Voip - Wireless P2P And New Enterprise Voice Over Ip

Understand how new network technologies impact VoIP!


Voice over Internet Protocol (VoIP) is revolutionizing the way people communicate – both in the corporate world and in personal life. The enormous success of VoIP has led to its adoption in a wide range of networking technologies. Each network technology has its unique features and poses distinct challenges for the performance of VoIP.


VoIP: Wireless, P2P and New Enterprise Voice over IPdescribes the issues arising in the deployment of VoIP in an emerging heterogeneous network environment. Along with a brief overview of the concepts, protocols, algorithms, and equipment involved in realizing VoIP, this book focuses on two areas: quality and performance issues in deploying VoIP over various network settings, and the new mechanisms and protocols in these emerging networks to assist the deployment of VoIP.


VoIP: Wireless, P2P and New Enterprise Voice over IP:


* Discusses the basics of VoIP, VoIP codecs and VoIP Protocols including SIP and H.323.

* Details new technologies such as P2P technology, VoWiFi, WiMax, and 3G Networks.

* Explains the QoS issues arising from deploying VoIP using the new technologies.

* Solves the performance issues that arise when VoIP is deployed over different network technologies.



This book is an invaluable resource for professional network engineers, designers, managers, researchers, decision makers and project managers overseeing VoIP implementations. Market analysts, consultants, and those studying advanced undergraduate and graduate courses on data, voice and multimedia communications will also find this book insightful.

Samrat Ganguly currently works as a Research Staff Member at NEC Laboratories America. He gained his PhD in Computer Science from Rutgers University. His research interests include VoIP over wireless mesh networks, streaming over 3G networks, Grid computing, and QoS issues. He has presented papers for conferences and workshops such as Infocom, PIMRC, and ICC.

Sudeept Bhatnagar works as a Research Staff Member at NEC Laboratories America. His research interests include VoIP and Enterprise networks, data streams, wireless mesh technologies and energy-efficient protocol design for sensor networks. He gained his PhD in Computer Science from Rutgers University.? He has published over 20 papers in the area of networking and won the best paper award at the High Performance and Switching and Routing workshop.

Preface.


PART I PRELIMINARIES.


