gt lt ipaddr gt access group lt acl gt per interface and per direction basis The packets received from cable modems and or individual hosts are filtered based on the cable modem or the host the packets are received from Use modem if the device is a cable modem Use host if the device is a CPE device attached to a cable modem Define the filter to be applied to the device and a given address The macaddr specifies the cable modem s or CPE device s unique MAC address Use the ipaddr option to specify the CM or CPE device s current IP address Use the acl option to assign the CM or CPE device to an access list This defines the per CM or per host filter requirements implemented at the CMTS rather than at the CM Access list numbers
28. ap counter 78 5897 01 Chapter 4 Troubleshooting the System Troubleshooting Using Cable Flap Lists E Set Cable Flap List Aging You can specify the number of days to record and retain flapping activity on cable modems 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 flap list use the following command in global configuration mode Table 4 21 Instructions to Set Cable Flap List Aging Command Purpose CMTS01 config cable flap list aging days Specify the number of days to record and retain flapping activity for the cable modems connected to this Cisco uBR7200 series Verify Cable Flap List Aging To verify that cable flap list aging is set enter the show cable flap list command CMTS01 show cable flap list Mac Addr CableIF Ins Hit Miss CRC P Adj Flap Time 0010 7b6b 5d1d C3 0 U0 0 688 169 0 0 3 Now D 22 528 2 50 0010 7b6b 5e15 C3 0 U0 a 707 185 0 0 5 Nov d L2929 752 0010 7b6b 5e27 C3 0 U0 t 707 198 0 0 5 NOW S 12229255 0010 7b6b 5d29 C3 0 U0 1 709 205 0 0 5 Nov 5 12 29 52 0010 7b6b 5e2b C3 0 U0 a 710 204 0 0 7 Nov 5 12 30 16 Set Cable Flap List Insertion Time You can set the cable flap list insertion time When a cable modem makes an insertion request more frequently than the amount of insertion time defined by this command the cable modem is placed in the flap list for activity recording The valid rang
29. are 1 to 99 for fast IP access lists 100 to 199 for show extended IP access lists amp Note Access list numbers of 700 to 799 do not apply gt Caution The system applies filters after the cable modem registers with the CMTS Filter definitions are not saved across system reboots and must be applied each time a CM registers The software supports traps to alert CMTS administrators on CMs going offline or back online A typical registration and login procedure is shown below 1 The CM registers with the Cisco uBR7200 series The Cisco uBR7200 series sends traps to management systems in use for the network The management system sets per modem filters using SNMP or rsh 2 3 4 The user logs in at the server 5 The login server obtains required modem and CPE information from the Cisco uBR7200 series 6 The login server sets per CPE filter in the Cisco uBR7200 series The per CPE filter overrides the per modem filter settings 7 Ifthe CM goes offline for a brief period of time filters defined using the Cisco uBR7200 series remain active If a CM stays offline for more than 24 hours filter settings are reset 8 Ifthe user logs out or the login server detects that the user is not online the login server sets default filters for the CM or the CPE device Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide I 78 5897 01 E Chapter 4 Troubleshooting the System E Manag
30. ations The flap list should be saved to a database computer and cleared at least once a day Important upstream performance data can be obtained by tracking flap list trend data Important installation quality control and performance data is directly available from the flap list Mi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Troubleshooting Using Cable Flap Lists E Following is a sample response to the show cable flap command uBR7200 show cable flap Mac Addr CableIF Ins Hit Miss CRC P Adj Flap Time 0010 9500 461f C3 0 U1 56 8857 887 0 1 16 Jun i 14 09 12 0010 9500 446e C3 0 U1 38 8686 2935 0 al 80 Jun 2 19 03 57 0010 9500 38ec C3 0 U2 63 8932 1040 0 8 38 Jun 2 23 50 53 0010 9500 4474 C3 0 U2 65 8913 1053 0 3 37 Jun 2 09 30 09 0010 9500 4672 C3 0 U2 56 8990 2327 0 6 24 Jun 2 10 44 14 0010 9500 38f0 C3 0 U2 50 8964 2083 0 5 11 Jun 2 20 46 56 0010 9500 e8cb C3 0 U2 0 6537 183 0 5 Jun 2 22 35 48 0010 9500 38f6 C3 0 U3 50 9016 2511 0 2 04 Jun 2 07 46 31 0010 9500 4671 C3 0 U4 43 8755 3212 1 89 Jun 1 9 36 20 0010 9500 38eb C4 0 U0 57 36133 1608 0 6 26 Jun 2 20 04 58 0010 9500 3ce2 C4 0 U0 44 35315 1907 0 99 Jun 2 6 42 47 0010 9500 e8d0 C4 0 U2 0 3213 246 0 5 Jun 3 04 15 30 0010 9500 4674 C4 0 U4 56 36037 2379 0 4 21 Jun 3 00 34 12 0010 9500 4677 C4 0 U4 40 35781 2381 0 4 91 Jun 2 2 14 38 gt 0010 9500 4614 C5 0 U5 40 218
31. atus of the RNG RSP should be set to CONTINUE or SUCCESS The range is from 2 through 15 dB The default is 2 dB of power adjustment Specifies the percentage of power adjustment packets required to switch from the regular power adjustment method to the noise power adjustment method Range is from 10 through 100 percent The default is 30 percent D Note The threshold default is 1 dB The tolerable value default is 2 dB The power adjustment is 30 percent A Caution Default settings are adequate for system operation Amplitude averaging is an automatic procedure In general Cisco does not recommend you adjust values Cisco does recommend however that you clean up your cable plant should you encounter flapping cable modems Note In some instances you might adjust certain values 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 Set Frequency Threshold to Affect Power Adjustment To control power a
32. ays statistics gathered by SNMP agents on modem states Router show interface cable Displays statistics on the quality of the cable interface Router show interface cable sid Displays statistics on the service IDs of the specified modems Understanding Show Command Responses General Show Commands Key show commands include e show cable modem show interface cable show cable qos profile show cable modulation profile show cable spectrum group Additional or changed show commands using Cisco IOS Release 12 0 7 XR2 Cisco IOS Release 12 1 1a T1 or higher CMTS images include the following The show cable qos command shows cable qos profile n command where the optional argument n can be used to display a specific profile The show int cx y sid command displays more complete Service ID SID status information The show cable modem command displays a list of options for a single modem to be specified by entering either the RF CPE device s IP address or MAC address SNR information for each cable modem on each interface summary display of the total number of modems connected for each upstream channel total number of registered and unregistered modems for the specified interface or upstream total number of offline modems for the specified interface or upstream and status for each offline modem before it went offline The show cable burst profile command has been removed Its functions have been incorporated into t
33. bug cable remote query remote query debugging is on For IP address 209 165 200 223 Nov 10 15 56 50 241 docsIfSignalQualityEntry 5 4 380 Nov 10 15 56 50 241 docsIfMibObjects 2 2 1 3 2 360 Nov 10 15 56 50 245 docsIfDownstreamChannelEntry 6 4 30 Nov 10 15 56 50 245 docsIfUpstreamChannelEntry 6 3 12422 Nov 10 15 56 50 249 docsIfSignalQualityEntry 6 4 Nov 10 15 56 50 477 I jo 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 empty See 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 Note The polling interval will be changed To change the community string you must unconfigure the snmp server community command and reconfigure it with the new community string Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 m Chapter 4 Troubleshooting the System E Understanding Show Command Responses Monitoring and Maintaining Remote Querying Use the following show commands to gather status information about the specified modems Command Purpose Router show cable flap list Displays statistics on the quality of the modem connection Router show cable modem Displays statistics on modem states Router show cable modem remote query Displ
34. cause excessive flap list event recording Cisco recommends setting this threshold value to 3 dBmV or higher To set the power adjustment threshold for flap list events use the following command in global configuration mode Table 4 23 Instruction to Set Cable Flap List Power Adjustment Threshold Command Purpose CMTS01 config cable flap list power adjust threshold dbmv Specify the minimum power adjustment that will constitute a flap list event Verify Cable Flap List Power Adjustment Threshold To verify the cable flap list power adjustment threshold enter the show cable flap list command CMTSO1 show cable flap list Mac Addr CablelIF Ins Hit Miss CRC P Adj Flap Time 0010 7b6b 5d1ld C3 0 U0 0 688 169 0 0 3 Nov 5 12228250 0010 7b6b 5e15 C3 0 U0 T 707 185 0 0 5S Now 5 12 29 52 0010 7b6b 5e27 C3 0 U0 1 707 198 0 0 5 Nov 5 122259255 0010 7b6b 5d29 C3 0 U0 i 709 205 0 0 SB Now amp 12129252 0010 7b6b 5e2b C3 0 U0 1 710 204 0 0 7 Nov 5 12 30 16 Set 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 modem card An 8 miss rate is normal for the Cisco cable modem cards When the number of misses exceeds the threshold the cable modem is placed in the flap list Note A high miss rate can indicate intermittent upstream problems fiber laser clipping or common path
