The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.
This chapter describes open and resolved severity 1 and 2 caveats and select severity 3 caveats:
The bug IDs are sorted alphanumerically.
Note The Caveats section includes the bug ID and a short description of the bug. For details on the symptoms, conditions, and workaround for a specific caveat you must use the Bug Search Tool.
Cisco Bug Search Tool (BST), the online successor to Bug Toolkit, is designed to improve effectiveness in network risk management and device troubleshooting. You can search for bugs based on product, release, and keyword, and aggregates key data such as bug details, product, and version. For more details on the tool, see the help page located at http://www.cisco.com/web/applicat/cbsshelp/help.html .
Symptom: When UCD change occurs, some data structures related to US scheduler of secondary upstream service flows do not get properly updated. One example is minislot size. Hence any traffic through these service flow might get affected.
Workaround: There is no workaround.
Symptoms: When setting wideband interface to secondary through SNMP, it doesn't work as expected.
Conditions: This symptom is observed in a wide band cmts which configure the wide band interfaces.
Workaround: Modify the wideband configuration through the CLI.
Symptoms: When query for the entPhysicalName output there is a mismatch in the SFP output for Cisco IOS Release 12.3(21)BC and 12.2(33)SCA or the Cisco Wideband SPA showed twice when using the show inventory command.
Conditions: When there are Cisco Wideband SPAs on a Cisco Wideband SIP, use the show inventory command or query for the entPhysicalName, the Symptom happens.
This Symptom does not affect other functions of a Cisco Wideband SPA.
Workaround: This a cosmetic mismatch of the SFP output string. Be aware that the outputstring is different between Cisco IOS Release 12.3(21)BC and 12.2(33)SCA.
Symptoms: The Number of Downstream PHS rules for a Cable MAC Domain stays the same even though more Downstreams can be added to the MAC Domain (via Modular Downstreams).
Conditions: A MAC Domain can have 4K Downstream PHS rules. This is the current limit.
Workaround: There is no workaround.
Symptoms: With the wideband multicast BPI and wideband host HA configuration, the line card crashes while syncing BPI data.
Conditions: This occurs when there are a large number of BPI multicast keys in wideband host data. It causes line card memory corruption and eventually crashes the line card.
Workaround: Disable the wideband multicast BPI configuration or disable the wideband host HA configuration.
Symptoms: SLOWRPC error message seen in IPC code while the Cisco uBR10000 is booting up.
Workaround: There is no workaround.
Symptoms: On a Cisco uBR10000 Service flow counts are not updated for downstream service flows handled by the 24 RF channel SPA. As a result dynamic service flows for voice may be torn down when the T8 (inactivity) timer expires.
Conditions: Occurs when SPA in Bay 0 is inserted but the GigE link is disconnected or down.
Workarounds: Ensure that the SPA0 GigE link is up whenever SPA 0 exists.
Symptoms: On a Cisco uBR10000 running Cisco IOS release 12.3(23)BC3, the following message is seen when the show cable modem is used: "Warning: Zero Blaze index for SFID 173 "
Conditions: Cosmetic issue, not affecting the real data flow
Workarounds: There are no workarounds.
Symptoms: The indexes maintained for the 24 RF-channel SPA do no get freed after modems using SPA downstream get reset or deleted by using the clear cable modem cx/y/z all reset|delete command.
Conditions: The 5x20 host of the modular cable interface is using non-default downstream channel ID.
Workarounds: Use the clear cable modem all reset command.
Symptoms: SNMP Set of docsIf3MdCfgIpProvMode returns COMMIT_FAILED_ERROR. It should be supported to set.
Conditions: SNMP Set of docsIf3MdCfgIpProvMode.
Workarounds: Use CLI to change the IP prov Mode
Symptoms: When a policy-map is applied inbound on a GRE tunnel, the GRE tunnel outbound traffic is policed.
Symptoms: AFter PRE Switchover, show cable privacy root-cert provides no ouput
Conditions: The problem is only on uBR10K, and occurs after PRE failovers. Resetting all modems does not bring back the certificates on the PRE, although the modems do come online(pt) on the line cards. Performing a LC failover after the PRE failover does cause the values to be re-populated.
Workarounds: Wait till the Modems come up an learn the certificiations, and they will be repopulated again.
Symptoms: Throughput rate shows (slightly) more than than the expected range.
Conditions: Happens when DMIC feature enabled and modem marked with given MAX rate values. This can also happen when QoS profile has got lower Max rates.
Workarounds: No known workaroud exists. This behaviour is mostly due to smaller value of the MAX-rate, which is not very much applicable with customer scenario. Also the slight change on the throughput values does not have impact on other functionalities.
Symptoms: The show cable qos profile command shows an incorrect value for the number of modems that has come online with the CM generated QOS profile, in the standby PRE.
Conditions: When the CM comes online with DOCSIS1.0 config file, it creates a profile which can be seen in "show cable qos profile". Modems are registered with qos profile.
The show cable qos profile command does not show the correct value for the number of modems that has come online with the cm-created profile in the standby PRE, but the modems are registered with the cm-created profile in the active PRE.
Workaround: There is no workaround.
Symptoms: The multicast fastswitching path has overwritten the ToS value of the multicast packet. ToS value is correct via process-switching path.
Workaround: There is no workaround.
Symptoms: When a cisco uBR series CMTS is configured to perform CPE IP to MAC address resolution through the use of DHCP LEASEQUERY messages rather than ARP the address resolution will fail when it is inspired by downstream packets to the unresolved destination.
Workaround: Temporarily allow downstream ARP resolution with the cable bundle interface commands cable arp and cable proxy-arp .
Symptoms: IGMP join from a cable CPE is timed out improperly by the CMTS
Conditions: IGMP query interval is set to a large value on the cable bundle interface.
Workarounds: There are no workarounds.
Symptoms:When MVPN is configured on the CMTS, and a CPE joins a multicast group that a source is already transmitting to, then the (S,G) entry is not created in mvrf table of the CMTS.
Workarounds: There are no workarounds.
Symptoms: Traceback observed after a uBR10000 PRE switchover%COMMON_FIB-4-FIBNULLHWIDB: Missing hwidb for fibhwidb Tunnel1 (ifindex 144)
Conditions: Multicast VPNs are configured
Workarounds: There are no workarounds.
