No Voice on first ring on VG224 with SCCP

[manumohan200]

Hi,

I am having a Vg224 registered with CCM using SCCP. In an analog phone when a call comes and if it is picked after first ring, there is no voice on either ends. The voice flows if the receiver is picked after two rings.

When I removed the "caller-id enable" on the voice-port, the issue is resolved.

1) Can anyone tell how this command is related to my problem?

2) Now the issue I am facing is I am not getting any CLID for incoming calls because caller id is not enabled on that port. Is there anyway I can enable CLID, same time by which I can answer my calls within first ring? Please help.

Thanks,

Manu

[pcameron]

This is due to Bug ID CSCsi81450. At this stage, the only workaround in SCCP operation is to disable the caller ID on the voice port, or wait until the port has rung a few times instead of picking it up in the middle of the first ring cycle.

You can downgrade to an earlier release of IOS such as 12.4.9T7. I can't see a release schedule for the fix in 12.4.15T code, but you could also try 12.4.15T2 when it is released on Cisco.com around the 18th of January 2008.

[alijames]

The fix is definitely in 12.4(15)T. I verified it this morning.

Cheers

Alistair

[Risat]

I found this bug in version 12.4(9)T7 today. Fixed by disabling called ID.

[adns_jeremy]

I know this is basically solved, but does anyone know how to prove this was the case via debugs (for documentation purposes)?

[pcameron]

According to the bug notes, the developers needed quite a few debugs to be enabled for them to pick up the differences between a good and bad call -

deb voip ccapi inout

deb voip vtsp all

deb voip dsmp all

deb voip dsm all

deb voip hpi all

deb voip dspapi all

deb vpm signal

deb sccp all

It's not really feasible to capture all these debug traces and break them down in this forum.

The Bug release notes may help you out -

Symptom:

One-way audio when calling to an analog phone attached to a SCCP controlled FXS port on a Cisco IOS VoIP gateway.

The typology when this problem is seen is shown here:

analog phone---fxs---vg224---sccp---CCM

Conditions:

A voice-port configured for 'caller-id' as shown in the example below may experience one-way audio (no audio in the direction towards the analog phone). This can occur when the FXS port is SCCP controlled and the called party on the attached analog phone picks up the call before the first ring completes.

voice-port 2/4

ring cadence pattern02

mwi

timeouts ringing infinity

caller-id enable

Trigger:

When the voice-port has caller-id configured.

Impact:

Causes one way audio in voice calls between analog phone and SCCP phone

connected to Cisco IP Phone

Workaround:

Remove 'caller-id' under the voice-port , switch to MGCP or H323 instead of SCCP/STCAPP or wait for couple rings before going offhook on the FXS port.

[Thomas Dominic]

Why not configure it for MGCP? If the problem is with the underlying protocol and IOS interaction why not change it if not the IOS.