1327:) over the P1 reference point. POTS phone connect to A-MGW over the z interface. The signalling is converted to H.248 in the A-MGW and passed to AGCF. AGCF interprets the H.248 signal and other inputs from the A-MGW to format H.248 messages into appropriate SIP messages. AGCF presents itself as P-CSCF to the S-CSCF and passes generated SIP messages to S-CSCF or to IP border via IBCF (Interconnection Border Control Function). Service presented to S-CSCF in SIP messages trigger PES AS. AGCF has also certain service independent logic, for example on receipt of off-hook event from A-MGW, the AGCF requests the A-MGW to play dial tone.
1209:(CoIx): The physical and logical linking of carriers and service providers based on simple IP connectivity irrespective of the levels of interoperability. For example, an IP interconnection of this type is not aware of the specific end to end service and, as a consequence, service specific network performance, QoS and security requirements are not necessarily assured. This definition does not exclude that some services may provide a defined level of interoperability. However, only SoIx fully satisfies NGN interoperability requirements.
1203:(SoIx): The physical and logical linking of NGN domains that allows carriers and service providers to offer services over NGN (i.e., IMS and PES) platforms with control, signalling (i.e., session based), which provides defined levels of interoperability. For instance, this is the case of "carrier grade" voice and/or multimedia services over IP interconnection. "Defined levels of interoperability" are dependent upon the service or the QoS or the Security, etc.
1938:-based format used for describing control logic. iFCs represent a provisioned subscription of a user to an application. They are stored in the HSS as part of the IMS Subscription Profile and are downloaded to the S-CSCF upon user registration (for registered users) or on processing demand (for services, acting as unregistered users). iFCs are valid throughout the registration lifetime or until the User Profile is changed.
25:
1984:. For this situation, to provide some protection against the most significant threats, 3GPP defines some security mechanisms, which are informally known as "early IMS security," in TR33.978. This mechanism relies on the authentication performed during the network attachment procedures, which binds between the user's profile and its IP address. This mechanism is also weak because the signaling is not protected on the
877:(S-CSCF) is the central node of the signaling plane. It is a SIP server, but performs session control too. It is always located in the home network. It uses Diameter Cx and Dx interfaces to the HSS to download user profiles and upload user-to-S-CSCF associations (the user profile is only cached locally for processing reasons and is not changed). All necessary subscriber profile information is loaded from the HSS.
121:
66:
477:
399:
legacy networks to the new generation of networks based on IP networks. AGCF acts a SIP User agent towards the IMS and performs the role of P-CSCF. SIP User Agent functionality is included in the AGCF, and not on the customer device but in the network itself. Also added voice call continuity between circuit switching and packet switching domain (
1352:
660:(IMPI) is a unique permanently allocated global identity assigned by the home network operator. It has the form of a Network Access Identifier(NAI) i.e. user.name@domain, and is used, for example, for Registration, Authorization, Administration, and Accounting purposes. Every IMS user shall have one IMPI.
398:
emulation service) are introduced to the wire-line network for the sake of inheritance of services which can be provided in PSTN network. AGCF works as a bridge interconnecting the IMS networks and the Megaco/H.248 networks. Megaco/H.248 networks offers the possibility to connect terminals of the old
2002:
also did a similar effort given their fixed networks scopes, although the procedures are different. To compensate for the lack of IPsec capabilities, TLS has been added as an option for securing the Gm interface. Later 3GPP Releases have included the Digest-MD5 method, towards a Common-IMS platform,
1847:
Used to exchange User
Profile information (e.g., user-related data, group lists, user-service-related information or user location information or charging function addresses (used when the AS has not received the third-party REGISTER for a user)) between an AS (SIP AS or OSA SCS) and HSS. Also allow
1921:
The S-CSCF might apply filter criteria to determine the need to forward SIP requests to AS. It is important to note that services for the originating party will be applied in the originating network, while the services for the terminating party will be applied in the terminating network, all in the
982:
The AS-ILCM (Application Server - Incoming Leg
Control Model) and AS-OLCM (Application Server - Outgoing Leg Control Model) store transaction state, and may optionally store session state depending on the specific service being executed. The AS-ILCM interfaces to the S-CSCF (ILCM) for an incoming
487:
The IP multimedia core network subsystem is a collection of different functions, linked by standardized interfaces, which grouped form one IMS administrative network. A function is not a node (hardware box): An implementer is free to combine two functions in one node, or to split a single function
1303:(ECUR) is used, the ECF (event charging function) first reserves a number of credit units in the user's account and then authorizes the MRFC or the AS. After the service is over, the number of spent credit units is reported and deducted from the account; the reserved credit units are then cleared.
1213:
An NGN interconnection mode can be direct or indirect. Direct interconnection refers to the interconnection between two network domains without any intermediate network domain. Indirect interconnection at one layer refers to the interconnection between two network domains with one or more
632:
Various identities may be associated with IMS: IP multimedia private identity (IMPI), IP multimedia public identity (IMPU), globally routable user agent URI (GRUU), wildcarded public user identity. Both IMPI and IMPU are not phone numbers or other series of digits, but
1708:
Application server sends SIP message to MRFC to play tone and announcement. This SIP message contains sufficient information to play tone and announcement or provide information to MRFC, so that it can ask more information from application server through Cr
Interface.
2003:
yet in its own and again different approach. Although all 3 variants of Digest-MD5 authentication have the same functionality and are the same from the IMS terminal's perspective, the implementations on the Cx interface between the S-CSCF and the HSS are different.
748:
which not only protects the network, but also the IMS terminal. The use of an additional SBC between the IMS terminal and the P-CSCF is unnecessary and infeasible due to the signaling being encrypted on this leg. The terminal discovers its P-CSCF with either
991:
Public
Service Identities (PSI) are identities that identify services, which are hosted by application servers. As user identities, PSI takes the form of either a SIP or Tel URI. PSIs are stored in the HSS either as a distinct PSI or as a wildcarded PSI:
1959:
Shared - When provisioning, only a reference number (the shared iFC number) is assigned to the subscriber. During registration, only the number is sent to the CSCF, not the entire XML description. The complete XML will have previously been stored on the
1314:
IMS-based PES (PSTN Emulation System) provides IP networks services to analog devices. IMS-based PES allows non-IMS devices to appear to IMS as normal SIP users. Analog terminal using standard analog interfaces can connect to IMS-based PES in two ways:
1338:
over Gm reference point. The conversion from POTS service over the z interface to SIP occurs in the customer premises VoIP gateway. POTS signaling is converted to SIP and passed on to P-CSCF. VGW acts as SIP user agent and appears to P-CSCF as SIP
288:. From a logical architecture perspective, services need not have their own control functions, as the control layer is a common horizontal layer. However, in implementation this does not necessarily map into greater reduced cost and complexity.
675:). Also known as Address of Record (AOR). There can be multiple IMPU per IMPI. The IMPU can also be shared with another phone, so that both can be reached with the same identity (for example, a single phone-number for an entire family).
1917:
One of the most important features of IMS, that of allowing for a SIP application to be dynamically and differentially (based on the user's profile) triggered, is implemented as a filter-and-redirect signalling mechanism in the S-CSCF.
1296:(IEC) is used, a number of credit units is immediately deducted from the user's account by the ECF and the MRFC or AS is then authorized to provide the service. The service is not authorized when not enough credit units are available.
739:
that is the first point of contact for the IMS terminal. It can be located either in the visited network (in full IMS networks) or in the home network (when the visited network is not IMS compliant yet). Some networks may use a
1062:(BGCF) is a SIP proxy which processes requests for routing from an S-CSCF when the S-CSCF has determined that the session cannot be routed using DNS or ENUM/DNS. It includes routing functionality based on telephone numbers.
1042:(MRB) is a functional entity that is responsible for both collection of appropriate published MRF information and supplying of appropriate MRF information to consuming entities such as the AS. MRB can be used in two modes:
911:
reasons. It's the HSS that assigns the S-CSCF to a user, when it's queried by the I-CSCF. There are multiple options for this purpose, including a mandatory/optional capabilities to be matched between subscribers and
455:
Some operators opposed IMS because it was seen as complex and expensive. In response, a cut-down version of IMS—enough of IMS to support voice and SMS over the LTE network—was defined and standardized in 2010 as
280:(SIP). According to the 3GPP, IMS is not intended to standardize applications, but rather to aid the access of multimedia and voice applications from wireless and wireline terminals, i.e., to create a form of
1998:, which adopted also the IMS architecture but has no USIM/ISIM capabilities in their terminals, published deltas to the 3GPP specifications where the Digest-MD5 is a valid authentication option. Later on,
1274:(IOI) is a globally unique identifier shared between sending and receiving networks. Each domain has its own charging network. Billing systems in different domains will also exchange information, so that
1737:
Used for the interworking with another IMS network, when the BGCF has determined that a breakout should occur in the other IMS network to send SIP message from BGCF to the IBCF in the other network
1285:(IMS-GWF) which looks like a regular SIP application server. The IMS-GWF can signal the S-CSCF to terminate the session when the user runs out of credits during a session. The AS and MRFC use the
1643:
Used for the interworking with the PSTN/CS domain, when the BGCF has determined that a breakout should occur in another IMS network to send SIP message from BGCF to the BGCF in the other network
949:
mode. An AS can be located in the home network or in an external third-party network. If located in the home network, it can query the HSS with the
Diameter Sh or Si interfaces (for a SIP-AS).
379:, inter-operability between IMS using different IP-connectivity networks, routing group identities, multiple registration and forking, presence, speech recognition and speech-enabled services (
302:
Since it is becoming increasingly easier to access content and contacts using mechanisms outside the control of traditional wireless/fixed operators, the interest of IMS is being challenged.
1319:
Via A-MGW (Access Media
Gateway) that is linked and controlled by AGCF. AGCF is placed within the Operators network and controls multiple A-MGW. A-MGW and AGCF communicate using
469:
1343:
Both A-MGW and VGW are unaware of the services. They only relay call control signalling to and from the PSTN terminal. Session control and handling is done by IMS components.
329:(RCS), which is also known as joyn or Advanced Messaging, and now RCS is operator's implementation. RCS also further added Presence/EAB (enhanced address book) functionality.
338:
IMS was defined by an industry forum called 3G.IP, formed in 1999. 3G.IP developed the initial IMS architecture, which was brought to the 3rd
Generation Partnership Project (
404:
1629:
Used for the interworking with the PSTN/CS domain, when the BGCF has determined that a breakout should occur in the same IMS network to send SIP message from BGCF to MGCF
1963:
Non-shared - when provisioning, the entire XML description of the iFC is assigned to the subscriber. During registration, the entire XML description is sent to the CSCF.
2123:
964:
983:
leg and the AS-OLCM interfaces to the S-CSCF (OLCM) for an outgoing leg. Application Logic provides the service(s) and interacts between the AS-ILCM and AS-OLCM.
1218:. The intermediate network domain(s) provide(s) transit functionality to the two other network domains. Different interconnection modes may be used for carrying
1416:
Used by AS to find the HSS holding the user profile information in a multi-HSS environment. DH_SLF_QUERY indicates an IMPU and DX_SLF_RESP return the HSS name.
440:
3GPP release 10 added support for inter device transfer, enhancements to the single radio voice call continuity (SRVCC), enhancements to IMS emergency sessions.
1582:
Originate a session on behalf of a user or public service identity, if the AS has no knowledge of a S-CSCF assigned to that user or public service identity
840:
Up to
Release 6 it can also be used to hide the internal network from the outside world (encrypting parts of the SIP message), in which case it's called a
793:
It inspects the signaling and ensures that the IMS terminals do not misbehave (e.g. change normal signaling routes, disobey home network's routing policy).
727:
Several roles of SIP servers or proxies, collectively called Call
Session Control Function (CSCF), are used to process SIP signaling packets in the IMS.
1215:
488:
into two or more nodes. Each node can also be present multiple times in a single network, for dimensioning, load balancing or organizational issues.
1330:
Via VGW (VoIP-Gateway) or SIP Gateway/Adapter on customer premises. POTS phones via VOIP Gateway connect to P-CSCF directly. Operators mostly use
84:
1385:
Used by MRFC to fetch documents (e.g. scripts, announcement files, and other resources) from an AS. Also used for media control related commands.
251:
2067:
1430:
Used by I-CSCF or S-CSCF to find a correct HSS in a multi-HSS environment. DX_SLF_QUERY indicates an IMPU and DX_SLF_RESP return the HSS name.
831:
type of DNS records), so that remote servers can find it, and use it as a forwarding point (e.g., registering) for SIP packets to this domain.
2232:
1117:(ISUP) from the MGCF to the CS network. The SGW does call control protocol conversion between SIP and ISUP/BICC under the control of the MGCF.
434:
291:
Alternative and overlapping technologies for access and provisioning of services across wired and wireless networks include combinations of
1399:
Used to send subscriber data to the S-CSCF; including filter criteria and their priority. Also used to furnish CDF and/or OCF addresses.
1260:
Rf interface to send accounting information to a CDF located in the same domain. The CDF will collect all this information, and build a
2402:
2027:
347:
1270:(ICID) as a unique identifier generated by the first IMS entity involved in a SIP transaction and used for the correlation with CDRs.
609:
613:
1256:
Offline
Charging : All the SIP network entities (P-CSCF, I-CSCF, S-CSCF, BGCF, MRFC, MGCF, AS) involved in the session use the
1172:
Media Resources are those components that operate on the media plane and are under the control of IMS core functions. Specifically,
712:
38:
1034:
The MRFP is a media plane node used to mix, source or process media streams. It can also manage access right to shared resources.
771:
It sits on the path of all signaling, and can inspect every signal; the IMS terminal must ignore any other unencrypted signaling.
444:
1948:
Trigger point - logical condition(s) which is verified against initial dialog creating SIP requests or stand-alone SIP requests.
138:
2052:
1977:
754:
2129:
807:(QoS) over the media plane. It is used for policy control, bandwidth management, etc. The PDF can also be a separate function.
2336:
2317:
2298:
2279:
2166:
696:
T-GRUU do not reveal the IMPU and are valid until the contact is explicitly de-registered or the current registration expires
1973:
1461:
Allows operators to control QoS in a user plane and exchange charging correlation information between IMS and GPRS network
1244:
are addresses distributed to each IMS entities and provide a common location for each entity to send charging information.
1102:
508:
in another network or country (the visited network). The only requirement is that they can use IP and run SIP user agents.
365:
2062:
750:
1862:
Transports CAMEL subscription information, including triggers for use by CAMEL-based application services information.
235:
1972:
It is envisaged that security defined in TS 33.203 may not be available for a while especially because of the lack of
937:, and interface with the S-CSCF using SIP. An example of an application server that is being developed in 3GPP is the
608:
of the user, and can provide information about the subscriber's location and IP information. It is similar to the GSM
819:(I-CSCF) is another SIP function located at the edge of an administrative domain. Its IP address is published in the
395:
182:
164:
102:
52:
2382:
2372:
924:
1779:
Used by the AS to request that media resources be assigned to a call when using MRB in-line mode or in query mode
1101:
A signalling gateway (SGW) interfaces with the signalling plane of the CS. It transforms lower layer protocols as
368:(a different organization from 3GPP) based their CDMA2000 Multimedia Domain (MMD) on 3GPP IMS, adding support for
1082:
1031:
The MRFC is a signalling plane node that interprets information coming from an AS and S-CSCF to control the MRFP
768:
It is assigned to an IMS terminal before registration, and does not change for the duration of the registration.