Symptoms: After a N+1 line card switchover to protect and revert back to working, the standby PRE may reset with some configurations.
Conditions: The problem has been observed when removing some DSG configuration after the revert back, particularly when executing the command "no cable dsg tg". In the error case, the standby PRE resets and the configuration is re-synced with the active PRE.
Workarounds: There are no workarounds.
Symptoms: Modems registerd on remote modular interface may go offline and quickly back online during line card revertback when "cable default-phy-size" or "cable upstream x ingress cancellation" are not same as default value.
Conditions: This condition occurs only when "cable default-phy-size" or "cable upstream x ingress-noise-cancellation" are not same as default value or only modems registered on remote modular interface will be affected, or only during line card revertback.
Workaround: Use the default cable default-phy-size or default cable upstream x ingress-noise-cancellation commands on the interface.
Symptoms: Using the show int <wb intf> downstream command displays 0/0 for "reserved/reservable" bandwidth
Conditions: With some wideband interface reserved bandwidth execute N+1 switchover
Workarounds: No workarounds. Can have correct data from output using the show hw-module bay bay number wideband wideband interface number command.
Symptoms: When RSA keys for use by SSH are generated on a Cisco uBR10000 series CMTS with the configuration command crypto key generate rsa the generated RSA keys are not synchronized across to the standby PRE. This means that SSH will not work if the standby becomes active.
Workaround: Use telnet to connect to the system when the standby PRE is active.
Symptoms: Traffic is not encrypted even with BPI enabled.
Conditions: If BPI is enabled and there is no SPA in bay 0, traffic will be sent in the clear instead of being encrypted.
Workaround: A workaround is to always leave a SPA in bay 0. If for some reason the SPA in bay 0 must be removed and there is still a SPA in bay 1, move the SPA in bay 1 to bay 0 and continue service with the SPA in bay 0.
Symptom: Some voice Calls DS service flow counters increase drastically after LC SO. It will reduce to its normal values but will become abnormal value again if the time between two executions of the show interface Cx/y/z service-flow xxx counters/qos command is long enough.
Symptom: Inactive sessions are observed in the multicast explicit tracking database.
Conditions: IGMP leave received for a group followed by a CLC switchover
Symptom: If the modular interface is deleted from legacy interface,trace back "lb: Mo1/0/0:2:handle_stats_report_common(): no stats data "will show up and modem from other Line card could wait to come on line on inf that interface.
Conditions: CMTS has configured modular cable interface with load balance group, and this load balance group includes interface from other Line card.
Workaround: Modular interfaces is not included in Load balance group that has interface from other line card.
Symptom: Occasionally when inter cable line card load balancing is enabled, a spurious memory access occurs.
Symptom: The show interface bundle command or show interface bundle sum/stat command shows the wrong rate, then the rate value becomes 0 after a while.
Conditions: The data rate reaches a large value, such as 2G. It depends on the load-interval value and the rate.
Symptom:When modem comes up during off-peak time when it is not supposed to be monitored as per enforce-rule configured, the smp is not synced to standby LC.
Conditions: If an LC- Switchover is done during off-peak time, even if the modem enters peak-time it is not monitored as per the enforced rule configured.The smp is synced to standby LC only once the modem is monitored during peak-time.
Symptom: An INFO level alarm is raised when using non-default config for "max-ports"and "connector" on an upstream port even though the port is actually up and running.
Source Severity ACO Description [Index]
------ -------- --- -------------------
Cable5/0-US19 INFO NORMAL Physical Port Administrative State Down [1]
Conditions: Non-default value is configured for "max-ports" and "connector" on Cable upstream port.
Workaround: There is no workaround.
Symptom: Customer is trying to snmpwalk the CMTS (UBR 10000). He sees that a packet has been sent, but never gets a response back. The SNMPWALK times out eventually.
Conditions: Customer has a UBR10000 series router running 12.3(21a)BC4
Workaround: Don't use the MIB object 'sysClearARP' to clear arp table, use CLI instead.
Symptom:Duplicate traps are generated at the end of 'file mode SAMIS' write operations when configuring SNMP traps for Cable billing operations.
Conditions:Setup per http://www.cisco.com/en/US/docs/ios/cable/configuration/guide/cmts_use-bsd_bill.html#wp1027195
Workaround: There are no workarounds.
Symptoms: Unable to set the MIB objects "ccwbRFChanQamIPAddress", "ccwbRFChanQamMacAddress" and "ccwbRFChanQamUdpPort" separately.
Conditions: This occurs on a Cisco uBR10012 router running ubr10k2-k9p6u2-mz.122-122_33_SCA when the MIB objects are individually set using the SNMP set command.
Workaround: Set the MIB objects "ccwbRFChanQamIPAddress", "ccwbRFChanQamMacAddress" and "ccwbRFChanQamUdpPort" using one SNMP set command.
Symptom: A incorrect value may be displayed in the show interface Cablex/y/z with 256QAM is enabled. The value should be BW 37500 Kbit. A degradation of service may be experienced when the behavior is observed.
Conditions: uBR10012 with IOS's 123-17b.BC3 & 123-23.BC2.
Workaround: Reverting the modulation from 256QAM to 64QAM and back to recover.
Symptoms: Wideband modems associated with the first shared port adapter (SPA) do not display wideband counters as expected for the downstream service flows.
Conditions: This occurs on a Cisco uBR10012 router running Cisco IOS Release 12.2SBU05. The wideband modems associated with the first SPA in 1/0/0 bay have their downstream service flow counters incremented as expected. But the wideband modems in 1/0/1 bay do not show incrementing counters for their downstream service flows.
Workaround: There is no workaround.
Symptom: A Cisco uBR10012 running 12.3(23)BC1 may experience a memory leak in "Pool Manager". Use show processes memory to view memory. Alternatively, you can monitor via the ciscoMemoryPoolUsed MIB object.
Conditions: Mixture of best effort data traffic, UGS voice traffic and SNMP polling.
Symptom: Duplicated CALEA request to CMTS when doing FCNA with BTS version 4.5 or before. SII code working well with BTS 5.0 or later due to no duplicated PacketCable CALEA requestion at FCNA. This fix make CMTS CALEA working with early version BTS at FCNA case.
