Podcast
Questions and Answers
What is the primary goal of IMS in the telecommunications world?
What is the primary goal of IMS in the telecommunications world?
- To provide differentiation in services and strengthen customer relationships (correct)
- To replace traditional telephony services
- To offer cheap or free calls over the Internet
- To adopt proprietary solutions
What type of sessions can IMS provide?
What type of sessions can IMS provide?
- Only non-real-time multimedia sessions
- Only video sessions
- Both real-time and non-real-time multimedia sessions (correct)
- Only voice sessions
What is the main advantage of IMS in the telecommunications world?
What is the main advantage of IMS in the telecommunications world?
- It is a standardized solution (correct)
- It is only available for mobile networks
- It provides low-quality services
- It offers proprietary solutions
What is the primary focus of IMS?
What is the primary focus of IMS?
What is the role of IMS in the telecommunications world?
What is the role of IMS in the telecommunications world?
What is the main benefit of IMS for operators?
What is the main benefit of IMS for operators?
What is the main goal of IMS for subscribers?
What is the main goal of IMS for subscribers?
What is the key way to retain subscribers according to IMS?
What is the key way to retain subscribers according to IMS?
What is the main goal of IMS in Next Generation Networks (NGNs)?
What is the main goal of IMS in Next Generation Networks (NGNs)?
Which of the following is NOT a component of IMS architecture?
Which of the following is NOT a component of IMS architecture?
What is the role of HSS in IMS architecture?
What is the role of HSS in IMS architecture?
Which IMS component is responsible for routing mobile-to-mobile calls?
Which IMS component is responsible for routing mobile-to-mobile calls?
What is the purpose of IMS-based interworking architecture?
What is the purpose of IMS-based interworking architecture?
What is the role of P-CSCF in IMS architecture?
What is the role of P-CSCF in IMS architecture?
Which IMS component is responsible for user registration and re-registration?
Which IMS component is responsible for user registration and re-registration?
What is the primary function of S-CSCF in IMS architecture?
What is the primary function of S-CSCF in IMS architecture?
What is the primary function of the IMS?
What is the primary function of the IMS?
What is the role of the Serving CSCF (S-CSCF)?
What is the role of the Serving CSCF (S-CSCF)?
What is the main difference between 3GPP Release 5 and 3GPP Release 6?
What is the main difference between 3GPP Release 5 and 3GPP Release 6?
What is the role of the Proxy CSCF (P-CSCF)?
What is the role of the Proxy CSCF (P-CSCF)?
What is the primary function of the Interrogating CSCF (I-CSCF)?
What is the primary function of the Interrogating CSCF (I-CSCF)?
What is the role of SIP in the IMS architecture?
What is the role of SIP in the IMS architecture?
What is the main goal of IMS standardization?
What is the main goal of IMS standardization?
What is the role of the Home Subscriber Server (HSS) in the IMS architecture?
What is the role of the Home Subscriber Server (HSS) in the IMS architecture?
What is IMS also known as?
What is IMS also known as?
Who can deploy IMS?
Who can deploy IMS?
What does IMS offer to make interoperability of new MM services easier?
What does IMS offer to make interoperability of new MM services easier?
What is the primary goal of IMS for operators?
What is the primary goal of IMS for operators?
How does IMS solve service scalability?
How does IMS solve service scalability?
What is the core of IMS?
What is the core of IMS?
Why is IMS important?
Why is IMS important?
What type of decision is IMS deployment considered?
What type of decision is IMS deployment considered?
What is the role of the S-CSCF in the IMS architecture?
What is the role of the S-CSCF in the IMS architecture?
What is the function of the I-CSCF in the IMS architecture?
What is the function of the I-CSCF in the IMS architecture?
What is the role of the P-CSCF in the IMS architecture?
What is the role of the P-CSCF in the IMS architecture?
What is the function of the MRFC in the IMS architecture?
What is the function of the MRFC in the IMS architecture?
