Troubleshooting Tips for the Cisco uBR904 Cable Modem

The following sections are provided:

Feature Summary

This document provides MSOs (multiple service operators) with a set of software tools for troubleshooting a cable modem for data-over-cable connections. These tools are Cisco IOS troubleshooting commands used for verifying communication between the cable modem and other peripheral devices installed in the HFC network, such as the headend Cisco uBR7246, a DHCP server, and TFTP server.

Benefits

???A MAC layer system log file exists inside the cable modem, which provides you with a snapshot of detailed reasons why an interface might reset and all the negotiations that occurred between the cable modem and the CMTS (a Cisco uBR7246 positioned at the headend). Over 220 possible description fields exist in this log. The log is displayed using the show controller cable-modem 0 mac log EXEC command.

???Debug does not need to be turned on to troubleshoot a cable modem.

???Cable technicians can understand the progression of normal data-over-cable communication events, from which they can resolve faulty system connections.

???A cable technician can remotely telnet into a Cisco uBR904 cable modem, which could be installed in a customer???s home, and perform simple diagnostic tasks.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 1

Feature Summary

List of Terms

CATV???Originally stood for Community Antenna Television. CATV now refers to any cable (coaxial/fiber) based system that provides television services.

Cable modem???Any device that modulates and demodulates digital data onto a CATV plant.

Cable router???A modular chassis-based router optimized for the data over CATV HFC applications.

Channel???A specific frequency allocation and bandwidth. Downstream channels used for television in the U. S. are 6 MHz wide.

CM???Cable modem.

CMTS???Cable Modem Termination System. Any DOCSIS compliant headend cable router, such as the Cisco uBR7246.

Downstream???The set of frequencies used to send data from a headend to a subscriber.

Headend???Central distribution point for a CATV system. Video signals are received here from satellite (either co-located or remote), frequency converted to the appropriate channels, combined with locally originated signals, and rebroadcast onto the HFC plant. For a CATV data system, the headend is the typical place to link between the HFC system and any external data networks.

HFC???Hybrid fiber-coaxial (cable). Older CATV systems were provisioned using only coaxial cable. Modern systems use fiber transport from the headend to an optical node located in neighborhood to reduce system noise. Coax runs from the node to the subscriber. The fiber plant is generally a star configuration with all optical node fibers terminating at a headend. The coaxial cable part of the system is generally a trunk-and-branch configuration.

Host???Any end-user computer system that connects to a network. The term host here refers to computer systems connected to the LAN interface of the cable modem.

MAC layer???Media Access Control sublayer. Controls access by the cable modem to the CMTS and to the upstream data slots.

MCNS???Multimedia Cable Network System Partners Ltd., a consortium of cable companies representing the majority of homes in the U.S. and Canada who have decided to derive a standard with the goal of having interoperable cable modems.

MSO???Multiple System Operator

QAM???Modulation scheme mostly used in the downstream direction (QAM-64, QAM-256). QAM-16 is expected to be usable in the upstream direction. Numbers indicate number of code points per symbol. The QAM rate or the number of points in the QAM constellation can be computed by 2 raised to the power of <number of bits/symbol>.

QPSK???Modulation scheme used in the upstream direction. Supports two data bits per symbol.

Subscriber Unit (SU)???An alternate term for cable modem. See cable modem.

Upstream???The set of frequencies used to send data from a subscriber to the headend.

2 Release 11.3(4)NA

List of Terms

Prerequisites

Cisco IOS Release 11.3(4)NA or later must be running inside the cable modem. Enter the show version EXEC command to display the software version level.

Supported MIBs and RFCs

The Cisco uBR904 cable modem supports the following:

???Radio Frequency Interface Specification???This specification is developed by the Multimedia Cable Network System (MCNS) corsortium. It defines the radio-frequency interface specification for high-speed data-over-cable systems.

???Cisco Standard MIBs???The Cisco Standard MIBs consist of CiscoWorks. CiscoWorks is the network management program for planning, troubleshooting, and monitoring Cisco internetworks. CiscoWorks uses SNMP protocols to monitor all SNMP devices.

???For more information about CiscoWorks on CCO, follow this path:

Products & Ordering: Cisco Products: Network Management: CiscoWorks

???For more information about CiscoWorks on the Documentation CD-ROM, follow this path:

Cisco Product Documentation: Network Management: CiscoWorks

???RF Interface MIB???The Radio Frequency Interface (RFI) MIB is specific to cable Data Over Cable Interface Specification (DOCSIS) implementations. The RIF MIB provides an interface that permits management of the Cisco uBR904 cable modem over the cable or Ethernet interface. Using SNMP management applications, this MIB allows access to statistics such as MAC, driver configuration, and counters through its interface.

???Cable Device MIB???The Cable Device MIB records statistics related to the configuration and status of the Cisco uBR904 cable modem. Statistics include an events log and device status. The Cable Device MIB is very similar to the RFI MIB in that both allow access to statistics; they are different in that the Cable Device MIB reports statistics on the Cisco uBR904 cable modem, while the RFI MIB reports statistics on the radio frequency transmissions over the cable television line.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 3

CMTS to Cable Modem Network Topology

CMTS to Cable Modem Network Topology

Figure 1 shows the physical relationship between the devices in the HFC network and the cable modem.

Figure 1 Sample Topology

DS-RF 54-860 Mhz

Digital TV

Fiber

Transceiver

80 km

1000 ft

Fiber node (Telephone pole, underground box)

Drop box

Distribution Top amplifier amplifier

13304

Cisco u BR904

cable modem

4 Release 11.3(4)NA

Understand How Basic Initialization Works

Troubleshooting Tips

Perform the following steps to troubleshoot a cable modem:

???Step 1???Understand How Basic Initialization Works

???Step 2???Connect to the Cable Modem

???Step 3???Display the Cable Modem???s MAC Log File

???Step 4???Interpret the MAC Log File and Take Action

???Step 5???(Optional) Use Additional Troubleshooting Commands

Understand How Basic Initialization Works

Before you troubleshoot a cable modem, you should be familiar with the cable modem initialization process. See Figure 2 and Table 1. Understanding this flowchart and sequence of events helps you determine where and why connections fail.

