1st Edition

IP Telephony Interconnection Reference Challenges, Models, and Engineering

    390 Pages 141 B/W Illustrations
    by CRC Press

    Addressing the growth of IP telephony service offerings within the corporate and residential realm, IP Telephony Interconnection Reference: Challenges, Models, and Engineering examines the technical and regulatory issues related to IP telephony interconnection at the large scale. It describes business and interconnection models, reviews emerging architectures such as IMS and TISPAN, identifies commonly-encountered issues, and supplies solutions to technical issues.

    The authors offer a detailed overview of SPEERMINT activity and proposed architecture, the current work undertaken in i3 Forum, and the use of ENUM for interconnection—describing practices in both fixed and mobile networks. Among the first books to present information on interprovider communications and interconnection of IP telephony clouds, the text supplies a clear and up-to-date picture of the VoIP protocol jungle.

    • Provides detailed guidance on how to implement VoIP interconnect services
    • Presents an overview of deployed architectures in fixed and mobile networks used for interconnection and roaming purposes
    • Enumerates regulatory issues with a focus on Europe and the United States
    • Proposes interconnection models
    • Suggests viable solutions to technical issues

    This reference supplies an overview of interconnection practices in PSTN/mobile. It proposes solutions for overcoming service engineering issues and includes a set of recommendations to ease the proliferation of interconnection agreements and schemes. Keeping you up to speed with recent developments in IP telephony, the book facilitates the understanding of the technical and regulatory requirements needed to provide global services to your customers and successfully navigate the upcoming migration to a completely IP-based model.

    Acronyms and Abbreviations

    The Rise of IP-Based Voice and the Need for Global IP Telephony Reachability
    Introduction
    New Challenges on VoIP Service Offerings
    Why Global IP Telephony Reachability Is Needed
    The VoIP Protocols Jungle
         Overview 
         SIP 
         SDP 
         RTP/RTCP 
         SIP-I 
         SIP-T 
         BICC 
         IAX 
         DUNDi 
         TRIP 
         TGREP 
         ENUM
    What Is This Book about?

    IP TELEPHONY: OVERVIEW

    Traffic Analysis VoIP versus PSTN /Mobile
    This Chapter at a Glance
    Fixed VoIP 
         Focus on France 
         Focus on Portugal 
         Focus on Latin America 
         Focus on South Korea 
         Focus on the United States
    Mobile VoIP
    Peer-to-Peer (P2P)
    References

    IMS: IP Multimedia Subsystem
    What Is IMS? 
         Transport Layer 
         Control Layer 
         Service Layer
    IMS Functional Elements 
         Call Session Control Function (CSCF) 
         Home Subscription Server (HSS) 
         PSTN Gateways 
         Application Servers (AS) 
         IMS Flow Examples
    References
    Further Reading

    TISP AN Overview
    Overview 
         Brief History Concerning NGN Standardization 
         Basic Principles 
         TISPAN Functional Architecture 
         Brief Description of the Subsystems
              Service Level 
              Transport Layer Protocols
         SIP 
         Diameter 
         H.248 Interface between NGN and Legacy Networks 
         PSTN/ISDN Interconnection
         IP-Based External Network Interconnection 
         Interoperator IP Backbone Network
    References

    Interconnection Practices in PSTN
    Overview
    Interconnection Services Access 
         Interconnection Points 
         Interconnection Circuits
         Interconnection Services 
         Signaling
    Traffic Interconnection Circuits 
         Interconnection through Circuits Provided by Other Operators
    Traffic Registration
    Interconnection Planning and Developing 
         Interconnection Establishment Previous Information
    Services and New Services
    Security and Protection
    Numbering
    Technical Characteristics 
         Interconnection Circuits Transmission Characteristics
         Signaling Interfaces between Exchanges
              Signaling Network Structure
              Synchronization between Networks 
         Quality of Service (QoS) 
         Operation, Management, and Maintenance
    Capacity Resale
    Prices
    Transit
    PSTN Interconnection: Economic Models 
         CPNP (Calling Party Network Pays) 
         BAK (Bill and Keep) 
         Optimize Interconnection Costs
    References
    Further Reading

    Roaming Practices in Mobile Networks
    Overview
    Roaming
    Types of Roaming
    Roaming Agreements
    Roaming Data
    IMS Roaming
    References

    Interconnection Practices in GPRS Networks
    Interconnection Practices in GPRS Networks
    IMS Interconnection 
         Requirements for Voice Calls 
         SIP Profile 
         Advanced Services
    References

    IP TELEPHONY INTERCONNECTION: REQUIREMENTS AND BUSINESS MODEL

    Terminology and Definitions
    VoIP Service Providers and Telephony Service Providers
    VoIP Service Providers 
         Traditional Service Providers 
         VoIP Service Providers à la Internet
    Definitions 
         Address of Record 
         Address of Contact 
         Back-to-Back User Agent (B2BUA) 
         Call 
         Initiator, Calling Party, Caller 
         Invitee, Invited User, Called Party, Callee 
         Registrar 
         End Point
    IP Network Provider and Service Provider
    IP Telephony Administrative Domain (ITAD) 
         Proxy Server (PS) 
         Location Server (LS) 
         Interconnection Node (IN) 
              Signaling Path Border Element (SBE) 
              Data Path Border Element
    IP Telephony Administrative Domain and Autonomous Systems
    Frontiers between ITADs and ASs
    Adjacent Domains
    Balanced/Unbalanced Traffic
    Symmetric/Asymmetric Telephony Paths
    Interconnection and Peering
    Anonymization
    Assumptions
    References

