name: P-CSCF
full_form: Proxy-Call Session Control Function
context: When an MS/UE indicates a request for a P-CSCF address in the PCO IE in a Create PDP Context Request message on GERAN/UTRAN or for E-UTRAN in initial access request (e.g. Attach Request, PDN Connectivity Request), the GGSN/P-GW shall respond with one or more P-CSCF server addresses if preconfigured for this APN. If the GGSN/P-GW has no P-CSCF address available, the GGSN/P-GW shall ignore the request. If the GGSN/P-GW provides more than one P-CSCF IPv4/IPv6 address in the response, the GGSN/P-GW shall sort the addresses with the highest priority P-CSCF server first in the PCO IE. The GGSN/P-GW may use different prioritisations for different Mses/UEs, e.g. for load sharing between the P-CSCF servers.
  The GGSN/P-GW may use a keep alive mechanism and/or other type based on local policy (e.g. statistical monitoring) to be able to detect a failure of P-CSCF address(es) preconfigured in the APN. The keep alive mechanism should make use of STUN or CRLF as specified for the UE in 3GPP TSÂ 24.229Â [47], clause K.2.1.5. As an alternative, ICMP echo request/response may be used. The GGSN/P-GW shall then provide only those P-CSCF address(es) that are available in a Create PDP Context Response/Create Session Response.
  The coding of the PCO IE is described in the 3GPP TSÂ 24.008Â [54]. This procedure shall be followed regardless of whether or not the MS/UE uses a dedicated PDP context/EPS bearer for IMS signalling, and irrespective of the Gx status for the APN.
description: The P-CSCF is a network function that manages IMS signalling. It provides call control and routing services to the MS/UE.
explanation: Categorized as a Network Function because it manages call setup and teardown.
biotag_Context: O,O,O,O,O,O,O,O,B-Network Function,O,O,O,B-Parameter,B-Message,O,O,O,B-Protocol,O,O,O,O,O,O,O,B-Network,O,O,O,O,O,O,O,B-Network,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,B-Parameter,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Device,O,B-Organization,O,O,O,O,O,O,O,O,B-Protocol,O,O,O,O,O,O,O,O,O,O,O,O,B-Network Function,O,O,O,O,O,O,O,B-Protocol,O,O,O,O,O,O,O,O,B-Parameter,B-Message,O,O,O,O,B-Organization,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,O,B-Protocol,O,O,O,B-Network,O,O,O,O,O,B-Interface,O,O,O,O
biotag_Description: O,B-Network Function,O,O,O,O,O,O,B-Network,O,O,O,O,O,O,O,O,O,O,O