What is the function of the MRFP in the IMS architecture?
What is the function of the MRFP in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What type of platforms can the S-CSCF interface with?
What type of platforms can the S-CSCF interface with?
Where does the initial SIP request from a mobile travel to first?
Where does the initial SIP request from a mobile travel to first?
What type of services can a SIP server provide in addition to session control?
What type of services can a SIP server provide in addition to session control?
What enables operators to leverage existing infrastructure for IMS services?
What enables operators to leverage existing infrastructure for IMS services?
What interfaces with the CSE by CAP?
What interfaces with the CSE by CAP?
What is the primary function of the OSA application server framework?
What is the primary function of the OSA application server framework?
What does the OSA application server interface with through the OSA API?
What does the OSA application server interface with through the OSA API?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What do the OSA SCS and IM-SSF interface with respectively?
What do the OSA SCS and IM-SSF interface with respectively?
What is the primary function of the IM-SSF?
What is the primary function of the IM-SSF?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What is the benefit of IMS for operators in terms of revenue?
What is the benefit of IMS for operators in terms of revenue?
What is the core of IMS combining?
What is the core of IMS combining?
What does IMS offer to make interoperability of new MM services easier?
What does IMS offer to make interoperability of new MM services easier?
What is the impact of IMS architecture on service scalability?
What is the impact of IMS architecture on service scalability?
Who can deploy IMS?
Who can deploy IMS?
What is the primary goal of IMS for operators?
What is the primary goal of IMS for operators?
What is IMS also known as?
What is IMS also known as?
What is the primary function of the P-CSCF in the IMS architecture?
What is the primary function of the P-CSCF in the IMS architecture?
What is the main function of the I-CSCF in the IMS architecture?
What is the main function of the I-CSCF in the IMS architecture?
What is the purpose of the P-CSCF compressing and decompressing SIP messages?
What is the purpose of the P-CSCF compressing and decompressing SIP messages?
What is the role of the P-CSCF in forwarding SIP messages from a mobile to a SIP server?
What is the role of the P-CSCF in forwarding SIP messages from a mobile to a SIP server?
What is the role of the I-CSCF in hiding an operator's network internal structure?
What is the role of the I-CSCF in hiding an operator's network internal structure?
What is the role of the P-CSCF in detecting emergency sessions?
What is the role of the P-CSCF in detecting emergency sessions?
What is the role of the P-CSCF in maintaining a security association with the mobile?
What is the role of the P-CSCF in maintaining a security association with the mobile?
What is the role of the P-CSCF in creating CDRs?
What is the role of the P-CSCF in creating CDRs?
What is the primary function of the S-CSCF in the IMS architecture?
What is the primary function of the S-CSCF in the IMS architecture?
What is the main task of the S-CSCF in session control?
What is the main task of the S-CSCF in session control?
What is the role of the P-CSCF in the IMS architecture?
What is the role of the P-CSCF in the IMS architecture?
What is the function of the Policy Control Function (PCF) in the P-CSCF?
What is the function of the Policy Control Function (PCF) in the P-CSCF?
What is the relationship between the S-CSCF and the HSS?
What is the relationship between the S-CSCF and the HSS?
What is the purpose of the S-CSCF in relation to application servers?
What is the purpose of the S-CSCF in relation to application servers?
What is the primary function of the S-CSCF in relation to user sessions?
What is the primary function of the S-CSCF in relation to user sessions?
What is the role of the P-CSCF in relation to mobile devices?
What is the role of the P-CSCF in relation to mobile devices?
What is the main goal of IMS in Next Generation Networks (NGNs)?
What is the main goal of IMS in Next Generation Networks (NGNs)?
What is the primary function of IMS-based interworking architecture?
What is the primary function of IMS-based interworking architecture?
What is the role of IMS in the telecommunications world?
What is the role of IMS in the telecommunications world?
What is the primary focus of IMS?