    Business Actors and Relationships
    Panorama of Main VoIP Service Providers 
         Incumbent Operators 
         “Virtual” VoIP Operators     
          Proprietary Third-Party VoIP Service Providers
    Cooperation Agreements between Different Types of VoIP Service Providers
    Business Actors Involved in VoIP Interconnection 
         Customer 
         End User 
         Service Provider
         Network Provider
    Business Relationships 
         SLA (Service Level Agreement) 
         CPA (Connectivity Provisioning Agreement) 
         NIA (Network Interconnection Agreement) 
              SIA (Service Interconnection Agreement) 
         Conclusion
    References

    IP Telephony Interconnection: Service Requirements
    Introduction
    Telephony Service Providers: Toward Global IP Telephony Services 
         No Assumption on the Intraprovide Service Engineering 
         Support of Various Interconnection Models
         IP Version Agnostic 
         Global Coverage 
         Support of numbering Schemes Other Than E.164 
         Discovery of Remote Voip Service Providers and Their Capabilities 
         Service Interconnection Agreement Flexibility 
         Interoperability
         Exchange of Homogenous IP Telephony Routing Data 
         Avoid Signaling Loop 
         Ability to Configure the Call Route Selection Process 
         Support of Multiple Interprovider Telephony Routes
         Optimization of Signaling Paths and Media Paths 
         Resilience and Availability of the VoIP Service at the Service and Control Layers 
         Synchronize Service Layer and Control Layer
         Ability to Detect IP Network Provider Spirals 
         Ability to Evaluate the QoS Treatment When Selecting a Given Inter-ITAD Path 
         Operation and Maintenance (O&M) 
         Charging and Billing 
         Interprovider Interconnection Agreements Assurance and Monitoring 
         Support of Import and Export Policies 
         Security
         Protect against SPAM over Telephony (SPIT) 
         Support of Privacy and Confidentiality 
         No Assumption on the Negotiated Media Session 
         Load 
         Path-Coupled and Path-Decoupled Models 
         Planned Maintenance Operations
    Customer Requirements
         Global Reachability 
         Transparency of Interdomain Media Sessions 
         Quality of Service (QoS) 
         Cost 
         Reliability and Robustness 
         Ability to evaluate the QoS provided by the VoIP Service 
         Service Mobility and Roaming 
         Confidentiality and Privacy 
         Anonymization and Customization 
         Freedom of CODEC Usage 
         Free to Subscribe to a Service Offering 
         Service Not Bound to a Specific Interface 
         Environmental Impact
         Support of Emergency Calls 
         Ability to Support Heterogeneous Calls 
         SLA Verification
    References
    Further Readings

    Telephony Interconnection: Regulatory Constraints
    European Commission Activities 
         Analysis 
         Constraints on Service Providers Following the Adoption of the Review Proposals
    Current Activities in Europe and the United States 
         Ofcom 
         OPTA 
         BNetzA 
         AGCOM 
         ANACOM 
         RTR 
         FCC (Federal Communication Commission)
    References

    IP TELEPHONY INTERCONNECTION: STATE-OF-THE-ART AND INTERCONNECTION MODELS

    Related Ongoing Activities
    Introduction
    Current Number Portability Practices 
         The Need for Number Portability 
         Types of Number Portability 
         Service Provider Number Portability Schemes 
              All Call Query (ACQ) 
              Query on Release (QoR) Scheme 
              Call Dropback Scheme 
              Onward Routing (OR) Scheme 
         Comparisons of the Various Schemes 
         Database Queries and Call Routing 
         Potential Implications for VoIP
    ENUM 
          Overview and Use Cases 
         ENUM Deployment Models 
         Source-Based ENUM Query/Answer Mechanism
    ISN
    i3 Forum 
         SIP Profile 
         Media 
         Dimensioning
    SPEERMINT IETF Working Group 
         Overview 
         The SPEERMINT Reference Architecture 
         Interconnection Relationships
    VIPR 
    Voice Peering Fabric
    Cable Operators 
         PacketCable Overview
         PacketCable Architecture 
         Interconnect Functional Component
         ENUM Server Provisioning Protocol (ESPP)
    References
    Further Readings

    VoIP Interconnection Models
    Introduction
    Interconnection Models 
         Star Model 
         Centralized Model 
         Hybrid Model  
         Cascaded Model
    Analysis of Interconnection Models
    Reference
    Interconnection Nodes: Usage of Session
    Border Controllers
    Deployment Context
    Technical Features 
         Topology Hiding 
         Media Traffic Shaping 
         Fixing Capability Mismatches
         NAT Traversal 
         Access Control 
         Protocol Repair 
         Media Encryption
    Focus on Interconnection Segment
    Interconnection Scenarios 
         SBCs at the Border of Each ITAD 
         Shared Interconnection SBC 
         Telephony Exchange Point
    References

