2. IMS Resources
• 3rd Generation Partnership Project (3GPP) unites
telecommunications standard development organizations;
• IMS specification began in 3GPP Release 5 as part of the core
network evolution from circuit-switching to packet-switching and
was refined by subsequent Releases;
• http://www.3gpp.org/technologies/keywords-acronyms/109-ims
3. IMS Resources
• Telecommunications and Internet converged Services and
Protocols for Advanced Networking;
• Key standardization body in creating the Next Generation
Networks (NGN) specifications;
• Adopt the 3GPP IMS (IP Multimedia Subsystem) standard for
SIP-based applications, but also add further functional blocks
and subsystems;
• http://www.etsi.org/tispan/
4. IMS Resources
• Internet Engineering Task Force;
• 3GPP IMS use Internet Protocol, which have been
traditionally standardized by the IETF. Therefore, 3GPP
collaborate with IETF in developing protocols that fulfills their
requirement;
• Technical documents produced by IETF are called RFCs.
Only when a particular Internet-Draft becomes an RFC can it
be considered a stable specification.
• http://www.ietf.org/
5. IMS Concept
• The IP Multimedia CN (Core Network) subsystem comprises all CN elements for
provision of multimedia services. This includes the collection of signalling and
bearer related network elements as defined in TS 23.002 [1]. IP multimedia
services are based on an IETF defined session control capability which, along
with multimedia bearers, utilises the IP-Connectivity Access Network (this may
include an equivalent set of services to the relevant subset of CS Services);
• Source: 3GPP TS 23.228 V12.5.0 (2014-06);
6. IMS Concept (Cont’d)
• In order to achieve access independence and to maintain a smooth
interoperation with wireline terminals across the Internet, the IP multimedia
subsystem attempts to be conformant to IETF "Internet standards". Therefore,
the interfaces specified conform as far as possible to IETF "Internet standards"
for the cases where an IETF protocol has been selected, e.g. SIP;
• Source: 3GPP TS 23.228 V12.5.0 (2014-06);
7. IMS Concept (Cont’d)
• The IP multimedia core network (IM CN) subsystem enables PLMN operators
to offer their subscribers multimedia services based on and built upon
Internet applications, services and protocols. There is no intention here to
standardise such services within the IM CN subsystem, the intention is that such
services will be developed by PLMN operators and other third party suppliers
including those in the Internet space using the mechanisms provided by the
Internet and the IM CN subsystem. The IM CN subsystem should enable the
convergence of, and access to, voice, video, messaging, data and web-
based technologies for the wireless user, and combine the growth of the
Internet with the growth in telecommunications;
• Source: 3GPP TS 23.228 V12.5.0 (2014-06);
11. SIP
AS
IM
SSF
OSA
CSC
Service Enabler
• The S-CSCF (IMS Core) does not handle service
interaction issues;
• The service platforms could consists of IM SSF,
OSA SCS or SIP Application Server;
• The ISC interface is between the Serving CSCF
and service platform(s);
• Easy 3rd Party Integration;
• The S-CSCF (IMS Core) shall decide whether an
Application Server is required to receive
information based on (filter) information received
from the HSS.
S-CSCF
Camel
AS
3rd
Party
AS
12. IMS Service
• Presence;
• Group and List Management;
• Push-to-Talk over Cellular;
• Voice over IP, Instant Messaging and Multimedia (Voice, Text, Video);
• Conferencing;
• Voice Call Continuity;
• IPTV over IMS;
3GPP - The 3rd Generation Partnership Project (3GPP) unites [Six] telecommunications standard development organizations (ARIB, ATIS, CCSA, ETSI, TTA, TTC), known as “Organizational Partners” and provides their members with a stable environment to produce the Reports and Specifications that define 3GPP technologies.
3GPP specifications and studies are contribution-driven, by member companies, in Working Groups and at the Technical Specification Group level.
The Four Technical Specification Groups (TSG) in 3GPP are;
Radio Access Networks (RAN),
Service & Systems Aspects (SA),
Core Network & Terminals (CT) and
GSM EDGE Radio Access Networks (GERAN).
Remember: 3GPP do not produce standards. Instead, they produce Technical Specifications (TS) and Technical Reports (TR) that are approved by TSGs (above). Once approved they are submitted to the organizational partners to be submitted to their respective standardization process.
3GPP names its specification by Release. For example, 3GPP release 5 contains the first version of the IMS.