What is the primary focus of IMS?
What is the main advantage of IMS for subscribers?
What is the main advantage of IMS for subscribers?
What is the role of the S-CSCF in the IMS architecture?
What is the role of the S-CSCF in the IMS architecture?
What is the role of the P-CSCF in the IMS architecture?
What is the role of the P-CSCF in the IMS architecture?
What is the primary function of the IMS-based interworking architecture?
What is the primary function of the IMS-based interworking architecture?
What is the main role of the IMS in Next Generation Networks (NGNs)?
What is the main role of the IMS in Next Generation Networks (NGNs)?
What is the focus of the IMS-based interworking architecture for NGN networking?
What is the focus of the IMS-based interworking architecture for NGN networking?
What is the primary advantage of IMS for operators?
What is the primary advantage of IMS for operators?
What is the role of IMS in achieving service convergence?
What is the role of IMS in achieving service convergence?
What is the primary goal of IMS standardization?
What is the primary goal of IMS standardization?
What is the benefit of IMS for subscribers?
What is the benefit of IMS for subscribers?
What is the key to IMS-based revenue generation for operators?
What is the key to IMS-based revenue generation for operators?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What is the main advantage of IMS in terms of service delivery?
What is the main advantage of IMS in terms of service delivery?
What enables operators to create and deliver person-to-person MM services more effectively?
What enables operators to create and deliver person-to-person MM services more effectively?
What is a key benefit of IMS architecture?
What is a key benefit of IMS architecture?
What is the core of IMS?
What is the core of IMS?
Who can deploy IMS?
Who can deploy IMS?
What type of decision is IMS deployment considered?
What type of decision is IMS deployment considered?
What is a key benefit of IMS for operators?
What is a key benefit of IMS for operators?
What does IMS offer to make interoperability of new MM services easier?
What does IMS offer to make interoperability of new MM services easier?
What is the main benefit of IMS for end-users?
What is the main benefit of IMS for end-users?
What is the role of the IMS in supporting IP multimedia sessions?
What is the role of the IMS in supporting IP multimedia sessions?
What is the primary goal of IMS standardization?
What is the primary goal of IMS standardization?
What is the main advantage of IMS for operators in terms of revenue?
What is the main advantage of IMS for operators in terms of revenue?
What is the role of SIP in the IMS architecture?
What is the role of SIP in the IMS architecture?
What is the main benefit of IMS for service convergence?
What is the main benefit of IMS for service convergence?
What is the primary goal of IMS in terms of network architecture?
What is the primary goal of IMS in terms of network architecture?
What is the main advantage of IMS in terms of interoperability and standardization?
What is the main advantage of IMS in terms of interoperability and standardization?
What type of interface does the S-CSCF use to interface with all service platforms?
What type of interface does the S-CSCF use to interface with all service platforms?
What is the primary function of the OSA application server framework?
What is the primary function of the OSA application server framework?
What protocol is used over the ISC interface for signaling?
What protocol is used over the ISC interface for signaling?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What is the role of the S-CSCF in the IMS architecture?
What is the role of the S-CSCF in the IMS architecture?
What does the OSA SCS interface with?
What does the OSA SCS interface with?
What is the primary benefit of IMS for operators in terms of revenue?
What is the primary benefit of IMS for operators in terms of revenue?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What is the primary function of the Multimedia Resource Function Processor (MRFP)?
What is the primary function of the Multimedia Resource Function Processor (MRFP)?
What is the role of the Breakout Gateway Control Function (BGCF)?
What is the role of the Breakout Gateway Control Function (BGCF)?
What type of platforms can the S-CSCF interface with?
What type of platforms can the S-CSCF interface with?
What is the primary function of the Multimedia Resource Function Controller (MRFC)?
What is the primary function of the Multimedia Resource Function Controller (MRFC)?
Where does the initial SIP request from a mobile travel to first?
Where does the initial SIP request from a mobile travel to first?