35. col 0 uncorrectable 106 noise 0 microreflections Total Modems On This Upstream Channel 3 3 active Default MAC scheduler Queue Rng Polls 0 20 fifo queueing 0 drops Queue Cont Mslots 0 104 fifo queueing 0 drops Queue CIR Grants 0 20 fair queueing 0 drops Queue BE Grants 0 30 fair queueing 0 drops Queue Grant Shpr 0 30 calendar queueing 0 drops Reserved slot table curre Req IEs 280185 Req Data Init Mtn IEs 800 Long Grant IEs 26 Short Avg upstream channel util Avg percent contention sl Avg percent initial rangi Avg percent minislots los ntly has 2 CBR entries IEs 0 Stn Mtn IEs 49 Grant IEs 15 ization 1 ots 297 ng slots 1 t on late MAPs 0 Total channel bw reserved 192000 bps CIR admission control not Current minislot count Scheduled minislot count New items in the display include enforced 21165412 Flag 1 21176227 Flag 1 Detailed slot queue statistics Queue CIR Grants 0 20 fair queueing 0 drops in the example above means that the queue for CIR service grants has a current depth of 0 a maximum depth of 20 Weighted fair queueing shows grants in this queue CBR slot scheduling table state The above reserved slot table has 2 CBR entries This shows that at the time the command was issued the MAC scheduler had admitted 2 CBR slots in the reserved slot table Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapte
36. d show tech support page lt password gt The page option causes the output to display a page of information at a time Use the Return key to display the next line of output or use the space bar to display the next page of information If not used the output scrolls that is does not stop for page breaks The password option leaves passwords and other security information in the output If not used passwords and other security sensitive information in the output are replaced with the label lt removed gt this is the default Use this command to help collect general information about the router when you are reporting a problem This command displays the equivalent of the following show commands show buffers show controllers show interfaces show running config show processes cpu show processes memory show stacks show version Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide EN 78 5897 01
37. d Cable slot port is up administratively down Description Indicates whether the interface hardware is currently active or taken down by the administrator line protocol is up administratively down Indicates whether the software processes that handle the line protocol believe the interface is usable or if it has been taken down by the administrator hardware Hardware type and address Internet address Internet address followed by subnet mask MTU Maximum Transmission Unit MTU of the interface BW Bandwidth of the interface in kilobits per second DLY Delay of the interface in microseconds rely Reliability of the interface as a fraction of 255 calculated as an exponential average over 5 minutes For example 255 255 is 100 reliability load Load on the interface as a fraction of 255 calculated as an exponential average over 5 minutes For example 255 255 is complete saturation Encapsulation Encapsulation method assigned to this interface ARP type Type of Address Resolution Protocol ARP and timeout value assigned Last input Number of hours minutes and seconds since the last packet was successfully received by an interface output Number of hours minutes and seconds since the last packet was successfully transmitted by an interface Last clearing of show interface counters Time when the counters that measure cumulative statistics such as number of bytes
38. distortion To set the miss threshold for recording a flap list event use the following command in global configuration mode Table 4 24 Instructions to Set Cable Flap List Miss Threshold Command Purpose CMTSO1 config cable flap list miss threshold misses Specify the number of MAC layer keepalive misses that will result in the cable modems being place in the flap list Mi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Troubleshooting Using Cable Flap Lists E Verify Cable Flap List Miss Threshold To verify the cable flap list miss threshold enter the show cable flap list command CMTS01 show cable flap list Mac Addr CableIF Ins Hit Miss CRC P Adj Flap Time 0010 7b6b 5d1d C3 0 U0 0 688 169 0 0 3 Nev 5 1228850 0010 7b6b 5e15 C3 0 U0 t 707 185 0 0 S Nev 5S 12229252 0010 7b6b 5e27 C3 0 U0 1 TOT 198 0 0 New 5 12529355 0010 7b6b 5d29 C3 0 U0 Ep 709 205 0 0 S NewS 12 29 52 0010 7b6b 5e2b C3 0 U0 T 710 204 0 0 PNO rS 12530716 Set Cable Flap List Size You can specify the maximum number of cable modems that can be listed in the cable flap list tables The valid range is from 1 to 8192 cable modems The default is 8192 cable modems To specify the maximum number of cable modems that can be recorded in the flap list use the following command in global configuration mode Table 4 25 Instructions to Set Cable Flap L
39. djustment 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 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pe E 78 5897 01 Chapter 4 Troubleshooting the System Setting Downstream Test Signals E Table 4 28 Cable Upstream Freq adj Averaging Syntax Descriptions Syntax Valid Values n Specifies the upstream port number averaging Specifies that a percentage of frequency adjustment packets is required to change the adjustment method from the regular power adjustment method to the noise power adjustment method of frequency adjustment Specifies the percentage of frequency adjustment packets required to switch from the regular power adjustment method to the noise power adjustment method Valid range is from 10 through 100 percent 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 50 Setting 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 s
40. e Sync Message Interval Command Purpose CMTS01 config if eable sync interval msec Specify the interval in milliseconds between successive sync message transmissions from the Cisco uBR7200 series Valid values are from 1 to 200 msec Default 10 msec no cable sync interval Return the sync message interval to its default value of 10 msec Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Managing Cable Modems on the HFC Network E Verify Sync Message Interval To verify whether or not 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 Activate Cable Modem Authentication The Cisco uBR7200 series 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 from cable interface configuration mode Table 4 2 Instructions to Activate Cable Modem Authentication Command Purpose CMTS01 config if cable shared secret 0 7 Enable cable modem authentication 0 specifies an authoriz tion k ey unencrypted authentication key 7 sp
41. e cable 6 0 Cable6 0 is up line protocol is up Hardware is BCM3210 FPGA address is 00e0 le5f 7a60 bia 00e0 le5f 7a60 Internet address is 1 1 1 3 24 MTU 1500 bytes BW 27000 Kbit DLY 1000 usec rely 255 255 load 1 255 Encapsulation loopback not set keepalive not set ARP type ARPA ARP Timeout 04 00 00 Last input 4d07h output 00 00 00 output hang never Last clearing of show interface counters never Queueing strategy fifo Output queue 0 40 0 drops input queue 0 75 0 drops 5 minute input rate 0 bits sec 0 packets sec 5 minute output rate 0 bits sec 0 packets sec 10908 packets input 855000 bytes 0 no buffer Received 3699 broadcasts 0 runts 0 giants 0 throttles 3 input errors 3 CRC 0 frame 0 overrun 0 ignored 0 abort 5412 packets output 0 output errors 0 output buffer 0 underruns 13082 interface resets 646488 bytes 0 collisions failures 0 output buffers swapped out Note For more recent images such as Cisco IOS Release 12 1 1a T1 or higher the show interface upstream command is enhanced to display details on the MAC scheduler state for an upstream port Refer to Enhanced Show Interface Upstream Output section on page 4 30 Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses E Table 4 16 Show Interface Cable Command Field Descriptions Fiel
42. e is from 60 to 86400 seconds To set the cable flap list insertion time use the following command in global configuration mode Table 4 22 Instructions to Set Cable Flap List Insertion Time Command Purpose CMTSO1 config cable flap list insertion time seconds Specify the insertion time in seconds Any cable modem that makes an insertion request more frequently than this period of time is placed in the flap list Verify Cable Flap List Insertion Time To verify cable flap list insertion time enter the show cable flap list command CMTSO1 show cable flap list Mac Addr CableIF Ins Hit Miss CRC P Adj Flap Time 0010 7b6b 5d1ld C3 0 U0 0 688 169 0 0 3 Nov 5 12 28 50 0010 7b6b 5e15 C3 0 U0 ai 707 185 0 0 S Now 5 12229252 0010 7b6b 5e27 C3 0 U0 T 707 198 0 0 Se iNowS 12929455 0010 7b6b 5d29 C3 0 U0 1 709 205 0 0 5 Ney 3 1229 52 0010 7b6b 5e2b C3 0 U0 1 710 204 0 0 7 Nev S 12230216 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 EzE Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists Set 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 modem meets or exceeds the threshold the cable modem is placed in the flap list The valid range is from to 10 dBmV Note A power adjustment threshold of less than 2 dBmV might
43. e the cable clock force global configuration command To disable the selection and return to the default use the no form of this command cable clock force primary secondary no cable clock force Setting the cable clock to primary forces the primary source to act as the clock reference Setting the cable clock to secondary forces the secondary source to act as the clock reference The clock card automatically uses the primary external source if available If the primary source fails the clock card enters holdover mode and after a few seconds switches to the secondary external source The clock card switches back to the primary source when it becomes available Note This command overrides the default behavior of the clock card when the clock card is in holdover mode If the clock card is not in holdover mode this command is ignored You cannot force the reference to a port if the clock card is in free running mode The clock card enters holdover mode if the forced reference is lost even if the other external reference is available Set Midplane TDM Clock as Primary Reference Note A Caution To make the midplane TDM clock the primary timing reference for the clock card use the cable clock source midplane global configuration command To disable the selection and return to the default use the no form of this command cable clock source midplane Because the clock card automatically provides the timing referenc
