Content for TS 24.229 Word version: 18.4.0

1… 3… 4… 4.5… 5… 5.1.1.4… 5.1.2… 5.1.4… 5.2… 5.2.3… 5.2.6… 5.2.7… 5.3… 5.4… 5.4.1.2.2… 5.4.1.3… 5.4.2 5.4.3… 5.4.3.3… 5.4.4… 5.5… 5.7… 5.7.2… 5.8… 5.11… 6… 6.6… 7… 7.2A… 7.2A.6… 7.3… 7.9A… 8… A… A.2… A.2.1.4… A.2.1.4.7… A.2.1.4.8… A.2.1.4.10A… A.2.1.4.12… A.2.2… A.2.2.4… A.2.2.4.7… A.2.2.4.8… A.2.2.4.10A… A.2.2.4.12… A.3… A.3.3… B… C… E… F… H… I… K… L… L.2A… M… N… O… Q… R… S… U… U.2A… V… W…

3.1 Terms 3.2 Symbols 3.3 Abbreviations
...

3 Definitions of terms, symbols and abbreviations p. 57

3.1 Terms p. 57

For the purposes of the present document, the following terms apply.

3GPP PS data off status:

indicates state of usage of the 3GPP PS data off. 3GPP PS data off status at the UE can be either "active" or "inactive".

Country:

For the purposes of emergency service URNs in the present document, i.e. a service URN with a top-level service type of "sos" as specified in RFC 5031, an ISO 3166-1 alpha-2 code as specified in ISO 3166-1 [207] is used to identify a region or a country.

Entry point:

In the case that "border control concepts", as specified in TS 23.228, are to be applied in an IM CN subsystem, then these are to be provided by capabilities within the IBCF, and the IBCF acts as an entry point for this network (instead of the I-CSCF). In this case the IBCF and the I-CSCF can be co-located as a single physical node. If "border control concepts" are not applied, then the I-CSCF is considered as an entry point of a network. If the P-CSCF is in the home network, then the I-CSCF is considered as an entry point for this document. Similary, in case that "border control concepts", as specified in TS 23.218, are to be applied in an ISC interface, then these are to be provided by capabilities within the ISC gateway function, and the ISC gateway function acts as an entry point for this network.

Exit point:

If operator preference requires the application of "border control concepts" as specified in TS 23.228, then these are to be provided by capabilities within the IBCF, and requests sent towards another network are routed via a local network exit point (IBCF), which will then forward the request to the other network (discovering the entry point if necessary). Similary, in case that "border control concepts", as specified in TS 23.218, are to be applied in an ISC interface, then these are to be provided by capabilities within the ISC gateway function, and requests sent towards another network are routed via a local network exit point (ISC gateway function).

Geo-local number:

Either a geo-local service number as specified in TS 23.228 or a number in non-international format according to an addressing plan used at the current physical location of the user.

Home-local number:

Either a home local service number as specified in TS 23.228 or a number in non-international format according to an addressing plan used in the home network of the user.

Main URI:

In the case that the UE supports RFC 6140 and performs the functions of an external attached network, the main URI is the URI which is used for the registration procedures in the To header of the REGISTER request as specified in RFC 6140; it represents the public user identities associated to that UE.

Newly established set of security associations:

Two pairs of IPsec security associations that have been created at the UE and/or the P-CSCF after the 200 (OK) response to a REGISTER request was received.

Old set of security associations:

Two pairs of IPsec security associations still in existence after another set of security associations has been established due to a successful authentication procedure.

Temporary set of security associations:

Two pairs of IPsec security associations that have been created at the UE and/or the P-CSCF, after an authentication challenge within a 401 (Unauthorized) response to a REGISTER request was received. The SIP level lifetime of such created security associations will be equal to the value of reg-await-auth timer.

Integrity protected:

See TS 33.203. Where a requirement exists to send information "integrity-protected" the mechanisms specified in TS 33.203 are used for sending the information. Where a requirement exists to check that information was received "integrity-protected", then the information received is checked for compliance with the procedures as specified in TS 33.203.