What is the primary function of the I-CSCF in the IMS architecture?
What is the primary function of the I-CSCF in the IMS architecture?
What is the primary function of the S-CSCF in the IMS architecture?
What is the primary function of the S-CSCF in the IMS architecture?
What is the primary function of the MRFP in relation to media streams?
What is the primary function of the MRFP in relation to media streams?
What type of services can the S-CSCF interface with, according to the ISC interface?
What type of services can the S-CSCF interface with, according to the ISC interface?
What protocol is used for signaling over the ISC interface?
What protocol is used for signaling over the ISC interface?
What is the primary function of the OSA application server framework?
What is the primary function of the OSA application server framework?
What does the OSA SCS interface with?
What does the OSA SCS interface with?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What enables operators to leverage existing infrastructure for IMS services?
What enables operators to leverage existing infrastructure for IMS services?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What is the primary function of the IM-SSF?
What is the primary function of the IM-SSF?
What is the primary advantage of IMS for end-users?
What is the primary advantage of IMS for end-users?
What is the primary goal of IMS standardization?
What is the primary goal of IMS standardization?
Which of the following is a type of CSCF in IMS architecture?
Which of the following is a type of CSCF in IMS architecture?
What is the primary role of IMS in terms of revenue generation?
What is the primary role of IMS in terms of revenue generation?
What is the primary function of SIP in IMS architecture?
What is the primary function of SIP in IMS architecture?
What is the primary goal of IMS in terms of service convergence?
What is the primary goal of IMS in terms of service convergence?
What is the primary benefit of IMS in terms of interoperability?
What is the primary benefit of IMS in terms of interoperability?
Which release of 3GPP is targeted at supporting real-time services?
Which release of 3GPP is targeted at supporting real-time services?
What is the main driver for operators to rapidly push IMS?
What is the main driver for operators to rapidly push IMS?
What is the primary advantage of IMS in terms of service convergence?
What is the primary advantage of IMS in terms of service convergence?
What is unique about IMS in the telecommunications world?
What is unique about IMS in the telecommunications world?
What is the primary function of the MRFP in the IMS architecture?
What is the primary function of the MRFP in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What type of relationships can IMS help build?
What type of relationships can IMS help build?
What type of platforms can the S-CSCF interface with?
What type of platforms can the S-CSCF interface with?
What is IMS designed to provide?
What is IMS designed to provide?
Where does the initial SIP request from a mobile travel to first?
Where does the initial SIP request from a mobile travel to first?
What is a key benefit of IMS for operators?
What is a key benefit of IMS for operators?
What is the primary function of the MRFC in the IMS architecture?
What is the primary function of the MRFC in the IMS architecture?
What is a key aspect of IMS architecture?
What is a key aspect of IMS architecture?
What is a key goal of IMS?
What is a key goal of IMS?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What enables operators to leverage existing infrastructure for IMS services?
What enables operators to leverage existing infrastructure for IMS services?
What is the primary function of the OSA application server framework?
What is the primary function of the OSA application server framework?
What type of services can a SIP server provide in addition to session control?
What type of services can a SIP server provide in addition to session control?
What enables operators to leverage existing infrastructure for IMS services?
What enables operators to leverage existing infrastructure for IMS services?
What interfaces with the CSE by CAP?
What interfaces with the CSE by CAP?
What do the OSA SCS and IM-SSF interface with respectively?
What do the OSA SCS and IM-SSF interface with respectively?
What is the primary function of the IM-SSF?
What is the primary function of the IM-SSF?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What does the OSA application server interface with through the OSA API?
What does the OSA application server interface with through the OSA API?
What is the main reason why IMS is seen as a key solution for operators to retain subscribers?
What is the main reason why IMS is seen as a key solution for operators to retain subscribers?
What is the primary focus of IMS in terms of network convergence?
What is the primary focus of IMS in terms of network convergence?
What is the main advantage of IMS being a standardized solution?