Symptoms:The configuration command default cable upstream rate-limit is interpreted as no cable upstream rate-limit instead of cable upstream rate-limit token-bucket shaping .
Workaround: Configure the cable upstream rate-limit token-bucket shaping command instead of the default CLI.
Symptom: Running-config and the show controllers command have different values for upstream center frequency. Also, 16 KHz resolution is not proper for newer line card.
Conditions: Configure fixed upstream center frequency.
Workaround: This is a sort of cosmetic issue, no side effect.
Symptom: Seeing %LCINFO-4-LCHUNG error messages line card is not coming up.
Conditions: With multiple loads and unloads of fdiag image line card is not coming online.
Workaround: There are no workarounds.
Symptom: When the cable dhcp-giaddr policy strict command is configured at the Cisco CMTS, the CPEs behind the CMs are expected to get the DHCPOFFER message with its source IP address belonging to the secondary IP Network Address range of the downstream Cable interface in the CMTS. Currently the DHCPOFFER has the source IP-Address from the downstream's primary IP Network address range.
Conditions: The issue occurs when the cable dhcp-giaddr policy strict command is configured at the CMTS cable downstream interface.
Symptom: A Cisco uBR10012 may reload due to a bus error.
Conditions: This has been seen on a UBR10000 running 12.3(23)BC1.
Workaround: There is no workaround.
Symptom: Incorrect last test pass time from cli show diagnotstic result subslot x/y detail
Conditions: When we execute the offline-filed diagnostic tests, the last test pass time is not showing correctly.
Workaround: Use the show diagnostics events subslot x/y command to see the correct last test pass time.
The Cisco uBR10012 router has spurious memory traceback observed while testing Field Diagnostics.
Conditions: After loading the fdiag iamge to the line card starting and stoping the ood tests some times crashing the PRE.
Workaround: There is no work-around.
Symptom:All the CPEs/Hosts/MTAs behind the Cable Modems on existing bundle sub-interface will be disappeared or deleted from the CPE table when a new Cable Bundle sub-interface is added with ip address. Same issue will also happen when newly created bundle sub-interface is deleted.
IP connectivity will be broken from CMTS to those CPEs/Hosts/MTAs as they are deleted from CPE table.
Conditions: Above issue has been observed on uBR10k with PRE2 running IOS 12.3(21a)BC8, 12.3(23)BC2 and 12.3(23)BC4 images.
Workaround: There is no workaround.
Symptom: CPE devices behind CableHome devices are not able to acquire IP address via DHCP when the cable helper-address x.x.x.x host command is used under the cable bundle interface.
Conditions: Problem is seen on a CMTS ubr10k with IOS 123-23.BC4. The problem has only been observed for the CPE devices with CableHome devices like Netgear. CPE device behind Cable Modem do acquire IP address via DHCP just fine and work as expected.
Workaround: Configure the cable helper-address x.x.x.x command without host option at the end of the command line under the cable bundle interface.
Symptom: the behavior of the priority setting isn't working correctly. A default MQoS group is required for proper implementation of MQoS over an MPLS VPNs. The default group config must appear before any other MQoS group config in the startup config in order for the feature to work correctly after a reload. For example:
However, testing shows that the default group with priority 255 matches all mcast traffic indicating that priority 255 is in fact a higher not a lower priority. Thus, session-range 239.255.70.7 255.255.255.255 will never get used.
Workaround: There are no workarounds.
1. delete the service class used by multicast default group-qos
3. all group-qos configurations under qos group are removed on standby PRE, while exist on active PRE
4. try to modify group-qos under qos group on active PRE, standby PRE will be reset for configuration mismatch.
Workaround: Delete all group-qos configuration before deleting the service class used by multicast default group-qos.
Symptom: Wideband SPA may not accept the SFP with S/N starting with "AG" after OIR the SFP.You will see below log message when you run into this condition.
*Jul 1 19:38:42.887: %SPAWBCMTS-4-SFP_UNINITIALIZED: Modular-Cable 1/0/0, Unknown SFP inserted in port 0 failed initialization
This message itself will display when non-Cisco SFP is inserted into the SPA, but the above
SFP is indeed made from Cisco.
Conditions: SFP has S/N starting with "AG", and OIR has been performed on the the SFP one or several times.
Workaround: Execute the hw-module bay x/y/z reload command.
Symptom: Interrupt counts displayed by the show command show controller Modular-Cable brief are incorrect since these counts are accumulated on per jacket card basis and not per SPA i.e. controller Modular-Cable basis.
Conditions: Normal operating conditions.
Workaround: There is no workaround.
Symptom: Cisco uBR10012 PRE crash.
Conditions: Executed the show ip interface brief command soon after load and bootup
Workaround: There is no workaround.
Symptoms: If the show cable modem command is used after a PRE switchover, cable modems are duplicated with the same MAC address.
Conditions: This issue occurs on a Cisco uBR10000 series router running Cisco IOS Release 12.3(00)BC3.
Workaround: There is no workaround.
Symptom:After line card switchover or revertback, some modems go offline, and us phy register shows late map issue.
Conditions: This condition occurs when dynamic map-advance safety is configured not big enough.
Workaround: Use a large dynamic map-advance safety value or use static map-advance.
Symptoms: In some situation, we do LC SO and revertback, we got the CMs on some upstream offline, and never online again because the PHY is in error state. It occurs on both BC2 and BC3 image.
Conditions: There are many upstream channels in no-shut state in 520H line card. Do switchvover and then revertback. Sometimes we can see this bug.
Workaround: When this problem happens, shut/no-shut the interface could recover this problem.
Conditions: When doing pre-switchover, ISSU or running the clear cable mode command , there is a chance to hit this line card crash issue.
Workaround: There are no workarounds.
Symptom: Protect card are forwarding data for two or more working cards. And some CM fall offline.
Conditions: There are some interfaces admindown in working cards.
Workaround: Revert back to the working card.
Symptom: Traceback was observed on both active RP and standby RP.
Conditions: Issue line card switchover when active RP is syncing configuration to standby RP.
Workaround: Do not perform a linecard failover until standby RP reach Standby_Hot state (for SSO mode) or Standby_Cold (for other PRE HA mode, like, RPR mode) .