753:, or it may be configured (e.g. during initial provisioning or via a 3GPP IMS Management Object (MO)) or in the
2032:
934:
890:
it decides to which application server(s) the SIP message will be forwarded, in order to provide their services
1230:
Offline charging is applied to users who pay for their services periodically (e.g., at the end of the month).
2392:
2057:
844:(THIG). From Release 7 onwards this "entry point" function is removed from the I-CSCF and is now part of the
415:
1951:
Application server URI - specifies the application server to be forwarded to when the trigger point matches.
1334:
between VoIP gateways and P-CSCFs for security and to hide network topology. VoIP gateway link to IMS using
887:
it sits on the path of all signaling messages of the locally registered users, and can inspect every message
834:
it queries the HSS to retrieve the address of the S-CSCF and assign it to a user performing SIP registration
1144:
1094:
865:
762:
621:
403:), fixed broadband connection to the IMS, interworking with non-IMS networks, policy and charging control (
281:
146:
44:
671:(IMPU) is used by any user for requesting communications to other users (e.g. this might be included on a
2397:
1335:
849:
634:
561:
326:
277:
418:, multimedia session continuity, enhanced emergency sessions, SMS over SGs and IMS centralized services.
2047:
1985:
1193:
745:
501:
496:
The user can connect to IMS in various ways, most of which use the standard IP. IMS terminals (such as
2187:
941:
Function (VCC Server). Depending on the actual service, the AS can operate in SIP proxy mode, SIP UA (
242:. Its original formulation (3GPP Rel-5) represented an approach for delivering Internet services over
1331:
1238:
services, or real-time credit control of postpaid services. Both may be applied to the same session.
1124:(MGCF) is a SIP endpoint that interfaces with the SGW over SCTP. It also controls the resources in a
861:
741:
1131:
779:
411:
284:(FMC). This is done by having a horizontal control layer that isolates the access network from the
2407:
2377:
1548:
Used to exchange messages between an IBCF and another IBCF belonging to a different IMS network.
533:
513:
208:
142:
80:
1562:
Used to forward media streams from a TrGW to another TrGW belonging to a different IMS network.
2412:
2352:
2077:
2017:
1235:
1231:
960:
314:
292:
2153:, Advances in Intelligent and Soft Computing, Berlin, Heidelberg: Springer, pp. 247–254,
803:
It may include a Policy Decision Function (PDF), which authorizes media plane resources e.g.,
592:(UPSF), is a master user database that supports the IMS network entities that actually handle
2417:
2208:
2087:
1106:
1090:
1086:
938:
853:
426:
400:
227:
technologies are available on smartphones; IMS provides a standard protocol across vendors.
970:
894:
689:
instance. There are two types of GRUU: Public-GRUU (P-GRUU) and Temporary GRUU (T-GRUU).
430:
306:
8:
2387:
2106:
1995:
1286:
1257:
1156:
1110:
2270:
The 3G IP multimedia subsystem (IMS) : Merging the Internet and the Cellular Worlds
2268:
1751:
Used for call control services by AGCF to control H.248 A-MGW and residential gateways
1046:
Query mode: AS queries the MRB for media and sets up the call using the response of MRB
1013:
930:
820:
804:
1890:
Facilitates the management of subscriber information related to services and settings
1848:
AS to activate/deactivate filter criteria stored in the HSS on a per-subscriber basis
2332:
2313:
2294:
2275:
2162:
1723:
Used to exchange messages between CSCFs. AGCF appears as a P-CSCF to the other CSCFs
1579:
Forward SIP requests which are destined to a public service identity hosted by the AS
1447:
Used to exchange messages between SIP user equipment (UE) or Voip gateway and P-CSCF
1074:
908:
904:
593:
216:
2248:
1506:
Used for online flow-based bearer charging. Functionally equivalent to Ro interface
1351:
2154:
2037:
880:
it handles SIP registrations, which allows it to bind the user location (e.g., the
857:
220:
2158:
1827:
Used to exchange policy and charging related information between P-CSCF and PCRF
783:
645:
351:
231:
2145:
1143:(MGW) interfaces with the media plane of the CS network, by converting between
1114:
1078:
686:
601:
525:
457:
318:
215:
services. Historically, mobile phones have provided voice call services over a
394:
release R1.1, the function of AGCF (access gateway control function) and PES (
2366:
1475:
Used to exchange policy decisions-related information between P-CSCF and PDF
1219:
1180:
1139:
1126:
787:
744:(SBC) for this function. The P-CSCF is at its core a specialized SBC for the
672:
605:
285:
224:
2143:
Zhao, Peng; Wei, Qun; Xia, Hailun; Zeng, Zhimin (2012), Tan, Honghua (ed.),
1526:
Notify the AS of the registered IMPU, registration state and UE capabilities
1489:
Used to exchange policy decisions-related information between PCEF and PCRF
639:
480:
3GPP / TISPAN IMS architectural overview – HSS in IMS layer (as by standard)
2072:
1174:
597:
569:
553:
509:
497:
380:
376:
262:
131:
2082:
2042:
2022:
1876:
Used by MRFC to fetch documents (scripts and other resources) from an AS
973:
service capability server (OSA SCS): Interfaces SIP to the OSA framework;
758:
517:
387:
1601:
ISUP signalling to SIP signalling and forwards SIP signalling to I-CSCF
1049:
In-Line Mode: AS sends a SIP INVITE to the MRB. The MRB sets up the call
719:, subscriber service profiles, service triggers, and other information.