What is the main advantage of IMS being a standardized solution?
What type of multimedia sessions does IMS provide in addition to real-time sessions?
What type of multimedia sessions does IMS provide in addition to real-time sessions?
What is the primary benefit of IMS standardization for end-users?
What is the primary benefit of IMS standardization for end-users?
What is the main challenge faced by operators in today's competitive market?
What is the main challenge faced by operators in today's competitive market?
Which type of access network is NOT explicitly mentioned as part of the IMS scope in 3GPP Release 7?
Which type of access network is NOT explicitly mentioned as part of the IMS scope in 3GPP Release 7?
What is the main benefit of IMS for operators in terms of services?
What is the main benefit of IMS for operators in terms of services?
What is the main role of IMS in the telecommunications world?
What is the main role of IMS in the telecommunications world?
What is the primary function of the Serving CSCF (S-CSCF)?
What is the primary function of the Serving CSCF (S-CSCF)?
What is the key difference between 3GPP Release 5 and 3GPP Release 6?
What is the key difference between 3GPP Release 5 and 3GPP Release 6?
What is the main focus of IMS in terms of subscriber relationships?
What is the main focus of IMS in terms of subscriber relationships?
What is the primary benefit of IMS for operators in terms of controlling CAPEX and OPEX?
What is the primary benefit of IMS for operators in terms of controlling CAPEX and OPEX?
What is the primary function of the Proxy CSCF (P-CSCF)?
What is the primary function of the Proxy CSCF (P-CSCF)?
What is the primary focus of IMS standardization in 3GPP Release 7?
What is the primary focus of IMS standardization in 3GPP Release 7?
What enables IMS to provide a flexible and scalable architecture for operators?
What enables IMS to provide a flexible and scalable architecture for operators?
What is the primary function of the MRFP in the IMS architecture?
What is the primary function of the MRFP in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What is the role of the BGCF in the IMS architecture?
What type of platforms can the S-CSCF interface with?
What type of platforms can the S-CSCF interface with?
Where does the initial SIP request from a mobile travel to first?
Where does the initial SIP request from a mobile travel to first?
What is the primary function of the MRFC in the IMS architecture?
What is the primary function of the MRFC in the IMS architecture?
What is the role of the I-CSCF in the IMS architecture?
What is the role of the I-CSCF in the IMS architecture?
What is the primary function of the S-CSCF in the IMS architecture?
What is the primary function of the S-CSCF in the IMS architecture?
What type of media streams does the MRFP process?
What type of media streams does the MRFP process?
What is the primary role of the OSA SCS and IM-SSF in the IMS architecture?
What is the primary role of the OSA SCS and IM-SSF in the IMS architecture?
What is the purpose of the CSE in IMS?
What is the purpose of the CSE in IMS?
What is the primary function of the OSA application server framework?
What is the primary function of the OSA application server framework?
What interfaces with the CSE by CAP?
What interfaces with the CSE by CAP?
What type of services can be developed using the OSA application server framework?
What type of services can be developed using the OSA application server framework?
What is the primary advantage of using the CSE in IMS?
What is the primary advantage of using the CSE in IMS?
What is the primary function of the IM-SSF?
What is the primary function of the IM-SSF?
What is the primary consideration for IMS deployment?
What is the primary consideration for IMS deployment?
What is the primary purpose of IMS-based interworking architecture?
What is the primary purpose of IMS-based interworking architecture?
What is the main benefit of IMS in Next Generation Networks (NGNs)?
What is the main benefit of IMS in Next Generation Networks (NGNs)?
Which component is responsible for routing mobile-to-mobile calls in IMS architecture?
Which component is responsible for routing mobile-to-mobile calls in IMS architecture?
What is the primary role of the IMS in NGNs?
What is the primary role of the IMS in NGNs?
Which IMS component is responsible for user registration and re-registration?
Which IMS component is responsible for user registration and re-registration?
