I have few doubts in my mind about world wide voice and data Network

[Mukesh Tiwari]

I have few questions in my mind these are always making me confuse if any body have knowledge about these so please share your knowledge:

1-How different telecom service providers are connecting to each other?

2-How International call is being process between different telecom service providers or in other words how diffrent countries are communicating to each other for voice or data?

3-How multiple internet service providers are communicating? 

4-If I have one branch with MPLS VPN CONNECTIVITY OF A service provider in India and another branch is located in UK there is no A service provider’s network available so how both branch will connect ? 

[paolo bevilacqua]

Seeing the low rating that my 100% correct posts made to help have received here, I have removed them. Thank you and good luck.