I've an Cisco 1861 with B-ACD and the FXS ports are controlled via MGCP from a CCM 5.1(3a). The DN of the ports are 5570 to 5573.
DN 5570 has a CFNA to DN 5571, and DN 5571 has a CFNA to DN 5570.
The issue is that when a call is received on the B-ACD and it tries to pass the call to DN 5570. If it doesn't answer the call is forwarded to DN 5571, and if it doesn't answer the B-aCD drops the call and DN 5571 became unavailable. On the 1861, the status is this:
sh mgcp conn
Endpoint Call_ID(C) Conn_ID(I) (P)ort (M)ode (S)tate (CO)dec (E)vent[SIFL] (R)esult[EA] (ME)dia (COM)Addr:Port
1. aaln/S0/SU0/2 C=,1255,-1 I=0x0 P=0,0 M=0 S=9,0 CO=1 E=3,10,10,3 R=0,0 ME=0 COM=0.0.0.0:0
Mode : 0=INVALID, 1=SENDONLY, 2=RECVONLY, 3=SENDRECV, 4=INACTIVE, 5=LOOPBACK,
6=CONTTEST, 7=DATA, 8=NETWLOOP, 9=NETWTEST, 10=CONFRNCE
State : 0=IDLE, 1=SETTING, 2=CONNECTING, 3=CONFERENCING, 4=ACTIVE, 5=CONF_DESTROYING,
6=DISCONNECTING, 7=INACTIVE, 8=VOICE_CONNECTING, 9=VOICE_ACTIVE, 10=CONF_DISSOCIATING,
11=CALLLEGS_DISSOCIATED, 12=HP_CONNECTING, 13=HP_CONNECTED, 14=HP_CONFERENCING,
15=HP_ACTIVE, 16=VOIP_CONF_DESTROY, 17=ERROR, 18=CONNECTING_INACTIVE,
19=CONF_DESTROYING_INACTIVE, 20=CONT_TEST, 21=SETUP_WAIT, 22=WAIT_NSE_SENT,
23=TWC_ACTIVE, 24=WAIT_STATE, 25=HANDOVER
So the state indicates a Voice active on the port. But there is no call on the DN. If you try to call the DN you get fast busy. I've tried shuting down and up the port and the dial-peer, but the problem persist.
The current workaround is to erase the mgcp configuration on the 1861, and then put it back again. But it's not a good solution.
I have some ATAs on the LAN, and when the same procedure apllies to that DN, the issue doesn't happens. Tha's because the ATA is SCCP controlled.
Any suggestion will be appreciated.