44. e to the midplane TDM clock the midplane cannot in turn act as the reference for the clock card This means that the cable clock source midplane command does not take effect unless a port adapter is configured as the primary clock reference source for the midplane Although the cable clock source midplane command is configurable it is ignored until a port adapter that can serve as the midplane clock reference source is supported in the Cisco uBR7246 VXR Currently there are no port adapters on the Cisco uBR7246 VXR that support this Display Clock Values To display clock reference status information for the clock card use the show cable clock privileged EXEC command show cable clock 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Managing the Cisco uBR7246 VXR Clock Card The following sample output from the show cable clock command shows both external sources are available and the clock card is providing the clock reference Router show cable clock Clockcard primary input is present Clockcard secondary input is present Cable clock reference is clockcard primary input Cable3 0 Timestamp clock reference is from Clockcard Cable4 0 Timestamp clock reference is from Clockcard Show Clock Hardware Information and Register Values To display hardware information register values and current counters for the cable clock card
45. e upstream interface Upstream is up administratively down Indicates the administrative state of the upstream interface Received broadcasts Number of broadcast packets received through this upstream interface multicasts Number of multicast packets received through this upstream interface unicasts Number of unicast packets received through this interface discards Number of packets discarded by this interface errors Sum of all errors that prevented upstream transmission of packets through this interface unknown protocol Number of packets received that were generated using a protocol unknown to the Cisco uBR7246 packets input Number of packets received through this upstream interface that were free from errors corrected Number of error packets received through this upstream interface that were corrected uncorrectable Number of error packets received through this upstream interface that could not be corrected noise Number of upstream packets corrupted by line noise microreflections Number of upstream packets corrupted by microreflections Guaranteed rate service queue depth Number of bandwidth requests queued up in the Guarantee rate queue This queue is only available to modems that have a reserved minimum upstream rate in their Class of Service Best effort service queue depth Number of bandwidth requests queued up in the Best effort queue This queue is avail
46. ecifies an encrypted authentication key CMTS01 config if no cable shared secret Disable cable modem authentication p Tips Be sure you enter the correct slot and port number in the cable interface configuration mode Verify that the cable modem is using BPI and that it is assigned to a QoS with privacy active Verify that the cable modem configuration file contains a matching key Verify Cable Modem Authentication To verify whether cable modem authentication is activated or deactivated enter the command more system running config and look for the cable interface configuration information If cable modem authentication is deactivated it appears in this output as no cable secret shared Activate Cable Modem Upstream Address Verification Cable modem upstream address verification ensures that only cable modems that have received DHCP leases through the Cisco uBR7200 series can access the HFC network The Cisco uBR7200 series discards all packets received from or for hosts that have not received DHCP assigned addresses Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System E Managing Cable Modems on the HFC Network To activate cable modem upstream address verification use the following cable interface configuration command Table 4 3 Instructions to Activate Cable Modem Upstream Address Verification Command Purpose CMTS01 c
47. ed and repaired EEPROM format version Version number of the EEPROM format EEPROM contents hex Dumps of EEPROM programmed data 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Managing the Cisco uBR7246 VXR Clock Card Show Clock Frames To display information about the midplane TDM clock reference use the show frame clocks privileged EXEC command show frame clocks The following sample output from the show frame clocks command shows that there are no clock sources configured and the clock card is the default clock source Router show frame clocks Priority 1 clock source not configured input none Priority 2 clock source not configured input none Priority 3 clock source not configured input none Priority 4 clock source not configured input none Current clock source Clockcard input Primary priority 5 Table 4 34 describes the fields shown in the show frame clocks display Table 4 34 Show Frame clocks Parameter Descriptions Field Description Priority 1 4 clock source The configuration of the four network clock sources Current clock source The current clock source its input and priority In this example the clock card is providing the clock source Show General Information To display general information about the router when reporting a problem use the show tech support privileged EXEC comman
48. ed channel or a suitable channel and moves all cable modems on the upstream port The example below shows the Cisco uBR7200 series ability to 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 uBR config cable spectrum group cable spectrum group frequency 22000000 2 frequency 22000000 3 uBR config cable spectrum group 2 frequency 20000000 uBR config cable spectrum group 2 frequency 20000000 2 uBR config cable spectrum group 2 frequency 20000000 2 uBR config cable spectrum group 2 frequency 22000000 2 2 The 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 since there is a single RF domain Otherwise there are free and in use sets for each upstream port since each upstream port has its own RF domain Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pa B 78 5897 01 Chapter 4 Troubleshooting the System Sample output noisyl show cable spec Group Frequency No Band Mhz 1 0 000 0 000 1 1 000 0 000 1 2 000 0 000 1 3 0
49. ension to the DOCSIS MIBs Using the show cable flap list command the flap list statistics are accessed A sample appears below Each of the columns in the display are described in Table 4 20 MAC ID CableIF Ins _Hit Miss CRC P Adj Flap Time 0010 7b6b 60ad C3 0 UO O 14386 1390 1 38 41 Nov 24 21 34 24 0010 7b6b 65a3 C3 0 U0 0 14503 1264 1 33 37 Nov 24 21 28 09 0010 7b6b 6b9d C3 0 U0 O 14060 1726 3 40 43 Nov 24 21 18 36 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide I 78 5897 01 PEEN Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists Table 4 20 Flap List Statistics Description Statistic Description MAC ID This is the MAC layer address of a cable modem The first six digits indicate the vendor ID of the cable modem manufacturer followed by six digits indicating a unique host address Each cable modem s MAC address is unique Cable IF This is the physical upstream interface on the Cisco uBR7200 It denotes the cable modem card slot number the downstream port number on the RF line card and the upstream port number on the same cable modem card The flap list data can be sorted based on the upstream port number which is useful when isolating reverse path problems unique to certain combining groups Insertions Link insertion is the process whereby a modem performs an initial maintenance procedure to establish link with the CMTS The Ins column is the flapping modem
50. equest messages are displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable arp To deactivate debugging of arp requests use the following command CMTS01 no debug cable arp Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide I 78 5897 01 EN Chapter 4 Troubleshooting the System E Using Cable Interface Debug Commands Debug Environmental Monitor Messages This command activates debugging of the Cisco uBR7200 series environmental monitor When this command is activated all environmental monitor messages are displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable envm To deactivate debugging of the environmental monitor use the following command CMTS01 no debug cable envm Debug Cable 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 uBR7200 series console The format for the command follows CMTS01 debug cable err To deactivate debugging of MAC protocol errors use the following command CMTSO1 no debug cable err Activate Debug of Baseline Privacy This command activates debugging of baseline privacy The format for the command follows CMTSO1 debug cable privacy To deactivate debugging of baseline privacy use the following command CMTSO1 n
51. er provides the safety factor for the dynamic map advance algorithm This parameter is specified in usecs and controls the amount of extra lookahead time in MAPs to account for inaccuracies of the measurement system and software latencies The default value is 1000 usecs You can vary this between 500 to 1500 usecs This parameter is a delta value added to the dynamic map advance that the algorithm computes Using larger safety factors increases the run time lookahead in MAPs but reduces the upstream performance Use the static keyword for the map advance command The Cisco uBR7200 series will use a fixed lookahead time in MAPs regardless of the real propagation delay of the farthest cable modem on the network This fixed lookahead time is computed based on the worst case parameters such as farthest DOCSIS propagation delay for the CMs A Caution Cisco recommends if you are adjusting the dynamic map advance algorithm that you do not reduce the safety factor below the default value of 1000 usecs in a production network until you are confident that the reduced safety factor suffices for your deployment The default value is chosen to be a safe operating point for the algorithm Configure Per Modem Filters You can configure the Cisco uBR7200 series 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 st