Instance ID:

An URN generated by the device that uniquely identifies a specific device amongst all other devices, and does not contain any information pertaining to the user (e.g., in GPRS instance ID applies to the Mobile Equipment rather than the UICC). The public user identity together with the instance ID uniquely identifies a specific UA instance. If the device has an IMEI available, it generates an instance ID based on its IMEI as defined in clause 13 of TS 23.003. If the device has an MEID as defined in 3GPP2 S.R0048-A [86F] available, it generates an instance ID based on its MEID as defined in RFC 8464. If the device does not have an IMEI available and does not have an MEID available, the instance ID is generated as a string representation of a UUID as a URN as defined in RFC 4122.

Resource reservation:

Mechanism for reserving bearer resources that is required for certain access technologies.

Local preconditions:

The indication of segmented status preconditions for the local reservation of resources as specified in RFC 3312.

Alias URI, Alias SIP URI:

A URI is an alias of another URI if the treatment of both URIs is identical, i.e. both URIs belong to the same set of implicitly registered public user identities, and are linked to the same service profile, and are considered to have the exact same service configuration for each and every service.

Globally Routeable SIP URI:

a SIP URI of which the hostname part can be resolved to the IP address of the entry entity of the network reponsible for the identity represented by the userpart.

Initial registration:

The registration procedure for a public user identity initiated by the UE in the absence of any valid registration.

Registration expiration interval:

An indication on how long a registration is valid, indicated using the Expires header field, or the "expires" header field parameter within the Contact header field, according to the procedures specified in RFC 3261.

Reregistration:

The registration procedure initiated by the UE to refresh or update an already existing registration for a public user identity.

Registration of an additional public user identity:

The registration procedure initiated by the UE to explicitly register an additional public user identity during the life time of the registration of another registered public user identity, where both public user identities have the same contact address and P-CSCF.

Emergency registration:

A special registration that relates to binding of a public user identity to a contact address used for emergency service.

Initial emergency registration:

An emergency registration that is also an initial registration.

Emergency reregistration:

An emergency registration that is also a reregistration.

Back-to-Back User Agent (B2BUA):

As given in RFC 3261. In addition, for the usage in the IM CN subsystem, a SIP element being able to handle a collection of "n" User Agents (behaving each one as UAC and UAS, according to SIP rules), which are linked by some application logic that is fully independent of the SIP rules.

UE private IP address:

It is assumed that the NAT device performs network address translation between a private and a public network with the UE located in the private network and the IM CN subsystem in the public network. The UE is assumed to be configured with a private IP address. This address will be denoted as UE private IP address.

UE public IP address:

The NAT device is assumed to be configured with one (or perhaps more) public address(es). When the UE sends a request towards the public network, the NAT replaces the source address in the IP header of the packet, which contains the UE private IP address, with a public IP addressed assigned to the NAT. This address will be denoted as UE public IP address.

Encapsulating UDP header:

For the purpose of performing UDP encapsulation according to RFC 3948 each IPsec ESP packet is wrapped into an additional UDP header. This header is denoted as Encapsulating UDP header.

Port_Uenc:

In most residential scenarios, when the NAT device performs address translation, it also performs translation of the source port found in the transport layer (TCP/UDP) headers. Following RFC 3948, the UE will use port 4500 as source port in the encapsulating UDP header when sending a packet. This port is translated by the NAT into an arbitrarily chosen port number which is denoted as port_Uenc.

Multiple registrations:

An additional capability of the UE, P-CSCF and S-CSCF, such that the UE (as identified by the private user identity and instance-id), can create multiple simultaneous registration bindings (flows), associated with one or more contact addresses, to any public user identity, Without this capability, a new registration from the UE for a public user identity replaces the existing registration binding, rather than merely creating an additional binding.

IMS flow set:

An IMS flow set is a set of flows as defined in RFC 5626. The flows in an IMS flow set are determined by a combination of transport protocol, IP addresses, and ports. An IMS flow set is established by a successful IMS registration procedure.