Symptom: Show cable clock command may show that number of TCC Cards in the Chassis: 255". In fact, it should only show up "2" maximum for slot 1/1 and slot 2/1.
Conditions: Removed TCC or DTCC cards and performed a PRE switchover.
Workaround: Perform another PRE2 switchover.
Symptom: When perform PRE switchover, it gave the following errors: UBR10K-1#redundancy force-failover main-cpu. Proceed with switchover to standby PRE? [confirm]y
% HCCP 1 50 Switchover in progress.
HA system in transient state, switchover aborted.
Conditions: One or more CLC is locked out.
Workaround: Execute the redundancy linecard-group unlockout x/y command, do PRE switchover, and then lockout x/y again.
Symptom: With an unrecognized LCP linecard present in the uBR10k chassis the standby PRE will not be allowed to come up.
Workaround: Remove the unsupported line card from the chassis.
Symptoms: IPC timeout does not trigger linecard switchover.
Conditions: The sync-pulse failure was designed to trigger linecard switchover but based on the HCCP design, IPC timeout should trigger linecard switchover.
Workaround: There is no workaround.
Symptom: All modems go offline on the protect port after LC swithover and never come back online.
Conditions: The cable default-phy-burst command is configured as some value other than default(=2000).
Workaround: Shut/no shut the upstream port, and configure the cable default-phy-burst command with the default value.
Symptoms: Inconsistent running-configuration between active and standby after route processor switchover.
Conditions: This occurs with global N+1 configured and after a route processor switchover.
Workaround: There is no workaround.
Symptom:US throughput would drop by half after 12-18 minutes for WB modems
Conditions: Images using 12.3(23)BC
Running config would have cable upstream X rate-limit token-bucket shaping, where X is the upstream number
Workaround: Configure the CMTS without the shaping command. Example:
cable upstream X rate-limit token-bucket, where X is the upstream number.
Symptom: PRE crashes. The crash might happen in only 12.2S based images since the fix was not ported from 12.3 based images correctly.
Symptoms: If DSA/DSC-REQ is sent by the eMTA with DOCSIS Nominal Grant Interval set to 0 then CLC would crash.
Conditions: Misbehaving eMTA with DOCSIS Nominal Grant Interval for a UGS-AD service flow is set to 0 which according to the spec is incorrect.
Workarounds: Turn off silence suppression.
Symptom: BPI+ sessions may fail when root certificates are not present in the router.
Conditions: This issue occurs when the router checks for “root-cert” or “euro-root-cert” certificate at boot-time or when it receives a BPI+ session request.
Workaround: The “root-cert” and “euro-root-cert” certificates are included in the IOS image itself from Cisco IOS Release 12.2(33)SCA2 onwards. These files are no longer required to be stored on the bootflash.
Symptom: If the CM is cleard on the CMTS, the CMTS forwards its DHCP Discover via the VRF of the first bundle interface, just as expected. If the CM is rebooted instead, the CMTS forwards its DHCP Discover via another VRF. The subsequent DHCP Request is sent via the correct VRF, so that it cannot be correlated to the DHCP Offer.
Conditions: When multiple bundle interfaces with unique VRFs are associated with the same downstream:
Workaround: Either terminate VRFs on a single DHCP server ignoring VRF values or keep clearing the CMs with a script.
Symptom:Gate is refused due to exceeded activity although the subscriber has no gate assigned to it.
Conditions: Running packet cable.
Workaround: Increase the Activity count in the gate set message.
Symptom: When removing the configuration “cable privacy accept-self-signed” and attempting to configure a manufacturer's self-signed certificate onto the bootflash: of the CMTS by using the filename “root-cert” or “euro-root-cert”, the self-signed certificate appears to be loaded, but the devices still cannot come online(pt). BPI+ negotiation fails as the self-signed manufacturer certificates are not configured as ‘trusted’.
Conditions: Attempts to provision a non-DOCSIS compliant cable modem whose BPI+ certificate is not signed by a signing authority (eg: self-signed) while the CMTS is configured to reject self-signed certificates will fail. Attempting to load a copy of the manufacturer’s cert into the bootflash of the device as a workaround does not work.
Workaround: There is no workaround. Only modems chaining to the US or EU root certificates are considered valid.
Symptom: Backup TCC card may experience a reload with following messages in PRE log
%IPCOIR-3-TIMEOUT: KA Timeout: slot2/1, LRCV:00:00:14
LKA:00:00:09 LRMV:never, NKA:00:00:00, cpu 16%/5% 18%
%IPCOIR-3-TIMEOUT: KA Timeout: slot2/1, LRCV:never LKA:never
LRMV:never, NKA:00:00:00, cpu 16%/5% 18%
%IPCOIR-2-CARD_UP_DOWN: Card in slot 2/1 is down. Notifying
Conditions: The issue has been experienced on uBR10K running 12.3(23)BC1
Workaround: There are no workarounds.
Symptom: Two upstream ports on the same PHY receiver of a MC520H line cards show SNR degradation about 10 dB.
Conditions: Ingress-noise cancellation on.
Workaround: There are no workarounds
Symptom: When invoking the 'show cable modem' or related commands the following warning will be displayed "Warning: Zero Blaze index for SFID "
Conditions: When the CM/SF is in this state the traffic to the CM won't be impacted but the stats counters for the SF will report invalid numbers.
Workaround: The CM that is impacted can be reset during maintenance windows.
Symptom: DHCP assignement failed to CPE
Conditions: Using 2 CPEs on on CM with the second using the UNICAST DHCP DISCOVER (broadcast bit == 0)
Workaround: Delete the modem using the clear cable modem mac addres delete command. Then use a CPE settting Broadcast bit.
Symptom:520U card crashes due to memory corruption running 12.3(23)BC1.
Conditions: This only occurs when the CLC is subjected to a constant 80 to 100 % CPU load over a long period of time, a storm created by repeated and non rate limited cli invocations targeting the line card. Show tech and show controller are couple of examples of the cli calls that are invoked every 2 seconds as part of the scripts to reproduce the bug .
Workaround: Show tech and show controller cli calls result in reading of a long list of internal register values from the IPC mac controller while disabling the interrupts for a long time, which is not desirable when the system is under severe stress.
As a workaround, the mac device registers are not read when the show tech or show controller cli calls are invoked under normal circumstances. If the mac controller internal register values are need to be read, a debug flag is provided to accomplish that.
