I have installed a UC560 about 2 months ago for one of our customers who is a Travel and Tourism office. The customer went from Analog lines on the old phone system, to a PRI with the UC560. They are using the SPA508 phones, and the UC560 has ver 15.x. They customer has started getting complaints via email from prospective tourists that they cannot get through to their office by phone. It occurs on all DID numbers, not just their main published number. Outbound local and LD calls are not affected, in fact, the customer can call the prospective tourist back using the UC560 and phones.
The callers state that they hear 2 rings, followed by a dial tone, and disconnect. The q931 debug on the UC560 shows a call connecting, lasting about 10-12, followed by a Normal Call Clearing code. Our translations department sees a disconnect coming from the calling party when they look at the D-channel information.
I will post the config later. But the the PRI is setup as T1, 23 Bchannels, and primary-ni. The Central Office switch is set for NI2. I have seen a mismatch causing all calls to have problems, but not just a minority of the Long Distance calls that the customer receives.
No local calls or LD calls made from within our Telco footprint (in or out of state) have a problem calling in.
If you are running the latest software pack, it could be caused by the new toll-fraud app...
Try disabling toll-fraud app completely:
voice service voip
no ip address trusted authenticate
Note: (other setups for toll-fraud)
Explicitly enable those source IP addresses from which you would like to add to the trusted list for legitimate VoIP calls. Up to 100 entries can be defined. This below configuration will accept calls from those host 203.0.113.100/32, as well as from the network 192.0.2.0/24. Call setups from all other hosts will be rejected. This is the recommended method from a voice security perspective.
voice service voip
ip address trusted list
ipv4 203.0.113.100 255.255.255.255
ipv4 192.0.2.0 255.255.255.0
Configure the router to accept incoming call setups from all source IP addresses.
Actually, the IOS version is uc500-advipservicesk9-mz.150-1.XA2. I do not see that command there. The calls came through with our PRI test equipment connected to the PRI, so I will open a TAC case in the morning.