1529:
Supply the AS with information to allow it to execute multiple services
942:
881:
848:(IBCF). The IBCF is used as gateway to external networks, and provides
828:
685:(GRUU) is an identity that identifies a unique combination of IMPU and
504:(PDAs) and computers) can register directly on IMS, even when they are
296:
212:
1685:
Allows an MRFC to control media stream resources provided by an MRFP.
1991:
1967:
736:
1523:
Reference point between S-CSCF and AS. Main functions are to :
238:(3GPP), as a part of the vision for evolving mobile networks beyond
1016:(e.g. voice stream mixing) and playing of tones and announcements.
625:(SLF) is needed to map user addresses when multiple HSSs are used.
541:
521:
447:
simulation service, network-provided location information for IMS,
369:
266:
2107:
Technical Specification Group Services and System Aspects (2006),
1657:
Used for exchanging messages between IMS and external IP networks
2357:
2121:
1275:
797:
505:
476:
437:
security, enhancements to services centralization and continuity.
451:
submit and delivery without MSISDN in IMS, and overload control.
1999:
1324:
716:
596:. It contains the subscription-related information (subscriber
537:
468:
391:
254:
1089:(MTP), while IMS uses SIP over IP. For media, CS networks use
354:), when SIP-based multimedia was added. Support for the older
2307:
1320:
1160:
1152:
946:
824:
775:
565:
557:
529:
310:
247:
1981:
1071:
774:
It provides subscriber authentication and may establish an
549:
422:
359:
339:
322:
273:
258:
243:
782:
security association with the IMS terminal. This prevents
421:
3GPP release 9 added support for IMS emergency calls over
1935:
1264:(CDR), which is sent to the billing system of the domain.
1148:
545:
484:
Each of the functions in the diagram is explained below.
448:
355:
239:
1945:
Priority - determines the order of checking the trigger.
1887:
UE and SIP AS (SIP AS, OSA SCS, IM-SSF) PES AS and AGCF
2012:
1793:
Used to exchange offline charging information with CDF
996:
a distinct PSI contains the PSI that is used in routing
722:
343:
2327:
Wuthnow, Mark; Stafford, Matthew; Shih, Jerry (2010).
2265:
1810:
Used to exchange online charging information with OCF
1705:
Used to exchange session controls between AS and MRFC
837:
it also forwards SIP request or response to the S-CSCF
568:
and non IMS-compatible systems, are supported through
2266:
Camarillo, Gonzalo; GarcĂa-MartĂn, Miguel A. (2007).
2128:, Mobile Communications International, archived from
800:, which reduces the round-trip over slow radio links.
711:
The HSS subscriber database contains the IMPU, IMPI,
1703:
Used to exchange information between S-CSCF and MRFC
2326:
1234:, also known as credit-based charging, is used for
75:
may be too technical for most readers to understand
2291:The IMS : IP multimedia concepts and services
2267:
2144:
2122:Alexander Harrowell, Staff Writer (October 2006),
1980:interfaces and prevalence of devices that support
1968:Security aspects of early IMS and non-3GPP systems
1615:Used to exchange messages between S-CSCF and BGCF
796:It can compress and decompress SIP messages using
643:) or alphanumeric identifiers (a SIP URI, such as
2109:IP Multimedia Subsystem (IMS), Stage 2, TS 23.228
1248:(CDF) addresses are used for offline billing and
999:a wildcarded PSI represents a collection of PSIs.
903:there can be multiple S-CSCFs in the network for
407:), emergency sessions. It also added SMS over IP.
2364:
2329:IMS : A New Model for Blending Applications
219:-style network, rather than strictly over an IP
1077:(CS) networks. For signalling, CS networks use
1012:(MRF) provides media related functions such as
693:P-GRUU reveal the IMPU and are very long lived.
637:(URIs), that can be digits (a Tel URI, such as
2142:
2068:SIP extensions for the IP multimedia subsystem
953:SIP AS: Host and execute IMS specific services
900:it enforces the policy of the network operator
893:it provides routing services, typically using
560:) are all supported. Other phone systems like
305:Examples of global standards based on IMS are
1790:P-CSCF, I-CSCF, S-CSCF, BGCF, MRFC, MGCF, AS
1309:
1281:Online charging : The S-CSCF talks to a
342:), as part of their standardization work for
16:Architectural framework of telecommunications
1904:Conversion of POTS services to SIP messages
257:by requiring support of networks other than
230:IMS was originally designed by the wireless
2308:Syed A. Ahson, Mohammed Ilyas, ed. (2009).
790:and protects the privacy of the subscriber.
53:Learn how and when to remove these messages
2028:OMA Instant Messaging and Presence Service
1925:
986:
708:expresses a set of IMPU grouped together.
350:networks. It first appeared in Release 5 (
246:. This vision was later updated by 3GPP,
2288:
1346:
1214:intermediate network domain(s) acting as
183:Learn how and when to remove this message
165:Learn how and when to remove this message
103:Learn how and when to remove this message
87:, without removing the technical details.
2243:
2241:
1829:Replacement for the Gq reference point.
1350:
957:IP Multimedia Service Switching Function
475:
472:3GPP / TISPAN IMS architectural overview
467:
1765:Reference point between AGCF and CSCF.
