We have implemented an Expressway MRA system with CUCM 11.5.
Clients are Android mobile client with newest Jabber. All of clients connecting via MRA (ExpE-ExpC).
When client connected to wireless network (still MRA, over ExpE-ExpC), all of calls will be successful.
But when connected to stable 4G network, sometimes the client cannot ring, just display an "Unanswered Call" notification.
Tried to debug at CUCM/Expressway pair - and I can see that CUCM sends an
- Gets back a Trying from ExpC
- after that sends a CANCEL
Just a note, not all of the time this issue is occured. Sometimes yes, sometimes not.
What could be caused this issue? Why CUCM send Cancel before receive Ringing and 200OK?
Is it a timer? The SIP profile in CUCM is "Standard SIP Profile for Mobile Device" with default values:
I assume the internet connection is stable - as CANCEL arrived in time to client.
No, there was not 183 Session in progress, just 180 Ringing - at the successful call.
When call was unsuccesfull, there was not any 180 ringing back, and CUCM send CANCEL .
If it is a timer, it just occured at mobile calls, as wirelessly connected Jabber clients working definitely well.
Please take a look to the following diagrams (from CUCM trace)
The successfull call was the following:
The Cancel at 11:59:28 is when the caller on-hooked the phone. So this CANCEL was occured by tester staff.
But at the unsuccessfull call, there was not any ringing back, and maybe the Callmanager send a Cancel at 11:59:20 , eight (8) seconds earlier as caller on-hooked call. So this CANCEL was not occured be test-staff, it is occured by Callmanager.
on the android client, use the "send problem report" option and analyze this, if needed add to this post
To tell the true - I cannot found any interesting at log. Attached it.
The time when we see a missed call notifocation (as the only one) at client side is:
2018-05-25 11:59:23,164 INFO [0x00000001b4fb2b40] [miscs/YLCLocalNotificationManager.m(379)] [UI.Action.System] [-[YLCLocalNotificationManager sessionDidEnd:]] - jabber post a notification[You have missed a call] at 2018-05-25 09:59:23 +0000