AdminGuide:BasicConcepts:Outbound lines
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Outbound and Inbound lines
The term "Outbound and Inbound lines" refers to all the SIP lines through which the PBX can perform and receive calls to and from external numbers, i.e. not an internal service or extension (local SIP account).
Configuration of these lines is performed in the Gateway and VoIP Domains panel.
Calls to external numbers
Calls destined to external numbers are not forwarded directly to the outbound lines, but rather are presented to the Outbound routing engine. This engine decides whether the calling user/entity is authorized to perform the call (based on the destination number) and which outbound lines can be used to perform the call.
Calls can reach the Outbound routing engine from the Numbering Plan or directly as a failover action of a previous destination (e.g. an incoming call to an extenion can be forwarded to an external number in case of no answer). In both the cases, the requested outbound call has two associated parameters, which are the Outbound identity and the Outbound Routing Class.
Outbound Identity
The Outbound Identity is the extension number which will be accounted for that call, and will be used to derive the CLID used in the outbound call (according to the corresponding calling number manipulation table). The Outbound Identity can be explicitly set in case of failover actions, whereas it is automatically assigned in case of calls performed by a SIP account or in case of calls transferred/forwarded:
- Calls performed by a SIP account
- The Outbound identity is set equal to the extension associated to the SIP Account.
- Calls forwarded by a device (telephone-driven Call Forwarding)
- Same as above
- Calls forwarded using KalliopePBX (Unconditional) Call Forwarding service
- The Outbound Identity is set equal to the forwarding extension number
- Transferred calls (using KalliopePBX star-codes or telephone functions)
- The Outbound Identity is set equal to the transferring extension number
In all these cases, if the caller requests to present itself as anonymous (according to the different CLIR supported methods), the outbound identity retains the extension number throughout all the lifetime of the call, and actual calling number restriction is performed when placing the call to the outbound line (or to the destination SIP accounts, in case of internal calls).
Outbound Routing Class
The Outbound Routing Class defines the actual handling of the call, i.e. whether it is allowed or not, and (in the former case) the sequence of outbound lines to be used to perform the call.
Except when explicitly set in the failover action, the choice of the Outbound Routing Class is automatically derived by the Outbound Identity..