1671:Allows control of user-plane resources
1413:AS (SIP AS, OSA, IM-SSF) <-> SLF
1355:TISPAN IMS architecture with interfaces
846:Interconnection Border Control Function
375:3GPP release 6 added interworking with
323:Unstructured Supplementary Service Data
309:which is the basis for Voice over LTE (
276:protocols wherever possible, e.g., the
2365:
2310:IP multimedia subsystem (IMS) handbook
2053:Service capability interaction manager
1901:POTS, Analog phones and VoIP gateways
1187:
918:
2238:
2100:
1207:Connectivity-oriented interconnection
842:Topology Hiding Inter-network Gateway
85:make it understandable to non-experts
2203:
2201:
2111:, 3rd Generation Partnership Project
1654:I-CSCF, S-CSCF, external IP network
1301:event charging with unit reservation
1103:Stream Control Transmission Protocol
884:of the terminal) and the SIP address
723:Call Session Control Function (CSCF)
564:(POTS—the old analogue telephones),
321:(ViLTE), SMS/MMS over WiFi and LTE,
201:IP Multimedia Core Network Subsystem
114:
59:
18:
2151:Knowledge Discovery and Data Mining
1912:
1782:SIP, in query mode (not specified)
1053:
1019:Each MRF is further divided into a
977:
810:It also generates charging records.
13:
2293:(2 ed.). Chichester : Wiley.
2274:(2 ed.). Chichester : Wiley.
2259:
1585:Convey charging function addresses
1532:Convey charging function addresses
1167:
1070:A PSTN/CS gateway interfaces with
1021:media resource function controller
390:networks by working together with
236:3rd Generation Partnership Project
14:
2429:
2403:Telecommunications infrastructure
2346:
2198:
2125:A Pointless Multimedia Subsystem?
1427:(I-CSCF or S-CSCF) <-> SLF
1155:don't match (e.g., IMS might use
1151:. It can also transcode when the
1122:media gateway controller function
1060:Breakout Gateway Control Function
1025:media resource function processor
679:Globally Routable User Agent URI:
491:
410:3GPP release 8 added support for
386:3GPP release 7 added support for
34:This article has multiple issues.
1201:Service-oriented interconnection
1065:
1003:
925:Next generation network services
701:Wildcarded Public User Identity:
683:Globally Routable User Agent URI
352:evolution from 2G to 3G networks
145:, and discuss this issue on the
130:may have confusing or ambiguous
119:
64:
23:
2233:"What is Voice over LTE, VoLTE"
2146:"A New Mechanism of EAB in RCS"
706:wildcarded Public User Identity
653:IP Multimedia Private Identity:
575:
463:
42:or discuss these issues on the
2225:
2180:
2136:
2115:
2033:IP connectivity access network
1464:COPS (Rel5), diameter (Rel6+)
1222:signalling and media traffic.
664:IP Multimedia Public Identity:
658:IP Multimedia Private Identity
1:
2249:"3GPP Stage 2 Specifications"
2093:
2058:System Architecture Evolution
1955:There are two types of iFCs:
1720:P-CSCF, I-CSCF, S-CSCF, AGCF
1289:Ro interface towards an OCF.
669:IP Multimedia Public Identity
581:HSS – Home subscriber server:
552:) and wireless access (e.g.,
2159:10.1007/978-3-642-27708-5_33
1105:(SCTP, an IP protocol) into
1095:Real-time Transport Protocol
959:(IM-SSF): Interfaces SIP to
866:network-to-network interface
763:General Packet Radio Service
622:subscriber location function
590:user profile server function
7:
2188:"3GPP Release Descriptions"
2006:
1242:Charging function addresses
1225:
823:(DNS) of the domain (using
635:uniform resource identifier
562:plain old telephone service
502:personal digital assistants
362:networks was also provided.
327:Rich Communication Services
278:Session Initiation Protocol
10:
2436:
2289:Poikselkä, Miikka (2007).
2048:Peer-to-peer video sharing
1844:AS (SIP AS, OSA SCS), HSS
1332:session border controllers
1310:IMS-based PES architecture
1252:(OCF) for online billing.
1194:next-generation networking
922:
332:
2331:. Boca Raton: CRC Press.
2312:. Boca Raton: CRC Press.
1272:Inter Operator Identifier
1113:(SS7) protocol), to pass
862:session border controller
742:Session Border Controller
1941:The iFC is composed of:
1374:Technical specification
1294:immediate event charging
1266:Each session carries an
1250:Online Charging Function
346:mobile phone systems in
282:fixed-mobile convergence
2383:LTE (telecommunication)
2373:Audio network protocols
1932:initial filter criteria
1926:Initial filter criteria
1576:Main functions are to:
1278:charges can be applied.
1268:IMS Charging Identifier
1192:There are two types of
1010:Media Resource Function
987:Public Service Identity
528:), mobile access (e.g.