The sequence numbers shown in Figure 2 are explained in Table 1, which appears after the illustration. The cable modem will complete all the steps in this flowchart each time the cable modem needs to reestablish ranging and registration with the CMTS.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 5

Troubleshooting Tips

Figure 2 Cable Modem Initialization Flowchart

Power

on

6 Release 11.3(4)NA

request also includes the name of a file that contains additional configuration parameters, the TFTP server???s address, and the Time of Day (TOD) server???s address.

Connect to the Cable Modem

Telnet to the IP address assigned to the cable interface or Ethernet interface. If the interface is not up, you need to access the Cisco IOS software via the RJ-45 console port, which is a physical port on the back of the cable modem.

Because the MAC log file only holds a snapshot of 1023 entries at a time, you should try to display the cable modem???s log file within 5 minutes of when the reset or problem occurs.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 7

Troubleshooting Tips

Display the Cable Modem???s MAC Log File

A MAC layer circular log file is inside the cable modem. This file contains a history of log messages, such as state event activities and timestamps, which are used for troubleshooting purposes. This log file contains the most valuable information for a cable technician or engineer to debug the cable interface.

The MAC log file is displayed by entering the show controller cable-modem 0 mac log EXEC command.

The most useful display fields in this log file are the reported state changes. These fields are preceded by the message CMAC_LOG_STATE_CHANGE. These fields show how the cable modem progresses through the various processes involved in establishing communication with the CMTS and registration. The maintenance_state is the normal operational state, and the

is the normal state when the interface is shutdown.

Here is the normal progression of states as displayed by the MAC log:

wait_for_link_up_state ds_channel_scanning_state wait_ucd_state wait_map_state ranging_1_state ranging_2_state dhcp_state establish_tod_state security_association_state configuration_file_state registration_state establish_privacy_state maintenance_state

Note To translate this output into more meaningful information, see the ???Interpret the MAC Log File and Take Action??? section on page 10.

Here is what an example MAC log file looks like when the cable modem interface successfully comes up and registers with the cable network. The output you see is directly related to the messages that are exchanged between the cable modem and the CMTS (the Cisco uBR7246).

8 Release 11.3(4)NA

Display the Cable Modem???s MAC Log File

Troubleshooting Tips for the Cisco uBR904 Cable Modem 9

Troubleshooting Tips

You can display other aspects of the MAC layer by using variations of the show controller cable-modem 0 mac command:

uBR904# show controller cable-modem 0 mac ?

For examples and descriptions on how to use these keywords, see the show controller cable-modem mac command reference page.

Interpret the MAC Log File and Take Action

The MAC log file explains a detailed history of initialization events that occurred in the cable modem. All pertinent troubleshooting information is stored here.

The following sample log file is organized by chronological sequence event. Sample comments are also included.

Event 1???Wait for the Link to Come Up

The MAC layer informs the cable modem???s drivers that it needs to reset. This is the first event that happens after the modem powers up and begins initialization. The fields LINK_DOWN and LINK_UP are similar to a shut and no shut on a standard Cisco interface.

uBR904# show controller cable-modem 0 mac log

10 Release 11.3(4)NA

Interpret the MAC Log File and Take Action

A frequency band is a group of adjacent channels. These bands are numbered from 88 to 99. Each band has starting and ending digital carrier frequencies and a 6 MHz step size. For example, a search of EIA channels 95-97 is specified using band 89. The starting frequency is 93 Mhz, the ending frequency is 105 Mhz.

The cable modem???s default frequency bands correspond to the North American EIA CATV channel plan for 6 MHz channel slots between 90 MHz and 858 MHz. For example, EIA channel 95 occupies the slot 90-96 MHz. The digital carrier frequency is specified as the center frequency of 93 MHz.

Channel 95 is usually specified using the analog video carrier frequency of 91.25 Mhz, which lies 1.75 Mhz below the center of the slot.

The search table is arranged so that the first frequencies tried are above 450 Mhz. Because many CATV systems have been upgraded from 450 MHz to 750 MHz coaxial cable, digital channels have a high chance of being assigned in the new spectrum. The search table omits channels below 90 MHz and above 860 MHz since the DOCSIS specification does not mandate their coverage.

Some CATV systems use alternative frequency plans such as the IRC (Incrementally Related Carrier) and HRC (Harmonically Related Carrier) plans. Most of the IRC channel slots overlap the EIA plan. The HRC plan is not supported by Cisco???s cable modems since so few cable plants are using this plan.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 11

Troubleshooting Tips

Event 3???Obtain Upstream Parameters

The cable modem waits for an upstream channel descriptor messages (UCD) from the headend Cisco uBR7246. This is done to retrieve transmission parameters for the upstream channel.

Event 4???Start Ranging for Power Adjustments

The ranging process adjusts cable modem???s transmit power. The cable modem performs ranging in two stages, ranging state 1 and ranging state 2.

12 Release 11.3(4)NA

Interpret the MAC Log File and Take Action

Event 5???Establish IP Connectivity

After ranging is complete, the cable interface on the cable modem is up. Now the cable modem accesses a remote DHCP server to get an IP address. The DHCP request also includes the name of a file that contains additional configuration parameters, the TFTP server???s address, and the Time of Day (TOD) server???s address.

The field CMAC_LOG_DHCP_ASSIGNED_IP_ADDRESS indicates the IP address assigned from the DHCP server to the cable modem interface. The field CMAC_LOG_DHCP_TFTP_SERVER_ADDRESS marks the TFTP server???s address. The field CMAC_LOG_DHCP_TOD_SERVER_ADDRESS indicates the time of day server???s address. The field CMAC_LOG_DHCP_CONFIG_FILE_NAME shows the filename containing the transmission parameters. The fieldshows that all the IP connectivity was a success.

Event 6???Establish the Time of Day

The Cisco uBR904 cable modem accesses the Time of Day server for the current date and time, which is used to create time stamps for logged events. The fieldindicates a successful time of day sequence.

Event 7???Establish Security

The cable modem establishes a security association. The security_association_state is normally bypassed since ???full security??? as defined by MCNS DOCSIS is not supported.

???Full security??? was a request made by MSOs for a very strong authorization and authentication check by the CMTS. This request was not granted by cable modem manufacturers. Cisco fully supports baseline privacy, which protects user???s data from getting ???sniffed??? on the cable network.