What is the primary goal of IMS in NGNs?
What is the primary goal of IMS in NGNs?
What is the primary purpose of IMS-based interworking architecture?
What is the primary purpose of IMS-based interworking architecture?
What is the primary role of IMS in NGNs?
What is the primary role of IMS in NGNs?
Study Notes
Introduction to IMS
- IMS (IP Multimedia Subsystem) is a standardized solution in the telecommunications world.
- It is a new architecture based on new concepts, new technologies, new partners, and ecosystem.
- IMS provides real-time and non-real-time multimedia sessions over an all-IP network.
IMS Architecture
- IMS is divided into three different types of CSCFs (Call Session Control Functions):
- Serving CSCF (S-CSCF)
- Proxy CSCF (P-CSCF)
- Interrogating CSCF (I-CSCF)
- IMS uses SIP (Session Initiation Protocol) to support signaling and session control for real-time services.
IMS Components
- MRFP (Multimedia Resource Function Processor) provides resources to be controlled by the MRFC.
- Sources media streams (for multimedia announcements)
- Processes media streams (e.g., audio transcoding, media analysis)
- Tones and announcements (applied on receipt of ACK, self-timed with BYE, or stopped on BYE)
- Supports DTMF within the bearer path.
- MRFC (Multimedia Resource Function Controller) interprets signaling information from an S-CSCF or a SIP-based Application Server and controls the media streams resources in the MRFP accordingly.
- BGCF (Breakout Gateway Control Function) selects to which PSTN network a session should be forwarded.
IMS Benefits
- Offers standardized service enablers and network interfaces for easier interoperability of new multimedia services.
- Enables operators to create and deliver person-to-person multimedia services in a way that protects the operator business model and generates new revenue.
- Provides service scalability by combining the best of two worlds: datacom industry and telecom industry.
IMS Standardization
- IMS was initially standardized by 3GPP (3rd Generation Partnership Project) as part of its Release 5 specifications.
- Release 6 supports real-time services.
- Release 7 standardization extends IMS scope to any IP access network, including fixed access networks (e.g., DSL).
IMS Call Flow
- Registration and re-registration process
- Basic message flow
- Routing of mobile-to-mobile calls - session initiation
IMS (IP Multimedia Subsystem)
- Also known as Multimedia NGN (Next Generation Network)
- A strategic decision for service providers, not just a network technology decision
- Can be deployed by traditional service providers or new entities entering the IP services market
IMS Benefits
- Offers standardized service enablers and network interfaces for easier interoperability of new MM services
- Enables creation and delivery of person-to-person MM services while protecting the operator business model and generating new revenue
- Solves service scalability issues with its architecture
- Supports composing services and expanding existing ones
IMS Architecture
- Combines the best of both datacom and telecom industries
- Core components include S-CSCF, P-CSCF, and I-CSCF
S-CSCF (Serving Call State Control Function)
- Provides session control services for a user
- Maintains session states for registered users and performs tasks such as:
- Registration
- Session control
- Proxy server
- Interactions with application servers
- Other functions (e.g., service-related event notifications, generating Call Detail Records)
P-CSCF (Proxy Call State Control Function)
- A mobile's first contact point inside a local IMS
- Acts as a SIP Proxy Server
- Performs functions such as:
- Forwarding SIP requests from a mobile to the mobile's home network
- Forwarding SIP messages from the network to a mobile
- Compression and decompression of SIP messages
- Maintaining a security association with the mobile
I-CSCF (Interrogating Call State Control Function)
- An optional function that hides an operator's network internal structure from an external network
- Serves as a central contact point for sessions destined to a subscriber of that network
- Selects an S-CSCF for a user's session based on capabilities required by the user
Application Servers
- SIP Application Server: provides session control and value-added services
- Camel Service Environment (CSE): provides legacy Intelligent Network (IN) services
- OSA Application Server: provides a standardized way for third-party applications to access the IMS
Flow of Information
- Registration and re-registration processes involve S-CSCF, P-CSCF, and I-CSCF
- Basic message flow includes SIP registration, session establishment, and call setup
- Mobile-to-mobile calls are routed through the IMS architecture
IMS Overview
- IMS (IP Multimedia Subsystem) is the technology that will prevail in Next Generation Networks (NGNs) for converging IP networks and facilitating vertical handoff.
