We have a Cisco 2811 with UCM E 7.0 running our phone system. It is connected to the PSTN by a VWIC2-1MFT-T1/E1 card connected to a PRI from the phone company.
From time to time of late, we are experiencing fast-busy signals when trying to make outgoing calls (dial 9 for secondary dial-tone). At these times as well, the AL light on the VWIC card lights and the CD light goes out. To my rudimentary sensibilities, this means that there is some sort of issue where the phone company has gone down since our system appears to be fine.
After several rounds of monitoring with the phone company they are talking about errors that they see from the CSU (which, if I'm not mistaken, means the T1 Card on the 2811) and they are able to loop the circuit continuously with test patterns on all 23 channels without errors. So it seems conceivable that our router has trouble of its own. The question, I guess, is how do I determine what that trouble is?
I know there are a large number of debug commands for checking what's what, but I am much more out of my depth dealing with a PSTN interface vs. an internet interface. Telecom terminology and methods are unfamiliar to me. I realize that even as I ask this question, I will need to provide more info, but I am not sure what to add at this point other than the basics:
(C2800NM-ADVIPSERVICESK9-M), Version 12.4(22)T, RELEASE SOFTWARE (fc1) Cisco 2811 (revision 53.50) with 247808K/14336K bytes of memory. Processor board ID FTX1119A4KS 2 FastEthernet interfaces 24 Serial interfaces 1 terminal line 1 Channelized/Clear T1/PRI port Version 7.0(1) Cisco Unified Communications Manager Express
I hope I've provided enough information to be of use to someone with more experience here than I have.
Edit: Requested sh int data:
Serial0/0/0:23 is up, line protocol is up (spoofing) Hardware is DSX1 MTU 1500 bytes, BW 64 Kbit/sec, DLY 20000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation PPP, loopback not set Keepalive set (10 sec) Last input 00:00:09, output never, output hang never Last clearing of "show interface" counters 4w0d Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0 Queueing strategy: weighted fair Output queue: 0/1000/64/0 (size/max total/threshold/drops) Conversations 0/1/256 (active/max active/max total) Reserved Conversations 0/0 (allocated/max allocated) Available Bandwidth 48 kilobits/sec 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 287135 packets input, 1452745 bytes, 0 no buffer Received 0 broadcasts, 56961 runts, 0 giants, 0 throttles 129163 input errors, 129163 CRC, 0 frame, 0 overrun, 0 ignored, 64394 abort 287962 packets output, 1463850 bytes, 0 underruns 0 output errors, 0 collisions, 0 interface resets 0 unknown protocol drops 0 output buffer failures, 0 output buffers swapped out 67 carrier transitions Timeslot(s) Used:24, SCC: 0, Transmitter delay is 0 flags
And here's the interface section of sho run that matches:
interface Serial0/0/0:23 no ip address encapsulation ppp isdn switch-type primary-ni isdn incoming-voice voice isdn supp-service name calling
dial-peer voice 100 pots description PSTN destination-pattern 9T port 0/0/0:23