Troubleshooting Tips for the Cisco uBR904 Cable Modem 13

Troubleshooting Tips

Event 8???Transfer Operational Parameters

After the DHCP and security operations are successful, the cable modem downloads operational parameters from a cable company???s TFTP server. These parameters are transferred via a configuration file. The fieldshows the filename containing the transmission parameters.

Event 9???Perform Registration

The cable modem registers with the headend Cisco uBR7246. After the cable modem is initialized, authenticated, and configured, the cable modem is authorized to forward traffic into the cable network. A successful registration is indicated by the field CMAC_LOG_REGISTRATION_OK.

Event 10???Comply with Baseline Privacy

Keys for baseline privacy are exchanged between the cable modem and the CMTS (the

Cisco uBR7246 cable router). During this event, a link level encryption is performed so that a user???s data cannot be ???sniffed??? by anyone else who is on the cable network.

Here is a trace that shows baseline privacy enabled. The key management protocol is responsible for exchanging 2 types of keys: KEKs and TEKs. The KEK (key exchange key, also referred to as the authorization key) is used by the headend CMTS to encrypt TEKs (traffic encryption keys) it sends to the cable modem. The TEKs are used to encrypt/decrypt the data. There is a TEK for each SID configured to use privacy.

14 Release 11.3(4)NA

Use Additional Troubleshooting Commands

Event 11???Enter the Maintenance State

As soon as the cable modem is completely up and running, it enters the operational maintenance state.

Use Additional Troubleshooting Commands

You can use other show controller and debug cable modem commands to troubleshoot different aspects of a cable modem. However, the most useful command is the show controller cable-modem 0 mac command.

To display additional controller information inside a cable modem, enter one or more of the following commands in Privileged EXEC mode:

To debug different components of a cable modem, enter one or more of the following commands in Privileged EXEC mode:

Troubleshooting Tips for the Cisco uBR904 Cable Modem 15

Command Reference

Command Reference

This section provides new commands for troubleshooting the Cisco uBR904 cable modem.

All other commands used with this feature are documented in the Cisco IOS Release 11.3 command references.

???show controller cable-modem

???show controller cable-modem bpkm

???show controller cable-modem mac

???show controller cable-modem phy

???show controller cable-modem des

???show controller cable-modem filters

???show controller cable-modem lookup-table

???show controller cable-modem tuner

???show interface cable-modem

16 Release 11.3(4)NA

show controller cable-modem

show controller cable-modem

To display high-level controller information about a cable modem, use the show controller cable-modem Privileged EXEC command.

Syntax Description

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

Following is a sample output for this command:

uBR904# show controller cable-modem 0

BCM Cable interface 0:

CM unit 0, idb 0x200EB4, ds 0x82D4748, regaddr = 0x800000, reset_mask 0x80 station address 0010.7b43.aa01 default station address 0010.7b43.aa01

PLD VERSION: 32

MAC State is ranging_2_state, Prev States = 7

MAC mcfilter 01E02F00 data mcfilter 01000000

DS: BCM 3116 Receiver: Chip id = 2

US: BCM 3037 Transmitter: Chip id = 30B4

Tuner: status=0x00

Rx: tuner_freq 699000000, symbol_rate 5055849, local_freq 11520000 snr_estimate 33406, ber_estimate 0, lock_threshold 26000

QAM in lock, FEC in lock, qam_mode QAM_64

Tx: tx_freq 20000000, power_level 0x3E, symbol_rate 1280000

DHCP: TFTP server = 4.0.0.32, TOD server = 4.0.0.188

Security server = 0.0.0.0, Timezone Offest = 0.0.4.32

Config filename =

buffer size 1600

RX data PDU ring with 32 entries at 0x201D40 rx_head = 0x201D40 (0), rx_p = 0x82D4760 (0)

RX MAC message ring with 8 entries at 0x201E80 rx_head_mac = 0x201EB8 (7), rx_p_mac = 0x82D4810 (7)

TX BD ring with 8 entries at 0x201FB8, tx_count = 0 tx_head = 0x201FB8 (0), head_txp = 0x82D4888 (0) tx_tail = 0x201FB8 (0), tail_txp = 0x82D4888 (0)

TX PD ring with 8 entries at 0x202038, tx_count = 0 tx_head_pd = 0x202038 (0)

tx_tail_pd = 0x202038 (0)

Troubleshooting Tips for the Cisco uBR904 Cable Modem 17

Command Reference

Global control and status: global_ctrl_status=0x00

interrupts:

irq_pend=0x0008, irq_mask=0x00F7

Related Commands

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem phy show controller cable-modem tuner show interface cable-modem

18 Release 11.3(4)NA

show controller cable-modem bpkm

show controller cable-modem bpkm

To display information about the baseline privacy key management exchange between the cable modem and the headend CMTS, use the show controller cable-modem bpkm Privileged EXEC command.

show controller cable-modem number bpkm

Syntax Description

numberController number inside the cable modem.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

The following output is displayed when the headend CMTS does not have baseline privacy enabled:

uBR904# show controller cable-modem 0 bpkm

tek state: No resources assigned

Related Commands

show controller cable-modem show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem phy show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 19

Command Reference

show controller cable-modem des

To display information about the Data Encryption Standard (DES) engine registers, use the show controller cable-modem des Privileged EXEC command.

show controller cable-modem des

Syntax Description

This command has no key words or arguments.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

DES engine registers are displayed in the following example:

uBR904# show controller cable-modem 0 des downstream des:

ds_des_key_table:

key 0: even 0, odd 0

key 1: even 0, odd 0

key 2: even 0, odd 0

key 3: even 0, odd 0 ds_des_cbc_iv_table:

iv 0: even 0, odd 0

iv 1: even 0, odd 0

iv 2: even 0, odd 0

iv 3: even 0, odd 0 ds_des_sid_table:

sid_1=0x0000, sid_2=0x0000, sid_3=0x0000, sid_4=0x0000 ds_des_sid_enable=0x80, ds_des_ctrl=0x2E ds_des_sv=0x0F00

ds_unencrypted_length=0x0C upstream des:

us_des_key_table:

key 0: even 0, odd 0

key 1: even 0, odd 0

key 2: even 0, odd 0

key 3: even 0, odd 0 us_des_cbc_iv_table:

iv 0: even 0, odd 0

iv 1: even 0, odd 0

iv 2: even 0, odd 0

iv 3: even 0, odd 0 pb_req_bytes_to_minislots=0x10 us_des_ctrl=0x00, us_des_sid_1= 0x1234 ds_unencrypted_length=0x0C

20 Release 11.3(4)NA

show controller cable-modem des

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem phy show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 21

Command Reference

show controller cable-modem filters

To display the registers in the MAC hardware that are used for filtering received frames, use the show controller cable-modem filters Privileged EXEC command.

show controller cable-modem filters

Syntax Description

There are no key words or arguments for this command.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Some of the filtering parameters are MAC hardware addresses, Station IDs (SID), and upstream channel IDs.

