Hi expert,
I came across one type of drop call in tems.
Drop Type: ‘SIP Bye Request’ failure
Can anyone help me to the the reason for this
What is the reason code for this
Multiple reason behind this
Wait I’ll share code
But what are the generic reason for this drop
The code is 503
Please explain…
What will be the action plan
This all are 18 xxx cause code
All related to registration fail
Most of the network facing this for this you guys have to tune S1 link and Nas optimisation
S1 -U or S1-C …
U will come after c
90,91,93 cause code 
Yes
In volte there are two types of cause code
When cause code come that means call drop or call block not in picture cause code means service affected which is indirect to call block muting and etc
When reason code comes that is the main thing
Where a particular shit happens because of that reason
But here are discussion On RLF means drop it is mostly in u plane
Yes you right
C- plane cause code please explane
If you want to save drop because of rlf you can extend timer in sync and out sync
And extended RLF FEATURE this can also help to reduce drop
Its all know
do you guys have partial drops???
How we can identify the RLF failure at MME end any specific cause code
In mean drop due to partial handover
No specific cause code drop happens on cell edge where coverage week in 4g because of restblishment drops are less
No its paging in Total drop but not in Active E-Rab
Which BTS??? Ericsson or Nokia