Dropping calls

[Colin.Evans]

For the last week we have been dropping calls. The users have told me that the call starts to crackle and then it just goes dead. I have called BT and they have told me the line is OK. I need to know if this could be the 3300 as we don't have maintenance on the box.

Here is a copy of the errors we are getting, these are repeating every second.

Maintenance  4683  Info  2011/May/13  10:42:20  ISDN VDsu Mod 1 Port 1  All alerts are CLEARED   ISDN VDsu Mod 1 Port 1  MaintenanceLog;0 
Maintenance  4682  Warning  2011/May/13  10:42:20  Call Control - Maintenance  MC269CA Universal E1 at location 06 1 02 01 Type of diagnostics : Background Scope of report : Hybrid Reason(s) for report: - Far end alarm : Present   Call Control - Maintenance  MaintenanceLog;0 
Maintenance  4681  Warning  2011/May/13  10:42:20  ISDN VDsu Mod 1 Port 1  Layer 1 YELLOW alarm ACTIVE   ISDN VDsu Mod 1 Port 1  MaintenanceLog;0 
Maintenance  4680  Warning  2011/May/13  10:42:20  Call Control - Maintenance  MC269CA Universal E1 at location 06 1 02 01 Type of diagnostics : Background Scope of report : Hybrid Reason(s) for report: - Far end alarm : Absent   Call Control - Maintenance  MaintenanceLog;0

Here is a copy of the DST REPORT

Universal E1          6 1  2  1                                                 
Link is Available                                                               
         duty                             bit                                   
         cycle       framing              error                                 
Time     (%)         losses     slips     rate                                 
------------------------------------------------                               
11:06    100            0           0         0                                 
11:00     98           57           0         0                                 
10:00     98           28           0         0                                 
 9:00    100            1           0         0                                 
 8:00    100            0           0         0                                 
 7:00    100            0           0         0                                 
 6:00    100            0           0         0                                 
 5:00    100            0           0         0                                 
 4:00    100            0           0         0                                 
 3:00    100            0           0         0                                 
 2:00    100            0           0         0                                 
 1:00    100            0           0         0                                 
 0:00    100            0           0         0                                 
23:00    100            0           0         0                                 
22:00    100            0           0         0                                 
21:00    100            0           0         0                                 
20:00    100            0           0         0                                 
19:00    100            0           0         0                                 
18:00    100            6           0         0                                 
17:00    100            1           0         0                                 
16:00    100            7           0         0                                 
15:00    100            9           0         0                                 
14:00     98           49           0         0                                 
13:00    100            4           0         0                                 
12:00     98           16           0         0                                 
------------------------------------------------                               

Please help.

[bluewhite4]

I've never worked with E1's, so maybe I'll be way off on this suggestion but if this was a T1/PRI and I was seeing the framing losses like that...

I'd demand an end-to-end test. We've made the telco's here do that, and when they run the all 0's or 1's and 0's tests, they've seen the errors that we see.

[Colin.Evans]

I have got in touch with the telco "ahh I see your PBX is maintained with us, it is probably that that is faulty". They are running tests and am waiting a result. Will let you know what they find.

[bobcheese]

Hi Colin,

I have been working on SX2000/3300 here in the UK for many years now. Take it from me, in 99% of cases where you experience framing losses and duty cycles anything less than 90% without the system being unexpectedly rebooted it will be a BT fault.
We deal with faults like this on a weekly basis and we would normally ask BT to come out to the fault even if they say no fault found on the service desk (they will tell you that there is a charge if no fault is found) but generally there will be when an engineer looks at it.

[ralph]

Same thing here in the US.   We hear "We're good to the smart jack so it's a CPE problem."
Worse yet, try working with the carrier on a D-Channel issue....

Ralph

[Colin.Evans]

Well this is still on going. Keep calling BT (TELCO) and they keep looking at it. Still getting framing errors. They reckoned they fixed it but that was OOH so no errors were produced. The errors are only happening when the users are on the phone so testing OOH isn't very helpful. I am on site tomorrow so will be able to chase them a bit more . Will let you know what happens.

[brantn]

"Problem is leaving here fine." good luck.

[Colin.Evans]

I cant believe that this has been going on for over a month now. BT has replaced everything and we have just had a data specialist from BT come in. He has discovered that CRC4 wasn't enabled on the external interface. Could this have caused all the problems. As far as I know, this has been turned off since the Mitel was installed over 4 years ago.

I have just checked the dtstat logs again and there have been no errors for the past 24 hours so maybe they had fixed the problem with the last hardware change.

I will keep you posted to see if this is finally over.

[Colin.Evans]

 
All is well. It was a BT problem after all. They swapped a peice of kit in the exchange and all the problems disappeared.

Only took 2 months to sort out. Thanks BT for taking your sweet time.

[ralph]

It's amazing that the carrier never has a problem until they actually look at it.

Thanks for the update.

Ralph