This command is only useful for development engineers.

Sample Display

MAC and SID filter information is displayed in the following example:

uBR904# show controller cable-modem 0 filters downstream mac message processing:

ds_mac_da_filters:

filter_1=0010.7b43.aa01, filter_2=0000.0000.0000 filter_3=0000.0000.0000, filter_4=0000.0000.0000

ds_mac_da_filter_ctrl=0x71, ds_mac_msg_sof=0x0000 ds_mac_da_mc=01E02F00

map_parser_sids:

sid_1=0x0000, sid_2=0x0000, sid_3=0x0000, sid_4=0x0000 ds_mac_filter_ctrl=0x00, us_channel_id=0x0000 ds_pid=0x0000, mac_msg_proto_ver=FF 00 reg_rang_req_sid=0x0000

downstream data processing: ds_data_da_filter_table:

filter_1 0010.7b43.aa01, filter_2 0000.0000.0000 filter_3 0000.0000.0000, filter_4 0000.0000.0000

ds_data_da_filter_ctrl=0x61, ds_pdu_sof=0xDEAD ds_data_da_mc=01000000

upstream processing:

us_ctrl_status=0x04, Minislots per request=0x01 burst_maps:

map[0]=0 map[1]=0 map[2]=0 map[3]=0 bytes_per_minislot_exp=0x04 us_map_parser_minislot_adv=0x03, maint_xmit=0x0000 us_sid_table:

sid_1=0x0000, sid_2=0x0000, sid_3=0x0000, sid_4=0x0000 max_re_req=0x0010, rang_fifo=0x00

22 Release 11.3(4)NA

show controller cable-modem filters

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem phy show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 23

Command Reference

show controller cable-modem lookup-table

To display the mini-slot lookup table inside a cable modem, use the show controller cable-modem lookup-table Privileged EXEC command.

show controller cable-modem lookup-table

Syntax Description

This command has no keywords or arguments.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

This command shows the details of the lookup table. The driver uses this table to convert the size of a frame that the cable modem wants to transmit into a bandwidth request to the CMTS in ???mini-slots.??? The contents of this table are affected by the upstream symbol rate that is negotiated between the CMTS and the cable modem.

This command is only useful for development engineers.

Sample Display

The lookup table is displayed in the following example:

uBR904# show controller cable-modem 0 lookup-table

PHY Overhead Lookup Table:

01 01 01 01 01 01 01 02 02 02 02 02 02 02 02 02

02 02 02 02 02 02 02 03 03 03 03 03 03 03 03 03

03 03 03 03 03 03 03 04 04 04 04 04 04 04 04 04

04 04 04 04 04 04 04 05 05 05 05 05 05 05 05 05

05 05 05 05 05 05 05 06 06 06 06 06 06 06 06 06

06 06 06 06 06 06 06 07 07 07 07 07 07 07 07 07

07 07 07 07 07 07 07 08 08 08 08 08 08 08 08 08

08 08 08 08 08 08 08 09 09 09 09 09 09 09 09 09

09 09 09 09 09 09 09 0A 0A 0A 0A 0A 0A 0A 0A 0A

0A 0A 0A 0A 0A 0A 0A 0B 0B 0B 0B 0B 0B 0B 0B 0B

0B 0B 0B 0B 0B 0B 0B 0C 0C 0C 0C 0C 0C 0C 0C 0C

0C 0C 0C 0C 0C 0C 0C 0D 0D 0D 0D 0D 0D 0D 0D 0D

0D 0D 0D 0D 0D 0D 0D 0E 0E 0E 0E 0E 0E 0E 0E 0E

0E 0E 0E 0E 0E 0E 0E 0F 0F 0F 0F 0F 0F 0F 0F 0F

0F 0F 0F 0F 0F 0F 0F 10 10 10 10 10 10 10 10 10

10 10 10 10 10 10 10 11 11 11 11 11 11 11 11 11

11 11 11 11 11 11 11 12 12 12 12 12 12 12 12 12

12 12 12 12 12 12 12 13 13 13 13 13 13 13 13 13

13 13 13 13 13 13 13 14 14 14 14 14 14 14 14 14

14 14 14 14 14 14 14 15 15 15 15 15 15 15 15 15

15 15 15 15 15 15 15 16 16 16 16 16 16 16 16 16

16 16 16 16 16 16 16 17 17 17 17 17 17 17 17 17

17 17 17 17 17 17 17 18 18 18 18 18 18 18 18 18

18 18 18 18 18 18 18 19 19 19 19 19 19 19 19 19

19 19 19 19 19 19 19 1A 1A 1A 1A 1A 1A 1A 1A 1A

1A 1A 1A 1A 1A 1A 1A 1B 1B 1B 1B 1B 1B 1B 1B 1B

1B 1B 1B 1B 1B 1B 1B 1C 1C 1C 1C 1C 1C 1C 1C 1C

24 Release 11.3(4)NA

show controller cable-modem lookup-table

1C 1C 1C 1C 1C 1C 1C 1D 1D 1D 1D 1D 1D 1D 1D 1D

1D 1D 1D 1D 1D 1D 1D 1E 1E 1E 1E 1E 1E 1E 1E 1E

1E 1E 1E 1E 1E 1E 1E 1F 1F 1F 1F 1F 1F 1F 1F 1F

1F 1F 1F 1F 1F 1F 1F 20 20 20 20 20 20 20 20 20

20 20 20 20 20 20 20 21 21 21 21 21 21 21 21 21

21 21 21 21 21 21 21 22 22 22 22 22 22 22 22 22

22 22 22 22 22 22 22 23 23 23 23 23 23 23 23 23

23 23 23 23 23 23 23 24 24 24 24 24 24 24 24 24

24 24 24 24 24 24 24 25 25 25 25 25 25 25 25 25

25 25 25 25 25 25 25 26 26 26 26 26 26 26 26 26

26 26 26 26 26 26 26 27 27 27 27 27 27 27 27 27

27 27 27 27 27 27 27 28 28 28 28 28 28 28 28 28

28 28 28 28 28 28 28 29 29 29 29 29 29

29 29 29 29 29 29 29 2A 2A 2A 2A 2A 2A 2A 2A 2A

2A 2A 2A 2A 2A 2A 2A 2B 2B 2B 2B 2B 2B 2B 2B 2B

2B 2B 2B 2B 2B 2B 2B 2C 2C 2C 2C 2C 2C 2C 2C 2C

2C 2C 2C 2C 2C 2C 2C 2D 2D 2D 2D 2D 2D 2D 2D 2D

2D 2D 2D 2D 2D 2D 2D 2E 2E 2E 2E 2E 2E 2E 2E 2E

2E 2E 2E 2E 2E 2E 2E 2F 2F 2F 2F 2F 2F 2F 2F 2F

2F 2F 2F 2F 2F 2F 2F 30 30 30 30 30 30 30 30 30

30 30 30 30 30 30 30 31 31 31 31 31 31 31 31 31

31 31 31 31 31 31 31 32 32 32 32 32 32 32 32 32

32 32 32 32 32 32 32 33 33 33 33 33 33 33 33 33

33 33 33 33 33 33 33 34 34 34 34 34 34 34 34 34

34 34 34 34 34 34 34 35 35 35 35 35 35 35 35 35

35 35 35 35 35 35 35 36 36 36 36 36 36 36 36 36

36 36 36 36 36 36 36 37 37 37 37 37 37 37 37 37

37 37 37 37 37 37 37 38 38 38 38 38 38 38 38 38

38 38 38 38 38 38 38 39 39 39 39 39 39 39 39 39

.

.

.

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters show controller cable-modem mac show controller cable-modem phy show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 25

Command Reference

show controller cable-modem mac

To show detailed MAC layer information for a cable modem, enter the show cable controller cable-modem number mac Privileged EXEC command.

show controller cable-modem number mac [errors | hardware | log | resets | state]

Syntax Description

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

MAC log messages are written to a circular log file even when debugging is not turned on. These messages include timestamps, events, and information pertinent to these events. Enter the show controller cable-modem number mac log command to view MAC log messages.

If the cable modem interface fails to come up or resets periodically, the MAC log will capture what happened. For example, if an address is not obtained from the DHCP server, an error is logged, initialization starts over, and the cable modem scans for a downstream frequency.

The most useful keywords for troubleshooting a cable modem are log, errors, and resets. See Sample Display 1, Sample Display 2, and Sample Displays 3.

26 Release 11.3(4)NA

show controller cable-modem mac

Sample Display 1

The following sample display shows the MAC log file for a cable-modem interface that has successfully come up:

Troubleshooting Tips for the Cisco uBR904 Cable Modem 27

Command Reference

If the DHCP server could not be reached, the error would look like this in the MAC log:

Sample Display 2

MAC error log information is displayed in the following example, which is also reported via SNMP:

uBR904# show controller cable-modem 0 mac errors

62856.934 R02.0 No Ranging Response received. T3 time-out. 62857.436 R02.0 No Ranging Response received. T3 time-out. 62859.450 R02.0 No Ranging Response received. T3 time-out. 62860.962 R02.0 No Ranging Response received. T3 time-out. 62908.796 D05.0 TFTP Request sent. No Response/No Server.

62949.080 D05.0 TFTP Request sent. No Response/No Server.

62989.368 D05.0 TFTP Request sent. No Response/No Server.

63029.650 D05.0 TFTP Request sent. No Response/No Server.

63069.932 D05.0 TFTP Request sent. No Response/No Server.

If the DHCP server could not be reached, the error would look like this in the MAC error display:

uBR904# show controller cable-modem 0 mac errors

28 Release 11.3(4)NA

show controller cable-modem mac

Sample Displays 3

The show controller cable-modem 0 mac resets command shows only the entries in the cable MAC log that begin with the field CMAC_LOG_RESET. Collectively presenting these fields provides you with a summary of the most recent reasons why the cable interface was reset.

Reset messages and brief explainations are included in the following examples and in Table 1. However, the reset messages in Table 2 do not commonly occur.

In the following example, the configuration file downloaded from the TFTP server could not be read. The file might not exist, or the file has incorrect permissions.

uBR904# show controller cable-modem 0 mac resets

The following example shows that the DHCP server could not be reached. The DHCP server took too long to respond.

uBR904# show controller cable-modem 0 mac resets

497989.804 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED 498024.046 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED 498058.284 CMAC_LOG_RESET_DHCP_WATCHDOG_EXPIRED

This next example indicates that an event in the cable interface driver caused the interface to reset. This is often because a shut or clear command is currently being issued on the interface.

uBR904# show controller cable-modem 0 mac resets

527986.444 CMAC_LOG_RESET_FROM_DRIVER 528302.042 CMAC_LOG_RESET_FROM_DRIVER 528346.600 CMAC_LOG_RESET_FROM_DRIVER 528444.494 CMAC_LOG_RESET_FROM_DRIVER

Troubleshooting Tips for the Cisco uBR904 Cable Modem 29

Command Reference

Table 2 Possible but Uncommon Cable Interface Reset Causes (Continued)

30 Release 11.3(4)NA

Sample Display 4

This example display for the show controller cable-modem 0 mac hardware command shows the detailed configuration of the interface driver and MAC layer hardware. The most interesting bit is the station address (hardware address). The rest of the display is only of use to a software engineer. The MIB statistics reflect the MAC hardware counters for various events, but these counters are typically reset every few seconds, so their contents are not accurate in this display.