IMS flow token:

A IMS flow token is uniquely associated with a IMS flow set. When forwarding a request destined towards the UE, the P-CSCF selects the flow from the IMS flow set denoted by the IMS flow token as appropriate according to TS 33.203 and RFC 3261.

IMS registration related signalling:

Signalling carrying the SIP messages sent by the UE and the network during the IMS registration procedure, i.e., SIP REGISTER request, SIP SUBSCRIBE request, and their responses.

IP Association:

A mapping at the P-CSCF of a UE's packet source IP address, the "sent-by" parameter in the Via header field, and, conditionally, the port with the identities of the UE. This association corresponds to the IP address check table specified in TS 33.203.

Authorised Resource-Priority header field:

a Resource-Priority header field that is either received from another entity in the trust domain relating to the Resource-Priority header field, or which has been identified as generated by a subscriber known to have such priority privileges for the resource priority namespace and level of priority used within that namespace.

Temporarily authorised Resource-Priority header field:

a Resource Priority header field that has been temporarily approved by the P-CSCF, the S-CSCF, or an IBCF. Temporarily authorised Resource-Priority heaer field appears in an INVITE request only, and is applied only in the direction P-CSCF to S-CSCF to AS, S-CSCF to AS, or IBCF to S-CSCF to AS, for the request, and the reverse direction for 1xx responses to that request. Subsequent requests in the same dialog will require an authorised Resource-Priority header field in order to obtain priority privileges. It is only valid when all entities are in the same trust domain for the Resource-Priority header field.

Network-initiated resource reservation:

A mechanism of resource reservation where the IP-CAN on the behalf of network initiates the resources to the UE.

Trace depth:

When SIP signalling is logged for debugging purposes, trace depth is the level of detail of what is logged.

P-CSCF restoration procedures:

the procedures for the IP-CAN and the UE to handle P-CSCF service interruption scenarios (see TS 23.380).

HSS based P-CSCF restoration procedures:

the procedures for the IP-CAN, the IM CN subsystem, the HSS and the UE to handle P-CSCF service interruption scenarios (see TS 23.380). In 5GS the procedure is called UDM/HSS based P-CSCF restoration (see TS 23.380) since the UDM participates in the procedure.

PCRF based P-CSCF restoration procedures:

the procedures for the IP-CAN, the IM CN subsystem, the PCRF and the UE to handle P-CSCF service interruption scenarios (see TS 23.380). In 5GS the procedure is called PCF based P-CSCF restoration (see TS 23.380) since the PCF takes the role of the PCRF.

Public network traffic:

traffic sent to the IM CN subsystem for processing according to normal rules of the NGN. This type of traffic is known as public network traffic.

Private network traffic:

traffic sent to the IM CN subsystem for processing according to an agreed set of rules specific to an enterprise. This type of traffic is known as private network traffic. Private network traffic is normally within a single enterprise, but private network traffic can also exist between two different enterprises if not precluded for regulatory reasons.

Privileged sender:

A privileged sender is allowed to send SIP messages where the identities in P-Asserted-Identity will be passed on in the P-CSCF and are not subject to further processing in the P-CSCF.

S-CSCF restoration procedures:

the procedures for the IM CN subsystem and the UE to handle S-CSCF service interruption scenarios (see TS 23.380).

Loopback routeing:

A method of routeing a SIP request back to the visited network for local breakout according to the roaming architecture for voice over IMS with local breakout as specified in TS 23.228.

UE performing the functions of an external attached network:

an independent network connected to an IMS network over the Gm interface, through a single point and which is seen by the IMS network as a specific UE; e.g. an IP-PBX.

Static Mode of Operation:

a mode of operation where the UE performing the functions of an external attached network does not initiate any IMS level registration procedures towards the operator IMS.

Canonical form of a SIP URI:

Canoncial form of a SIP URI takes the form "sip:username@domain" as specified in Section 10.3 of RFC 3261. SIP URI comparisons are performed as defined in Section 19.1.4 of RFC 3261.