- IMS is also known as Multimedia NGN.
IMS Architecture
- IMS provides standardized service enablers and network interfaces for achieving interoperability of new multimedia services.
- The core of IMS combines the best of two worlds: datacom industry and telecom industry.
IMS Components
- Multimedia Resource Function Processor (MRFP): provides resources, sources and processes media streams, and supports DTMF within the bearer path.
- Multimedia Resource Function Controller (MRFC): interprets signaling information and controls media streams resources in MRFP.
- Breakout Gateway Control Function (BGCF): selects the PSTN network for a session and forwards session signaling to MGCF and BGCF in the destination PSTN network.
Service Architecture
- The service architecture involves a SIP request from a mobile, which travels from the originating mobile to the visited P-CSCF, then to the I-CSCF (if used) in the originating mobile's home network.
- The I-CSCF selects an S-CSCF in the home network for the user session and forwards the SIP request.
- The S-CSCF interfaces with internal and external service platforms using the ISC interface and the signaling protocol is SIP.
IMS Standardization
- IMS was initially standardized by 3GPP as part of Release 5 specifications, targeted at supporting non-real-time services.
- Release 6 supports real-time services, and Release 7 extends IMS scope to any IP access network, including fixed access networks.
IMS Benefits
- IMS offers standardized service enablers and network interfaces for achieving interoperability of new multimedia services.
- IMS enables service scalability, supports composing services and expanding existing services, and protects the operator business model while generating new revenue.
IMS Types of CSCFs
- Serving CSCF (S-CSCF)
- Proxy CSCF (P-CSCF)
- Interrogating CSCF (I-CSCF)
IMS Overview
- IMS (IP Multimedia Subsystem) is a new architecture that provides real-time and non-real-time multimedia sessions over an all-IP network.
- It targets convergence of services supplied by different types of networks, including fixed, mobile, and Internet.
- IMS is standardized by the 3rd Generation Partnership Projects (3GPP).
IMS Standardization
- IMS was initially standardized by 3GPP as part of its Release 5 specifications, targeting non-real-time services.
- Release 6 targets real-time services.
- Release 7 extends IMS scope to any IP access network, including fixed access networks, wireless local area networks (WLANs), and wireless metropolitan area networks (WiMAX).
IMS Architecture
- IMS provides all network entities and procedures to support real-time voice and multimedia IP applications.
- It uses SIP (Session Initiation Protocol) to support signaling and session control for real-time services.
- IMS architecture consists of three types of CSCFs (Call Session Control Functions):
- Serving CSCF (S-CSCF)
- Proxy CSCF (P-CSCF)
- Interrogating CSCF (I-CSCF)
Service Platforms
- There are three types of standardized platforms:
- SIP Application Server
- Open Service Access (OSA) Service Capability Server (SCS)
- IP Multimedia Service Switching Function (IM-SSF)
- S-CSCF interfaces with internal and external service platforms.
- OSA SCS and IM-SSF are gateways to other service environments.
SIP Application Server
- A SIP server can provide various value-added services.
- A lightweight SIP-based server enables the CSCF to utilize SIP-based services and interact with ISP application servers without additional components.
Camel Service Environment (CSE)
- CSE provides legacy Intelligent Network (IN) services.
- It allows operators to leverage existing infrastructure for IMS services.
- CSE interacts with the CSCF through IM-SSF.
OSA Application Server
- OSA application server framework provides a standardized way for third-party applications to access the IMS.
- The OSA application server interfaces with the CSCF through the OSA SCS by OSA API.
