Preface Preliminaries. Introduction to VoIP Networks. Public Switched Telephone Network (PSTN) Switching Routing Connection hierarchy Telephone

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2 VoIP quality and performance issues Delay Jitter Packet loss Echo and talk overlap Approaches to maintaining VoIP quality Network-level QoS VoIP codecs VoIP applications and services Fax Emergency numbers Roaming Voice over IM Push-to-talk Conferencing Integration with other applications VoIP Codecs. Codec design overview VoIP codec design goals Speech coding techniques Waveform codecs Pulse code modulation (PCM) Differential PCM (DPCM) Source coding Hybrid coding Adaptive multirate Narrowband codecs PCM-based G.711 ADPCM-based G.721 codecs RPE-based GSM codec Low-delay CELP-based G.728 codec DoD CELP-based G codec CS-ACELP-based G.729 codec ilbc Comparison of narrowband codecs Wideband and multirate codecs Adaptive MultiRate WideBand (AMR-WB) Speex VoIP softwares Linphone

3 SJphone Skype RAT Performance of Voice Codecs. Factors affecting VoIP quality Effects due to encoding Effects on the decoder Monitoring network conditions Voice quality assessment Subjective measures and MOS score Absolute Category Rating (ACR) Degradation Category Rating (DCR) Comparison Category Rating (CCR) Conversational opinion score E-Model Sensitivity to delay Sensitivity to loss Perceptual Evaluation of Speech Quality (PESQ) PESQ analysis for VoIP codecs Cross correlation Tools for lab testbed setup Network emulator Voice input/output tools Recording tools Experiment configurations VoIP Protocols. Introduction Signaling protocols Session Initiation Protocol (SIP) Architecture overview SIP components SIP operation Session Description Protocol (SDP) H.323 H.323 architecture overview H.323 components H.323 protocols H.323 operation Media Gateway Control Protocol (MGCP)

4 Components Architecture overview MGCP operation Media transport protocols Real-time Transport Protocol (RTP) Voip In Overlay Networks. Overlay Networks. Internet communication overview Communication operations Communication roles Internet routing Clientûserver architecture Limitations of the Internet Overlay networks Types of overlay network Infrastructure overlays P2P overlays Design considerations for infrastructure versus P2P overlays Routing in overlay networks Applications of overlay networks Content distribution network Overlay multicast Anonymous data delivery Robust routing High bandwidth streaming P2P Technology. P2P communication overview Peer node Node join and leave Bootstrapping Communication process Classification of P2P networks Unstructured overlays Centralized resource discovery Controlled flooding Structured overlays û Distributed Hash Tables (DHTs) Hashing Usage in DHT Limitations with respect to DHT

5 Standard hash functions Consistent hashing Increasing information availability Types of DHT Chord Koorde CAN Kademlia Semi-structured overlays FastTrack DHT-based systems Keyword search using DHT VoIP over Infrastructure Overlays. Introduction VoIP over overlay û generic architecture Methods to enhance VoIP quality Path switching Packet buffering Packet replication Coding Estimating network quality Probe traffic Network delay (d) Link jitter loss ( j) Link network loss (n) Link cluster factor (c) Estimating path quality Path delay Path network loss Path jitter loss Path cluster factor Route computation Perceived enhancement of VoIP quality VoIP over P2P. VoIP over P2P overlay û generic architecture VoIP issues in P2P overlay Architectural issues Network issues Case study: Skype

6 Skype architecture Skype operation Installation and configuration Login and authentication Global index Call setup and routing NAT traversal Conferencing Encryption Skype performance Standardization VoIP In Wireless Networks. IEEE Wireless Networks. Network architecture overview Components Network configurations Ad hoc networks Infrastructure networks Infrastructure mesh networks Network access management Association Authentication Mobility Basic medium access protocol Distributed Coordination Function (DCF) Carrier sensing Random access Station protocol Hidden terminal problem PCF Physical layer Spread spectrum techniques in IEEE b OFDM in IEEE a MIMO in IEEE n Modulation and rate control Network resource management Interference model Channel allocation Power control IEEE standardization overview