Originating home network:

the home network of a user originating a transaction, and if applicable, the associated dialog.

Originating visited network:

the visited network of a user originating a transaction, and if applicable, the associated dialog.

Terminating home network:

the home network of a user terminating a transaction, and if applicable, the associated dialog.

Terminating visited network:

the visited network of a user terminating a transaction, and if applicable, the associated dialog.

Type of emergency service:

The type of emergency service is either an emergency call type standardized by 3GPP (see clause 10.1 of TS 22.101) or a similar capability not standardised by 3GPP and defined by national regulatory requirements. The generic (sos) service, identified by urn:service:sos, does not have a type of emergency service (even though usage of the generic (sos) service in the emergency call is defined).

Resource sharing:

one dedicated EPS bearer is sharing resources among several ongoing sessions such that the highest GBR (and optionally MBR) to be shared for the set of PCC/QoS rules bound to the same bearer is used as input for the calculation of the GBR (and optionally MBR) of that bearer among the sessions sharing the resources.

Fully-Qualified Domain Name (FQDN):

the syntax of the FQDN used in this specification is defined in Section 25.1 of RFC 3261.

Trusted WLAN:

A trusted non-3GPP access, where the non-3GPP access is a WLAN IP access.

Untrusted WLAN:

An untrusted non-3GPP access, where the non-3GPP access is a WLAN IP access.

Calling number verification status determination:

A feature which enables the terminating UE to determine whether number has been verified by the network as specified in RFC 8224.

Calling number verification using signature verification and attestation information:

A feature which enables a calling identity validation as specified in RFC 8224 and uses an attestation information to vouch for the accuracy of the source of origin of the call. Attestation information consists of an attestation level and an origination identifier and may be included in the Identity header field as defined in RFC 8588 and in the Attestation-Info and Origination-Id header fields as defined in subclauses 7.2.18 and 7.2.19.

Priority verification using assertion of priority information:

A feature which enables validation of a priority level provided in the Resource-Priority header field as specified in RFC 8443 and, by extension for emergency sessions, the header field value "psap-callback" provided in the Priority header field as specified in RFC 9027. As specified in RFC 8443 the Identity header field is used for the purpose of authentication of the Resource-Priority header field and, by extension for emergency sessions, the Priority header field value "psap-callback".

For the purposes of the present document, the following terms and definitions given in RFC 3261 apply (unless otherwise specified see clause 6).

Client

Dialog

Final response

Header

Header field

Loose routeing

Method

Option-tag (see Section 19.2 of RFC 3261)

Provisional response

Proxy, proxy server

Recursion

Redirect server

Registrar

Request

Response

Server

Session

(SIP) transaction

Stateful proxy

Stateless proxy

Status-code (see Section 7.2 of RFC 3261)

Tag (see Section 19.3 of RFC 3261)

Target Refresh Request

User agent client (UAC)

User agent server (UAS)

User agent (UA)

For the purposes of the present document, the following terms and definitions given in clauses 4.1.1.1 and 4a.7 of TS 23.002 apply:

3GPP AAA proxy

3GPP AAA server

Breakout Gateway Control Function (BGCF)

Call Session Control Function (CSCF)

Home Subscriber Server (HSS)

Location Retrieval Function (LRF)

Media Gateway Control Function (MGCF)

MSC Server enhanced for IMS centralized services

Multimedia Resource Function Processor (MRFP)

Packet Data Gateway (PDG)

Subscription Locator Function (SLF)

WLAN UE

For the purposes of the present document, the following terms and definitions given in TS 23.122 apply:

Equivalent Home PLMN (EHPLMN)

Home PLMN (HPLMN)

Visited PLMN (VPLMN)

For the purposes of the present document, the following terms and definitions given in clauses 3.1, 8 and 13 of TS 23.218 apply:

Filter criteria

Initial filter criteria

Initial request

ISC gateway function

Media Resource Broker (MRB)

