1st Edition

IP Telephony Interconnection Reference
Challenges, Models, and Engineering



ISBN 9781439851784
Published November 4, 2011 by CRC Press
390 Pages 141 B/W Illustrations

USD $105.00

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Book Description

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.

Table of Contents

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

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Author(s)

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.