Field Notice: FN - 62439 - 2800/3800 FXO - Used for E911 CAMA May Experience Intermittent Voice Port Lockups

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Updated:September 11, 2006

Document ID:FN62439

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September 11, 2006

NOTICE:

THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.

Products Affected

Product
EM-HDA-4FX0
PVDM2-16
PVDM2-32
PVDM2-48
PVDM2-64
PVDM2-8
VIC2-2FXO
VIC2-4FXO
EM-HDA-3FXS/4FXO
EM-HDA-6FXO
EM-HDA-8FXS

Problem Description

Cisco has identified an issue where in some VoIP gateways the analog CAMA voice ports used for emergency E911 service stop functioning. This is seen only on analog CAMA voice ports that utilize the PVDM2 module on the 2800/3800 VoIP gateways. The symptom is that the analog CAMA voice ports that utilize a DSP on the PVDM2 module in this failed state stop processing calls. A software change is available to automatically recover the DSP and begin normally processing calls again.

Background

The FXO modules used for CAMA E911 installations on 2800/3800 series VoIP gateways rely upon the PVDM2 DSP module for signaling and voice channels. An issue with the signaling channels on the PVDM2 module has been identified where some modules may cause the signaling channel for the analog CAMA voice port to stop functioning.

The majority of PVDM2 modules do not exhibit the problem. PVDM2 modules that exhibit this problem have been seen to do so from initial installation and there does not appear to be any further degradation with regards to the length of use. The frequency of this lockup issue is inconsistent when a failing module has been detected. It has been found that the majority of problems found on impacted modules tend to affect the first DSP on a PVDM2 module.

Problem Symptoms

It has been found that when this problem occurs on a DSP, the typical symptom is that all active and subsequent analog CAMA calls through the voice ports that utilize that DSP for analog CAMA signaling will fail at the same time. The DSP in default flex mode can service up to 16 voice ports at a time. Single failures on voice ports seen on a gateway would not be symptomatic of this problem. To see which voice ports are mapped to which DSP, issue the enable command show voice dsp signaling .

An FXO CAMA port that is in this state can be identified through the use of a test command. The commandtest voice port X/Y/Z si-reg-read 38 2 (where X/Y/Z is the port number of the analog CAMA port) reads registers 38 and 39 from the FXO voice port on a 2800/3800 series VoIP gateway. The output displayed from this command is sent at debug level to the system and the user must first issue the terminal monitor command to see the output.

Note: The output of si-reg-read 38 2 depends on the impedance setting ((voice-port)# impedance ... ) as follows:

For 600r, 600c, complex3, complex4, complex6: reg38=0x00 and reg39=0x01.

For 900r, 900c, complex1, complex2, complex5: reg38=0x01 and reg39=0x00

The normal output from this command will display the a single octet value for registers 38 and 39 only as shown here:

router#test voice port 0/3/3 si-reg-read 38 2
router#

Values read from SiLabs Codec connected to DSP 0, channel 11:
--------------------------------------------------------------
Register 38 = 0x00
Register 39 = 0x01

The exact output when a port is in this state will vary, but typically it will display more than registers 38 and 39 and also with register values greater than a single octet, as shown here:

router#test voice port 0/3/3 si-reg-read 38 2
router#

Values read from SiLabs Codec connected to DSP 0, channel 11:
--------------------------------------------------------------
Register 38 = 0x5CB8
Register 39 = 0xFFFF
Register 40 = 0xFFFF
Register 41 = 0xFFFF

Workaround/Solution

The changes in CSCse15025 will prevent the problem from occurring in many of the cases. For those cases where the problem still may occur, the software will automatically detect the problem and reset the associated DSP to recover. Note that if the DSP is reset all active calls that are using that DSP will be dropped. It is recommended that customers who are using the 2800/3800 series VoIP gateways with the FXO port for CAMA E911 connectivity upgrade to a release of software with the changes in CSCse15025. Once upgraded, if the below output is seen in the gateway logs, please contact the TAC for assistance.

---
*May 26 18:24:25.709: TDM pointers (Cnt=1): 0000 0000 0015 0015. Deltas: 0001 0000.

*May 26 18:24:25.709: Received alarm indication from dsp(0/3)0030 0000 0080 0000 0013 4100 2E2E 2F2E 2E2F 6D6F 6475 6C65 732F 7363 6865 6475 6C65 2F64 6562 7567 2E63 2833 3634 2900

*May 26 18:24:25.709: ../../modules/schedule/debug.c(364)
---

This reflects the current output that occurs when the new code is triggered.

These logged messages are displayed at a debug level of logging on the system. Because of this, it is recommended that appropriate syslog be enabled on the gateway or enable logging buffered set to debug level to capture the output. The buffered logging is a FIFO log file with limited memory. The default value is only 4096 bytes that may cause the messages to overflow the log. The buffered logging size can be increased to higher values based upon the available free processor memory on the gateway as seen with the command show memory processor statistics . For example, the global command logging buffered 50000 debug would enable the buffered log for a size of 50000 bytes. The output of the buffered log can be seen with the show log command.

DDTS

To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.

DDTS	Description
CSCse15025 (registered customers only)	Intermittent analog/cas voice port lockup or robotic voice. NOTE: This fix also includes the change for CSCsd90851 (which is a firmware only change), plus provides the automatic recovery capability.

Other Considerations

Note: This issue does not exist when using the NM-HD-1V, NM-HD-2V, NM-HDV, NM-1V, NM-2V or any variants of these products.

The mainline images in addition to 12.3(11)T11 that also contain the fix within 12.4 mainline are:

12.4(3e)

12.4(7b)

12.4(8a)

How To Identify Hardware Levels

The output of the show diag command will display information on the FXO CAMA interface and PVDM2 modules installed. The PVDM2 module with a Fab Version 03 with a Deviation Number of 0 may be susceptible to this problem.

In order to determine if you have a PDVM2 module issue the sh diag command:

PVDM Slot X:
    64-channel (G.711) Voice/Fax PVDMII DSP SIMM PVDM daughter card
    Hardware Revision        : X.X
    Part Number              : 73-XXXX-XX
    Board Revision           : A0
    Deviation Number         : 0
    Fab Version              : 03
    PCB Serial Number        : FOCXXXXXXXX
    RMA Test History         : 00
    RMA Number               : 0-0-0-0
    RMA History              : 00
    Processor type           : 00
    Product (FRU) Number     : PVDM2-XX
    Version Identifier       : NA

In order to determine if the gateway is using hardware that contains the change referenced in this Field Notice, issue the sh diag command and check the Deviation Number or Fab Version fields.

Here is a sample output of a show diag . A board containing the fix will either have a Deviation Number of 83077 or a Fab Version above 03.

PVDM Slot X:
    64-channel (G.711) Voice/Fax PVDMII DSP SIMM PVDM daughter card
    Hardware Revision        : X.X
    Part Number              : 73-XXXX-XX
    Board Revision           : XX
    Deviation Number         : 0
    Fab Version              : 04

OR


    PVDM Slot X:
    64-channel (G.711) Voice/Fax PVDMII DSP SIMM PVDM daughter card
    Hardware Revision        : X.X
    Part Number              : 73-XXXX-XX
    Board Revision           : XX
    Deviation Number         : 83077 
    Fab Version              : 03

Revision History

Revision	Date	Comment
1.0	11-SEP-2006	Initial Public Release

For More Information

If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:

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