52. erface being examined interface resets Number of times an interface has been completely reset Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses E Table 4 16 Show Interface Cable Command Field Descriptions continued Field Description output buffer failures Number of times the output buffer has failed output buffer swapped out Number of times the output buffer has been swapped out See the following sample output for the downstream cable interface of slot 6 on port 0 from the show interface cable downstream command router show interface cable 6 0 downstream Cable6 0 Downstream is up 111947771 packets output 1579682655 bytes 0 discarded 0 output errors Table 4 17 Show Interface Cable Downstream Command Field Descriptions Field Description Cable Indicates the location of the downstream interface Downstream is up administratively down Indicates the administrative state of the interface packets output Total number of packets transmitted out of this interface bytes Total number of bytes transmitted out of this interface discarded Total number of packets discarded output errors Sum of all errors that prevented downstream transmission of packets out of this interface See the following sample output for the upstream cable interface located in slot 3 port
53. erval max Set the upper bound on initial ranging period for the auto ranging algorithm no cable insertion interval Reset fixed initial ranging period to default value of 500 msecs Also invokes fixed initial ranging algorithm cable insertion interval lt 100 2000 gt Enabled fixed initial ranging period algorithm with specified fixed period msecs Configure the Dynamic Map Advance Algorithm A CMTS administrator can enhance the upstream throughput from a cable modem connected to the Cisco uBR7200 series The system employs a new algorithm that auto 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 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide n Chapter 4 Troubleshooting the System E Managing Cable Modems on the HFC Network A Caution Only a trained CMTS administrator should adjust these values To configure the dynamic map advance algorithm use the following command in cable interface configuration mode Table 4 5 Instructions to Configure the Dynamic Map Advance Algorithm Command Purpose CMTS01 config if cable map advance dynamic lt n gt static Specify a value to enhance the upstream throughput from a cable modem connected to the Cisco uBR7200 series The lt n gt paramet
54. eter is only meaningful for cable modems A CMTS will return a zero The S N Ratio column provides values for remote queried modems The US Power column reveals the transmit power level for the upstream channel in dBmV The DS Power column reveals the received power level at the downstream modem in dBmV Note If the power level measurement is not supported set this parameter to zero Also if the interface is down this value will be the CMTS configured value the most current CM value or zero The Tx Timing Offset shows the current round trip time at the CM The value is used to synchronize upstream transmission to the CMTS and is measured in units of 6 25 microseconds The Micro dB Reflection column is the total microreflections including in channel response as perceived on this interface measured in Dbc below the signal level Note The value is not assumed to return an absolutely accurate value but gives a rough indication of microreflections received on this interface The Offline Time column reveals when a modem went offline The Previous State column reveals the modem s status prior to going offline See the modem ranging states given earlier The Rx Power column reveals the last receive power measurement for a modem that is offline before it went offline SM Exhaust Count reveals the number of times the CMTS declared that modem offline The modem can be marked offline for various reasons Refer
55. f no cable downstream rate limit Enables or disables rate limiting and traffic token b cket shaping weighted discard expwt lt n gt shaping on the downstream of a cable interface amp Note Using Cisco IOS Release 12 0 5 T1 or higher the software adds downstream calendar queuing routines and grant shaping application of the calendar queues Key command usage is elaborated below To enable rate limiting on the given downstream port using the token bucket policing algorithm issue the cable downstream rate limit token bucket command To enable rate limiting on the given downstream port using the token bucket policing algorithm with traffic shaping issue the cable downstream rate limit token bucket shaping command To enable rate limiting on the given downstream port using the token bucket policing algorithm with a specific traffic shaping time granularity issue the cable downstream rate limit token bucket shaping granularity 8 command Acceptable values are 1 2 4 8 or 16 msecs To enable rate limiting on the given downstream port using the token bucket policing algorithm with a specific maximum traffic shaping buffering delay issue the cable downstream rate limit token bucket shaping granularity 8 command Acceptable values are 128 256 512 or 1028 msecs To remove rate limiting on the given downstream port issue the cable downstream rate limit token bucket command To enable rate limiting o
56. for the show cable freqhop specmgmt spectrum group command Missed Hop Pent not set is is is is is down down down down down 100 not set To force a frequency hop decision on the port or ports enter test cable hop cable if upstream portnum Show Cable Hop Command Hop Thres Period sec 3 ba So i a a 0 F F FH FF FF F F FH Corr FEC Errors SO OO Do Uncorr FEC Errors Co Oo OC oO o oo Using Cisco IOS Release 12 0 5 T1 or higher headend images you can use the following command to obtain specific upstream interface information show cable hop cable if upstream lt portnum gt Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Managing Cable Modems on the HFC Network E Table 4 14 Show Cable Hop Parameter Descriptions Field Description Upstream Port The upstream port for this information line Port Status Show down if frequency is unassigned admindown if the port is shutdown or the center frequency of the channel if the port is up Poll Rate The rate station maintenance polls are generated msec Missed Poll Count The number of missing polls Min Poll Sample The number of polls in the sample Missed Poll Pent The ratio of missing polls to the number of polls expressed as a percentage Hop Thres Pcn
57. he port is shutdown or the center frequency of the channel if the port is up Poll Rate The rate station maintenance polls are generated msec Missed Poll Count The number of missing polls Min Poll Sample The number of polls in the sample Missed Poll Pent The ratio of missing polls to the number of polls expressed as a percentage Hop Thres Pcnt The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage Hop Period The maximum rate at which frequency hopping will occur seconds 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Polling Cable Modems Table 4 15 Upstream Port Parameter Descriptions continued Field Description Corr FEC Errors The number of correctable FEC errors on this upstream port Uncorr FEC Errors The number of uncorrectable FEC errors on this upstream port Sample output noisyl show cable hop Upstream Port Poll Missed Min Missed Hop Hop Corr Uncorr Port Status Rate Poll Poll Poll Thres Period FEC FEC ms Count Sample Pcnt Pent sec Errors Errors Cable3 0 U0 down O00 Fes frequency not set ae ea 0 0 Cable3 0 U1 admindown COO ee interface is down ae ee ee 9 0 Cable3 0 U2 admindown 000 interface is down eR o 0 Cable3 0 U3 admindown O00 ck interface is down HRS KY 0 Cable3 0 U4 admindown OOO X X interface is down AARE SR
58. he show cable modulation profile command which now includes an added option number that displays the modulation profile number Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pas B 78 5897 01 Chapter 4 Troubleshooting the System Understanding Show Command Responses E The show cable flap list and show cable modem commands now indicate when the Cisco uBR7200 series router has detected an unstable return path for a particular modem and has compensated with a power adjustment An asterisk appears in the power adjustment field for a modem when a power adjustment has been made an exclamation point appears when the modem has reached its maximum power transmit level and cannot increase its power level any further The show controller upstream command is enhanced to display the following information on cable interfaces Upstream channel utilization in minislots Contention slots Initial ranging slots Minislots lost due to the MAP interrupt being too late You can also limit your search for modem status to specific cable interfaces Show Cable Modem Using Cisco IOS Release 12 0 7 XR2 Cisco IOS Release 12 1 1a T1 or higher the show cable modem command includes all DOCSIS states as well as other useful troubleshooting information such as last received upstream RF power level and maximum number of provisioned customer premises equipment Note DOCSIS cable modems are required to pass th