Multimedia Resource Function Controller (MRFC)

Standalone transaction

Subsequent request

For the purposes of the present document, the following terms and definitions given in clauses 3.1, 4.3.3.1, 4.3.6, 4.6, 4.13, 4.15a, 5.2, 5.4.12.1, 5.10, Annex U, and Annex W of TS 23.228 apply:

Border control concepts

Geo-local service number

Home local service number

Implicit registration set

Interconnection Border Control Function (IBCF)

Interrogating-CSCF (I-CSCF)

IMS Application Level Gateway (IMS-ALG)

IMS application reference

IMS Application Reference Identifier (IARI)

IMS communication service

IMS Communication Service Identifier (ICSI)

IMS Services for roaming users in deployments without IMS-level roaming interfaces

Local service number

IP-Connectivity Access Network (IP-CAN)

P-CSCF enhanced for WebRTC (eP-CSCF)

Policy and Charging Rule Function (PCRF)

Private user identity

Proxy-CSCF (P-CSCF)

Public Service Identity (PSI)

Public user identity

Roaming Architecture for Voice over IMS with Local Breakout

Serving-CSCF (S-CSCF)

Statically pre-configured PSI

WebRTC IMS Client (WIC)

For the purposes of the present document, the following terms and definitions given in TS 23.292 apply:

ICS UE

SCC AS

For the purposes of the present document, the following terms and definitions given in TS 23.167 apply:

eCall over IMS

Emergency-CSCF (E-CSCF)

Geographical location information

Location identifier

Location information

For the purposes of the present document, the following terms and definitions given in TR 33.203 apply:

GPRS-IMS-Bundled Authentication (GIBA)

Port_pc

Port_ps

Port_uc

Port_us

Protected server port

Protected client port

spi_uc

spi_us

For the purposes of the present document, the following terms and definitions given in TR 21.905 apply:

IMS Credentials (IMC)

International Mobile Equipment Identity (IMEI)

IMS SIM (ISIM)

Serial NumbeR (SNR)

Type Approval Code (TAC)

Universal Integrated Circuit Card (UICC)

Universal Subscriber Identity Module (USIM)

User Equipment (UE)

For the purposes of the present document, the following terms and definitions given in RFC 2401 Appendix A apply:

Security association

A number of different security associations exist within the IM CN subsystem and within the underlying access transport. Within this document this term specifically applies to either:

the security association that exists between the UE and the P-CSCF. For this usage of the term, the term "security association" only applies to IPsec. This is the only security association that has direct impact on SIP; or
the security association that exists between the WLAN UE and the PDG. This is the security association that is relevant to the discussion of Interworking WLAN as the underlying IP-CAN.

For the purposes of the present document, the following terms and definitions given in TS 23.234 apply.

Interworking WLAN

For the purposes of the present document, the following terms and definitions given in ITU-T E.164 [57] apply:

International public telecommunication number

For the purposes of the present document, the following terms and definitions given in RFC 5012 apply:

Emergency service identifier

Emergency service URN

Public Safety Answering Point (PSAP)

PSAP URI

For the purposes of the present document, the following terms and definitions given in RFC 5627 apply:

Globally Routable User Agent URI (GRUU)

For the purposes of the present document, the following terms and definitions given in RFC 5626 apply:

Flow

For the purposes of the present document, the following terms and definitions given in TS 33.310 Annex E and documents referenced therein:

TLS session

For the purposes of the present document, the following terms and definitions given in TS 24.292 apply:

CS media

For the purposes of the present document, the following terms and definitions given in TS 24.301 apply:

IMS Voice over PS Session (IMSVoPS) indicator

Persistent EPS bearer context

For the purposes of the present document, the following terms and definitions given in TS 33.328 apply:

End-to-access edge security

For the purposes of the present document, the following terms and definitions given in 3GPP2 S.R0048-A v4.0 [86F] apply:

Mobile Equipment Identity (MEID)

Manufacturer code

Serial number

For the purposes of the present document, the following terms and definitions given in TS 24.302 apply:

Restrictive non-3GPP access network

S2a

S2b

S2c

Trusted non-3GPP access

Untrusted non-3GPP access

Unauthenticated IMSI

Firewall traversal tunnel

For the purposes of the present document, the following terms and definitions given in TS 32.240 apply:

Charging Data Function (CDF);

Charging Data Record (CDR)

Online Charging Function (OCF)

For the purposes of the present document, the following terms and definitions given in TS 32.260 apply:

IM CN subsystem Charging Identifier (ICID)

For the purposes of the present document, the following terms and definitions given in RFC 8119 apply:

Service access number

For the purposes of the present document, the following terms and definitions given in TS 22.101 apply:

eCall

Minimum Set of Data (MSD)

For the purposes of the present document, the following terms and definitions given in TS 22.011 apply:

3GPP PS data off

3GPP PS data off exempt services

For the purposes of the present document, the following terms and definitions given in TS 23.402 apply.

TWAN

For the purposes of the present document, the following terms and definitions given in TS 24.604 apply.

Diverting user

Diverted-to party

For the purposes of the present document, the following terms and definitions given in TS 23.221 apply:

Restricted Local Operator Services

For the purposes of the present document, the following terms and definitions given in TS 23.501 apply:

Stand-alone Non-Public Network

3.2 Symbols p. 65

Void.

3.3 Abbreviations |R17| p. 65

For the purposes of the present document, the following abbreviations apply:

