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Community Member

Calls making short 'blip' and disconnecting

Hello everyone,

I'm having a strange issue and was wondering where I should start my troubleshooting. (We're using CallManager Express)

My receptionist tells me that during the week, randomly and intermittently, when someone calls the main phone line, the phone makes a short 'blip' sound and shows up as a missed call.

The night service setting was a suspicion but that's configured correctly everyday from 5pm to 8am the next day.

Has anyone seen this happen and could help me?

Thanks,

Ali

11 REPLIES
Hall of Fame Super Gold

Re: Calls making short 'blip' and disconnecting

Are you using FXO? Perhaps an incomplete incoming call. Try calling the number from outside, hang up as you hear first ringback or even before.

Community Member

Re: Calls making short 'blip' and disconnecting

Thanks for the reply.

It's actually an E&M card.

IN OUT

PORT CH SIG-TYPE ADMIN OPER STATUS STATUS EC

============== == ============ ===== ==== ======== ======== ==

0/0/0 -- fxs-ls up dorm on-hook idle y

0/0/1 -- fxs-ls up dorm on-hook idle y

0/1/0:0 01 e&m-wnk up dorm idle idle y

0/1/0:0 02 e&m-wnk up dorm idle idle y

0/1/0:0 03 e&m-wnk up dorm idle idle y

0/1/0:0 04 e&m-wnk up dorm idle idle y

0/1/0:0 05 e&m-wnk up dorm idle idle y

0/1/0:0 06 e&m-wnk up dorm idle idle y

0/1/0:0 07 e&m-wnk up dorm idle idle y

0/1/0:0 08 e&m-wnk up dorm idle idle y

0/1/0:0 09 e&m-wnk up up seized seized y

0/1/0:0 10 e&m-wnk up dorm idle idle y

0/3/0 -- e&m-imd up up idle seized y

0/3/1 -- e&m-wnk up dorm idle idle y

The problem is that this occurs intermittently, and personally I haven't seen it happen but heard from them saying this is causing some issues because they're losing their calls...

Ali

Hall of Fame Super Gold

Re: Calls making short 'blip' and disconnecting

Does it happens on ds0-group 0 in T1 0/1/0 ?

What "show controller" says ?

Could be some wink timing issue.

You can enable debug vpm signal with logging to buffer or syslog server, and ask the receptions to take a note of the time when it happens. Then try to correlate the event to debug.

Can you reproduce by calling from outside and hang up quickly?

Community Member

Re: Calls making short 'blip' and disconnecting

Here's the output of sh controllers t1

sh controllers t1

T1 0/1/0 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Version info Firmware: 20060623, FPGA: 20, spm_count = 0

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (785 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

73 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

73 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

0 Line Code Violations, 0 Path Code Violations,

8169 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

8169 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

I'm not sure if there are any inconsistencies in the output - the T1 is configured as follows:

controller T1 0/1/0

mode ccs frame-forwarding

framing esf

linecode b8zs

channel-group 1 timeslots 13-24

ds0-group 0 timeslots 1-10 type e&m-wink-start dtmf dnis

I like the idea of having a syslog server capturing all the events and having them notify me when they encounter the problem... I'll get started on that as well.

As far as reproducing the issue, I don't really believe I can do so... since the call is dropped by itself and not by the caller. For example if you called them, they hear a short blip on the phone and that's it. It'll show your call as a missed call before they're even able to answer it.

Ali

Re: Calls making short 'blip' and disconnecting

Ali,

You are receiving slips on your T1. This is possibily due to a clocking issue. Please make sure you are following the guidelines for clocking on TDM interfaces using voice. I would definitely start there, even though clocking issues are more known for horrible voice quality and one-way audio. Here is a link.

http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a008031a072.shtml

Not sure of your complete configuration, but more than likely you will want to configure the commands below. Post a config if you can.

network-clock-participate slot 0

network-clock-select 1 t1 0/1/0

Please rate any helpful posts

Thanks

Fred

Community Member

Re: Calls making short 'blip' and disconnecting

Very informative, thanks Fred.