uBR904# show controller cable-modem 0 mac hardware

PLD VERSION: 32

BCM3220 unit 0, idb 0x200EB4, ds 0x82D4748, regaddr = 0x800000, reset_mask 0x80

station address 0010.7b43.aa01 default station address 0010.7b43.aa01 MAC mcfilter 01E02F00 data mcfilter 01000000

09pak=0x82DEC74 buf=0x2254EA status=0x80 pak_size=0

10pak=0x82DEA7C buf=0x224DE2 status=0x80 pak_size=0

11pak=0x82DE884 buf=0x2246DA status=0x80 pak_size=0

12pak=0x82DE68C buf=0x223FD2 status=0x80 pak_size=0

13pak=0x82DE494 buf=0x2238CA status=0x80 pak_size=0

14pak=0x82DE29C buf=0x2231C2 status=0x80 pak_size=0

15pak=0x82DE0A4 buf=0x222ABA status=0x80 pak_size=0

16pak=0x82DDEAC buf=0x2223B2 status=0x80 pak_size=0

17pak=0x82DDCB4 buf=0x221CAA status=0x80 pak_size=0

18pak=0x82DDABC buf=0x2215A2 status=0x80 pak_size=0

19pak=0x82DD8C4 buf=0x220E9A status=0x80 pak_size=0

20pak=0x82DD6CC buf=0x220792 status=0x80 pak_size=0

21pak=0x82DD4D4 buf=0x22008A status=0x80 pak_size=0

22pak=0x82DD2DC buf=0x21F982 status=0x80 pak_size=0

23pak=0x82DD0E4 buf=0x21F27A status=0x80 pak_size=0

24pak=0x82DCEEC buf=0x21EB72 status=0x80 pak_size=0

25pak=0x82DCCF4 buf=0x21E46A status=0x80 pak_size=0

26pak=0x82DCAFC buf=0x21DD62 status=0x80 pak_size=0

Troubleshooting Tips for the Cisco uBR904 Cable Modem 31

Command Reference

27pak=0x82DC904 buf=0x21D65A status=0x80 pak_size=0

28pak=0x82DC70C buf=0x21CF52 status=0x80 pak_size=0

29pak=0x82DC514 buf=0x21C84A status=0x80 pak_size=0

30pak=0x82DC31C buf=0x21C142 status=0x80 pak_size=0

31pak=0x82DC124 buf=0x21BA3A status=0xA0 pak_size=0 RX MAC message ring with 8 entries at 0x201E80

rx_head_mac = 0x201EB0 (6), rx_p_mac = 0x82D480C (6)

00pak=0x82E0DEC buf=0x22CC72 status=0x80 pak_size=0

01pak=0x82E021C buf=0x22A242 status=0x80 pak_size=0

02pak=0x82E060C buf=0x22B052 status=0x80 pak_size=0

03pak=0x82E11DC buf=0x22DA82 status=0x80 pak_size=0

04pak=0x82DFC34 buf=0x228D2A status=0x80 pak_size=0

05pak=0x82E09FC buf=0x22BE62 status=0x80 pak_size=0

06pak=0x82DEE6C buf=0x225BF2 status=0x80 pak_size=0

07pak=0x82DFA3C buf=0x228622 status=0xA0 pak_size=0 TX BD ring with 8 entries at 0x201FB8, tx_count = 0

tx_head = 0x201FB8 (0), head_txp = 0x82D4888 (0) tx_tail = 0x201FB8 (0), tail_txp = 0x82D4888 (0)

00pak=0x000000 buf=0x200000 status=0x00 pak_size=0

01pak=0x000000 buf=0x200000 status=0x00 pak_size=0

02pak=0x000000 buf=0x200000 status=0x00 pak_size=0

03pak=0x000000 buf=0x200000 status=0x00 pak_size=0

04pak=0x000000 buf=0x200000 status=0x00 pak_size=0

05pak=0x000000 buf=0x200000 status=0x00 pak_size=0

06pak=0x000000 buf=0x200000 status=0x00 pak_size=0

07pak=0x000000 buf=0x200000 status=0x20 pak_size=0 TX PD ring with 8 entries at 0x202038, tx_count = 0

tx_head_pd = 0x202038 (0) tx_tail_pd = 0x202038 (0)

00status=0x00 bd_index=0x0000 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E FF FF

01status=0x00 bd_index=0x0001 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E FF FF

02status=0x00 bd_index=0x0002 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E FF FF

03status=0x00 bd_index=0x0003 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E FF FF

04status=0x00 bd_index=0x0004 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E 00 00

05status=0x00 bd_index=0x0005 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 2E 00 00

06status=0x00 bd_index=0x0006 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 00 00 00

07status=0x20 bd_index=0x0007 len=0x0000 hdr_len=0x0000 ehdr: 00 00 00 00 00 00

MIB Statistics

DS fifo full = 0, Rerequests = 0

DS mac msg overruns = 0, DS data overruns = 0 Qualified maps = 0, Qualified syncs = 0

CRC fails = 0, HDR chk fails = 0 Data pdus = 0, Mac msgs = 0 Valid hdrs = 0

BCM3220 Registers: downstream dma:

ds_data_bd_base=0x001D40, ds_mac_bd_base=0x001E80 ds_data_dma_ctrl=0x98, ds_mac_dma_ctrl=0x98 ds_dma_data_index=0x0000, ds_dma_msg_index=0x0000

upstream dma:

us_bd_base=0x001FB8, us_pd_base=0x002038 us_dma_ctrl=0x00, us_dma_tx_start=0x00

global control and status: global_ctrl_status=0x00

interrupts:

irq_pend=0x0018, irq_mask=0x00E7

32 Release 11.3(4)NA

show controller cable-modem mac

timing recovery circuit: loop_enable=0x00, minislot_divisor=0x00

K0_ctrl=0x06, K1_ctrl=0x07, acq_threshhold=0x01 err_threshhold=0x04, timeout_threshold=0xFF nco_bias=0x4F7004F7, ranging_offset=0x00000000 ts_err=0x00, sync_valid=0x00, delta_F=0x00 timeout_err=0x00

spi:

dynamic_ctrl=0x09, static_ctr=0x9F, autonomous=0x01 irq_ack=0x00, spi_cmd=0x51, spi_addr=0x11 spi_data= FF/00/00/00/00/00/00

burst profiles: profile 0:

01 19 1D 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

profile 1:

01 19 1D 03 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

profile 2:

01 19 1D 04 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

profile 3:

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Sample Display 5

The show controller cable-modem 0 mac state command summarizes the state of the cable MAC layer. If the cable MAC layer is in the wait_for_link_up_state, the information shown in the display corresponds to the last time the interface was up. This allows useful information to be acquired from this display even though the modem has not been able to range and register. The normal operational state of the interface is the maintenance_state.

uBR904# show controller cable-modem 0 mac state

8993000000 105000000 6000000

90111250000 117250000 6000000

91231012500 327012500 6000000

92333015000 333015000 6000000

93339012500 399012500 6000000

94405000000 447000000 6000000

95123015000 129015000 6000000

96135012500 135012500 6000000

97141000000 171000000 6000000

Troubleshooting Tips for the Cisco uBR904 Cable Modem 33

Command Reference

34 Release 11.3(4)NA

show controller cable-modem mac

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem phy

show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 35

Command Reference

show controller cable-modem phy

To display detailed contents about the registers used in the downstream physical hardware used by a cable modem, use the show controller cable-modem phy Privileged EXEC command.

show controller cable-modem phy {receive | transmit}

Syntax Description

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

This command is only useful for development engineers.

Sample Display

Physical receive registers are displayed in the following example:

uBR904# show controller cable-modem 0 phy receive

BCM3116 Receiver Registers: Chip ID = C2C1

FEC uncorrectable error count: 0

Bit Error Rate Count: 0

36 Release 11.3(4)NA

show controller cable-modem phy

Physical transmit registers are displayed in the following example:

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem tuner show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 37

Command Reference

show controller cable-modem tuner

To display the settings for the upstream and downstream tuners used by a cable modem, use the show controller cable-modem tuner Privileged EXEC command.

show controller cable-modem tuner

Syntax Description

There are no key words or arguments for this command.

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

The cable modem???s tuner settings are displayed in the following example. See Table 3 for output field possibilities and descriptions.

uBR904# show controller cable-modem 0 tuner

Tuner: status=0x00

Rx: tuner_freq 507000000, symbol_rate 5360736, local_freq 11520000 snr_estimate 17488, ber_estimate 0, lock_threshold 26000

QAM not in lock, FEC not in lock, qam_mode QAM_64

Tx: tx_freq 20000000, power_level 0x3E, symbol_rate 1280000

Table 3 Show Controller Cable-Modem Tuner Field Descriptions

FieldDescription

tuner_freq Indicates the current downstream frequency.

symbol_rate Indicates the downstream or upstream symbol rate in use.

snr_estimate Signal to noise estimate in dB X 1000.

ber_estimate Bit error rate estimate (always 0).

QAM status Indicates if QAM/FEC loc has been acquired and the modulation mode in use.

power_level Transmit power level as set in the hardware. The units are unique to the hardware used. Use the show controller cable-modem 0 mac state EXEC command to see the power level in dBmV.

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table

38 Release 11.3(4)NA

show controller cable-modem tuner

show controller cable-modem mac show controller cable-modem phy show interface cable-modem

Troubleshooting Tips for the Cisco uBR904 Cable Modem 39

Command Reference

show interface cable-modem

To display information about the cable modem interface on a cable modem, use the show interface cable-modem EXEC command.

show interface cable-modem number [accounting | counters | crb | irb | type]

Syntax Description

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

Traffic passing through the cable modem interface is shown in the following example:

uBR904# show interface cable-modem 0 cable-modem0 is up, line protocol is up

Hardware is BCM3220, address is 0010.7b43.aa01 (bia 0010.7b43.aa01) Internet address is 188.188.1.60/16

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 00:07:04, output 00:00:41, 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

4495 packets input, 1153221 bytes, 0 no buffer Received 8 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort 12841 packets output, 1708272 bytes, 0 underruns

0 output errors, 0 collisions, 11 interface resets

0 output buffer failures, 0 output buffers swapped out

40 Release 11.3(4)NA

show interface cable-modem

The following example displays the number of packets and each protocol type passing through the cable modem interface:

uBR904# show int cable-modem 0 accounting

MIB counters on the cable interface are displayed in the next example:

uBR904# show int cable-modem 0 counters

Routing and bridging information on the cable modem interface is displayed in the next example:

uBR904# show int cable-modem 0 crb

cable-modem0

Bridged protocols on cable-modem0: ip

Related Commands

show controller cable-modem

show controller cable-modem bpkm show controller cable-modem des show controller cable-modem filters

show controller cable-modem lookup-table show controller cable-modem mac

show controller cable-modem phy show controller cable-modem tuner

Troubleshooting Tips for the Cisco uBR904 Cable Modem 41

Debug Commands

Debug Commands

The following new debug commands are available to troubleshoot a cable modem:

???debug cable-modem bpkm

???debug cable-modem bridge

???debug cable-modem error

???debug cable-modem interrupts

???debug cable-modem mac

???debug cable-modem map

42 Release 11.3(4)NA

debug cable-modem bpkm

debug cable-modem bpkm

To debug baseline privacy information on a cable modem, use the debug cable-modem mac

Privileged EXEC command. The no form of this command turns debugging messages off.

[no] debug cable-modem bpkm {errors | events | packets}

Syntax Description

Command Mode

Privileged EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

Figure 3 shows the required keywords within the debug cable-modem bpkm command. You must choose one.

Figure 3 Sample Debug Cable-Modem Bpkm Output

Figure 4 shows output when the headend does not have privacy enabled.