1xx

A status-code in the range 101 through 199, and excluding 100

18x

A status-code in the range 180 through 189

2xx

A status-code in the range 200 through 299

3xx

A status-code in the range 300 through 399

4xx

A status-code in the range 400 through 499

5GC

5G Core Network

5GS

5G System

5G-AN

5G Access Network

5xx

A status-code in the range 500 through 599

6xx

A status-code in the range 600 through 699

AAA

Authentication, Authorization and Accounting

ANBR

Access Network Bitrate Recommendation

APN

Access Point

APN

Access Point Name

Application Server

ATCF

Access Transfer Control Function

AUTN

Authentication TokeN

AVP

Attribute-Value Pair

B2BUA

Back-to-Back User Agent

BFCP

Binary Floor Control Protocol

BGCF

Breakout Gateway Control Function

conditional

BRAS

Broadband Remote Access Server

BSSID

Basic Service Set Identifier

CCF

Charging Collection Function

CDF

Charging Data Function

CDR

Charging Data Record

Credentials Holder

Ciphering Key

Core Network

CPC

Calling Party's Category

CLF

Connectivity session Location and repository Function

CSCF

Call Session Control Function

DHCP

Dynamic Host Configuration Protocol

DNN

Data Network Name

DNS

Domain Name System

DOCSIS

Data Over Cable Service Interface Specification

DRVCC

Dual Radio Voice Call Continuity

DTD

Document Type Definition

DTLS

Datagram Transport Layer Security

DTMF

Dual Tone Multi Frequency

DVB

Digital Video Broadcast

DVB-RCS2

Second Generation DVB Interactive Satellite System

e2ae-security

End-to-access edge security

EATF

Emergency Access Transfer Function

Emergency Centre

ECF

Event Charging Function

ECI

E-UTRAN Cell Identity

ECN

Explicit Congestion Notification

E-CSCF

Emergency CSCF

Elementary File

eP-CSCF

P-CSCF enhanced for WebRTC

ePDG

Evolved Packet Data Gateway

EPS

Evolved Packet System

FAP

cdma2000® 1x Femtocell Access Point

FQDN

Fully Qualified Domain Name

GBA

Generic Bootstrapping Architecture

GBR

Guaranteed Bit Rate

GCID

GPRS Charging Identifier

GGSN

Gateway GPRS Support Node

GPON

Gigabit-capable Passive Optical Networks

GPRS

General Packet Radio Service

GRUU

Globally Routable User agent URI

GSTN

General Switched Telephone Network

HPLMN

Home PLMN

HSS

Home Subscriber Server

HTTP

HyperText Transfer Protocol

irrelevant

IARI

IMS Application Reference Identifier

IBCF

Interconnection Border Control Function

ICE

Interactive Connectivity Establishment

I-CSCF

Interrogating CSCF

ICS

Implementation Conformance Statement

ICID

IM CN subsystem Charging Identifier

ICSI

IMS Communication Service Identifier

Identifier

Integrity Key

IKEv2

Internet Key Exchange Protocol Version 2

IP Multimedia

IMC

IMS Credentials

IMEI

International Mobile Equipment Identity

IMS

IP Multimedia core network Subsystem

IMS-AGW

IMS Access Gateway

IMS-ALG

IMS Application Level Gateway

IMSI

International Mobile Subscriber Identity

IMSVoPS

IMS Voice over PS Session

IOI

Inter Operator Identifier

Internet Protocol

IP-CAN

IP-Connectivity Access Network

IPsec

IP security

IPv4

Internet Protocol version 4

IPv6

Internet Protocol version 6

ISC

IP Multimedia Subsystem Service Control

ISIM

IM Subscriber Identity Module

I-WLAN

Interworking - WLAN

IWF

Interworking Function

KMS

Key Management Service

LRF

Location Retrieval Function

mandatory

MAC

Message Authentication Code

MBR

Maximum guaranteed Bit Rate

MCC

Mobile Country Code

MCPTT

Mission Critical Push To Talk

MEID

Mobile Equipment IDentity

MGCF

Media Gateway Control Function

MGW

Media Gateway

MNC

Mobile Network Code

Media Function

MRB

Media Resource Broker

MRFC

Multimedia Resource Function Controller

MRFP

Multimedia Resource Function Processor

MSC

Mobile-services Switching Centre

MSD

Minimum Set of emergency related Data

MSRP

Message Session Relay Protocol

n/a

not applicable

NAI

Network Access Identifier

NA(P)T

Network Address (and Port) Translation

NASS

Network Attachment Subsystem

NAT

Network Address Translation

NCC

Network Control Center

NCC_ID

Network Control Center Identifier

NID

Network Identifier

Number Portability

optional

OCF

Online Charging Function

OLI

Originating Line Information

OMR

Optimal Media Routeing

PCC

Policy and Charging Control

PCF

Policy Control Function

PCO

Protocol Configuration Options

PCRF

Policy and Charging Rules Function

P-CSCF

Proxy CSCF

PDG

Packet Data Gateway

PDN

Packet Data Network

PDP

Packet Data Protocol

PDU

Protocol Data Unit

P-GW

PDN Gateway

PICS

Protocol Implementation Conformance Statement

PIDF-LO

Presence Information Data Format Location Object

PLMN

Public Land Mobile Network

PSAP

Public Safety Answering Point

PSI

Public Service Identity

PSTN

Public Switched Telephone Network

QCI

QoS Class Identifier

QoS

Quality of Service

RAND

RANDom challenge

RCS

Return Channel via Satellite

RCST

Return Channel via Satellite Terminal

RES

RESponse

RLOS

Restricted Local Operator Services

RTCP

Real-time Transport Control Protocol

RTP

