Call transfer and segment handling
When a call is transferred, Alianza initiates a new SIPREC session for the post-transfer segment.
Session teardown. Alianza does not send a
BYEto terminate the prior SIPREC session before starting the new one. This behaviour is expected to change in a future release.
| Item | Behaviour across segments |
|---|---|
| SIPREC SIP dialog | New INVITE with a new Call-ID per segment. |
XML session_id |
New value per segment. |
| XML participants | Updated to reflect the new call parties. |
X-Alianza-Recording-Session-Id header |
Stable across all segments — use this to group segments into a single logical call. |
Hold, resume, codec changes
Mid-call changes such as hold/resume or codec negotiation are handled via re-INVITE within the existing SIPREC session — Alianza does not send a BYE and start a new session for these events.
If your SRS does not support mid-call re-INVITE, flag this during onboarding (see Before you start) so your integration can be configured accordingly.
Joining segments into a single recording
If you store one file per SIPREC session today, expect multiple files per logical call when transfers occur. The X-Alianza-Recording-Session-Id is the only stable identifier across segments — use it as the join key in your storage layer.