Early-Only" Parameter In Replaces Header Rfc3891; Reason Header Field In Sip Message - Aastra 9143i Series Administrator's Manual

IP Phone Administrator Guide
Advanced Operational Features

"Early-Only" Parameter in Replaces Header RFC3891

The phones support the "early-only" parameter in the "Replaces" header
according to RFC3891. When the phone receives a Replaces header with the
early-only parameter, it replaces the existing dialog if the call is still in the early
state. If the call has been answered, then the Replaces request is rejected.

Reason Header Field in SIP Message

The IP Phones support the receiving of the Reason Header Field in a SIP
CANCEL message, as described in RFC3326. This allows a call that is answered
from somewhere else to still display in the Callers List. Also, the missed calls
indicator and counter do not change.
Limitation
If the call is answered somewhere else, the duration of the call does not display in
the Callers List.
6-52
Note: This feature is not supported in outgoing requests.
41-001160-03, Rev 00, Releaes 2.4