IP Multimedia Subsystem (IMS) Architecture and Protocols

Did you know that the global IP Multimedia Subsystem market was valued at USD 3.42 billion in 2024 and is projected to reach USD 7.41 billion by 2029 at a CAGR of 16.7% driven by accelerating 5G adoption, the shift from circuit-switched voice to VoNR, and enterprise demand for IMS-based private 5G voice and messaging services? This compelling growth trajectory underscores the critical importance of deep IMS architecture and protocol expertise for engineers working at the heart of modern mobile and converged communications.

Course Overview

The IP Multimedia Subsystem (IMS) Architecture and Protocols course by Alpha Learning Centre is meticulously designed to equip core network engineers, protocol specialists, and IMS architects with essential skills in understanding IMS architectural frameworks, mastering SIP-based session control, and configuring and troubleshooting IMS network functions across VoLTE, VoWiFi, VoNR, and Rich Communication Services deployments. This course covers the full IMS protocol stack, CSCF and HSS functions, SIP signalling, QoS and policy control, and IMS interworking with 4G and 5G networks to ensure participants can design, deploy, and optimise IMS environments with technical confidence.

Why Select This Training Course?

Selecting this IMS Architecture and Protocols course offers numerous advantages for professionals working on multimedia service delivery across mobile and converged networks. Participants will gain structured knowledge of IMS reference architecture, the roles of P-CSCF, S-CSCF, and I-CSCF, SIP signalling flows, Diameter-based interfaces, and the integration of IMS with LTE and 5G core networks providing the technical depth required for real-world IMS deployment, configuration, and troubleshooting roles.

For organisations, investing in this training ensures that core network and multimedia service teams have the structured, verifiable IMS expertise that modern operator environments demand. Research from Mordor Intelligence confirms that cloud-native IMS requires expertise in microservices orchestration, multi-vendor API integration, and VoNR session control yet most telecom engineers lack hands-on Kubernetes and cloud-native IMS experience, making structured IMS training one of the most strategically valuable investments an operator can make in its core network engineering teams.

Individuals who complete this course will benefit from enhanced career positioning in a specialised technical domain that is growing rapidly with 5G. Studies confirm that enterprise demand for IMS-based solutions is growing at 15.6% annually, driven by private 5G cores in factories, ports, and emergency services requiring IMS for push-to-talk, video, and telemetry creating sustained demand for engineers with certified IMS architecture and protocol expertise across operator, vendor, and enterprise environments.

Transform your IMS capabilities Register now for this critical advanced training programme.

Who Should Attend?

This course is suitable for:

• Core network engineers working on IMS, VoLTE, VoWiFi, and VoNR deployments
• Protocol and signalling engineers specialising in SIP and Diameter
• 4G and 5G core network architects designing multimedia service delivery
• Network operations engineers supporting IMS-based voice and messaging services
• Systems integrators deploying IMS solutions for operators and enterprises
• Technical consultants advising on IMS architecture and migration strategies
• Engineers transitioning from circuit-switched to IMS-based voice environments

What are the Training Goals?

This course aims to:

• Explain IMS reference architecture, functional entities, and interface definitions
• Describe the roles of P-CSCF, S-CSCF, I-CSCF, HSS, PCRF, and media gateway functions
• Master SIP signalling protocols including registration, session establishment, and termination flows
• Understand Diameter-based interfaces including Cx, Rx, and Gm reference points
• Analyse VoLTE, VoWiFi, and VoNR call flows and IMS bearer establishment procedures
• Apply QoS and policy control frameworks within the IMS architecture
• Evaluate IMS interworking with 4G EPC and 5G core network environments
• Troubleshoot IMS signalling issues using SIP trace analysis and protocol diagnostic techniques

How will this Training Course be Presented?

The IP Multimedia Subsystem Architecture and Protocols course employs a comprehensive and innovative approach to ensure maximum knowledge retention and skill development. Expert-led instruction from certified IMS professionals with live deployment experience forms the core of the course, providing up-to-date technical insight into both legacy and cloud-native IMS environments.

The course utilises a blend of theoretical understanding and practical applications, allowing participants to apply their knowledge to realistic IMS deployment and troubleshooting scenarios. Advanced educational methodologies create a personalised and engaging learning journey through:

• Instructor-led sessions by experienced IMS architects and core network engineers
• SIP signalling flow analysis workshops using annotated call flow diagrams
• Protocol trace interpretation exercises across VoLTE, VoWiFi, and VoNR scenarios
• IMS architecture design and function placement workshops
• Troubleshooting scenarios based on real-world IMS deployment issues
• Group discussions on cloud-native IMS, VoNR migration, and RCS deployment challenges

Join us now and elevate your IMS architecture and protocol expertise to new heights!

Course Syllabus

Module 1: IMS Fundamentals and Evolution

• Telecom evolution from circuit‑switched to all‑IP packet‑switched networks.​
• IMS definition, purpose, and role in Next Generation Networks (NGN).​
• IMS as a service delivery platform: convergence of voice, video, and data.​
• IMS standardisation: 3GPP, 3GPP2, ETSI TISPAN, and CableLabs PacketCable.​
• IMS market opportunities and business drivers for operators.​
• Benefits of IMS: service creation, interoperability, and cost‑effective delivery.​

Module 2: IMS Architecture Overview

• IMS reference architecture and functional layers: application, control, media, and transport.​
• IMS as a service‑oriented architecture (SOA) and separation of control/user planes.​
• IMS support for multiple IP Connectivity Access Networks (IP‑CANs): 3G, 4G, 5G, Wi‑Fi, fixed broadband.​
• IMS deployment models: centralised, distributed, and cloud‑native architectures.​
• IMS roaming architecture: home and visited network responsibilities.​

Module 3: IMS Core Network Functions

• Call Session Control Functions (CSCF): P‑CSCF, I‑CSCF, S‑CSCF roles and responsibilities.​
• Home Subscriber Server (HSS): subscriber data management and authentication.​
• Subscription Locator Function (SLF) for distributed HSS architectures.​
• Application Servers (AS): SIP AS, OSA‑SCS, IM‑SSF for service logic execution.​
• Media Resource Function (MRF): MRFC and MRFP for media processing and conferencing.​
• Media Resource Broker (MRB) for media resource allocation.​

Module 4: IMS Interworking Functions

• Breakout Gateway Control Function (BGCF) for PSTN call routing.​
• Media Gateway Control Function (MGCF) for circuit‑switched interworking.​
• Media Gateway (MGW) for media conversion between IP and circuit‑switched networks.​
• Signalling Gateway (SGW) for SS7 signalling interworking.​
• IMS‑Application Layer Gateway (IMS‑ALG) and Translation Gateway (TrGW).​
• Interconnection Border Control Function (IBCF) for carrier‑to‑carrier interconnection.​

Module 5: IMS Reference Points and Interfaces

• User‑to‑network interfaces: Gm (UE to P‑CSCF) interface and signalling flows.​
• Control layer interfaces: Mw (CSCF to CSCF), ISC (S‑CSCF to AS), Cx/Dx (CSCF to HSS).​
• Media control interfaces: Mr/Mr’ (S‑CSCF to MRFC), Mg (MGCF to MGW).​
• Policy and charging interfaces: Rx (P‑CSCF to PCRF), Gx (PGW to PCRF).​
• Charging interfaces: Rf (offline charging), Ro (online charging).​
• Utility interfaces: Sh/Dh (AS to HSS for user data), Ut (UE to AS for configuration).​

Module 6: Session Initiation Protocol (SIP) Fundamentals

• SIP architecture, components, and role in IMS session control.​
• SIP methods: REGISTER, INVITE, ACK, BYE, CANCEL, UPDATE, PRACK, and others.​
• SIP responses: provisional (1xx), success (2xx), redirection (3xx), client error (4xx), server error (5xx).​
• SIP message structure: request line, headers, and message body.​
• SIP transactions, dialogs, and sessions: lifecycle management.​
• SIP extensions for IMS: P‑headers, preconditions, and IMS‑specific requirements.​

Module 7: Session Description Protocol (SDP)

• SDP purpose and role in multimedia session negotiation.​
• SDP message structure: session‑level and media‑level descriptions.​
• Media types, formats, transport protocols, and codec negotiation.​
• SDP offer/answer model in SIP‑based session establishment.​
• Bandwidth, quality parameters, and media attributes in SDP.​

