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This document describes solutions to some common digital signal processor (DSP) related isses and ways to determine if the issue is hardware related or not.
DSP is not in UP State
Collect the output of the show voice dsp group all command.
Reset the DSPs if necessary and enter the test dsp device <slot> <dsp-id> reset command.
If the DSPs do not return to an UP state, reboot the router.
If one of the DSPs fails and cannot be recovered when you use any of these methods, enter the test dsp device <slot#> <DSP_ID> remove | reset | restore command in order to minimize the impact of DSPs that go into a DOWN state.
Return material authorize (RMA) any DSP that does not return to an UP state.
Troubleshoot Packet Voice Digital Signal (PVDM -2)
On the router, copy the startup configuration onto a TFTP server with the command copy startup-config-tftp.
Open the startup configuration file with a text editor.
Add these debugs at the start of the file:
do debug dsp-resource-manager flex download do debug dsp-resource-manager flex error do debug dsp-resource-manager flex detail do debug vpm dsp
Save the startup configuration file.
Copy the startup configuration file to the router's startup-config. For example, run copy tftp://<ip>/startup-config startup-confi in the route console. Debug is enabled in the startup configuration.
Reload the router and collect the logs.
Each time a query is sent, a timer is started and you must wait for its response. When a response is not received, the DSP_TIMEOUT message appears. There are several reasons why DSP timeouts occur:
Messages are sent to DSP in incorrect mode
Messages are sent in incorrect sequence
Messages are sent with incorrect parameters
Platform issues or internal DSP problems
There are several decoding events:
A: PLAYOUT_DELAY : Playout Delay Stats
B: PLAYOUT_ERROR : Playout Error Stats
C: RX_STAT : Receive Packet Stats
D: TX_STAT : Transmit Packet Stats
E: LEVEL_STATS : At Call Cleanup
F: ERROR_STATS : At Call Cleanup
G: FAX_RELAY : In Fax Relay Mode
H: MODEM_RELAY : In Modem Relay Mode
I: CLOCK_COMP : In PassThru Mode
See this example:
%DSMP-3-DSP_TIMEOUT: DSP timeout on DSP 0/1:1: event 0xDC, DSMP timed out, while waiting for statistics from the DSP. DSMP State = S_DSMP_COLLECTING_STATS
Timeouts that occur on a single DSP channel might indicate a hardware failure. Follow these steps:
Collect the output of show log as soon as the timeout event occurs.
See this example of a DSP alarm:
Mar 25 05:44:09.872: %DSPRM-2-DSPALARM: Received alarm indication from dsp (0/3). Resetting the DSP. Mar 25 05:44:09.872: %DSPRM-3-DSPALARMINFO: 001A 0000 0080 0000 0001 0050 6170 6963 6861 6E28 3132 3630 2900 0000 0000 0000 0000
Enter the command show voice dsp detailed and check if there was a crash in the restory (RST) number of resets per DSP and alarm indication (Al) fields. See this example:
Enter the command show voice dsp error and show specific errors. See this example:
DSP: 0/1:1 Timeout: 10317799.760 10316844.140 10316735.720 10316688.136 Number of errors overwritten: 213
Alarm: None recorded Message drop: None recorded DSP: 0/1:2 Timeout: 10316625.468 10316034.948 10315828.816 10315650.844 Number of errors overwritten: 63
Alarm: None recorded Message drop: None recorded DSP: 0/1:3 Timeout: 10316656.860 10301703.084 10301341.276 10300263.408Number of errors overwritten: 5
Configure the mini-logger and the crash-dump. See the Configure Crash Dump and Enable Mini-Logger section for instructions on how to configure the mini-logger and the crash-dump and collect the complete output of the show log command.
No More Ring Descriptors Error
This error is seen in two scenarios:
The DSP buffer is full
See this example:
Jun 19 16:25:04 UTC: %C5510-4-NO_RING_DESCRIPTORS: No more ring descriptors available on slot 0 dsp 2. Jun 19 16:25:09 UTC: %C5510-4-NO_RING_DESCRIPTORS: No more ring descriptors available on slot 0 dsp 2.
If the DSP crashes, use the approach in the DSP Alarms section.
If the DSP is full, enable the mini-logger and collect the output of the show log command as soon as the event occurs.
TDM Connect Issue
See this example for a TDM connect issue:
FLEXDSPRM-3-TDM_CONNECT failed to connect voice-port (0/0/0) to dsp_channel(0/0/0)
Cisco bug ID CSCuj64211 is a very common issue in this scenario. Reboot the router as a temporary solution to the problem until you can upgrade to one of the fixed releases of the product.
See these useful show commands:
show voice call status show voice call summary show call active voice brief show voice dsp group all show voice dsp show tdm connection slot <> Show tdm connection slot <> Show tdm map slot <> Show tdm connection slot <> wic <> Show tdm map slot <> wic <>
See these debugs that you must collect for a test call:
debug voip ccapi inout debug tdm debug vpm all debug voip vtsp all debug voip dsm all debug dsp-resource-manager flex all
For this issue, you can use Cisco IOS? Embedded Event Manager (EEM) script. See this example:
The DSP Mini-Logger and CrashDump utilities are useful tools that gather evidence that help troubleshoot DSP crashes. The Mini-Logger captures forensic evidence up to the point of the DSP crash, while CrashDump captures evidence during the crash and right after the crash occurs. Enter these commands in order to enable these features: