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Voice and Video Conferencing Fundamentals

Book Description

Voice and Video Conferencing Fundamentals

Design, develop, select, deploy, and support advanced IP-based audio and video conferencing systems

Scott Firestone, Thiya Ramalingam, Steve Fry

As audio and video conferencing move rapidly into the mainstream, customers and end users are demanding unprecedented performance, reliability, scalability, and security. In Voice and Video Conferencing Fundamentals, three leading experts systematically introduce the principles, technologies, and protocols underlying today’s state-of-the-art conferencing systems. Discover how to use these concepts and techniques to deliver unified, presence-enabled services that integrate voice, video, telephony, networks, and the Internet—and enable breakthrough business collaboration.

The authors begin with a clear, concise overview of current voice and video conferencing, including system components, operational modes, endpoints, features, and user interactivity. Next, they illuminate conferencing architectures, offering practical insights for designing today’s complex IP-based conferencing and collaboration systems.

Topics covered in this book include video codecs, media control, SIP and H.323 protocols and applications, lip synchronization in video conferencing, security, and much more. Throughout the book, the authors draw on their extensive experience as Cisco® technical leaders, showing how to avoid the most common pitfalls that arise in planning, deployment, and administration.

Voice and Video Conferencing Fundamentals is for every professional involved with audio or video conferencing: network and system administrators, engineers, technology managers, and Cisco solution partners alike. Whether you’re involved with design, development, selection, implementation, management, or support, you’ll find the in-depth knowledge you need to succeed.

Scott Firestone holds a master’s degree in computer science from MIT and has designed video conferencing and voice products since 1992, resulting in five patents. Thiya Ramalingam is an engineering manager for the Cisco Unified Communications organization. Thiya holds a master’s degree in computer engineering and an MBA degree from San Jose State University. Steve Fry, a technical leader in the Cisco Unified Communication organization, has spent the last several years designing and developing telephony and conferencing products.

  • Thoroughly understand the fundamentals of audio and video conferencing over IP networks

  • Architect networks for optimal performance and reliability in conferencing applications

  • Leverage new advances in video architecture, from emerging codecs to distributed implementations

  • Understand how SIP and H.323 compare, and when to use each

  • Optimize synchronization between audio and video

  • Secure conferencing traffic without compromising performance or connectivity

  • Learn how to evaluate vendors and make better buying decisions

  • Foreword

    Introduction

    Chapter 1 Overview of Conferencing Services

    Chapter 2 Conferencing System Design and Architecture

    Chapter 3 Fundamentals of Video Compression

    Chapter 4 Media Control and Transport

    Chapter 5 Signaling Protocols: Conferencing Using SIP

    Chapter 6 Signaling Protocols: Conferencing Using H.

    Chapter 7 Lip Synchronization in Video Conferencing

    Chapter 8 Security Design in Conferencing

    Appendix A Video Codec Standards

    This book is part of the Cisco Press® Fundamentals Series. Books in this series introduce networking professionals to new networking technologies, covering network topologies, sample deployment concepts, protocols, and management techniques.