Multimedia Resource Function (MRF)
- MRF consists of two components:
- Multimedia Resource Function Processor (MRFP)
- Multimedia Resource Function Controller (MRFC)
- MRFP provides resources to be controlled by the MRFC.
- MRFC interprets signaling information from an S-CSCF or a SIP-based Application Server and controls the media streams resources in the MRFP accordingly.
Breakout Gateway Control Function (BGCF)
- BGCF selects the PSTN network to which a session should be forwarded.
- It is responsible for forwarding the session signaling to the appropriate MGCF and BGCF in the destination PSTN network.
Learning Objectives
- Learn about the Architecture of IMS
- Understand different working elements of IMS Core
- Learn about IMS interfaces
- Learn about Application Servers to provide functionality
- Learn about Basic Call Flow in IMS
Learning Objectives
- Learn about the Architecture of IMS
- Understand the working elements of IMS Core
- Identify IMS interfaces
- Understand Application Servers to provide functionality
- Learn Basic Call Flow in IMS
Introduction
- Successful services are available on the Internet, including email, web browsing, chat, audio/video downloading/streaming, and internet telephony
- Operators face the problem of subscriber churn due to cheap/free calls over the internet provided by new service providers
- To retain subscribers, operators need to offer differentiation in personalization, service bundling, co-branding, business-to-business relations, tariffs, single sign-on, and quality of service
What is IMS?
- IMS (IP Multimedia Subsystem) is a standardized solution in the telecommunications world
- IMS provides real-time multimedia sessions (voice, video, conference) and non-real-time multimedia sessions (Push to talk, Presence, instant messaging) over an all-IP network
- IMS targets convergence of services supplied by different types of networks (fixed, mobile, internet)
IMS Benefits
- Quality of Service enhancements
- Service Integration
- Keeps charging with user relation
- Ease of use and Security
- Controlling CAPEX and OPEX
IMS Standardization
- Initially standardized by 3GPP as part of Release 5 specifications
- Release 6 targeted at supporting real-time services
- Release 7 standardization for any IP access network, including fixed access networks (e.g., DSL)
IMS Architecture
- IMS provides network entities and procedures to support real-time voice and multimedia IP applications
- Uses SIP to support signaling and session control for real-time services
- CSCFs can be divided into three types: Serving CSCF (S-CSCF), Proxy CSCF (P-CSCF), and Interrogating CSCF (I-CSCF)
- Multimedia Resource Function Processor (MRFP) provides resources to be controlled by the MRFC
- Multimedia Resource Function Controller (MRFC) interprets signaling information from an S-CSCF or a SIP-based Application Server and controls the media streams resources in the MRFP accordingly
- Breakout Gateway Control Function (BGCF) selects to which PSTN network a session should be forwarded
Service Architecture
- The S-CSCF is responsible for interfacing with internal and external service platforms
- Three types of standardized platforms: SIP application server, Open Service Access (OSA) Service Capability Server (SCS), and IP Multimedia Service Switching Function (IM-SSF)
SIP Application Server
- Provides various value-added services in addition to session control
- A lightweight SIP-based server enables the CSCF to utilize the SIP-based services and interact with the ISP application servers without additional components
Camel Service Environment (CSE)
- Provides legacy Intelligent Network (IN) services
- Allows operators to leverage existing infrastructure for IMS services
- The CSCF interacts with CSE through IM-SSF
OSA Application Server
- Provides a standardized way for a third-party to secure access to the IMS
- Interfaces with the CSCF through the OSA SCS by OSA API (Application Programming Interface)
Examples of Flow of Information
- Registration and Re-Registration
- Basic Message Flow
- Routing of Mobile-To-Mobile Calls - Session Initiation
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Learn about IMS, a standardized solution for telecommunications, and its architecture comprising three types of CSCFs. Understand how IMS enables real-time and non-real-time multimedia sessions over an all-IP network.