1 Introduction to VoIP Networks.


1.1 Public Switched Telephone Network (PSTN).


1.1.1 Switching.


1.1.2 Routing.


1.1.3 Connection hierarchy.


1.1.4 Telephone numbering.


1.1.5 Signaling.


1.1.6 Summary.


1.2 Fundamentals of Internet technology.


1.2.1 Packetization and packet-switching.


1.2.2 Addressing.


1.2.3 Routing and forwarding.


1.2.4 DNS.


1.3 Performance issues in the Internet.


1.3.1 Latency.


1.3.2 Packet loss.


1.3.3 Jitter.





1.4 Quality of Service (QoS) guarantees.


1.4.1 Integrated services.


1.4.2 Differentiated services.


1.4.3 Other modifications.


1.4.3.1 Route pinning.


1.4.3.2 Packet classification.


1.4.4 Admission control.


1.4.5 Status.


1.5 Summary.


2 Basics of VoIP.


2.1 Packetization of voice.


2.2 Networking technology.


2.3 Architecture overview.


2.3.1 Architectural requirements.


2.3.2 Functional components.


2.3.2.1 VoIP calling device.


2.3.2.2 Gateway.


2.3.2.3 Media server.


2.3.2.4 Session control server.


2.3.3 Protocols.


2.4 Process of making a VoIP call.


2.5 Deployment issues.


2.5.1 VoIP quality and performance issues.


2.5.2 Delay.


2.5.3 Jitter.


2.5.4 Packet loss.


2.5.5 Echo and talk overlap.


2.5.6 Approaches to maintaining VoIP quality.


2.5.6.1 Network-level QoS.


2.5.6.2 VoIP codecs.


2.6 VoIP applications and services.


2.6.1 Fax.


2.6.2 Emergency numbers.


2.6.3 Roaming.


2.6.4 Voice over IM.


2.6.5 Push-to-talk.


2.6.6 Conferencing.


2.6.7 Integration with other applications.


2.7 Summary.


3 VoIP Codecs.


3.1 Codec design overview.


3.1.1 VoIP codec design goals.


3.2 Speech coding techniques.


3.2.1 Waveform codecs.


3.2.1.1 Pulse code modulation (PCM).


3.2.1.2 Differential PCM (DPCM).


3.2.2 Source coding.


3.2.3 Hybrid coding.


3.2.4 Adaptive multirate.


3.3 Narrowband codecs.


3.3.1 PCM-based G.711.


3.3.2 ADPCM-based G.721 codecs.


3.3.3 RPE-based GSM codec.


3.3.4 Low-delay CELP-based G.728 codec.


3.3.5 DoD CELP-based G.723.1 codec.


3.3.6 CS-ACELP-based G.729 codec.


3.3.7 iLBC.


3.3.8 Comparison of narrowband codecs.


3.4 Wideband and multirate codecs.


3.4.1 Adaptive MultiRate WideBand (AMR-WB).


3.4.2 Speex.


3.5 VoIP softwares.


3.5.1 Linphone.


3.5.2 SJphone.


3.5.3 Skype.


3.5.4 RAT.


3.6 Summary.


4 Performance of Voice Codecs.


4.1 Factors affecting VoIP quality.


4.1.1 Effects due to encoding.


4.1.2 Effects on the decoder.


4.1.3 Monitoring network conditions.


4.2 Voice quality assessment.


4.3 Subjective measures and MOS score.


4.3.1 Absolute Category Rating (ACR).


4.3.2 Degradation Category Rating (DCR).


4.3.3 Comparison Category Rating (CCR).


4.4 Conversational opinion score.


4.5 E-Model.


4.5.1 Sensitivity to delay.


4.6 Sensitivity to loss.


4.7 Perceptual Evaluation of Speech Quality (PESQ).


4.7.1 PESQ analysis for VoIP codecs.


4.7.2 Cross correlation.


4.8 Tools for lab testbed setup.


4.8.1 Network emulator.


4.9 Voice input/output tools.


4.9.1 Recording tools.


4.9.2 Experiment configurations.


4.10 Summary.


5 VoIP Protocols.


5.1 Introduction.


5.2 Signaling protocols.


5.2.1 Session Initiation Protocol (SIP).


5.2.1.1 Architecture overview.


5.2.1.2 SIP components.


5.2.1.3 SIP operation.


5.2.2 Session Description Protocol (SDP).


5.2.3 H.323.


5.2.3.1 H.323 architecture overview.


5.2.3.2 H.323 components.


5.2.3.3 H.323 protocols.


5.2.3.4 H.323 operation.


5.2.4 Media Gateway Control Protocol (MGCP).


5.2.4.1 Components.


5.2.4.2 Architecture overview.


5.2.4.3 MGCP operation.


5.3 Media transport protocols.


5.3.1 Real-time Transport Protocol (RTP).


5.4 Summary.


PART II VOIP IN OVERLAY NETWORKS.