    Category: Cisco Press/Networking

    Covers: Voice and video conferencing

    1587052687

    Table of Contents

    1. Copyright
    2. About the Authors
    3. About the Technical Reviewers
    4. Acknowledgments
    5. Icons Used in This Book
    6. Command Syntax Conventions
    7. Foreword
    8. Introduction
      1. Goals and Methods
      2. Who Should Read This Book?
      3. How This Book Is Organized
    9. 1. Overview of Conferencing Services
      1. Conference Types
        1. Ad Hoc Conferences
          1. Ad Hoc Conference Initiation: Conference Button
          2. Ad Hoc Conference Initiation: Meet Me Button
        2. Reservationless Conferences
        3. Scheduled Conferences
          1. Setting Up Scheduled Conferences
          2. Joining a Scheduled or Reservationless Conference
          3. Scheduled and Reservationless Conference Features
            1. Whiteboard Collaboration
            2. Muting and Ejecting Participants
            3. Using Talk-Over Mode
            4. Dialing Out to Participants
            5. Sidebar Conferences
      2. Voice and Video Conferencing Components
      3. Video Conferencing Modes
        1. Voice-Activated Conferences
        2. Continuous Presence Conferences
        3. Lecture Mode and Round-Robin Conferences
      4. Types of Endpoints
        1. Desktop Conferencing Systems
        2. Room Conferencing Systems
        3. Telepresence Systems
      5. Video Controls: Far-End Camera Control
      6. Text Overlay
      7. Summary
    10. 2. Conferencing System Design and Architecture
      1. Components of a Conferencing System
        1. User Interface
          1. Web Portal
          2. Voice and Telephony User Interface
          3. Meet Me Button
        2. Conference Control
        3. Control Plane
        4. Media Plane
          1. Player/Recorder
          2. Video Mixer/Compositor
          3. Video Transrater
          4. Video Transcoder
          5. Audio Mixer
            1. Network (IP/UDP) Module
            2. RFC 2833 DTMF Detection and Generation
            3. Compensating for Network Issues: The Jitter Buffer
            4. Send-Side Voice Activity Detection Module
            5. Receive-Side Voice Activity Detection Module
            6. Speaker Selection Module
            7. Criteria for Determining Whether a Stream Should Be Mixed
            8. Encoder
      2. Conferencing Architectures
        1. Centralized Architecture
        2. Distributed Architecture
          1. Accessing the Focus
          2. Conference Policy Server
          3. Media Server
        3. Full-Mesh Networks
      3. Advanced Conferencing Scenarios
        1. Escalation of Point-to-Point-to-Multipoint Call
        2. Lecture Mode Conferences
        3. Panel Mode Conference
        4. Floor Control
        5. Video Mixing and Switching Scenarios
      4. Summary
      5. References
    11. 3. Fundamentals of Video Compression
      1. Evaluating Video Quality, Bit Rate, and Signal-to-Noise Ratio
      2. Video Source Formats
        1. Profiles and Levels
        2. Frame Rates, Form Factors, and Layouts
        3. Standard and High Definitions
        4. Color Formats
      3. Basics of Video Coding
        1. Preprocessing
        2. Post-Processing
        3. Encoder Overview
          1. Transform Processing
          2. Quantization
          3. Entropy Coding
            1. Run-Length Coding
            2. Variable-Length Coding
            3. Arithmetic Coding
          4. Binary Arithmetic Coders
          5. DCT Scanning
          6. Adaptive Encoding
            1. Content-Adaptive VLC
            2. Content-Adaptive Arithmetic Coder
      4. Hybrid Coding
        1. Hybrid Decoder
        2. P-Frames
        3. Hybrid Encoder
        4. Predictor Loop
        5. Motion Estimation
          1. 1/2 Pel and 1/4 Pel Motion Estimation
          2. Conventions for Motion Estimation
          3. Overlapped Block Motion Compensation
        6. B-Frames
        7. Predictor Loops for Parameters
        8. Error Resiliency
          1. Error Correction
          2. Start Codes
          3. Reversible VLCs
          4. Data Dependency Isolation
          5. Redundant Slices
          6. Data Prioritization
      5. Scalable Layered Codecs
        1. SNR and Spatial Scalability
        2. Temporal Scalability
      6. Switching Frames
      7. Video Codecs
        1. Video Stream Hierarchy
        2. Macroblocks
        3. HD-Capable Codecs
      8. Summary
      9. References
    12. 4. Media Control and Transport
      1. Overview of RTP
        1. RTP Header
          1. First Octet in the Header
          2. Payload Type
          3. Sequence Number
          4. Time Stamp
          5. Synchronization Source Identifier
          6. Contributing Source (CSRC) Identifiers
          7. Payload Header
          8. Payload
        2. RTP Port Numbers
        3. SSRC Collisions
        4. RTP Header Extensions
      2. Overview of RTCP
        1. RTCP Packet Headers
        2. RTCP Sender Report
        3. RTCP Receiver Report
        4. RTCP Source Description (SDES)
        5. RTCP BYE
        6. RTCP APP
      3. RTP Devices in Conference Systems
        1. RTP Translator
          1. Media Termination Points
          2. Transcoders and Transraters
        2. RTP Mixer
        3. Audio Mixer
        4. Video MCU
        5. Video Switcher
      4. Video Stream RTP Formats
        1. H.263
          1. H.263-1996
            1. Mode A
            2. Mode B
            3. Mode C
          2. H.263-1998 and H.263-2000
          3. Key Frame Detection in H.263
        2. H.264
          1. Basic Packet Structure
          2. SNALU
          3. Aggregation Packet
            1. STAP
            2. MTAP
          4. Fragmentation Unit Packet
          5. Key Frame Detection in H.264
      5. Detecting Stream Loss
      6. Summary
      7. References
    13. 5. Signaling Protocols: Conferencing Using SIP
      1. SIP Overview
        1. User Agent
        2. Proxy Server
        3. Redirect Server
        4. Registrar
      2. SIP Transactions and Dialogs
      3. SIP Messages
        1. SIP Requests
          1. Request Line
          2. Request Headers
        2. SIP Responses
      4. SIP Record Routing
      5. Event Subscription and Notification
      6. Session Description Protocol
      7. SIP Conferencing Models
        1. Conference URI
        2. Early and Delayed Offer
        3. DTMF Support
          1. RFC 2833
          2. KPML
      8. Ad Hoc Audio Conferencing
      9. Ad Hoc Video Conferencing
        1. Video SDP Extensions
          1. H.261 Codec Attributes
          2. H.263 Codec Attributes
          3. H.264 Codec Attributes
        2. Bandwidth Information in the SDP
        3. Multiple Stream Support and Grouping of Media Lines
        4. Escalation and De-escalation
        5. Media Control Support
      10. Scheduled Conferences
        1. Entry IVR
        2. In-Conference Features
        3. Roll Call
        4. Hold and Resume
        5. Mute and Unmute
        6. Outdial
      11. RSVP/QoS Support in Conferencing Flows
      12. Summary
      13. References
    14. 6. Signaling Protocols: Conferencing Using H.323
      1. H.323 Overview
      2. H.323 Endpoint Aliasing
      3. H.225 Call Signaling
        1. H.225 Message Format
        2. Common H.225 Message Types Used in H.323 Signaling
          1. Setup Message
          2. Call Proceeding
          3. Alerting
          4. Setup ACK
          5. Connect
          6. Notify
          7. Release Complete
      4. H.245 Control Protocol
        1. H.245 Messages
          1. Terminal Capability Set
          2. Simultaneous Capability Set
          3. H.245 User Input Indications
          4. Indicating DTMF Relay Support in the TCS Message
          5. Master-Slave Determination
          6. Open Logical Channel Requests
            1. Logical Channel Numbers
            2. Open Logical Channel for Audio Streams
            3. Open Logical Channel for Video: H.261 and H.263 Streams
            4. Payload Types and Formats
            5. Maximum Bit Rate
            6. Video Resolution (Picture Format) and Minimum Picture Interval
            7. Open Logical Channel for H.264 Streams
            8. H.264 Profile and Level
          7. Open Logical Channel Acknowledgment
          8. Close Logical Channel
          9. Close Logical Channel Acknowledgment
          10. Request Channel Close
          11. H.245 EndSession Command
        2. Video-Specific H.245 Messages
          1. H.245 Flow Control Command
          2. H.245 Miscellaneous Indication
          3. H.245 Miscellaneous Command
        3. H.323 Fast Connect Mode
      5. Using the Empty Capability Set
        1. Call Hold Signaling with the Empty Capability Set
        2. Call Transfer with the Empty Capability Set
      6. H.323 Device Types
        1. H.323 Terminals
        2. H.323 Gateways
        3. H.323 Multipoint Control Units
        4. H.323 Gatekeepers
      7. H.323 Gatekeeper Services
        1. Required H.323 Gatekeeper Features
          1. Address Translation
          2. Bandwidth Control
          3. Admission Control
          4. Zone Management
        2. Optional H.323 Gatekeeper Features
          1. Call Authorization
          2. Call Management
          3. Bandwidth Management
        3. Gatekeeper Signaling Options
          1. Direct Endpoint Signaling
          2. Gatekeeper Routed Call Signaling
        4. Gatekeeper RAS Signaling
          1. RAS Gatekeeper Discovery
          2. RAS Messages
            1. Registration Request
            2. Registration Confirm
            3. Registration Reject
            4. Admission Request
            5. Admission Confirm
            6. Admission Reject
        5. Mid-Call Bandwidth Requests
          1. Disengage Request
          2. Disengage Confirm
        6. Configuring a Gatekeeper in Cisco Unified CallManager