The

network-clock-participate wic 1

was already configured on the router, but I added

network-clock-select 1 t1 0/1/0

and it set the line as primary clock source. Before that it was

sh network-clocks

Network Clock Configuration

---------------------------

Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

Current Primary Clock Source

---------------------------

Priority Clock Source Clock State Clock Type

10 Backplane GOOD PLL

and now it's

sh network-clocks

Network Clock Configuration

---------------------------

Priority Clock Source Clock State Clock Type

1 T1 0/1/0 GOOD T1

10 Backplane GOOD PLL

Current Primary Clock Source

---------------------------

Priority Clock Source Clock State Clock Type

1 T1 0/1/0 GOOD T1

I tried adding network-clock-participate aim as well but it said the slot doesn't support or is empty so forget that...

Do you think this would alleviate the problem?

Here's a partial config of the router:

memory-size iomem 10

clock timezone PST -8

clock summer-time MST recurring 2 Sun Mar 2:00 1 Sun Nov 2:00

network-clock-participate wic 1

network-clock-select 1 T1 0/1/0

no ip source-route

ip tcp synwait-time 10

voice-card 0

no dspfarm

!

!

!

voice service voip

allow-connections h323 to h323

allow-connections h323 to sip

allow-connections sip to h323

allow-connections sip to sip

supplementary-service h450.12

h323

sip

registrar server expires max 3600 min 3600

voice class codec 1

codec preference 1 g711ulaw

voice translation-rule 1

rule 1 /6779/ /5001/

rule 2 /6779/ /2001/

rule 3 /0419/ /2098/

rule 4 /0418/ /7777/

!

voice translation-rule 2

voice translation-rule 9

rule 1 /^911$/ /911/

rule 2 /^9\(.*\)/ /\1/

!

!

voice translation-profile IncomingMain

translate called 1

controller T1 0/1/0

mode ccs frame-forwarding

framing esf

linecode b8zs

channel-group 1 timeslots 13-24

ds0-group 0 timeslots 1-10 type e&m-wink-start dtmf dnis

translation-rule 1

Rule 1 6779 5001

Rule 2 6775 2099

Rule 3 #### 2001

Rule 4 0418 7777

Rule 5 0417 2010

voice-port 0/0/0

!

voice-port 0/0/1

!

voice-port 0/1/0:0

translate calling 1

translate called 1

!

voice-port 0/3/0

auto-cut-through

operation 4-wire

signal immediate

!

voice-port 0/3/1

operation 4-wire

Thanks again,

Ali

Re: Calls making short 'blip' and disconnecting

Ali,

Well I would take a wait and see approach. Keep a look at your counters on the controllers and make sure the slips stop. Hopefully the voice drops will stop too. Yeah sorry about posting the slot command wasn't sure if that was a WIC or Slot.

Thanks

Fred

Community Member

Re: Calls making short 'blip' and disconnecting

I jotted down the Slip counts and hopefully the changes will take affect.

I'll give an update on the issue shortly.

I appreciate everyones replies greatly.

Ali

Community Member

Re: Calls making short 'blip' and disconnecting

Hey everyone,

Just an update from yesterday.

The output of show controllers t1 is now:

sh controllers t1

T1 0/1/0 is up.

Applique type is Channelized T1

Cablelength is long gain36 0db

No alarms detected.

alarm-trigger is not set

Soaking time: 3, Clearance time: 10

AIS State:Clear LOS State:Clear LOF State:Clear

Version info Firmware: 20060623, FPGA: 20, spm_count = 0

Framing is ESF, Line Code is B8ZS, Clock Source is Line.

CRC Threshold is 320. Reported from firmware is 320.

Data in current interval (149 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Total Data (last 24 hours)

0 Line Code Violations, 0 Path Code Violations,

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins,

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

No Slip Secs anymore...

I really do hope it results in fixing that issue.

I'll give an update in a few days.

Thanks!!

Ali

Community Member

Re: Calls making short 'blip' and disconnecting

Ok... things are lookin good!

I haven't heard of any dropped calls. Fred thanks for the command that fixed the issue.

Again, I appreciate everyones replies and assisting me in the issue.

Hall of Fame Super Gold

Re: Calls making short 'blip' and disconnecting

Thank you for letting us know and the nice rating!

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