Figure 4 Sample Debug Cable-Modem Bpkm Output

uBR904# debug cable bpkm

cm_bpkm_fsm(): machine: KEK, event/state: EVENT_4_TIMEOUT/STATE_B_AUTH_WAIT, new state:

STATE_B_AUTH_WAIT

cm_bpkm_fsm(): machine: KEK, event/state: EVENT_4_TIMEOUT/STATE_B_AUTH_WAIT, new state:

STATE_B_AUTH_WAIT

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to down

cm_bpkm_fsm(): machine: KEK, event/state: EVENT_1_PROVISIONED/STATE_A_START, new state:

STATE_B_AUTH_WAIT

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to up

Troubleshooting Tips for the Cisco uBR904 Cable Modem 43

Debug Commands

Related Commands

debug cable-modem bridge debug cable-modem error debug cable-modem interrupts debug cable-modem mac debug cable-modem map

44 Release 11.3(4)NA

debug cable-modem bridge

debug cable-modem bridge

Use the debug cable-modem bridge Privileged EXEC command to debug bridge filter processing information on a cable modem. The no form of this command turns debugging messages off.

[no] debug cable-modem bridge

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

When the interface is down, all bridge table entries learned on the Ethernet interface are set to discard because traffic is not bridged until the cable interface has completed initialization. After the interface is completely up (the line protocol), bridge table entries learned on the Ethernet interface program the cable???s MAC data filters. The cable MAC hardware filters out any received packets whose addresses, are not in the filters. In this way, the cable interface only receives packets addressed to its own MAC address or an address it has learned on the Ethernet interface.

Sample Display

Figure 5 shows sample display output for the debug cable-modem bridge Privileged EXEC command

Figure 5 Sample Debug Cable-Modem Bridge Output

uBR904# debug cable-modem bridge

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to downshut

cm_tbridge_add_entry(): MAC not initialized, discarding entry: 00e0.fe7a.186fno shut

cm_tbridge_add_entry(): MAC not initialized, discarding entry: 00e0.fe7a.186f

%LINEPROTO-5-UPDOWN: Line protocol on Interface cable-modem0, changed state to up

cm_tbridge_add_entry(): Adding entry 00e0.fe7a.186f to filter 2

Related Commands

debug cable-modem bpkm debug cable-modem error debug cable-modem interrupts debug cable-modem mac debug cable-modem map

Troubleshooting Tips for the Cisco uBR904 Cable Modem 45

Debug Commands

debug cable-modem error

[no] debug cable-modem error

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

This command displays detailed output about the sanity checking of received frame formats, the acquisition of downstream QAM/FEC lock, the receipt or non receipt of SYNC messages from the CMTS, reception errors, and bandwidth request failures.

Sample Display

Figure 6 shows sample display output for the debug cable-modem error command.

Related Commands

debug cable-modem bpkm debug cable-modem bridge debug cable-modem interrupts debug cable-modem mac debug cable-modem map

46 Release 11.3(4)NA

debug cable-modem interrupts

debug cable-modem interrupts

Use the debug cable-modem interrupts command to debug cable modem interrupts. The no form of this command turns debugging messages off.

[no] debug cable-modem interrupts

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

Figure 7 shows sample debug output for cable modem interrupts.

Figure 7 Sample Debug Cable-Modem Interrupts Output

uBR904# debug cable-modem interrupts

*** bcm3220_rx_mac_msg_interrupt ***

*** bcm3220_rx_mac_msg_interrupt ***

### bcm3220_tx_interrupt ###

*** bcm3220_rx_mac_msg_interrupt ***

### bcm3220_tx_interrupt ###

*** bcm3220_rx_mac_msg_interrupt ***

### bcm3220_tx_interrupt ###

### bcm3220_tx_interrupt ###

### bcm3220_tx_interrupt ###

### bcm3220_tx_interrupt ###

Related Commands

debug cable-modem bpkm debug cable-modem bridge debug cable-modem error debug cable-modem mac debug cable-modem map

Troubleshooting Tips for the Cisco uBR904 Cable Modem 47

Debug Commands

debug cable-modem mac

Use the debug cable-modem mac Privileged EXEC command to troubleshoot the cable modem MAC layer. The no form of this command turns debugging messages off.

[no] debug cable-modem mac {log [verbose] | messages}

Syntax Description

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Of all the available debug cable modem commands, the most useful is debug cable-modem mac log.

48 Release 11.3(4)NA

0 events dropped due to lack of a chunk

Troubleshooting Tips for the Cisco uBR904 Cable Modem 49

Debug Commands

Figure 9 compares the output of the debug cable-modem mac log command with the debug cable-modem mac log verbose command. The keyword verbose displays periodic events such as ranging.

Figure 9 Sample Debug Cable-Modem Mac Log and Verbose Output

uBR904# debug cable mac log

Cable Modem mac log debugging is on uBR904#

uBR904#

uBR904# debug cable mac log verbose

Cable Modem mac log debugging is on (verbose) uBR904#

Figure 10 shows display output for the debug cable mac messages Privileged EXEC command.

This command causes received cable MAC management messages to be displayed in a verbose format. The messages that are displayed are UCD, MAP, RNG-RSP, REG-RSP and UCC. In addition, transmitted REG-REQs are displayed in hex dump format. The output from this command is very verbose and is usually not needed for normal interface debugging. The command is most useful when attempting to attach a cable modem to an uncertified CMTS. For a description of the displayed fields of each message, refer to the MCNS DOCSIS RFI spec, v1.0.

Figure 10 Sample Debug Cable-Modem Mac Messages Output

50 Release 11.3(4)NA

debug cable-modem mac

Troubleshooting Tips for the Cisco uBR904 Cable Modem 51

Debug Commands

Related Commands

debug cable-modem bpkm debug cable-modem bridge debug cable-modem error debug cable-modem interrupts debug cable-modem map

52 Release 11.3(4)NA

debug cable-modem map

debug cable-modem map

Use the debug cable-modem map Privileged EXEC command to display the timing from MAP messages to sync messages and the timing between MAP messages. The no form of this command disables debugging output.

[no] debug cable-modem map

Usage Guidelines

This command first appeared in Cisco IOS Release 11.3 NA.

Sample Display

Figure 11 shows display output for the debug cable map Privileged EXEC command.

Figure 11 Sample Debug Cable-Modem Map Output

Related Commands

debug cable-modem bpkm debug cable-modem bridge debug cable-modem error debug cable-modem interrupts debug cable-modem mac

Troubleshooting Tips for the Cisco uBR904 Cable Modem 53

What to do Next

What to do Next

For more troubleshooting tips, see the chapter ???Troubleshooting the Installation??? in the Cisco Cable

Modem Installation and Configuration Guide.

54 Release 11.3(4)NA