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?