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IAD 2421 loosing connectivity under AAL2 Trunking

We are loosing connectivity after only a few minutes of idle time on our IAD. We are set-up aal2 and bles mode. The lines come up and we get dial tone and incoming calls when we start up the router. the problem starts on individual lines about 5 minutes after last using them. when we pick up a line, we get a busy signal and in order to get dialtone we need to hang up and pick up the line again.

This must be some type of signal timing issue. The CO gateway specifies Gr303-ABCD signaling with IDLE CAS Refresh every 5 seconds.

I have fiddled with the timing commands in the voice class permanent section but alas, no luck.

I will appreciate any and all help that we can get.


Re: IAD 2421 loosing connectivity under AAL2 Trunking

This can be because of a bug

Symptoms: A digital signal processor (DSP) may time out on a Cisco IAD2420 series because of a Host Port Interface (HPI) error.

Conditions: This symptom is observed on a Cisco IAD2420 series that is running Cisco IOS Release 12.2(11)T4 every time a call is placed or received.

Workaround: Use the command-line interface (CLI) to issue the following command to the DSPs that have a timeout symptom:

[no] voice dsp waitstate ws dsp_id

where ws is in the range of 1 to 3 with 1 being the default and dsp_id is a 1-based DSP number. The recommended ws value to set in this particular case is 2. Do not set the ws value higher than 2. The issuance of the CLI command will not take effect until the next DSP reset occurs either through an automatic mechanism or through test commands.

Try out the work around

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