59. he station maintenance poll in the CMTS constantly adjusts the modem transmit power frequency and timing The P Adj column indicates the number of times the modem s power adjustment exceeded the threshold value The power adjustment threshold may be set using the lt cable flap power threshold gt parameter with a value range of 0 to 10 dB and a default value of 2 dB Tuning this threshold is recommended to decrease irrelevant entries in the flap list Power Adjustment values of 2 dB and below will continuously increment the P Adj counter The modem transmitter step size is 1 5 dB whereas the headend may command 0 25 dB step sizes Power adjustment flap strongly suggests upstream plant problems such as e Amplifier degradation e Poor connections Thermal sensitivity e Attenuation problem 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists Table 4 20 Flap List Statistics Description Flap The Flap counter indicates the number of times the modem has flapped This counter is incremented when one of the following events is detected Unusual modem insertion or reregistration attempts The Flap and the Ins counters are incremented when the modem tries to reestablish the RF link with the CMTS within a period of time that is less than the user configurable insertion interval value Abnormal Miss Hit ratio
60. ify 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 will be shut down The functioning of the no cable downstream if output command has not changed The interface is shut down Pinging Unresponsive Cable Modems Ping 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 uBR7200 series universal broadband router and the cable modem The technology uses 1 64 the bandwidth of IP ping and works with cable modems that don t 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 Information the Ping DOCSIS feature includes a real time view and plot of requested power adjustments as well as 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 modem To ping a specific cable modem to determine if it is online use the following command in EXEC mode Table 4 31 Instructions to Ping a Cable Modem Command Purpose CMTS01 ping docsis addr
61. ignal 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 e Configure Unmodulated Test Signals e Configure PRBS Test Signals Configure Unmodulated Test Signals Table 4 29 Instructions to Configure Unmodulated Test Signals Step Command Purpose 1 router config if cable downstream if output Generates an unmodulated continuous wave signal continuous wave on the downstream channel The interface is shut down 2 Router config if no cable downstream if output Stops sending test signals s Note Remember to reenable the interface to resume normal operations Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 E Chapter 4 Troubleshooting the System E Pinging Unresponsive Cable Modems Configure PRBS Test Signals Table 4 30 Instructions to Configure PRBS Test Signals Step Command Purpose 1 router config if cable downstream if output prbs Generates a PRBS test signal on the downstream channel The interface is shut down A Router config if no cable downstream if output Stops sending test signals Note Remember to reenable the interface to resume normal operations Verify Test Signal Output To ver
62. ing Cable Modems on the HFC Network Configure 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 Table 4 7 Instructions to Configure the Maximum Number of Hosts Attached to a Cable Modem Command Purpose CMTS01 config if cable max hosts n Specify the maximum number of hosts that can be attached to a cable modem on this interface Valid range is from 0 to 255 hosts Default 0 CMTS01 config if no cable max hosts Reset the allowable number of hosts attached to a cable modem to the default value of 0 hosts Configure 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 uBR7200 series 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 uBR7200 series use the following command in cable interface configuration mode Table 4 8 Instructions to Configure Cable Modem Registration Timeout Command Purpose CMTSO1 config if cable registration timeout n Specify the maximum number of minutes allowed to elapse with no upstream activity before terminating the connection Valid range is from 2 to 60 minutes Default 3 minutes Clear Cable M
63. ist Size Command Purpose CMTS01 config cable flap list size number Specify the maximum size of the flap list Verify Cable Flap List Size To verify the cable flap list size enter the show cable flap list command CMTS01 show cable flap list Mac Addr CableIF Ins Hit Miss CRC P Adj Flap Time 0010 7b6b 5d1d C3 0 U0 0 688 169 0 0 3 Nov 5 12 28 50 0010 7b6b 5e15 C3 0 U0 1 707 185 0 0 Sy Nov 5 12529352 0010 7b6b 5e27 C3 0 U0 ai 707 198 0 0 5 Nov 5 12 29 55 0010 7b6b 5d29 C3 0 U0 t 709 205 0 0 S Nove 5 12 29 52 0010 7b6b 5e2b C3 0 U0 1 710 204 0 0 7 Nov 5 12 30 16 Clear 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 Table 4 26 Instructions to Clear Cable Flap List Command Purpose CMTSO1 config clear cable flap list mac addr Clear the entries in the cable flap list for the cable modem with this MAC address CMTSO1 config clear cable flap list all Clear the entries for all of the cable modems in the flap list Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 EE Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists Customize Other Flap List Values and Related Commands Note The following displays flap list with different sorting options show cable modem flap list cable lt n gt sort f
64. lap sort time sort interface The following sets the threshold value for link establishment no cable flap list insertion time lt sec gt A modem is tagged as flapping if the insertion time exceeds this value Its value can be set from 60 to 86400 seconds with a default of 180 seconds 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 12 with a default of 6 seconds The hits and miss counters are not affected no cable flap list miss threshold lt miss threshold gt The following clears the counters for a cable modem or all cable modems in the station maintenance list clear cable modem lt mac addr gt lt ip addr gt 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 lt mac addr gt lt ip addr gt 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 Works even if the IP layer in the modem is down or hasn t completed registration ping DOCSIS cable modem lt mac addr IP address gt The following displays the timing offset receive po
65. n the given downstream port using a weighted packet discard policing algorithm and to assign a weight for the exponential moving average of loss rate value issue the cable downstream rate limit weighted discard 3 command Acceptable values are to 4 Configure 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 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pa B 78 5897 01 Chapter 4 Troubleshooting the System Managing Cable Modems on the HFC Network E To configure this use the following command in cable interface configuration mode Table 4 12 Instructions to Configure Upstream Shaping Command Purpose CMTSO1 config if no cable upstream lt n1 gt rate limit Enables or disables DOCSIS rate limiting or token bucket shaping on an upstream channel lt n1 gt depends on the number of upstream channels on the specific cable modem card Using Cisco IOS Release 12 0 5 T1 or higher the software supports e Generic calendar queuing routines e New token bucket policing function e Grant shaping application of the calendar
66. nance 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 cable flap list miss threshold 6 seconds cable flap list power adjust 2 dB e cable flap list insertion time 180 seconds S Note Since the cable flap list was originally developed polling mechanisms have been enhanced since Cisco IOS Release 11 3 7 NA to have an increased rate of 1 sec when polls are missed Cable modems go offline faster than the frequency hop period This can cause the frequency to stay fixed while cable modems go offline To compensate for this as appropriate you can reduce the hop period to 10 seconds Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide I 78 5897 01 PEEN Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists p Tips In Cisco IOS Release 12 0 7 XR2 Cisco IOS Release 12 1 1a T1 and higher the system supports automatic power adjustments The show cable flap list and show cable modem commands now indicate when the Cisco uBR7200 series router has detected an unstable return path for a particular modem and has compensated with
67. ne 4138 1 1 00 3 1 0 30 128 182 0050 7366 124d Cable3 0 U0 8 online 4142 3 25 3 1 0 30 128 164 0050 7366 1245 Cable3 0 U0 9 online 4141 143 00 3 1 0430 1287185 0050 7366 17e3 Cable3 0 U0 10 online 4142 142 75 3 0 0 30 128 181 0050 7366 17ab Cable3 0 U0 11 online 142 1 3225 3 1 0530 128 169 0050 7366 17ef The show cable modem indicates when the Cisco uBR7200 series router has detected an unstable return path for a particular CM and has compensated with a power adjustment An asterisk appears in the power adjustment field for a CM when a power adjustment has been made an exclamation point appears when the CM has reached its maximum power transmit level and cannot increase its power level any further Columns are described below The prim Sid column reveals the primary lifeline service identifier assigned to the cable modem The SID column is the service identifier e The Online State column reveals the state of the modem values include offline Cable modem considered offline offline time the time the cable modem went offline the format is the same as other show cable modem commands month day time and year init r1 Cable modem sent initial ranging init r2 Cable modem is ranging init rc Cable modem ranging complete init d Dhcp request received init i Dhcp reply received IP address assigned init 0 Option file transfer started init t TOD exchange started online
68. nels 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 uBR7200 series console The format for the command is as follows CMTS01 debug cable ucd To deactivate debugging of cable upstream channel descriptor use the following command CMTS01 no debug cable ucd Managing the Cisco uBR7246 VXR Clock Card Cisco IOS Release 12 1 1a T1 introduced clock card commands that included e cable clock clear counters e cable clock force cable clock source midplane e show cable clock e show controllers clock reference Cisco IOS Release 12 1 1a T1 modified commands to support clock card operation include e show diag show frame clocks e show tech support e show version Clear Clock Counters To reset the counters that are displayed with the show controllers clock reference command use the cable clock clear counters privileged EXEC command cable clock clear counters This command resets any counters that were displayed from the last time the show controllers clock reference command was used Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Piss B 78 5897 01 Chapter 4 Troubleshooting the System Managing the Cisco uBR7246 VXR Clock Card E Force Alternate Clock amp To select the external timing source when the clock card is in holdover mode us
69. no debug cable startalloc Debug CMTS Transmissions This command activates debugging of transmissions from the Cisco uBR7200 series across the HFC network When this command is activated messages generated at the headend are displayed on the Cisco uBR7200 series console The format for the command follows CMTSO1 debug cable transmit To deactivate debugging of cable transmissions use the no debug cable transmit command CMTSO1 no debug cable transmit Debug Upstream Channel Change UCC Messages This command activates debugging of upstream channel change UCC messages generated when cable modems request or are assigned a new channel When this command is activated messages related to upstream channel changes are displayed on the Cisco uBR7200 series console The format for the command follows CMTSO1 debug cable ucc To deactivate debugging of cable upstream channel changes use the following command CMTSO1 no debug cable ucc Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 EEE Chapter 4 Troubleshooting the System E Managing the Cisco uBR7246 VXR Clock Card Debug Upstream Channel Description UCD 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 chan
70. o debug cable privacy Debug 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 is displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable keyman To deactivate debugging of the keys use the following command CMTSO1 no debug cable keyman Debug Cable MAC Messages 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 uBR7200 series console The format for the command follows CMTS01 debug cable mac messages Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pas B 78 5897 01 Chapter 4 Troubleshooting the System Using Cable Interface Debug Commands E To deactivate debugging of cable MAC messages use the following command CMTS01 no debug cable mac messages Debug Cable Maps 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 uBR7200 series console The format for the command follows CMTS01 debug cable map To deactivate debugging of cable maps use the following command CMTS01 no debug cable map Debug Cable Modems
71. odem 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 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pas D 78 5897 01 Chapter 4 Troubleshooting the System Table 4 9 Instructions to Clear Cable Modem Reset Command Managing Cable Modems on the HFC Network E Purpose CMTS01 config if clear cable modem mac addr reset CMTSO1 config if clear cable modem ip addr reset CMTSO1 config if clear cable modem all reset Verify Clear Cable Modem Reset Remove the cable modem with a specific MAC address from the station maintenance list and reset it Remove the cable modem with a specific IP address from the station maintenance list and reset it Remove all cable modems from the station maintenance list and reset them To verify whether or not 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 Tips Be sure you entered the correct cable modem IP address or MAC address when you typed the command It might take up to 30 seconds for the cable modem to start the reset sequence Note This command is useful if an SNMP manager is not available or if the cable modem is unable to obt
72. oftware Configuration Guide m Chapter 4 Troubleshooting the System E Understanding Show Command Responses Following is a response to the show cable modem maintenance command using Cisco IOS Release 12 0 5 T1 uBR7200 show cable modem maintenance Interface SID MAC Address SM Exhausted SM Aborted Count Time Count Time Cable4 0 U1 1 0010 7b6b 5e27 4 Apr 29 19 33 19 0 Cable4 0 U0 2 0010 7b6b 5e15 8 Apr 29 19 34 55 0 Cable4 0 U2 11 0050 731c b025 Apr 29 16 43 39 0 Cable4 0 U0 13 0050 731c b021 Apr 29 15 58 43 0 Cable4 0 U0 16 0050 731c b009 Apr 29 15 58 28 0 Cable4 0 U0 20 0050 731c bfed Apr 28 14 36 22 0 Cable4 0 U2 24 0050 731c b023 Apr 27 10 30 36 0 Cable4 0 U 27 0050 731c bfeb Apr 28 14 54 53 0 Cable4 0 U2 28 0050 731c bfdf Apr 28 14 50 55 0 Cable4 0 U 30 0050 7366 1a71 2 Apr 29 17 49 00 0 Cable4 0 U 31 0050 7366 1bab 3 Apr 29 16 21 47 0 Cable4 0 U 32 0050 731c bfe7 0 2 Jan 1 09 00 00 Cable4 0 U 33 0050 731c bfd3 4 Apr 29 15 09 28 0 Cable4 0 U2 35 0050 731c b041 1 Apr 29 16 17 41 0 Cable4 0 U 36 0050 7366 1lab9 2 Apr 29 16 53 26 0 Show Interface Cable 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 6 port 0 using the earlier Cisco IOS Release 12 1 5 T1 software router show interfac
73. om cable modems on the HFC network When this command is activated ranging messages generated when cable modems request or change their upstream frequencies are displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable range To deactivate debugging of cable modem ranging use the following command CMTS01 no debug cable range Debug Upstream Messages This command activates debugging of upstream messages from cable modems When this command is activated any messages generated by cable modems and sent to the Cisco uBR7200 series will be displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable receive To deactivate debugging of upstream messages use the following command CMTS01 no debug cable receive Debug Cable Modem Registration Requests This command activates debugging of registration requests from cable modems on the HFC network When this command is activated messages generated by cable modems as they make requests to connect to the network are displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable reg To deactivate debugging of cable registration use the following command CMTS01 no debug cable reg Debug Cable Modem Reset Messages This command activates debugging of reset messages from cable modems on the HFC network When this command is activated reset messages generated b
74. onfig if cable source verify dhcp Activate cable modem upstream verification The dhcp option specifies that queries be sent to verify unknown IP addresses in upstream data packets CMTSO1 config if no cable source verify Return to the default upstream verification state Verify Cable Modem Upstream Address Verification To verify whether cable modem upstream verification is activated or deactivated enter the command more system running config and look for the no cable source verify notation in the cable interface configuration information Be sure you enter the correct slot and port number when you enter the cable interface configuration mode Note If the Cisco uBR7200 series is reloaded or the ARP table is cleared all hosts on the network will be forced to release and renew their IP addresses Some systems may require restarting if the IP protocol stack is unable to renew using a broadcast IP address Configure Dynamic Contention Algorithms Cable Insertion Interval Range and Data Backoffs The Cisco uBR7200 series universal broadband router software includes An algorithm that dynamically controls the rate of upstream contention slots initial ranging and bandwidth requests e An algorithm that varies backoff parameters CMs use within each of the initial ranging and bandwidth request upstream contention subchannels These algorithms control the capacity of the contention subchannel and how efficien
75. outer Software Configuration Guide m Chapter 4 Troubleshooting the System E Troubleshooting Using Cable Flap Lists Table 4 19 show interface cable sid Command Field Descriptions continued Field Description Rate exceeded DS packet Number of downstream packets lost by this SID drops Ratelimit BWReqDrop Number of bandwidth requests not granted by this SID Ratelimit DSPktDrop Number of downstream packets lost by this SID Ist time online Time at which the modem with this SID connected Times online Number of times the modem with this SID has connected online Percentage of time the modem with this SID has been connected Online time The minimum average and maximum number of hours and minutes the modem with this SID has been connected Offline time The minimum average and maximum number of hours and minutes the modem with this SID has been disconnected Show Cable QoS Profile Following is a response to the show cable qos profile command The display shows ToS specifications uBR7200 show cable qos profile Service Prio Max Guarantee Max Max tx TOS TOS Create B class upstream upstream downstream burst mask value by priv gt bandwidth bandwidth bandwidth enab 1 0 0 0 0 0 0x0 0x0 cmts r no 2 0 64000 0 1000000 0 0x0 0x0 cmts r no 3 0 1000 0 1000 0 0x0 0x0 cmts no 4 3 256000 0 512000 0 0x0 0x0 cm no 5 5 1000000 0 10000000 0 0x0 0x0 cm no 6 3 256000 0 512000 0 0x0 0x0 cm yes Note
76. pleting registration The upstream or downstream is perhaps not stable enough for reliable link establishment Very low hits and miss counters and high insertion counters indicate provisioning problems Condition 3 Relatively high power adjustment counter 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 whereas the headend may 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 may be set using lt cable flap power threshold lt 0 10 dB gt gt from the Cisco IOS global configuration mode A properly operating HFC network with short amplifier cascades can use a 2 3 dB threshold Condition 4 High P Adj and CRC errors 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 the subscriber However they could receive slower service due to dropped IP packets in the upstream This condition will also result in input errors on the Cisco uBR7200 series cable interface Condition 5 High insertion rate Analysis If link re establishment happens too frequently then the modem is usually having a registration problem This is indicated by a high Ins counter which tracks the Fl