        7. Configuring Gatekeeper Support in a Cisco IOS Router
        8. H.225 Call Setup for Video Devices Using a Gatekeeper
      8. Using Service Prefixes with MCUs
      9. Summary
      10. References
    15. 7. Lip Synchronization in Video Conferencing
      1. Understanding Lip Sync Skew
        1. Human Perceptions
        2. Measuring Skew
        3. Delay Accumulation
        4. Delays in the Network Path
      2. Lip Sync Approaches
        1. Poor Man’s Lip Sync
        2. Common Reference Lip Sync
      3. Understanding the Sender Side
        1. Sender Audio Path
        2. Video Source Format
          1. Low-Resolution Video Input
          2. High-Resolution Video Input
        3. Sender Video Path
      4. Understanding the Receive Side
        1. Audio Receiver Path
        2. Receiver Video Path
        3. Types of Playout Devices
      5. RTP
        1. Canonical RTP Model
        2. RTP Time Stamps
        3. Using RTP for Buffer-Level Management
      6. Correlating Timebases Using RTCP
        1. NTP
        2. Forming RTCP Packets
        3. Using RTCP for Media Synchronization
        4. Lip Sync Policy
      7. Summary
      8. References
    16. 8. Security Design in Conferencing
      1. Security Fundamentals
      2. Threats
        1. Confidentiality Attacks
        2. Denial-of-Service Attacks
          1. Depletion of Network Bandwidth
          2. Depletion of Server Resources
          3. Replay Attacks
          4. Malware
          5. Connection Hijacking
          6. RTP Hijacking
        3. Authentication and Identity Attacks
          1. Theft of Service
          2. Man-in-the-Middle Attacks
        4. Network Infrastructure Attacks
          1. Reconnaissance
          2. Layer 2 Attacks
          3. CAM Table Flooding
          4. ARP Cache Poisoning
          5. DHCP Exhaustion
          6. Rogue DHCP Servers
        5. Endpoint Infrastructure Attacks
          1. Desktop Endpoint Attacks
          2. Firmware Attacks
          3. Rogue Configuration Files
        6. Server Attacks
          1. General Port-Based Attacks
          2. Web Server Vulnerabilities
          3. Unneeded Services and Insecure Services
      3. Configuring Basic Security
      4. Port Usage
        1. H.323 Port Usage
          1. H.323 Call Flow
          2. H.323 Port Summary
        2. SIP Port Usage
        3. SCCP Port Usage
        4. Preset Port Numbers
      5. NAT and PAT
        1. NAT Classifications
          1. NAT Mapping Characteristics
          2. NAT Filtering Characteristics
            1. Endpoint-Independent Filtering
            2. Address-Dependent Filtering
            3. Address- and Port-Dependent Filtering
          3. The Symmetric NAT
        2. NAT Complications for VoIP Protocols
        3. NAT ALGs
        4. NAT/FW Traversal Solutions
          1. VPN
          2. ISDN Gateway
          3. Universal Plug-and-Play
          4. IP-IP Gateway Inside the Firewall
          5. H.460
            1. H.460.17
            2. H.460.18
            3. H.460.19
            4. H.460.18 and H.460.19 Issues
          6. NAT/FW Traversal Using STUN/TURN/ICE
            1. STUN
            2. TURN
            3. ICE
      6. Encryption Basics
        1. Symmetric Encryption
        2. Secure Hashes
        3. Asymmetric Encryption: Public Key Cryptography
          1. Public Key Encryption
          2. Digital Signatures
          3. Certificates
          4. Certificate Management
            1. CA Certificate Installation
            2. Requesting an Endpoint Certificate
            3. Endpoint Authentication
            4. Certificate Revocation
        4. Nonrepudiation
        5. Key Distribution
          1. Certificates
          2. Diffie-Hellman
      7. IPsec and TLS for Secure Signaling
        1. IPsec
        2. TLS
      8. Media Encryption
        1. security-descriptions
        2. MIKEY
      9. H.323 Encryption: H.235
        1. H.235.1
        2. H.235.2
        3. H.235.3
        4. H.235.6
      10. SIP Encryption
        1. SIP-Digest
        2. SCCP Encryption
      11. Summary
      12. References
    17. A. Video Codec Standards
      1. H.261 Compression Standard
      2. H.263 Compression Standard
      3. Additional H.263 Annexes
        1. Annex C
        2. Annex L
        3. Annex N
        4. Annex P
        5. Annex Q
        6. Annex U
        7. Annex W
        8. Annex X
      4. H.264 Compression Standard
        1. Video Formats
        2. Motion Vectors
        3. B-Frames
        4. Intra Prediction
        5. Integer Transform
        6. Quantization
        7. Entropy Coding
        8. Deblocking Filter
        9. H.264 Error Resilience
        10. H.264-SVC
      5. MPEG-4, Part 2
        1. Video Formats
        2. Motion Vectors
        3. Prediction of DCT Coefficients
        4. Quantization
        5. Entropy Coding
        6. B-Frames
        7. Scalability
      6. Codecs, Bit Rates, and Annexes Supported by Endpoints
      7. Summary
      8. References