Real-time Transport Protocol

SAC

Service Area Code

SAI

Service Area Identifier

SBA

Service Based Architecture

SBI

Service Based Interface

S-CSCF

Serving CSCF

SCTP

Stream Control Transmission Protocol

SDES

Session Description Protocol Security Descriptions for Media Streams

SDP

Session Description Protocol

SDU

Service Data Unit

SIP

Session Initiation Protocol

SLF

Subscription Locator Function

SNPN

Stand-alone Non-Public Network

SNR

Serial Number

SQN

SeQuence Number

SRVCC

Single Radio Voice Call Continuity

STUN

Session Traversal Utilities for NAT

SVN

Satellite Virtual Network

SVN-MAC

SVN Medium Access Control label

TAC

Type Approval Code

TFT

Traffic Flow Template

Telepresence

TLS

Transport Layer Security

TRF

Transit and Roaming Function

TURN

Traversal Using Relay NAT

TWAG

Trusted WLAN Access Gateway

TWAN

Trusted WLAN

User Agent

UAC

User Agent Client

UAS

User Agent Server

UDM

Unified Data Management

UDPTL

UDP Transport Layer

UDVM

Universal Decompressor Virtual Machine

User Equipment

UICC

Universal Integrated Circuit Card

URI

Uniform Resource Identifier

URL

Uniform Resource Locator

URN

Uniform Resource Name

USAT

Universal Subscriber Identity Module Application Toolkit

USIM

Universal Subscriber Identity Module

VPLMN

Visited PLMN

WebRTC

Web Real-Time Communication

WIC

WebRTC IMS Client

WLAN

Wireless Local Area Network

prohibited

xDSL

Digital Subscriber Line (all types)

XGPON1

10 Gigabit-capable Passive Optical Networks

XMAC

expected MAC

XML

eXtensible Markup Language

3A Interoperability with different IP-CAN |R6| p. 69

The IM CN subsystem can be accessed by UEs resident in different types of IP-CAN. The main body of this document, and Annex A, are general to UEs and IM CN subsystems that are accessed using any type of IP-CAN. Requirements that are dependent on the type of IP-CAN are covered in Annexes B, E, H, L, M, O, Q, R, S, U and W.

At any given time, for a given SIP transaction or dialog, the UE sees only one type of IP-CAN, as reported to it by the lower layers. The UE follows the procedures of the IP-CAN specific Annex related to the last type of IP-CAN reported, even if it is different to one used previously. In particular, handover at the radio layers between two different access technologies can result in such a change while the dialog or transaction proceeds.

At any given time, for a given SIP transaction or dialog, the P-CSCF sees only one type of IP-CAN, as determined by interface to a particular resource architecture, e.g. policy and charging control, and by the access technology reported to it over that interface, or in the absence of this, by preconfiguration in the system. The P-CSCF follows the procedures of the IP-CAN specific Annex related to the last type of IP-CAN determined, even if it is different to one used previously. In particular, handover at the radio layers between two different access technologies can result in such a change while the dialog or transaction proceeds.

It is the responsibility of the IP-CAN to ensure that usage of different bearer resources are synchronised on the handover from one IP-CAN to another, e.g. so that a signalling bearer provided by one IP-CAN is a signalling bearer (if provided by that IP-CAN) after handover, and that the appropriate QoS and resource reservation exists after handover. There is no SIP signalling associated with handover at the IP-CAN, and therefore no change in SIP state at one entity is signalled to the peer SIP entity when handover occurs.

In particular the following constraints exist that can have an impact on P-CSCF usage:

some IP-CANs can explicitly label a bearer as a signalling bearer, while others provide a bearer that has appropriate QoS, but no explicit labelling. Therefore if handover occurs from an IP-CAN with explicit labelling, to an IP-CAN with no explicit labelling, and then back to an IP-CAN with explicit labelling, the signalling will then be on a bearer that is not explicitly labelled; and
some IP-CANs support signalling of grouping of media within particular bearers, while others do not. Therefore if handover occurs from an IP-CAN with grouping, to an IP-CAN with no grouping, and then back to an IP-CAN with grouping, the signalled grouping can have been lost.

When a UE supports multiple IP-CANs, but does not support handover between those IP-CANs, the Annex specific to that IP-CAN applies unmodified.

Where handover between IP-CANs occurs without a reregistration in the IM CN subsystem, the same identies and security credentials for access to the IM CN subsystem are used before and after the handover.

At the P-CSCF, the access technology can variously use the PCRF or PCF or NASS in support of both signalling and media bearer provision (or indeed use neither). How to determine which applies is up to network dependent rules, but can be specific to the access technology used by each different UE. Not all access technologies are defined for use with NASS, and not all access technologies are defined for use with the PCRF or PCF.