77. queues Upstream rate shaping option to the token bucket keyword e A default state change from 1 second burst policing to token bucket with shaping Upstream grant shaping is per CM SID Shaping can be enabled or disabled for the token bucket algorithm Before the introduction of this feature the CMTS would drop bandwidth requests from a CM it detected as exceeding its configured peak upstream rate Such request dropping affects the throughput performance of IP based protocols such as FTP TCP and SMTP With this feature the CMTS can shape buffer the grants for a CM that is exceeding its upstream rate rather than dropping the bandwidth requests CMTSO1 show interface c3 0 sid 1 counters Sid Inpackets Inoctets Outpackets Outoctets Ratelimit Ratelimit BWReqDrop DSPktDrop 1 67859 99158800 67570 98734862 2579 0 Configure Spectrum Management without the Cisco MC16S Cable Modem Card Blind Strategies and Time Scheduled Combined The Cisco uBR7200 series software supports combined blind and time scheduled spectrum management using Cisco IOS Release 12 0 5 T1 images or higher e Using blind spectrum management the number of lost station management messages exceeding a configured threshold default 10 initiates an upstream channel frequency reassignment The Cisco uBR7200 series moves all cable modems on the upstream port by sending UCD messages that contain the next frequency and input power level defined in the spectr
78. r 4 Troubleshooting the System Understanding Show Command Responses E e Counters for each type of upstream slot scheduled in the MAPs for this upstream channel The Init Mtn IEs 800 means that the MAC scheduler has added 800 initial maintenance information elements slots at the time the show command was issued e MAC scheduling statistics to display what percentage of the upstream bandwidth is utilized for each type of slot on an average Show Interface Cable SID 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 Note Cisco IOS Release 12 0 7 XR2 and 12 1 1a T1 adds the verbose option to provide SID details See the following display output for the verbose keyword extension for SID 1 on interface cable slot 3 port 0 router show interface c3 0 sid 1 counters verbose Sid al Input packets 39 Input octets 15964 Output packets gt 30 Output octets 8796 BW requests received 40 Grants issued 40 Rate exceeded BW request drops 0 Rate exceeded DS packet drops 0 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 EEN Chapter 4 Troubleshooting the System E Unde
79. ranging slots Indicates on average what percent of slots are in initial ranging state 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Understanding Show Command Responses Table 4 18 Show Interface Cable Upstream Command Field Descriptions continued Field Description Avg percent minislots lost on late MAPs Indicates on average what percent of slots are lost because a MAP interrupt was too late Current minislot count formerly Last Minislot Stamp current_time_base Indicates the current minislot count at the CMTS FLAG indicates the timebase reference This field is used only by developers Scheduled minislot count formerly Last Minislot Stamp scheduler_time_base Enhanced Show Interface Upstream Output Indicates the furthest minislot count allocated at the indicated time FLAG indicates the timebase reference This field is used only by developers The show interface cable upstream command is enhanced in Cisco IOS Release 12 0 7 XR2 Cisco IOS Release 12 1 1a T1 or information for the upstream port cmts show interface cable 3 0 Cable3 0 Upstream 0 is up 0 0 Received 13 broadcasts 0 discards 106 errors 123 packets input higher CMTS images to display detailed MAC scheduler state The example below illustrates the new display upstream 0 multicasts 110 unicasts unknown proto
80. rough successive states during registration and provisioning Using this information you can isolate why a cable modem is offline or unavailable 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 e The total number of modems The number of active modems e The number of registered modems The number of unregistered modems The number of offline modems The time the modem went offline e The status before the modem went offline The receive power before the modem went offline 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Understanding Show Command Responses See the sample command output below router show cable modem Interface Prim Online Timing Rec QoS CPE IP address MAC address Sid State Offset Power Cable3 0 U0 1 online 2257 0 00 3 0 0 30 128 142 0090 8330 0217 Cable3 0 U0 2 online 2262 0 650 3 0 0 30 128 145 0090 8330 020f Cable3 0 U0 3 online 2260 025 3 0 0 30 128 146 0090 8330 0211 Cable3 0 U0 4 online 2256 eho 3 0 0 30 128 143 0090 8330 0216 Cable3 0 U0 5 online 2265 O00 lt 3 0 0 30 128 140 0090 8330 0214 Cable3 0 U0 6 online 2256 0 00 3 0 0 30 128 141 0090 8330 0215 Cable3 0 U0 7 onli
81. rstanding Show Command Responses See the following display output for the verbose keyword extension for all SIDs on the specified interface router show interface c3 0 sid counters verbose Sid Input packets Input octets Output packets Output octets BW requests received Grants issued Rate exceeded BW request drops Rate exceeded DS packet drops Sid Input packets Input octets Output packets Output octets BW requests received Grants issued Rate exceeded BW request drops Rate exceeded DS packet drops Sid Input packets Input octets Output packets Output octets BW requests received Grants issued Rate exceeded BW request drops Rate exceeded DS packet drops 1 39 15964 30 8796 40 40 mo Se GOG GOTO GO O W Oo ER a T See the following display for the SIDs connected to the specified interface Lab CMTS show inter cab 3 0 sid Sid Prim Type Online Admin QoS Create IP Address MAC Address Sid State Status Time 23 stat init d enable 2 04 00 54 209 165 200 0 0050 7366 17ab 24 stat init d enable 2 04 00 58 2095165 20049 0050 7366 1803 25 stat init rc enable 2 04 01 05 209 6165 200 20 00d0 bad3 c459 26 stat init d enable 2 04 01 10 209 165 200 0 0050 7366 1801 27 stat offline enable 2 04 01 31 209 165 200 225 0090 8330 0213 28 stat offline enable 2 04 01 59 209 165 200 226 0090 8330 0211 29 stat offline enable 2 04 02 07 209 165 200 227 0090 8330 0214 30 dyn init o enable 2 04 0
82. s insertion count and indicates the number of times the RF link was abnormally re established An abnormality is detected when the time between link re establishment attempts is less than the user configurable parameter Normal modem activity follows the sequence below e The initial link insertion is followed by a keepalive loop between the CMTS and cable modem and is called station maintenance e Power on e Initial maintenance e Station maintenance e Power off When the link is broken initial maintenance is repeated to re establish the link Initial maintenance Time T1 Station maintenance Init maintenance Time T2 The Ins and Flap counters in the flap list are incremented whenever T2 T1 lt N where N is the insertion time parameter configured in lt cable flap list insertion time gt Default value for this parameter is TBD seconds A high Ins number indicates Intermittent downstream sync loss e DHCP or modem registration problems Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pas B 78 5897 01 Chapter 4 Troubleshooting the System Troubleshooting Using Cable Flap Lists Table 4 20 Flap List Statistics Description Hit and Miss Cyclical Redundancy Check CRC Power Adjustments P Adj The HIT and MISS columns are keepalive polling statistics between the Cisco uBR7200 series and the cable modem The station maintenance process occurs for every modem
83. splays Table 4 19 show interface cable sid Command Field Descriptions Field Description Sid Service identification number Prim Sid The primary service identifier assigned to the modem Type Indicates this SID was created statically at the time of registration or dynamically by the exchange of dynamic service messages between the CM and CMTS Online State Online means the modem owning this SID is processing traffic Offline means the modem owning this SID is not processing traffic Admin Status Disable means that the SID has been turned off Enable is the normal state QoS Quality of service Create time When the SID was created number of seconds since the system booted Input octets Inoctets Number of octets received by using this SID Input packets Inpackets Number of packets received by using this SID Output octets Outoctets Number of octets sent from this SID Output packets Outpackets Number of packets sent from this SID IP address IP address of the modem owning this SID MAC address MAC address of the modem owning this SID BW requests received Number of bandwidth requests received by this SID Grants issued Number of bandwidth requests granted by this SID Rate exceeded BW request drops Number of bandwidth requests not granted by this SID 78 5897 01 Cisco uBR7200 Series Universal Broadband R
