Table of Contents
What is Atcf IMS?
To ensure continuity of service, e-SRVCC function introduces two anchor points in the IMS network: access transfer control function (ATCF) which provides the anchor point for session initiation protocol (SIP) signaling; and access gateway transfer (ATGW) that provides the anchor point for the RTP stream.
What is Atcf?
The ATCF (Access Transfer Control Function) was introduced in Release 10 of the 3GPP specifications in order to reduce the voice interruption delay when conducting an SRVCC procedure. The ATCF acts as an anchor point for SIP signalling and sits between the P-CSCF and the I-CSCF/S-CSCF in the signalling flow.
What is ATU STI in IMS?
The Access Transfer Update – Session Transfer Identifier (ATU-STI) is a SIP URI assigned to a device during registration, if 3GPP Rel10 (or later) enhanced Single Radio VCC (eSRVCC) is to be applied to that device’s sessions. In releases prior to Sentinel VoLTE 2.6.
What is SCC AS in IMS?
IMS SCC includes the IMS Centralized Services and IMS Service Continuity Specifications. IMS SCC would be used in support of SR-VCC (Single Radio Voice Call Continuity), which allows a subscriber conducting a VoLTE call to handover to the 2G/3G network without the call dropping.
What is STN SR?
Session Transfer Number for SRVCC. A routing number used to identify an SCC AS or ATCF as part of and SR-VCC handover procedure.
What is Srvcc in VoLTE?
Single radio voice call continuity (SRVCC) is an LTE feature that allows a VoIP/IMS call in the LTE packet-switched domain to be transferred to a legacy circuit-switched domain (GSM/UMTS or CDMA2000).
What is terminating access domain selection?
Terminating-Access Domain Selection, or T-ADS (3GPP TS 23.292), is a function that determines where a call will be terminated for a VoLTE user and ensures that the IMS routes the call to the UE when it is in 2G/3G coverage.
What is SRVCC in IMS?
SRVCC stands for Single Radio Voice Call Continuity. Putting it simple, it is a Handover technology between “VoIP over IMS in LTE” and Voice Call (CS) in a legacy system (e.g, WCDMA). It means it is for Handover between a Packet call in LTE and a Circuit Call in a legacy system (WCDMA).
What is STN Sr in IMS?
What is the difference between CSFB and SRVCC?
CSFB is a service handover procedure while SRVCC is a coverage handover procedure.
What is VoLTE call flow?
Voice over LTE (VoLTE) is the standard for voice call setup in LTE networks. VoLTE uses IMS signaling to setup voice calls. The following VoLTE call flow describes the IMS call setup and release. An example of sending an SMS over IMS is also included. Sample RTP and RTCP messages are also shown in the flow.
What is CSFB and SRVCC?
CSFB (CS Fall Back): whenever the UE have the need to place a call, make it revert (fallback) for legacy networks. SRVCC (Single Radio Voice Call Continuity): ensure that purely LTE (VoLTE) calls are transferred (via handover) to the legacy networks in a transparent manner.