The debug cr10k-clc amd command can be called explicitly to turn on reading of the register contents of the mac controller.
Symptom: In the walk output of the table 'cpmProcessTable', process
corresponding to process id 256 is not listed.
Conditions: Steps to reproduce:
1. Configure snmp-server on the DUT.
2. On the DUT exec 'show processes cpu sorted | inc 256'. It returns the
details of the process for id 256.
3. For example, walk on the OID: '1.3.6.1.4.1.9.9.109.1.2.1.1'. This returns
the process names for all the running process. In this output the id 256 is
4. Get on the particualr instance returns 'No Such Instance' error message.
Workaround: There are no workarounds.
Symptom: Certain sprintf() calls in tcp/telnet.c are incorrect.
Conditions: They have the potential to overflow the destination buffers.
Workaround: snprintf() should be used with a bounding length of the size of the destination buffer.
Symptom: Secondary PRE2 crashes.
no exception-slave core-file ubr3
no exception-slave dump 172.18.98.28
no exception dump 172.18.98.28
After removing the last command of "no exception dump 172.18.98.28" and then wr
Workaround: Don't remove exception in 12.3(23)BC1.
Symptom: Upstream Load Balancing Breaks with DOCSIS 3.0 modems in w-online(pt) state.
Conditions: UBR10k running 12.3BC with D3.0 modems online.
Workaround: There is no known workaround for performing upstream channel change with modems in w-online(pt) state.
Symptom: This is a internal coding issue, and have the possibility to cause memeory overflow.
Conditions: Found by source code analysis.
Workaround: There is no workaround.
Symptom: Incorrect display of active calls when nRTPS/RTPS is configured. The RTPS/nRTPS is interpreted as a "call" in the output of the "show cable calls" and "show cable modem calls" commands.
Condition: The problem only occurred when nRTPS or RTPS is configured.
Workaround: Use the show packetcable gate summary command to check how many calls on going.
Symptom: Configure bundle sub-interface, and traceback occurs occasionally.
Conditions: If we create a bundle firstly and then delete it. After these, we use command "cable bundle " configure it to one interface, this bundle will be created again, and then if we configure a sub-interface of it, the traceback occurs. It's seen in 12.2S and 12.2SCA, but not seen in 23BC.
Workaround: There is no workaroud.
Symptom:Flowbits keep asserting after SPA OIRed, and traceback observed when "show pxf cpu queue xxx". The traceback can only observed in 12.3(23)BC.
Conditions:SPA OIR will trigger the flowbits problem. And queue deletion is condition for the traceback.
Workaround: There is no workaround.
Symptoms: When editing the service class name in an enforce-rule, tracebacks/crashes were observed on the linecard.
Workaround: When the registered service class name is to be changed, remove the enforce rule and configure it with the updated service class name.
Symptom:Static upstream LB may be unbalanced in some scenrios. It doesn't happen with dynamic or static downstream LB.
Conditions:Static LB was configured on an interface with more than one upstream.
Workaround: Enable dynamic LB. If interface has more than two upstream. There should be a little chance to get unbalance result.
Symptom: Standby PRE crash at the time more than 512 calls are on going.
Conditions: Only occured at the time 2 gates with the same offset are in the free gate list.
Workaround: Remove the Standy PRE.
Symptoms: CNR is not shown for freq stacked upstreams. For example, if the following configuration is used on a 1x4 mac domain:
Conditons: cable upstream 0 connector 0 shared, cable upstream 1 connector 0 shared
Only US0 will show a CNR value in the show controller cx/y/z upstream command. US1 will show only a MER value. This can break CNR based freq hopping as show cable hop thresholds does not display a CNR for the affected upstream either.
Workaround: Do not use freq stacking.
Conditions: If "debug cr10k_rp" is on, the traceback may be observed when an arp entry on a bundle interface is to be deleted, or at the first time being created.
Workaround: There is no workaround.
Symptom: AAA accounting records for commands executed from remote host using rsh are sent with empty username. The username sent in exec accounting record and command accounting record is empty.
Conditions: Occurs for the commands execute from remote host using rsh.
Workaround: One can consider stopping generation of accounting records with "null" username by using the aaa accounting suppress null-username command.
Symptom: When cable metering is enabled, the following scheduler thrashing error message has been seen in PRE log related to all cable linecards:
SLOT 5/0: Oct 14 23:31:32 EDT: %SCHED-3-THRASHING: Process thrashing on watched message event.
-Process= "CMTS METERING Collection Process", ipl= 4, pid= 105
-Traceback= 6013579C 60135880 60585190 60584C58 601134B4 60113498
Conditions: Above problem has been observed only when "cable metering" is configured on uBR10K with PRE2 running 12.3(23)BC2 image.
Workaround: There is no workaround.
Symptom: In a high availability configuration with multiple PREs the standby PRE may reload when a new linecard is inserted.
Conditions: This issue may occur when inserting a new linecard in the chassis.
Workaround: There is no workaround available.
Symptom: Spectrum Management sometimes fails to assign upstream frequencies to cable interfaces after an OIR operation. For example replacing an MC520U with an MC520H with OIR-compatibility enabled might trigger the problem.
– oir-compatibility configured for the slot
– MC5x20U pulled out, MC5x20H inserted
When the problem occurs the upstream channels will display "Frequency not set" in the US sections of the show controller command. The show running interface command will show that the affected US channels are included in a spectrum management group.
The failure might also occur after an MC520U or MC520S is installed into a previously empty, unconfigured slot.
Conditions: The problem might occur if an upstream channel is configured for Spectrum Management and included in a Fiber Node.
Workaround: Remove the failing US channels from the fiber node then re-insert them. If that doesn't correct the problem reload the CMTS.
Symptoms: All modems on a given upstream may go offline when the problem occurs.
Workaround: shut and follow by no shut of the cable upstream interface by using the following commands:
The open caveats are grouped based on their component types. The open caveats documented from prior releases that are unresolved might also apply to this release.
Symptoms: If the show cable modem command is used after a PRE switchover, cable modems are duplicated with the same MAC address.
Conditions: This issue occurs on a Cisco uBR10000 series router running Cisco IOS Release 12.3(00)BC3.
Workaround: There is no workaround.