514:digital subscriber line
209:architectural framework
197:IP Multimedia Subsystem
2209:"Dispelling LTE Myths"
2078:Ultra Mobile Broadband
2018:Generic Access Network
1986:user–network interface
1396:(I-CSCF, S-CSCF), HSS
1356:
1347:Interfaces description
1246:charging data function
1093:(PCM), while IMS uses
933:(AS) host and execute
746:User–network interface
610:home location register
586:home subscriber server
481:
473:
443:3GPP release 11 added
293:Generic Access Network
2353:A decent IMS tutorial
2088:Voice call continuity
1354:
1107:Message Transfer Part
1091:Pulse-code modulation
1087:Message Transfer Part
1040:Media Resource Broker
939:Voice call continuity
614:Authentication centre
479:
471:
325:(USSD) over LTE, and
2393:Network architecture
1922:respective S-CSCFs.
1598:MGCF -> I,S-CSCF
1573:I-CSCF <-> AS
1520:S-CSCF <-> AS
1283:IMS gateway function
1188:NGN interconnection
963:to communicate with
895:Electronic Numbering
864:specialized for the
431:multimedia telephony
207:) is a standardised
143:improve this article
2231:Ian Poole, editor.
1512:TS23.203, TS32.299
1495:TS29.211, TS29.212
1436:TS29.229, TS29.212
1405:TS29.229, TS29.212
1111:Signalling System 7
967:Application Servers
931:Application servers
919:Application servers
757:or assigned in the
640:tel:+1-555-123-4567
2398:Telecommunications
1612:S-CSCF -> BGCF
1388:TCP/SCTP channels
1357:
1262:call detail record
1014:media manipulation
821:Domain Name System
817:Interrogating-CSCF
805:quality of service
482:
474:
429:, enhancements to
223:network. Various
211:for delivering IP
137:Please review the
2338:978-1-4200-9285-1
2319:978-1-4200-6459-9
2300:978-0-470-01906-1
2281:978-0-470-01818-7
2168:978-3-642-27708-5
1910:
1909:
1807:AS, MRFC, S-CSCF
1196:interconnection:
1159:, PSTN might use
909:high availability
905:load distribution
860:). The IBCF is a
299:and "naked" SIP.
269:and fixed lines.
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2038:Mobile broadband
1913:Session handling
1734:BGCF/CSCF, IBCF
1640:BGCF -> BGCF
1626:BGCF -> MGCF
1359:
1358:
1216:transit networks
1130:(MGW) across an
1075:circuit switched
1054:Breakout gateway
978:Functional model
784:spoofing attacks
629:User identities:
217:circuit-switched
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2260:Further reading
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139:Manual of Style
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2378:3GPP standards
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2358:IMS Call Flows
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2347:External links
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1115:ISDN User Part
1079:ISDN User Part
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945:) mode or SIP
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897:(ENUM) lookups
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794:
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788:replay attacks
772:
769:
735:(P-CSCF) is a
724:
721:
698:
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602:authentication
577:
574:
493:
492:Access network
490:
465:
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458:Voice over LTE
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2132:on 2010-09-18
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1066:PSTN gateways
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1023:(MRFC) and a
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1004:Media servers
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673:business card
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531:
527:
523:
519:
515:
511:
507:
503:
499:
498:mobile phones
489:
485:
478:
470:
461:
459:
450:
446:
442:
439:
436:
432:
428:
424:
420:
417:
413:
409:
406:
402:
397:
393:
389:
385:
382:
378:
374:
371:
367:
364:
361:
357:
353:
349:
345:
341:
337:
336:
330:
328:
324:
320:
316:
315:Wi-Fi Calling
312:
308:
303:
300:
298:
294:
289:
287:
286:service layer
283:
279:
275:
270:
268:
264:
260:
256:
253:
249:
245:
241:
237:
233:
228:
226:
225:voice over IP
222:
218:
214:
210:
206:
202:
198:
187:
184:
169:
166:
158:
148:
144:
140:
134:
133:
132:abbreviations
128:This article
126:
117:
116:
107:
104:
96:
93:December 2010
86:
82:
76:
73:This article
71:
62:
61:
56:
54:
47:
46:
41:
40:
35:
30:
21:
20:
2418:IMS services
2328:
2309:
2290:
2269:
2227:
2216:. Retrieved
2213:www.3gpp.org
2212:
2191:
2182:
2172:, retrieved
2150:
2138:
2130:the original
2124:
2117:
2108:
2102:
2073:Text over IP
1990:
1971:
1954:
1940:
1934:(iFC) is an
1931:
1929:
1920:
1916:
1859:IM-SSF, HSS
1828:
1748:AGCF, A-MGW
1698:S-CSCF, MRFC
1472:P-CSCF, PDF
1368:Description
1342:
1313:
1300:
1293:
1282:
1271:
1267:
1261:
1249:
1245:
1241:
1240:
1229:
1212:
1206:
1200:
1191:
1179:
1175:Media Server
1173:
1171:
1138:
1125:
1121:
1069:
1059:
1057:
1039:
1037:
1024:
1020:
1018:
1009:
1007:
990:
981:
956:
928:
875:Serving-CSCF
874:
845:
841:
816:
732:
726:
710:
705:
700:
699:
682:
678:
677:
668:
663:
662:
657:
652:
651:
644:
638:
628:
627:
620:
618:
600:), performs
589:
585:
580:
579:
576:Core network
518:cable modems
510:Fixed access
495:
486:
483:
464:Architecture
454:
381:Push to talk
304:
301:
297:softswitches
290:
271:
263:Wireless LAN
229:
204:
200:
196:
194:
179:
161:
152:
129:
99:
90:
74:
50:
43:
37:
36:Please help
33:
2083:Video share
2043:Mobile VoIP
2023:Image share
1762:AGCF, CSCF
1682:MRFC, MRFP
1486:PCEF, PCRF
1444:UE, P-CSCF
1081:(ISUP) (or
856:functions (
759:PDP Context
435:media plane
2388:Multimedia
2367:Categories
2218:2021-04-08
2174:2021-04-08
2094:References
1503:PCEF, OCS
1458:PDF, GGSN
1134:interface.
