How to make VoLTE device Part 4

The VoLTE post are currently not making full sense, but mayb in 5th or 6th I will try to summarize all.

Right now , I am putting the learning's from each module here, so that we can form the whole picture.


So below is flow of SIP messages for MO and MT call.



MO                                                                                                               MT

----------------------------INVITE(SDP)---------------------------------------------------->
<---------------------------100 trying -----------------------------------------------------------

<-----------------------------183 session progress (SDP)-----------------------------------

---------------------------[UPDATE (SDP) ]------------------------------------------------->
<-------------------------------200 ok (SDP)---------------------------------------------------------

---------------------------[PRACK (SDP) ]------------------------------------------------->
<-------------------------------200 ok(SDP) ---------------------------------------------------------

<-------------------------------180 ringing------------------------------------------------------

// Now here 183 can come after UPDATE AND PRACK.
// Also UPDATE and PRACK are optionally ( as per my discussion with IMS person)
// The SDP stands for session description protocol , which has information about port id's , codecs .

It is necessary to exchange this information between both sides ( MO and MT ) , so that both sides know the port id and codec list.

Once MT picks up the call

<---------------------------200 Ok (SDP)--------------------------------------------------------
-----------------------------ACK---------------------------------------------------------------->

Then when I party disconnects

<-----------------------------------------BYE------------------------------------------------------->
<-----------------------------------------200 OK------------------------------------------------------>

Also in the above message, SDP is mostly exchanged once between MO and MT. It can be carried by the above messages.

Some more SIP messages as per scenario seen are 

If MT disconnects the call after getting ringing, then as per SIP messages flow 

<-------------------------180 ringing-------------------------------------

<-------------------------486 busy here ---------------------------------

If MO disconnects the cal before MT picks up,

<--------------------------------180 ringing-------------------------

--------------------------------------CANCEL --------------------->

<--------------------------------200 ok---------------------------------

If MT number can't be reached , netwok might send

<------------------------------------183 SDP---------------------------------

<-----------------------------------484 address incomplete ----------------

 

england welsh ireland scotland great britain united kingdom

we all hear all these countries names  and atleast I was thinking that united kingdom is simply something of past, which people still use.

But I was so wrong.

England, Welsh, Scotland and northern Ireland are countries...hmmm not as per ISO list of counties, but they have they own goverments, sports body.

For example , lot of time we hear wales vs england match.

Now  england+scotland+welsh  together forms great Britain, which is not  country but a name given to these groups

Actual country is United Kingdom which also includes Northern Ireland + Great Britain..but in lot of places people substitute one for other.

Also the other fascinating thing I found out is the flag of UK.  It comprises of flags of native countries,

Source wiki

Now I have to also read about these saints.                                                                                                    

Other interesting things I see are . Football Clubs situated in Welsh are part of EPL, but scotland has there own premier league. Swansea is in welsh.                                                                                     

Also as per FIFA, welsh and england are different, hence we don't see GARETH BALE playing with ROONEY, same goes for AARON RAMSEY.  If in FIFA , they play as UK then it will be quite a strong team.                                                                                                                                              

V for Vendetta ; Guy fawkes

The movie is great ...the opening dialogue where everything starts with V is simply awesome. I spent a lot of time rehearsing it.


Now basically I was watching Braveheart and lot of questions start following about william wallace, great britain, wales, ireland, iceland , scotland , isabella.

So i search led to another and so on .


Nov 5 is the main date around which the movie revolves. It is also known as Guy fawkes day.

Guy fawkes was a member of  a group of Catholic Christians, who were not happy with the laws of king James I of england ( james 6th of scotland) and wanted to blow parliament on its opening day on 5th Nov using gunpowder.

This person was given the job of lightening the gunpowder, but he got arrested.


Now I was always confused that why then in the movie the portray him as good guy.

I think in movie and now a days whenever people uses his mask, its more a symbol to fight against tyranny , oppression.