Module 8: Diameter Protocol in IMS

• Diameter protocol architecture and role in IMS for AAA and policy.​
• Diameter message format: commands, Attribute‑Value Pairs (AVPs), and sessions.​
• Diameter applications in IMS: Cx/Dx, Sh/Dh, Rx, Gx, Rf, Ro interfaces.​
• Diameter routing, peer discovery, and transport security.​
• Diameter vs. RADIUS: protocol comparison and migration considerations.​

Module 9: IMS Identities and Addressing

• IMS Public User Identity (IMPU): SIP URI and Tel URI formats.​
• IMS Private User Identity (IMPI): authentication and subscription identification.​
• Relationship between IMPU, IMPI, and device identities (IMEI).​
• Public Service Identity (PSI) for application and service identification.​
• Wildcarded Public User Identity for scalable provisioning.​

Module 10: IMS Registration Procedures

• IMS registration architecture and flows: UE, P‑CSCF, I‑CSCF, S‑CSCF, HSS.​
• Registration state machines and timers.​
• Constructing the SIP REGISTER request: headers, authentication, and security.​
• Authentication and Key Agreement (AKA) in IMS using Diameter Cx interface.​
• Re‑registration, de‑registration, and subscription refresh mechanisms.​
• Emergency registration procedures for public safety calls.​

Module 11: IMS Session Establishment and Termination

• IMS session setup: originating and terminating call flows.​
• Constructing the SIP INVITE request: routing headers, SDP offer, and preconditions.​
• Session routing through P‑CSCF, S‑CSCF, and Application Servers.​
• Media negotiation and codec selection using SDP offer/answer.​
• Resource reservation and QoS establishment using preconditions.​
• Session modification: re‑INVITE and UPDATE procedures.​
• Session release: BYE request and session teardown flows.​

Module 12: Policy and Charging Control (PCC) in IMS

• PCC architecture: PCRF, PCEF, BBERF, TDF, and their roles.​
• Policy Control Function (PCF) in 5G Core integration with IMS.​
• QoS management: QoS Class Identifier (QCI) in LTE and 5QI in 5G.​
• Dynamic policy rules and service data flow detection.​
• Charging architectures: online (OCS) and offline (OFCS) charging systems.​
• Rx interface: AF (P‑CSCF) to PCRF communication for session‑based policies.​
• Gx interface: PCEF to PCRF for bearer establishment and policy enforcement.​

Module 13: IMS Security Architecture

• IMS security domains: access security, network domain security, and application security.​
• Authentication and Key Agreement (AKA): IMS‑AKA procedures.​
• IPsec tunnel establishment between UE and P‑CSCF for signalling protection.​
• Security Association (SA) management and integrity protection.​
• Encryption of SIP signalling and media streams (SRTP).​
• Network domain security: hop‑by‑hop security using TLS and IPsec/IKEv2.​
• Privacy and identity protection: P‑Asserted‑Identity and anonymisation.​

Module 14: VoLTE (Voice over LTE) Architecture and Procedures

• VoLTE service architecture and IMS integration with LTE/EPS.​
• LTE bearer establishment: default and dedicated bearers for VoLTE.​
• VoLTE registration and IMS PDN connection setup.​
• VoLTE call establishment: mobile‑originated and mobile‑terminated flows.​
• Quality of Service (QoS) for VoLTE: guaranteed bit rate and latency requirements.​
• VoLTE supplementary services: call forwarding, call waiting, conference calling.​
• Circuit‑Switched Fallback (CSFB) and Single Radio Voice Call Continuity (SRVCC).​

Module 15: Voice over WiFi (VoWiFi) Architecture and Procedures

• VoWiFi architecture: trusted and untrusted non‑3GPP access.​
• Evolved Packet Data Gateway (ePDG) for secure VoWiFi connectivity.​
• IKEv2 and IPsec tunnel establishment for untrusted Wi‑Fi access.​
• VoWiFi registration and PDN connection procedures.​
• VoWiFi call flows and media stream handling.​
• Mobility between Wi‑Fi and LTE: handover procedures and ANDSF role.​
• VoWiFi optimisation: QoS, WMM, and 802.11e for voice quality.​

