Troubleshooting guide

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Cisco Broadband Local Integrated Services Solution Troubleshooting Guide
OL-5169-01
Chapter 7 Troubleshooting the CMTS
Troubleshooting the Cisco uBR7246VXR
Below is a sample debug output on the cable modem when there is an authorization failure:
6d02h: 527617.480 CMAC_LOG_CONFIG_FILE_PROCESS_COMPLETE
6d02h: 527617.480 CMAC_LOG_STATE_CHANGE registration_state
6d02h: 527617.484 CMAC_LOG_REG_REQ_MSG_QUEUED
6d02h: 527617.488 CMAC_LOG_REG_REQ_TRANSMITTED
6d02h: 527617.492 CMAC_LOG_REG_RSP_MSG_RCVD
6d02h: 527617.492 CMAC_LOG_COS_ASSIGNED_SID 1/2
6d02h: 527617.492 CMAC_LOG_RNG_REQ_QUEUED 2
6d02h: 527617.492 CMAC_LOG_REGISTRATION_OK
6d02h: 527617.496 CMAC_LOG_STATE_CHANGE establish_privacy_state
6d02h: 527617.496 CMAC_LOG_PRIVACY_FSM_STATE_CHANGE
machine: KEK, event/state: EVENT_1_PROVISIONED/STATE_A_START, new state:
STATE_B_AUTH_WAIT
6d02h: 527617.504 CMAC_LOG_BPKM_REQ_TRANSMITTED
6d02h: 527617.504 CMAC_LOG_BPKM_RSP_MSG_RCVD
6d02h: 527617.508 CMAC_LOG_PRIVACY_FSM_STATE_CHANGE
machine: KEK, event/state: EVENT_2_AUTH_REJECT/STATE_B_AUTH_WAIT, new state:
STATE_E_AUTH_REJ_WAIT
129.CABLEMODEM.CISCO: 6d02h: %CMBPKM-1-AUTHREJECT: Authorization request rejected by CMTS:
Unauthorized CM
6d02h: 527618.588 CMAC_LOG_RNG_REQ_TRANSMITTED
6d02h: 527618.592 CMAC_LOG_RNG_RSP_MSG_RCVD
Similarly, a debug cable privacy on the Cisco uBR7246VXR provides the following errors:
02:47:00: CMTS Received AUTH REQ.
02:47:00: Sending KEK REJECT.
02:47:05: %UBR7200-5-UNAUTHSIDTIMEOUT: CMTS deleted BPI unauthorized Cable Modem
0030.96f9.65d9
Note The cable modem keeps cycling from reject(pk) to init(r1) indefinitely.
Another possible error that can be encountered is that due to encryption export restrictions, some vendor
modems may require the following command on the Cisco uBR7246VXR in the interface configuration:
(config-if)#cable privacy 40-bit-des
Registration - reject (m) state
After configuration, the cable modem sends a registration request (REG-REQ) with a required subset of
the configuration settings as well as the cable modem and uBR message integrity checks (MIC). The
cable modem MIC is a hashed calculation over the configuration file settings which provides a method
for the cable modem to be sure the configuration file was not tampered with in transit. The Cisco
uBR7246VXR MIC is similar except it also includes a setting for a cable shared-secret authentication
string. This shared secret is known by the Cisco uBR7246VXR and the provisioning server and ensures
that only cable modems authenticated by provisioning servers will be allowed to register with the router.
A cable modem in reject(m) state has a bad Message Integrity Check (MIC), typically caused by:
• Mismatch between cable shared-secret under the cable interface and CMTS Authentication value
under Miscellaneous option in the DOCSIS CPE Configurator
• Corrupt configuration file (DOCSIS file)
To rectify the problem, verify that you have a valid configuration file and an identical value under CMTS
Authentication to what is configured in cable shared-secret <line> under the cable interface. Also
verify that the Cisco uBR7246VXR allows the creation of class of service profiles, or use a profile
created by the Cisco uBR7246VXR.