The responsibility for producing the Common IMS specifications in 3GPP lies largely with the Services and System Aspects (SA) group.
Since its creation in 2003, ETSI TISPAN (Telecommunications and Internet converged Services and Protocols for Advanced Networking) has been the key standardization body in creating the Next Generation Networks (NGN) specifications.
TISPAN is the ETSI core competence centre for:
Next generation networks
Fixed network interconnection
Fixed network evolution and next generation network access, and etc.
TISPAN is responsible for coordination of NGN functions
where an IP Multimedia Subsystem is referenced; this is in conjunction with 3GPP and in accordance with the agreements regarding Common IMS
which require cooperation with appropriate ETSI bodies or external organisations.
Source: http://portal.etsi.org/tispan/TISPAN_ToR.asp
NGN Release 1 was finalized in December 2005, provided the robust and open standards that industry required for the development, testing and implementation of the first generation of NGN systems. NGN Release 1 specifications adopt the 3GPP IMS (IP Multimedia Subsystem) standard for SIP-based applications, but also add further functional blocks and subsystems to handle non-SIP applications. Initially TISPAN worked on harmonizing the IMS core for both wireless and wireline networks.
However in early 2008, the common IMS specifications were transferred back to 3GPP so that one unique standards organization be responsible for providing a Common IMS fitting any network (fixed, 3GPP, CDMA2000, etc.).
NGN Release 2 was finalized early 2008, and added key element to the NGN such as IMS and non IMS based IPTV, Home Networks and devices, as well as NGN interconnect with Corporate Networks.
Initially, IMS was an all-IP system designed to assist mobile operators deliver next generation interactive and interoperable services, cost-effectively, over an architecture providing the flexibility of the Internet.
Session Initiation Protocol was selected as the signalling mechanism for IMS, thereby allowing voice, text and multimedia services to traverse all connected networks. 3GPP works closely with experts in the IETF to ensure maximum re-usability of internet standards, preventing fragmentation of IMS standards.
Note: TS 23.002 presents the possible architectures of the 3GPP System, covering both UTRAN, GERAN radio access technologies, Evolved Packet System, IMS etc. Source: 3GPP TS 23.002 V12.5.0 (2014-06) http://www.3gpp.org/DynaReport/23002.htm
IMS architecture can be simplified for understanding by applying ‘layer’. Separation of service from session control, transport and access in the general architecture is enabling the capabilities for fixed mobile convergence into single core network, and empower speedy service development and deployment on the top most layer.
The proposed architecture is meant to simplify the delivery of these services regardless of subscriber access method weather connecting via LAN, , WiMAX/WiFi, 3G, or home broadband services.
The architecture itself invites vendors to compete and offer IMS components to the carriers. This natural market behavior will help carriers with the IP communications services build out process by providing multiple vendors, several technology choices and price comparison for IMS technology.
As RFC standards provide some assurance that protocols will behave as expected regardless of the software delivering the service
The S-CSCF (IMS Core) shall decide whether an Application Server is required to receive information related to an incoming SIP session request to ensure appropriate service handling.. The decision at the S-CSCF is based on (filter) information received from the HSS.
Source : 3GPP TS 23.228 V5.15.0 (2006-06), Technical Specification Group Services and System Aspects
SIP AS Definition:
SIP Application Server: Host and execute IMS specific services;
IM-SSF Definition:
IP Multimedia Service Switching Function. Interfaces SIP to CAP to communicate with CAMEL Application Servers;
OSA CSC Definition:
OSA Service Capability Server (OSA SCS) : Interfaces SIP to the OSA framework;
CAMEL Definition:
The CAMEL Application Part (CAP) is a signalling protocol used in the Intelligent Network (IN) architecture. CAP is based on a subset of the ETSI Core and allows for the implementation of carrier-grade, value added services such as unified messaging, prepaid, fraud control and Freephone in both the GSM voice and GPRS data networks. CAMEL is a means of adding intelligent applications to mobile (rather than fixed) networks.
Source : Wikipedia
OSA Definition:
The Open Service Access or OSA is part of the third generation mobile telecommunications network or UMTS. OSA describes how services are designed in a UMTS network.
The standards for OSA are being developed as part of the 3rd Generation Partnership Project (3GPP). The standards for OSA are published by ETSI and 3GPP.
The API for OSA is called Parlay, (or Parlay/OSA or OSA/Parlay) as the APIs are developed jointly in collaboration by 3GPP, ETSI, and the Parlay Group.
Source : Wikipedia