    Implementation Models for IP Telephony Interconnection at Large
    Introduction
    DNS-Based Mode 
         Flooding Approach
              Signaling 
              Media Layer Interactions
    References

    IP: TELEPHONY INTERCONNECTION ENGINEERING ISSUES AND SOLUTION SPACE

    Service Engineering Issues
    Content of Agreements 
         Content of Service Level Agreements (SLA) 
         Content of Service Interconnection Agreement (SIA)
    Advertisement and Discovery
    End-to-End Signaling Path Optimization
    End-to-End Media Path Optimization
    Dynamic and Flexible Interprovider IP Telephony Routing
    IP Network Provider Spiraling
    Synchronization between the Service and Network Layer
    Interprovider Congestion
    Interprovider Load Balancing
    Optimize Interconnection Costs
    Optimize Interconnection Agreements
    Bidirectionality Issue
    Legal Intercept Issues
    Topology Hiding
    Correlating between Signaling and Media Streams
    Shaping and Policing
    Frozen Interconnection Architecture
    Interprovider Monitoring 
         General Overview 
              What Is Good Quality? 
              Probes 
              Signaling 
         Interprovider Monitoring Issues
    Service Interconnection Assurance and Fulfilment
    Security Issues
    References

    Solution Space
    Overview
    TRIP (Telephony Routing IP Protocol) 
         Why a Dynamic Protocol Is Needed 
         TRIP at a Glance 
         ITAD Numbers
         Transport Considerations 
         TRIP Messages 
         TRIP Attributes
    Extend TRIP to Advertise Diverse URI Schemes
         Needs 
         Proposal
    Advertise AS Path in the Telephony Signaling Protocol 
         INP Spiral Issues 
         Prevent INP Spiral
    Optimize Inter-ITAD Quality of Service (QoS) 
         Service Need 
         Solution Proposal
              QoS Route Capability 
              Modified TRIP Route Attribute 
              On the Utilization of QoS Information 
              Illustration Example
    Interprovider Multiple Paths 
         Path Diversity 
         Enhance TRIP to Support Multiple Paths 
              Procedure 
              Example
    Avoid Inter-ITAD Congestion Phenomenon 
              Avoid Congested Links and ITADs 
              TRIP-Based Procedure to Prevent Congestion

    Summary

    References

    VoIP Interconnection Perspectives

    Biography

    Mohamed Boucadair is a Senior IP Architect with France Telecom. He has worked for France Telecom R&D and has been part of the team working on VoIP services. He is now working at the France Telecom corporate division responsible for making recommendations on the evolution of IP/MPLS core networks. He has been involved in IST research projects, working on dynamic provisioning and inter-domain traffic engineering. He has also worked as an R&D engineer in charge of dynamic provisioning, QoS, multicast and intra/inter-domain traffic engineering. He has published many journal articles and written extensively on these subject areas. Mr. Boucadair holds several patents on VoIP, IPv4 service continuity, IPv6, etc.

    Maria Isabel Borges received a degree in Electronics and Telecommunications engineering from Aveiro University, Portugal, in 1989 and the MSc from the same University in 1998. From October 1989 to September 1990 she accomplished a post-graduation degree at the same University, and was involved in training students at the laboratory of propagation. From October 1990 to February 1991 she worked at TEKA Portuguesa on a Television Receiver Only system. She joined the PT Inovação, S.A. (PTIN), formerly Centro de Estudos de Telecomunicações, in 1991, working on applied research on optical communications, until 1995. Since then, she has been involved in several national and international R&D programs, namely in the area of development and integration of broadband access networks technologies, ATM, IP networking and Services, and VoIP systems. She is involved in training actions and consulting services. She is author or co-author of several publications on the above-mentioned subjects and a reviewer of IEEE Communications Magazine.

    Pedro Neves received his B.S. and M.S. degrees in Electronics and Telecommunications Engineering from the University of Aveiro, Portugal, in 2003 and 2006 respectively. Since 2007 he has also been pursuing a Ph.D. in Computer Engineering and Telecommunications at the same University. After graduation, he became a research fellow of the Telecommunications Institute, where he worked on European funded projects on broadband wireless access networks. In June 2006 he joined PT Inovação, working on heterogeneous wireless environments in the context of European and Eurescom funded projects. In 2010 he began his research activities in the area of cloud computing, with emphasis on the relationship of this paradigm with telecom operators. He participated in more than 10 international collaborative projects, is co-author of five international books, and has published more than 30 articles in journals and conference proceedings.

    Ólafur Páll Einarsson received a BSc degree in Electical Engineering from the University of Iceland in Reykjavik in 2005. From there he moved to Copenhagen to continue his education in Telecommunication Engineering at the Technical University of Denmark (DTU) and received an MSc degree in 2007. Following his education he started to work for Icelandic Telecom (Siminn) in R&D where he participated in several national and international research projects. Some of the main areas of specialty are SIM development, mobile security, and integrating a national mobile PKI architecture in Iceland.