Module 16: IMS Services and Applications

• IMS Multimedia Telephony Service (MMTel) and supplementary services.​
• Rich Communication Services (RCS) and Advanced Messaging.​
• Video calling and video conferencing over IMS.​
• Messaging services: native IMS messaging, SMS over IMS, and MMS.​
• Push‑to‑Talk over Cellular (PoC) and group communication.​
• Presence and instant messaging services.​
• Location‑based services and emergency services (E911/E112).​

Module 17: IMS Service Provisioning and Triggering

• Service profiles and initial Filter Criteria (iFC) in HSS.​
• Service triggering: matching criteria and AS invocation.​
• Application Server (AS) selection and service chaining.​
• Service continuity and user experience management.​

Module 18: IMS Roaming and Interconnection

• IMS roaming scenarios: home routing and visited network services.​
• Service‑oriented Interconnection (SoIx) and Connectivity‑oriented Interconnection (CoIx).​
• Interconnection Border Control Function (IBCF) and IPX network integration.​
• Roaming charging and settlement considerations.​

Module 19: IMS Signalling Analysis and Troubleshooting

• Protocol analyser tools: Wireshark, NetScout, and vendor‑specific platforms.​
• Capturing and analysing SIP traces in IMS networks.​
• Diameter message analysis on Cx, Sh, Rx, and Gx interfaces.​
• Common IMS signalling issues: registration failures, call setup failures, media problems.​
• Root cause analysis and troubleshooting methodology.​

Module 20: IMS Performance and Optimisation

• IMS Key Performance Indicators (KPIs): registration success rate, call setup success rate, latency.​
• Capacity planning and dimensioning for IMS networks.​
• Load balancing across CSCF and AS instances.​
• Voice quality optimisation: codec selection, jitter, packet loss mitigation.​
• End‑to‑end Quality of Experience (QoE) monitoring and improvement.​

Module 21: IMS in 5G Networks

• IMS evolution for 5G: integration with 5G Core (5GC).​
• Voice over 5G NR (Vo5G/VoNR) architecture and procedures.​
• Network slicing and IMS: dedicated slices for voice and multimedia services.​
• Service‑Based Architecture (SBA) and IMS northbound interfaces.

Training Impact

The impact of IMS architecture and protocols training is evident through the scale and complexity of IMS-dependent service deployments globally, which consistently demonstrate that organisations with structured IMS expertise achieve better deployment outcomes and faster resolution of signalling issues.

Research indicates that organisations implementing structured IMS training demonstrate measurable improvements in deployment efficiency. A case study from Nokia’s Digital Automation Cloud deployment for industrial private 5G sites demonstrated that engineers with certified IMS architecture knowledge were able to design and validate compact IMS cores delivering local voice, push-to-talk, and messaging services across hundreds of industrial locations an outcome directly dependent on the protocol-level IMS expertise this course develops, particularly in SIP session control, bearer management, and IMS interworking with 5G standalone core networks.

These case studies highlight the tangible benefits of implementing advanced IMS expertise:

• Improved multimedia service deployment quality through systematic understanding of IMS architecture, SIP signalling, and Diameter interface design
• Enhanced VoLTE and VoNR service quality through comprehensive knowledge of IMS bearer establishment, QoS policy control, and session continuity mechanisms
• Increased troubleshooting effectiveness through structured SIP trace analysis and protocol diagnostic methodology
• Strengthened 5G voice readiness through deep understanding of IMS interworking with 5G SA core and VoNR architecture

By investing in this advanced training, organisations can expect to see:

• Significant improvement in IMS deployment quality and multimedia service reliability across VoLTE, VoWiFi, and VoNR environments
• Improved ability to manage cloud-native IMS environments with advanced protocol knowledge and architecture design capability
• Enhanced decision-making through comprehensive IMS and 5G core integration expertise
• Increased organisational self-sufficiency through structured IMS engineering capability across design, deployment, and operations functions

Transform your career and organisational performance Enrol now to master IP Multimedia Subsystem (IMS) Architecture and Protocols!