Zentrunk infrasctructure includes 4 SIP Servers all located in the West coast and 7 RTP Servers speard around the world (refer below diagram).

Server Locations

When a call is initiated by the user (assuming that the user also has separate SIP and RTP servers), Plivo locates the source IP (RTP Server IP) and picks the closest Plivo PoP to handle the call. This algorithm reduces the delay and latency in establishing the call. To understand this better, let’s consider the following scenarios.

Example 1: Call Flow for a call made from Asia to Singapore

Bangalore (User’s SIP Server) ——-> Plivo’s SIP Servers (Seattle)
Bangalore (User’s RTP Server) ——-> Hong Kong (Plivo’s RTP Server)
Hong Kong (Plivo’s RTP Server) ——-> Singpore (Destination Number)

Asia To Singapore

Example 1: Call Flow for a call made from Australia to USA

Perth (User’s SIP Server) ——-> Plivo’s SIP Servers (Seattle)
Perth (User’s RTP Server) ——-> Sydney (Plivo’s RTP Server)
Sydney (Plivo’s RTP Server) ——-> Miami (Destination Number)

Australia To USA

Example 1: Call Flow for a call made from Europe to South America

Moscow (User’s SIP Server) ——-> Plivo’s SIP Servers (Seattle)
Moscow (User’s RTP Server) ——-> Frankfurt (Plivo’s RTP Server)
Frankfurt (Plivo’s RTP Server) ——-> Santiago (Destination Number)

Europe To South America

Example 1: Call Flow for a call made from South America to Australia

Salvador (User’s SIP Server) ——-> Plivo’s SIP Servers (Seattle)
Salvador (User’s RTP Server) ——-> Sao Paulo (Plivo’s RTP Server)
Sao Paulo (Plivo’s RTP Server) ——-> Melbourne (Destination Number)

South America To Australia