943:user agent
923:See also:
882:IP address
733:Proxy-CSCF
612:(HLR) and
588:(HSS), or
317:(VoWIFI),
261:, such as
213:multimedia
39:improve it
1992:CableLabs
1873:MRFC, AS
1851:Diameter
1836:TS29.214
1833:Diameter
1816:TS32.299
1813:Diameter
1799:TS32.299
1796:Diameter
1700:AS, MRFC
1509:Diameter
1492:Diameter
1478:Diameter
1433:Diameter
1419:Diameter
1402:Diameter
1382:MRFC, AS
1371:Protocol
1339:terminal.
1178:(MS) and
858:pinholing
765:(GPRS)).
737:SIP proxy
460:(VoLTE).
272:IMS uses
232:standards
147:talk page
45:talk page
2007:See also
1776:MRB, AS
1287:Diameter
1258:Diameter
1226:Charging
1109:(MTP, a
1027:(MRFP).
935:services
912:S-CSCFs.
854:firewall
598:profiles
570:gateways
542:CDMA2000
522:Ethernet
370:CDMA2000
267:CDMA2000
155:May 2011
1276:roaming
1236:prepaid
1097:(RTP).
1085:) over
798:SigComp
616:(AuC).
516:(DSL),
512:(e.g.,
506:roaming
333:History
141:, help
79:Please
2335:
2316:
2297:
2278:
2165:
2063:SIMPLE
2000:TISPAN
1754:H.248
1688:H.248
1674:H.248
1559:TrGWs
1545:IBCFs
1325:Megaco
1184:(MGW)
1153:codecs
868:(NNI).
717:MSISDN
538:W-CDMA
433:, IMS
392:TISPAN
255:TISPAN
1960:CSCF.
1879:HTTP
1321:H.248
1299:When
1292:When
1161:G.711
1132:H.248
965:CAMEL
947:B2BUA
825:NAPTR
776:IPsec
648:" ).
594:calls
566:H.323
558:WiMAX
530:5G NR
388:fixed
366:3GPP2
311:VoLTE
307:MMTel
248:3GPP2
234:body
2333:ISBN
2314:ISBN
2295:ISBN
2276:ISBN
2192:3GPP
2163:ISBN
1982:IPv4
1978:ISIM
1974:USIM
1865:MAP
1768:SIP
1740:SIP
1726:SIP
1712:SIP
1695:Mr'
1660:SIP
1646:SIP
1632:SIP
1618:SIP
1604:SIP
1590:SIP
1565:RTP
1556:Izi
1551:SIP
1542:Ici
1537:SIP
1517:ISC
1450:SIP
1323:.1 (
1147:and
1083:BICC
1072:PSTN
1038:The
1008:The
929:SIP
907:and
852:and
827:and
786:and
761:(in
755:ISIM
751:DHCP
713:IMSI
667:The
656:The
646:sip:
604:and
584:The
554:WLAN
550:GPRS
526:FTTx
445:USSD
425:and
423:GPRS
396:PSTN
377:WLAN
360:GPRS
358:and
348:UMTS
340:3GPP
274:IETF
259:GPRS
252:ETSI
250:and
244:GPRS
195:The
2155:doi
1994:in
1936:XML
1930:An
1884:Ut
1870:Sr
1856:Si
1841:Sh
1821:Rx
1804:Ro
1787:Rf
1773:Rc
1759:P2
1745:P1
1731:Mx
1717:Mw
1679:Mp
1665:Mn
1651:Mm
1637:Mk
1623:Mj
1609:Mi
1595:Mg
1570:Ma
1500:Gy
1483:Gx
1469:Gq
1455:Go
1441:Gm
1424:Dx
1410:Dh
1393:Cx
1379:Cr
1336:SIP
1157:AMR
1149:PCM
1145:RTP
971:OSA
961:CAP
850:NAT
829:SRV
815:An
780:TLS
778:or
546:GSM
534:LTE
449:SMS
427:EPS
416:SAE
412:LTE
405:PCC
401:VCC
356:GSM
313:),
240:GSM
205:IMS
199:or
83:to
2369::
2240:^
2211:.
2200:^
2190:.
2161:,
2149:,
2013:4G
1988:.
1898:z
1693:Mr
1163:).
1137:A
1120:A
1058:A
873:A
731:A
715:,
704:A
687:UE
619:A
572:.
556:,
548:,
544:,
540:,
536:,
532:,
524:,
520:,
500:,
414:/
383:).
344:3G
295:,
265:,
48:.
2341:.
2322:.
2303:.
2284:.
2251:.
2235:.
2221:.
2194:.
2157::
1976:/
372:.
203:(
186:)
180:(
168:)
162:(
157:)
153:(
149:.
135:.
106:)
100:(
95:)
91:(
77:.
55:)
51:(
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