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blank voicemail and call drops randomly

CCME 4.1/CUE 3.1 in Site A

CCM 4.2/Unty 4.1 in Site B

SiteA CCME4.1(C2821)<-->VPN router(C2821)<--1.5M WAN--> ASA5510<-->CCM 4.2 SiteB

CCME is integrated as H.323 gateway and an ICT trunk is configured.

The WAN link is a regular 1.5M internet connection, no QoS in SP's cloud. 25% * 1.5M is reserved for voice in the VPN interface.

Each site has local T1 PRI to PSTN.

Only G.711 codec is used in the entire system.


1. site to site voip calls drop randomly.

2. in CCME site, users are receiving blank voicemail randomly(both internal calls and PSTN calls) but the problem cann't duplicated.

3. in CCM site, users are receiving blank voicemail, but only with the voip calls from CCME site.


I see the WAN connection is not reliable and end-to-end QoS cann't be guaranteed due to no QoS in SP's cloud. This would be the reason of dropping calls. But the customer still wants the issue to be fixed without upgrade WAN link, is it possible?

After monitoring calls in CCME for one week, I see some calls with call disconnection cause "no resource", what is the possible reason for this?



Re: blank voicemail and call drops randomly

There should be only one RTP stream to a given destination UDP port on the CUE system. If it is found that is more than one RTP stream to the same CUE ip address and UDP port, determine the source of the secondary RTP stream and take necessary steps to disable that packet stream.

Re: blank voicemail and call drops randomly

Multiple things going on here:

For blank voice mails, be suspicious of CSCsk73870. Check if your CUE is 3.0.1 or 3.0.2

Blank voicemails can also because of routing issues, but generally those are not intermittent. But, since you're having issues with both sites I would check your routing / ACLs/ firewalls.

Resource unavailable is generally a codec mismatch that requires a transcoder which you don't have. It can also because a DSP has crashed and is unavailable, or because you have run out of DSP resources (transcoding or general use). Check the bottom of 'show voice dsp group all' for allocation errors.

Dropped calls can because of entirely too many things to guess. This is usually only determined by debugs, or maybe allocation errors on your DSPs.

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