Introduction:
This document describes solutions to some common digital signal processor (DSP) related issues and ways to determine if the issue is hardware related or not.
DSP is a part of the PVDM card. So, let's start by defining a PVDM.
A Packet Voice Digital Signal Processor Module (PVDM) is a hardware module that provides digital-signal-processor (DSP) resources to the system. A PVDM module can be populated with one or more DSPs. The DSP resources on a PVDM provide collaboration services including voice sessions, transcoding sessions, conference sessions, and video.
Types of PVDM
|
Type of PVDM |
Supported Cisco Routers |
|
28xx,38xx |
PVDM2 |
|
29xx,39xx |
PVDM2 and PVDM3 |
|
ISR 4Ks |
PVDM4 and SM-X |
|
C8300 |
PVDM4 , NIM-PVDM and SM-X |
NOTE: PVDMs can be installed on the motherboard for ISR G1 and ISR G2.
For ISR 4K, PVDM can be installed on the motherboard and NIM slots.
For C8300, PVDM can be installed on NIM slots.
Troubleshoot:
- “Show voice dsp group all” is the first command that everyone uses to check the state of a DSP.
- UP is a good state.
- FAIL and APP_DOWNLOADING are the bad states which one should be concerned about.
DSP is not in UP State
- Collect the output of the show voice dsp group all command.
|
- A soft reset can be performed if DSPs are in a bad state. Enter the test dsp device <slot> <dsp-id> reset command for ISR G1(28xx, 38xx) and G2(29xx, 39xx). For ISR 4Ks, use hw-module subslot x/y reload.
- Check the PVDM slot from the inventory by applying the command “Show inventory”
If the show inventory output shows this information, it signifies that the PVDM card is installed on the motherboard.
NAME: "PVDM subslot 0/4", DESCR: "PVDM4-32 Voice DSP Module"
PID: PVDM4-32 , VID: V02, SN: FOC13YYXXAVD
Once the PVDM card is placed on the NIM, the show inventory command indicates:
NAME: "subslot 0/1 db module 0", DESCR: "PVDM4-128 Voice DSP Module"
PID: PVDM4-128 , VID: V01, SN: FOC1YYXXBLL
- If the DSPs do not return to a UP state, RESEAT of PVDM card can be considered.
RESEAT means: Turning off the router, unplug the PVDM card, and plug it back in and then power on the router. It has to be done during off-hours.
Note: PVDM4 installed on NIM are hot swappable but the router must me shut down to insert or remove PVDM4 on the motherboard.
- 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 (G1/G2) and hw-module subslot x/y stop (ISR 4K/8K) command to minimize the impact of DSPs that go into a DOWN state. This command will remove the particular DSP from participation and the router won't consider it for processing any calls or media resource activities.
Scenario: Suppose if we got DSP issue in Production hours. If you wont remove the particular subslot, call processed by those slot is affected. To Avoid this we are removing it from taking the calls and making it not processing them
- If the above steps do not resolve the issue, Return material authorize (RMA) any DSP that does not return to a UP state.