Symptoms: The show interface cable modem command output is misaligned with the column headings and a heading is missing for the dual IP flag.
Conditions: The show interface cable modem output shows a 'Y' or 'N' but the field does not have a heading for this Dual IP field.
Workaround: The output needs to be aligned with the heading fields. See the show interface cable modem command documentation in the Cisco IOS CMTS Cable Command Reference.
Symptoms: In rare occasions, a service flow with minimal reserved rate requirement may get admitted but no traffic can be sent over it.
Conditions: This occurs when a service flow tries to reserve more than 99% of the bandwidth. Only 99% of the bandwidth that is shown as reservable in show interface cable downstream command can actually be reserved.
Workaround: There is no workaround.
Symptoms: The PRE2 revision number is not displayed in the show version command output.
Symptoms: Unable to set the MIB objects "ccwbRFChanQamIPAddress", "ccwbRFChanQamMacAddress" and "ccwbRFChanQamUdpPort" separately.
Conditions: This occurs on a Cisco uBR10012 router running ubr10k2-k9p6u2-mz.122-122_33_SCA when the MIB objects are individually set using the SNMP set command.
Workaround: Set the MIB objects "ccwbRFChanQamIPAddress", "ccwbRFChanQamMacAddress" and "ccwbRFChanQamUdpPort" using one SNMP set command.
Symptoms: The network interface on a Cisco uBR10012 router fails to acquire a global IPv6 address when using IPv6 autoconfiguration on an interface.
Conditions: The Cisco uBR10012 does not support stateless address autoconfiguration (SLAAC) for cable modems or CPEs. However, SLAAC should be supported for the CMTS router network interfaces.
Workaround: Configure a static IPv6 address on the network interface.
Symptoms: The range-backoff configuration value changes from "range-backoff 3 6" to "range-backoff automatic" for upstream in a frequency stacking scenario.
Conditions: This change is noticed after the following commands are executed to un-configure and re-configure the cable interface.
2. no cable upstream max-ports
Workaround: Modify the range_backoff value in the cmts_mac_hwsb_us_init file according to the linecard type.
Symptoms: If the associated HA ip host commands are removed followed by PRE switchovers from PREA to PREB and then from PREB to PREA. After re-configuring the Global HA commands, all modems disappear, re-range and then come back online.
Workaround: There is no workaround.
Symptoms: Traceback occurs when the Hot Standby Connection-to-Connection Protocol (HCCP) member is removed through the console and when the show hccp channel-switch command is run from the VTY session almost simultaneously.
Workaround: There is no workaround.
Symptoms: A Cisco uBR10012 router with N+1 line card redundancy might log debug-level tracebacks when the standby line card becomes ready for switchover.
Conditions: This occurs when there is too much information for a specific cable modem that prevents it from synchronizing with the standby linecard.
Workaround: There is no workaround.
Symptoms: When the N+1 line card switchover happens to protect and revert to working, the standby performance routing engine (PRE) switchover may reset with some configurations.
Conditions: This occurs when removing some DOCSIS Set-top Gateway (DSG) configuration after the revert back, particularly when running the no cable dsg tg command. In the error case, the standby PRE resets and the configuration is re-synchronized with the active PRE.
Workaround: There is no workaround. The standby PRE does not impact the current service.
Symptoms: When configuring certain rfswitch snmp-community string as a redundancy suboption, the CMTS does not automatically create the corresponding snmp-server community <password> view hccp_chansw_snmp_view RW entry resulting in the line card switchover failure.
Workaround: There is no workaround.
Symptoms: The Cisco uBR10012 router allows an SNMP community string length of 128 characters but is truncated by the internal SNMP agent to 64 characters.
Conditions: This occurs any time an SNMP community string is entered in the CMTS.
Workaround: Use only 64 characters or less SNMP community string length.
Symptoms: The cable modem termination system (CMTS) does not show an error message when the RF switch name is longer than the defined value.
Conditions: This occurs when the length of the RF switch name is longer than the defined value. The maximum length of an RF switch name is 30 characters. The RF switch name is truncated to 30 characters when it exceeds the defined value.
Workaround: The CMTS should display an error message and not add the RF switch name entry to the running configuration.
Symptoms: Traceback observed on both route processors (RP) after N+1 switchover using cable power off x/y command.
Conditions: This occurs when the standby route processor progresses to standby cold-config.
Workaround: There is no workaround.
Symptoms: The show cable clock command wrongly displays the number of TCC cards in the chassis.
Conditions: This occurs when new DTCC cards are inserted into slot 1/1 and 2/1 followed by a PRE2 switchover.
Workaround: Perform another PRE2 switchover.
Symptoms: PER2 generates the following message when CLC is locked out.
Conditions: This occurs when one or more cable line cards (CLC) are locked out.
Workaround: Run the show hccp detail | i lockout command before PRE2 switchover.
Symptoms: IPC timeout does not trigger line card switchover.
Conditions: The sync-pulse failure was designed to trigger line card switchover but based on the HCCP design, IPC timeout should trigger line card switchover.
Workaround: There is no workaround.
Symptoms: Inconsistent running-configuration between active and standby after route processor switchover.
Conditions: This occurs with global N+1 configured and after a route processor switchover.
Symptoms: Wideband modems associated with the first shared port adapter (SPA) do not display wideband counters as expected for the downstream service flows.
Conditions: This occurs on a Cisco uBR10012 router running Cisco IOS Release 12.2SBU05. The wideband modems associated with the first SPA in 1/0/0 bay have their downstream service flow counters incremented as expected. But the wideband modems in 1/0/1 bay do not show incrementing counters for their downstream service flows.
Workaround: There is no workaround.
Symptoms: Under rare conditions, a Hot Standby Connection-to-Connection Protocol (HCCP) switchover and revertback can cause all JIBs to shut down, the UP convertor to be disabled, and all modems to drop. This issue is not necessarily a cable modem termination system (CMTS) problem; sometimes it can be triggered by HCCP issues as well.
1. Enter the show controller x/y/z command. Note that the output will display: “i Disable”.
2. Enter the show hccp detail command. Note that the Member Loading output count is not 0.
Workaround: Recover the modems from offline status by performing the following steps:
2. Remove the problematic working member.
3. Normalize the new standalone card and get the modems back online. (Note that after the modems are back online, the hccp count value will still be greater than 0 5.)
4. Decide whether you want to add the working and protect members back.
5. Schedule a maintenance window to recover the hccp Member Loading non 0 count 1.
Recover the hccp Member Loading non 0 count 1 by performing the following steps:
1. Reset the secondary PRE to re-synchronize the database.
2. Check that the secondary PRE is working.
3. Perform a switchover to the PRE.
4. Enter the show hccp detail command. The Member Loading output count should be 0 5.
5. Perform the CLC switchover now to make sure HCCP works as designed. (This step assumes that you have the line card already put back into the global HCCP configuration.)
The resolved caveats are grouped based on their component types.
Symptoms: CMTS generates duplicate IPDR records for same service identifier (SID). This creates accounting issues for usage-based billing of cable modems.
Conditions: This occurs on Cisco uBR10012 platform running Cisco IOS Release 12.3(17b)BC4 when Subscriber Account Management Interface Specification (SAMIS) feature is used.
Workaround: There is no workaround.
Symptoms: CMTS sysUpTime parameter remains unchanged in IPDR document for all records thus making it unreliable for stop records. Similarly, IPDRcreationTime parameters are the same for interim records and are set to the data collection start time for the IPDR document. These may cause certain accounting issues.
Conditions: This issue occurs when Subscriber Account Management Interface Specification (SAMIS) feature is used.
Workaround: Poll the DOCS-QOS-MIB object directly.
Symptoms: A high CPU value is observed when many host IP addresses of modems are registered with static IP addresses.
Conditions: This is observed when some subinterfaces have cable source-verify command configured and the other subinterfaces in the same bundle have cable source-verify dhcp command configured.
Workaround: Configure the cable source-verify dhcp command on both the subinterfaces. For static IP addresses, reserve these addresses in the DHCP server.
Symptoms: Leasequery-filter is not filtering the downstream packets for unknown SID.
Conditions: This occurs when no cable arp and cable source-verify dhcp commands are configured under interface configuration mode, and the traffic is pumped from pagent with unknown destination IP address.
Workaround: There is no workaround.
Symptoms: CMTS_UNFRAG_CONCAT_BURST_SIZE does not reflect the platform line card cap.
Conditions: This occurs when operators are increasing the upstream throughput rate and the CMTS cable-default-phy burst is set to 0. When the maximum concat burst TLV is omitted, a maximum concat burst size of 3044 is assumed by the cable modem. In this case, cmts admission control is incorrectly using a fixed defined constant of 2000 as maximum burst size, and the flow is rejected.
Workaround: For MC28U/MC28UC/MC16U/MC16UXMC520T cards, the maximum burst size should be 4000 and not 2000.
Symptoms: Tracebacks occur every time when INVALIDSIDPOSITION error is displayed in a CMTS that has a large number of cable modems with a few going offline.
Workaround: There is no workaround.
Symptoms: When the show cable leasequery-filter command is executed, the downstream packets for unknown service IDs (SID) are not filtered.
Conditions: This is observed when network traffic is generated with unknown destination IP address.
Workaround: There is no workaround.
Symptoms: Upsteam traffic is not controlled according to the the penalty enforce class in VXR.
Conditions: This occurs when a cable modem is penalized and associated with the penalty service class. The upstream traffic is allowed to exceed the penalty class.
Symptoms: On a Cisco uBR10-MC5X20H line card, increasing upstream channel width causes modems to increase transmit power, while decreasing the channel width causes modems to decrease power transmit level.
Conditions: This occurs while the CMTS is reporting the same power received for the modems.
Workaround: Change the upstream receive power or change attenuation in combining.
Symptoms: When ATDMA is run for DOCSIS 2.0, the 1.x cable modems will be moved to a port which can not be registered by these modems.
Workaround: Run tdma-atdma for all modems in the 3.2 MHz channel width.
Symptoms: The cable load balancing (LB) group has a cluster of TDMA and ATDMA mode channels. During static load balancing, the 1.x cable modem might be moved to the ATDMA channel based on the load. This problem results in the 1.x cable modem taking a long time to come online.
Symptoms: The uBR10000 series router is not filtering some cable downstream packets. The issue is observed for IPv4 packets. The packets are sent from CMTS to CM/CPE and the downstream cable filters configured in the PRE2 of the router fails to filter it. However, it does not affect the functionality of the router and the packets from external sources are filtered as expected.
Symptoms: All the cable modems go offline with no alert or log message. When clear cable modem all del command is executed, no cable modem is ranging. The upconverter signal is ok and the ucd counter is also normal.
Conditions: As there is no log and other specific information, it is hard to get the root cause. This occurs only in a Cisco uBR10-MC5X20H line card.
Workaround: Use cable downstream rf-shutdown and no cable downstream rf-shutdown commands.
Symptoms: During installation of a new chassis with the DTCC card, when modems are moved from the old chassis to the new one, some of the modems do not come online and are stuck in the init(rc) state.
Conditions: This occurs frequently with the Cisco uBR10-MC5X20U line card and less frequently with the Cisco uBR10-MC5X20H line card when a new chassis with DTCC card is installed. No equalization coeff packet is sent from the CMTS till the modem is online. But in Cisco IOS Release 12.3(21)BC, equalization coeff packet is seen just after the modem is connected.
Workaround: Change the upstream modulation to Quadrature Phase-Shift Keying (QPSK) modulation.
Symptoms: Router crashes on running the test cable load-balance x.x.x ucc command.
Symptoms: Jitter and latency occurs in specific UGS upstream service flows that use LLQ scheduling mode instead of the DOCSIS compliant scheduling mode.
Conditions: This is observed when the upstream LLQ scheduling mode is enabled.
Symptoms: A Cisco uBR10k running Cisco IOS Release 12.3(17b)BC3 may report Cable Modems stuck in init(rc) state on certain Upstream Interfaces. Very high number of Input queue drops are also observed under the corresponding Downstream interfaces.
Conditions: This problem has only been observed on a Cisco uBR10K router with Cisco uBR10-MC5X20H-D card.
Workaround: Disable the PHS feature for voice calls (if enabled). To bring the affected cable modems back online run the hw-module subslot x/y reset exec command for each of the affected line cards.
Symptoms: A Parallel Express Forwarding (PXF) processor crash causes the PRE2 to crash as well. The PRE2 crash follows due to the memory allocation error:
Conditions: This occurrence is found in Cisco IOS Release 12.3(17b)BC9 with the PXF enabled on the ESR-PRE2.
Workaround: Disable the PXF processor.
Symptoms: The IPC between the cable line card and the SPA cannot be created when the SPA and the cable line card start open port at the same time.
Workaround: Reset the cable linecard.
Symptoms: The previously disabled JIB upstream port becomes enabled after the Cisco 520 linecard is reset.
Workaround: Run the shut/no shut cable interface command to correct the anomaly.
Symptoms: Issuing the shut and no shut command stream causes Parallel Express Forwarding (PXF) crash resulting in the "TBB Length” error.
Conditions: This is rare and occurs when there is continuous traffic to the cable modems on the interface to be shut down.
Symptoms: CMTS crashes after linecard switchover and Parallel Express Forwarding (PXF) reload.
Conditions: This occurs with ToS based p2p MQC feature enabled, and while p2p traffic passes through the CMTS after the linecard switchover, and the PXF reload using microcode reload pxf command.
Workaround: There is no workaround.
Symptoms: The HCCP sync-pulse logic can lead to unexpected resets and/or switchovers of working linecards due to defective Protect line cards.
Workaround: There is no workaround.
Symptoms: On a Cisco uBR10012 router, the active PRE2 crashes and failover to standby PRE occurs when the Protect line card is in active state.
Conditions: This is observed on a Cisco uBR10012 router running Cisco IOS Release 12.3(17b)BC4 and configured for global N+1 linecard redundancy (HCCP). The PRE crash happens when the protect linecard is in active state and the standby working linecard crashes due to a memory allocation failure. HCCP goes into an abnormal state causing the active PRE to crash.
Workaround: There is no workaround.
Symptoms: The Cisco uBR10012 router with PRE2 crashes at cmts_hccp_load_config.
Conditions: This is observed on the router running Cisco IOS Release 12.3(23)BC1.
Workaround: There is no workaround.
Symptoms: Queues created on the standby PRE.
Conditions: This occurs when primary downstream service flows with non zero DOCSIS priority synchronized to the standby PRE with priority set to zero. This results in queues on the standby PRE prior to switchover with incorrect parameters.
Workaround: There is no workaround.
Symptoms: A Cisco uBR10012 router with the Cisco UBR10-MC5X20 linecard may crash due to excessive memory allocation failures with low memory errors.
Conditions: This is observed on the router running Cisco IOS Release 12.3(21a)BC4 with ESR-PRE2 module.
Conditions: This occurs after a PRE switchover and running the no shut protect interface command.
Workaround: There is no workaround.
Symptoms: The standby PRE crashes at hccp_build_default_cmd_list.
Conditions: This occurs after a PRE switchover and running the no shut protect interface command.
Symptoms: On a wideband Shared Port Adapter (SPA), when one SFP module is disconnected the other module does not connect as expected.
Conditions: This occurs with Cisco uBR10012, Wideband SPA running Cisco IOS Release 12.3(21a)BC4.
Workaround: There is no workaround.
Symptoms: The ccwbWBCmStatusValue seems to be unresponsive on a Cisco uBR10012 router with PRE2-RP engine.
Conditions: This occurs on a Cisco uBR10000 (PRE2-RP) running ubr10k2-k8p6u2-mz.123-21a.BC4.bin image.
Symptoms: The Cisco router might crash while pasting (cut and paste) a set of IPv6 configuration commands for a router network interface to the router console.
Symptoms: The Cisco router might experience spurious memory access error when running the show buffer assigned dump command.
Workaround: There is no workaround. This is a cosmetic error and should not cause problems for the router's operation.
Symptoms: Parallel Express Forwarding (PXF) bus limits maximum MTU on the Cisco uBR10012 routers to 9216 bytes and causes data packets to drop.
Conditions: This issue is observed on the router running Cisco IOS Release 12.3(17)BC onwards.
Symptoms: Traceback is displayed when show vpdn sca command is used before the vpdn module is enabled.
Workaround: Use the vpdn enable command before configuring other vpdn commands.
The open caveats are grouped based on their component types.
Symptoms: The downstream packets for unknown service IDs (SID) are not filtered when running the show cable leasequery-filter command.
Conditions: This is observed when network traffic is generated with unknown destination IP address.
Symptoms: The access-group keyword option is not provided when running the show cable modem command.
Conditions: This issue is observed in Cisco IOS Release 12.2(33)SCA .
Symptoms: The show cable modem verbose command does not display the accurate total DS throughput value and the statistics display is delayed.
Conditions: This issue is observed when the command is run during unicast or multicast traffic across the cable modems.
Workaround: The statistics will be displayed correctly after the commands subsequent to show cable modem verbose command are executed.
Symptoms: In a Multiprotocol Label Switching (MPLS)-Virtual Private Network (VPN) environment, the Toaster punts packets to Route Processor (RP) for source verification and thereby impacting the performance.
Conditions: This behaviour is observed when the cable modem and the Customer Premises Equipment (CPE) are in different VPN routing/ forwarding (VRF) tables and the source-verification is enabled.
Symptoms: A Cisco uBR10012 router with N+1 linecard redundancy may result in debug level tracebacks.
Conditions: This occurance is found when information associated with a specific cable modem becomes too large and is prevented from being synchronized with the standby linecard.
Workaround: There is no workaround.
Symptoms: When the N+1 linecard switchover happens to protect and revert to working, the standby Performance Routing Engine (PRE) switchover may reset with some configurations.
Workaround: There is no workaround for this issue since the standby PRE reset does not impact the service.
Symptoms: Wideband modems that are associated with the first shared port adapter (SPA) do not display wideband counters as expected for down stream service flows.
Symptoms: The Cisco uBR10012 router CPU usage reaches abnormally high value of 90% for less than a minute when a large number of Border Gateway Protocol (BGP) routes flap.
Symptoms: A multicast route is removed unexpectedly when the RP PIM interface is shut down during the IGMP static configuration.
Conditions: This issue is observed when the igmp static group is configured as the default route interface.
There are no resolved caveats in Cisco IOS Release 12.2(33)SCA.