7 Voice over IEEE Wireless Networks. VoIP overwlan performance problems Channel access delay Interference from simultaneous transmissions External interference Disruption in connectivity Power drain VoIP capacity Packet aggregation Header compression Interference limited capacity Call admission control VoIP packet prioritization Downlink prioritization Uplink prioritization using IEEE e Extended distributed channel access (EDCA) Hybrid coordination function controlled channel access (HCCA)s Handoff performance Probing process Scanning using neighbor graph Synchronized scanning Multiscanning using dual radio Reliable delivery Client power management Capacity in mesh networks VoIP call routing IEEE WiMAX. WiMAX overview IEEE MAC protocol architecture QoS management MAC layer framing Aggregation Fragmentation Concatenation Physical layer OFDM OFDMA Slotted allocation

8 Subcarrier mapping OFDMA frame structure OFDMA MIMO Radio resource management Duplex modes Uplink bandwidth allocation Competing technologies Comparison with IEEE WLAN Comparison with 3G cellular technologies Comparison with LTE and UMB Voice over WiMAX. Introduction VoIP service delivery overwimax network Network entry process Inter-BS handoff process Power-save modes QoS architecture Serving downlink queues Serving uplink queues QoS provisioning Call admission control Uplink QoS control Unsolicited Grant Service (UGS) Real-time Polling Service (rtps) Non-real-time Polling Service (nrtps) Best effort service Enhanced QoS control for VoIP Supporting voice using UGS Supporting VoIP using rtps Enhanced rtps for VoIP MAC enhancement strategies Packet loss probability Packet delay Dynamic adaptation of MPDU size Performance of dynamic adaptation Comparison with competing technologies VOIP In Enterprise Networks. Private Branch Exchange (PBX). Private Branch Exchange (PBX)

9 Basic PBX functions PBX features IP-PBX Case study: Asterisk open-source IP-PBX Software architecture Asterisk operation Application gateway interface System requirements Asterisk as an application server Desirable features Network Address Translation (NAT) and Firewall. Introduction NAT fundamentals Applications of NAT IP address multiplexing Enhanced security Load balancing Failover protection Advantages Drawbacks Types of NAT Based on type of translation Basic NAT Address and port translation Based on session binding Static Dynamic Hybrid Based on allowed connections Full cone NAT Restricted cone NAT Port restricted cone NAT Symmetric NAT Firewall NAT traversal solutions Determining the type of NAT STUN protocol TURN protocol

10 Interactive connectivity establishment Application Layer Gateway (ALG) HTTP tunneling NAT traversal in H.323 VOIP Service Deployment. Supporting Services and Applications. Domain Name System (DNS) ENUM Network monitoring Direct Inward Dialing (DID) Emergency calling (911) Fax Security and Privacy. Security and privacy issues Generic issues Malware Spamming Denial of Service (DOS) Access technology weakness Improper implementation VoIP-related issues Misrepresentation Service theft Eavesdropping Call altering Call hijacking Privacy Solutions Authentication Message integrity Signaling message encryption Data encryption Privacy Recommendations IP Multimedia Subsystem (IMS). Introduction Architecture design goals IMS advantages

11 End-user experience Enterprise-user experience Benefits for network operators Benefits for service providers IMS architecture organization Network Attachment SubSystem (NASS) Resource Admission Control Subsystem (RACS) IMS core subsystem Call session control Proxy-CSCF Serving-CSCF Interrogating-CSCF Other functional control entities IMS QoS management QoS provisioning approach Guaranteed QoS Relative QoS QoS control mechanism in IMS Session control layer Transport layer olicy based QoS control Index Table of Contents provided by Blackwell's Book Services and R.R. Bowker. Used with permission.