Unity Call handler DTMF issue

It was around Halloween time. I was building one call handler for each local site. We start getting ticket saying unity Caller option "0" ring on caller input "2".Hmm. Really!! Who cares, it must be user error. Unfortunately, more ticket started to come. This is alarming for sure. Now it's the time get to the bottom of this. Lets' dig in.

I build another call handler. See if I can replicate the same issue. After making around 8-9 call. It is happening. What the hell is going on here?
Hmm, Opened a ticket with Cisco. We did some capture on ISR4321. but we're not able to see what DTMF code we were receiving on CUBE. Then Cisco said this model does not show DTMF. SO we did capture on cube network port.

Long story short......It was AT&T was sending us wrong DTMF.

At&T "After referring this issue to our Sonus TSM support, they did some maintenance to refresh DSP cards the customers failed calls went over. Please have the customer retry these calls to ensure their DTMF issue is now resolved."

 Good Day.

T-Shoot 101: SIP UDP packet disappear...

MY favourite quote

"In VOIP world figuring out a call flow, is very much like following the bouncing ball"

VOIP firewall!!

Root Cause!!

We engineer would like to think everything happened for a reason, right? But sometimes we see some unusual phone behavior  I can't find any explanation for my customer.

*one extension was used as a shared line but was only ringing on one phone only!!!

Phone reset resolve that issue.Reason: was registered to the different subscriber.
??

*Sometimes No dial tone.Normally phone reset to resolve this issue.But Cisco was kind enough to give us an engineer special firmware version for the phone.
>Not sure that resolve the issue.But still having the same phone stuck with an older version.
?Why now? same firmware we have been using for last six month everything was working fine.


* Couple of TAC Case was open phone going to VM and user can't dial out.On-call manager everything was fine.

Subscriber not backing up!!

 We have a total of 12 subscribers, including one publisher and two tftp servers. One of our subscriber that was added to cluster recently was not backing up on publisher, we are getting used is not backed up for more than 10+ days.


I dig some website and found this might be the case...
FYI: for us it was not the real issue. We had something to do network I still need figure out what was exactly caused this issue from the Networking firewall team!! Until then please wait...

Try restarting DRF Local/Master services.It should fix that issue but not 100% guaranteed (reference from some other Cisco support forum also it was a none bug on 8.6). If that still doesn’t resolve the issue,we will have  go to the Pub/Sub's OS Admin page to re-generate the IPSec certificate, and then restart the DRS service in Pub/PSAC2.

https://supportforums.cisco.com/discussion/11605411/cucm-drs-backup-fails-one-subscribers

https://supportforums.cisco.com/discussion/11806556/cucm-back-issue-unable-contact-server-master-or-local-agent-could-be-down

Lesson learnd 2

This one is much more interesting.More like silly mistake turn into huge issue and CNS case open..well they dig into that for hours couldn't find the issue.Until I am the only Hero more like problem maker (:P decided to show up and fix that issue! Feel sorry for those people they had to spend long stressful night... We have an urgent requirement that when reception forward call to someone calling party should not hear ringing... Hmm

The reason behind is they want to take their time before answer those phones. maybe they are super busy all callers have to wait for a while. Well, none of my headache.. Now my question it how do I achieve that.. Think brain think.

In North America, the standard ring-back tone is a repeating 2-second tone with a 4-second pause between. The tone is 440 Hz + 480 Hz. (A little wise talk)

As far as I know some country does offer music instead of ring back tone

So how did we achieve that..stay tuned..