Typical inbound call flow - Provider: Access 4
This is a typical call flow and outlines the important SIP messages
Because SBC Connect is connected to multiple providers, you’ll need to select the inbound call flow relivant to your call flow. More examples can be found: 🌐 Here
Notes on Access 4
Because the Access 4 SIP trunk is internet authenticated, then there is an additional 401 Unauthorized in the SIP ladder that isn’t nromally present in other providers, for example AAPT. This is normal and a second INVITE is used to authenticate the call.
sequenceDiagram participant C as Customer <br> A-Party participant S as SBCconnect participant P as Upstream Provider <br> Access 4 <br> B-Party Note over C,P: Typical Outbound Call <br> from A-Party to B-Party <br> Upstream Provider: Access 4 C->>S: Invite S->>C: 100 Trying S->>P: Invite P->>S: 100 Trying P->>S: 401 Unauthorized S->>P: ACK S->>P: Invite P->>S: 100 Trying P->>S: 200 OK S->>C: 200 OK S->>P: ACK C->>S: ACK C-->P: Media Flow loop During the call C->P: 183 Session Progress (both ways) end alt A-Party Disconnects Call C->>S: BYE S->>P: BYE P->>S: 200 OK S->>C: 200 OK else B-Party Disconnects Call P->>S: BYE S->>C: BYE C->>S: 200 OK S->>P: 200 OK end