84. t The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage Hop Period The maximum rate which frequency hopping will occur seconds Corr FEC Errors The number of correctable FEC errors on this upstream port Uncorr FEC Errors The number of uncorrectable FEC errors on this upstream port noisyl show cable hop Upstream Port Port Status Cable3 0 U0 down Cable3 0 U1 admindown Cable3 0 U2 admindown Cable3 0 U3 admindown Cable3 0 U4 admindown Cable3 0 U5 admindown Cable4 0 U0 10 800 Mhz Cable6 0 U0 down Poll Missed Min Missed Hop Hop Corr Uncorr Rate Poll Poll Poll Thres Period FEC FEC ms Count Sample Pent Pent sec Errors Errors QOG 4 e frequency not set eR BG 0 O00 kek amp interface is down te ROSE iO 0 OOO mk Hr oF interface is down Be ke i 0 QOO ese interface is down ES ee ae iG 0 OOA a ae interface is down ee Pe eee 0 000 w w x interface is down a ee 0 000 0 OC ee 100 300 0 0 OOG ee frequency not set ee ed 0 Using Cisco IOS Release 12 0 5 T1 or higher headend images you can use the following command to obtain specific upstream interface information show cable hop cable if upstream lt portnum gt Table 4 15 Upstream Port Parameter Descriptions Field Description Upstream Port The upstream port for this information line Port Status Show down if frequency is unassigned admindown if t
85. the System E Managing Cable Modems on the HFC Network p Tips The SNR estimate for a cable modem installed at a headend should be between 35 dB and 39 dB Although the exact value displayed will vary from cable modem to cable modem values collected on the same cable modem from measurement to measurement will be consistent Maximizing SNR optimizes cable modem reliability and service quality Managing Cable Modems on the HFC Network To manage cable modems connected to the network perform the following as appropriate e Configure Sync Message Interval e Activate Cable Modem Authentication e Activate Cable Modem Upstream Address Verification e Configure Dynamic Contention Algorithms Cable Insertion Interval Range and Data Backoffs e Configure the Dynamic Map Advance Algorithm e Configure Per Modem Filters e Configure the Maximum Number of Hosts Attached to a Cable Modem e Configure Cable Modem Registration Timeout e Clear Cable Modem Reset e Clear Cable Modem Counters e Configure Traffic Shaping e Configure Spectrum Management without the Cisco MC16S Cable Modem Card Cisco recommends using default values for most commands Default settings are adequate for most systems Configure Sync Message Interval To specify the interval between successive sync message transmissions from the Cisco uBR7200 series use the following command in cable interface configuration mode Table 4 1 Instructions to Configur
86. the sample Missed Poll Pent The ratio of missing polls to the number of polls displayed as a percentage Hop Thres Pcnt The level that the missed poll percentage must exceed to trigger a frequency hop expressed as a percentage Hop Period The maximum rate which frequency hopping will occur seconds Corr FEC Errors The number of correctable FEC errors on this upstream port Uncorr FEC Errors Cisco The number of uncorrectable FEC errors on this upstream port 78 5897 01 uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Managing Cable Modems on the HFC Network Sample output noisyl show cable hop Upstream Port Cable3 0 U0 Cable3 0 U1 Cable3 0 U2 Cable3 0 U3 Cable3 0 U4 Cable3 0 U5 Cable4 0 U0 Cable6 0 U0 Port Status down admindown admindown admindown admindown admindown 10 800 Mhz down Poll Rate ms 000 000 000 000 000 000 000 000 Missed Min POLL Count Or OF E e a en a a a AOO i e o POLL POLL Sample Pcnt frequency interface interface interface interface interface frequency Spectrum Management Debug and Test Commands To enable display of frequency hopping debugging messages enter debug cable To enable display of spectrum management debugging messages enter debug cable This command also enables display of channel width list and offer list
87. tivity 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 uBR7200 series 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 list MAC Address Upstream Ins Hit Miss CRC P Adj Flap Time 0010 7bb3 fd19 Cable5 0 U1 0 2792 281 0 x45 58 Jul 27 16 54 50 0010 7bb3 fcfc Cable5 0 U1 0 19 4 0 143 43 JuL 27 6755401 0010 7bb3 fcdd Cable5 0 U1 0 Lg 4 0 3 3 Jul 27 16 55 01 The symbol indicates that the CMTS is using the power adjustment method on this modem The symbol indicates that the modem has reached maximum transmit power Output of the show cable modem command appears below router show cable modem Interface Prim Online Timing Rec QoS CPE IP address MAC address Sid State Offset Power Cable3 0 U0 1 online 2257 0 00 3 0 0 30 128 142 0090 8330 0217 Cable3 0 U0 2 online 2262 0 50 3 0 0 30 128 145 0090 8330 020f Cable3 0 U0 3 online 2260 0 25 3 0 0 30 128 146 0090 8330 0211 Cable3 0 u0 4 online 2256 0 75 3 0 0 30 128 143 0090 8330 0216 Cable3 0 U0 5 online 2265 0550 3 0 0 30 128 140 0090 8330 0214 Cable3 0 U0 6 online 2256 0 00 3 0 0 30 128 141
88. tly a given contention subchannel capacity is utilized In high contention mode the Cisco uBR7200 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 channel s The CMTS trades upstream bandwidth between data grants and initial ranging slots The CMTS auto detects 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 Mi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Managing Cable Modems on the HFC Network E 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
89. to Show Cable Modem Maintenance page 4 23 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Understanding Show Command Responses See the following sample for detailed output of the show cable modem command router show cable modem detail MAC address Interface Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable3 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 Cable4 0 U0 U0 U0 UO U0 U0 U0 UO U0 U0 UO U0 UO 0 U0 0 Gra SID wo MWOAnaun amp WN Oa PWN rR Oo OD NAO ARUN oo uy Aoun RAR WN EF OC Koj 20 21 22 23 24 0090 8330 0090 8330 0090 8330 0090 8330 0090 8330 0050 7366 0090 8330 0050 7366 0090 8330 0050 7366 0050 7366 0050 7366 0050 7366 0050 7366 0050 7366 0050 7366 e97f 965 e931 e92d e97b 0050 7366 2953 0050 7366 e96b 0050 7366 e93f e96d 941 0050 7366 2939 0050 7366 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 0050 73 8 8 8 8 8 8 8 8
90. um management group The frequency change occurs rapidly without data loss and minimal latency 78 5897 01 Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide m Chapter 4 Troubleshooting the System E Managing Cable Modems on the HFC Network e Using time scheduled spectrum management the upstream channel frequency reassignment process is initiated at a configured time of day or week With combined blind and time scheduled strategies blind hop tables are given time variant configurability 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 10000000 uBR config cable spectrum group 2 time Tue 09 05 00 delete frequency 10000000 uBR config cable spectrum group 2 time Tue 09 00 00 frequency 5000000 uBR config cable spectrum group 4 time Fri 09 00 00 band 15000000 25000000 uBR config cable spectrum group 4 time Sat 09 00 00 delete band 15000000 25000000 Guided Frequency Hop Using guided frequency hop the upstream channel frequency is reassigned if a threshold number or percentage of cable modems 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 uBR7200 series locates the defin
91. use the show controllers clock reference privileged EXEC command show controllers clock reference Tips To reset the counters that are displayed with the show controllers clock reference command use the Clear Clock Counters command The following is sample output from the show controllers clock reference command Router show controllers clock reference ational clock card with T1 controller Control register 0x4 Status register 0x54 LIU Config Register 0 0x0 LIU Config Register 1 0x0 1 events reported in 266636 seconds Primary active 1 LOS 0 Secondary active 0 LOS 1 Holdovers 0 HW faults 0 Show Clock Diagnostic Information To display diagnostic information for the cable modem cards use the show diag command in privileged EXEC mode p Tips Use the show diag command to display diagnostic information about the port adapters installed in the router This command also displays information about the cable clock card if installed Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pass E 78 5897 01 Chapter 4 Troubleshooting the System Managing the Cisco uBR7246 VXR Clock Card E The following is sample output from the show diag command displaying diagnostic information for the cable clock card router show diag Clockcard ational clock card wi EEPROM contents at har Hardware Revision Part Number Board Revision Deviation Number Fab Version
92. wer and QoS values by cable interface SID and MAC address show cable modem lt ip address gt lt MAC address gt 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 uBR7200 interface show int slot port sid connectivity The following 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 Hi Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide 78 5897 01 Chapter 4 Troubleshooting the System Performing Amplitude Averaging a Performing Amplitude Averaging The Cisco uBR7200 series 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 uBR7200 series universal broadband router averages a configurable number of RNG REQ messages before it makes power adjustments By compensating for a potentially unstable return path the Cisco uBR7200 series router maintains connec
93. y cable modems are displayed on the Cisco uBR7200 series console The format for the command follows CMTS01 debug cable reset To deactivate debugging of cable reset messages use the following command CMTS01 no debug cable reset Cisco uBR7200 Series Universal Broadband Router Software Configuration Guide Pas B 78 5897 01 Chapter 4 Troubleshooting the System Using Cable Interface Debug Commands E Debug 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 uBR7200 series 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 specmgmt To deactivate debugging of cable spectrum management use the no debug cable specmgmt command CMTS01 no debug cable specmgmt Debug 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 modems on the HFC network are displayed on the Cisco uBR7200 series console The format for the command follows CMTSO1 debug cable startalloc To deactivate debugging of cable channel allocations use the no debug cable startalloc command CMTSO1

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