The first diagram shows the SIP signalling traffic involved in the establishment, modification and termination of sessions following the SIP RFC 3261 and any related RFCs.

These are the external SIP entities involved:

  • UACs: users hardphones, softphones, SIP-capable gadget.

  • SIP carriers/DDI Providers: carriers used to interconnect IvozProvider with external SIP networks (and, probably, with PSTN).

All the SIP traffic (in any of the supported transports: TCP, UDP, TLS, WSS) they send/receive is to/from this two internal SIP entities of IvozProvider:

In fact, users UACs only talk to Users SIP Proxy and “SIP carriers” and “DDI

Providers” only talk to Trunks SIP Proxy.

Inside IvozProvider these two proxies may talk to Application Servers running Asterisk for some client types but no external element is allowed to talk to Application Servers directly.