6 Overlay Networks.


6.1 Internet communication overview.


6.1.1 Communication operations.


6.1.2 Communication roles.


6.1.3 Internet routing.


6.1.4 Client–server architecture.


6.2 Limitations of the Internet.


6.3 Overlay networks.


6.3.1 Types of overlay network.


6.3.1.1 Infrastructure overlays.


6.3.1.2 P2P overlays.


6.3.1.3 Design considerations for infrastructure versus P2P overlays.


6.3.2 Routing in overlay networks.


6.4 Applications of overlay networks.


6.4.1 Content distribution network.


6.4.2 Overlay multicast.


6.4.3 Anonymous data delivery.


6.4.4 Robust routing.


6.4.5 High bandwidth streaming.


6.5 Summary.


7 P2P Technology.


7.1 P2P communication overview.


7.1.1 Peer node.


7.1.2 Node join and leave.


7.1.3 Bootstrapping.


7.1.4 Communication process.


7.2 Classification of P2P networks.


7.3 Unstructured overlays.


7.3.1 Centralized resource discovery.


7.3.2 Controlled flooding.


7.4 Structured overlays – Distributed Hash Tables (DHTs).


7.4.1 Hashing.


7.4.1.1 Usage in DHT.


7.4.1.2 Limitations with respect to DHT.


7.4.1.3 Standard hash functions.


7.4.2 Consistent hashing.


7.4.3 Increasing information availability.


7.5 Types of DHT.


7.5.1 Chord.


7.5.2 Koorde.


7.5.3 CAN.


7.5.4 Kademlia.


7.6 Semi-structured overlays.


7.6.1 FastTrack.


7.6.2 DHT-based systems.


7.7 Keyword search using DHT.


7.8 Summary.


8 VoIP over Infrastructure Overlays.


8.1 Introduction.


8.2 VoIP over overlay – generic architecture.


8.3 Methods to enhance VoIP quality.


8.3.1 Path switching.


8.3.2 Packet buffering.


8.3.3 Packet replication.


8.3.4 Coding.


8.4 Estimating network quality.


8.4.1 Probe traffic.


8.4.1.1 Network delay (d).


8.4.1.2 Link jitter loss ( j).


8.4.1.3 Link network loss (n).


8.4.1.4 Link cluster factor (c).


8.4.2 Estimating path quality.


8.4.2.1 Path delay.


8.4.2.2 Path network loss.


8.4.2.3 Path jitter loss.


8.4.2.4 Path cluster factor.


8.5 Route computation.


8.6 Perceived enhancement of VoIP quality.


8.7 Summary.


9 VoIP over P2P.


9.1 VoIP over P2P overlay – generic architecture.


9.2 VoIP issues in P2P overlay.


9.2.1 Architectural issues.


9.2.2 Network issues.


9.3 Case study: Skype.


9.3.1 Skype architecture.


9.3.2 Skype operation.


9.3.2.1 Installation and configuration.


9.3.2.2 Login and authentication.


9.3.2.3 Global index.


9.3.2.4 Call setup and routing.


9.3.2.5 NAT traversal.


9.3.2.6 Conferencing.


9.3.3 Encryption.


9.3.4 Skype performance.


9.4 Standardization.


9.5 Summary.


PART III VOIP IN WIRELESS NETWORKS.


10 IEEE 802.11 Wireless Networks.


10.1 Network architecture overview.


10.1.1 Components.


10.1.2 Network configurations.


10.1.2.1 Ad hoc networks.


10.1.2.2 Infrastructure networks.


10.1.2.3 Infrastructure mesh networks.


10.2 Network access management.


10.2.1 Association.


10.2.2 Authentication.


10.2.3 Mobility.


10.3 Basic medium access protocol.


10.3.1 Distributed Coordination Function (DCF).


10.3.1.1 Carrier sensing.


10.3.1.2 Random access.


10.3.2 Station protocol.


10.3.3 Hidden terminal problem.


10.3.4 PCF.


10.4 Physical layer.


10.4.1 Spread spectrum techniques in IEEE 802.11b.


10.4.2 OFDM in IEEE 802.11a.


10.4.3 MIMO in IEEE 802.11n.


10.4.4 Modulation and rate control.


10.5 Network resource management.


10.5.1 Interference model.


10.5.2 Channel allocation.


10.5.3 Power control.


10.6 IEEE 802.11 standardization overview.


10.7 Summary.


11 Voice over IEEE 802.11 Wireless Networks.


11.1 VoIP overWLAN performance problems.


11.1.1 Channel access delay.


11.1.2 Interference from simultaneous transmissions.


11.1.3 External interference.


11.1.4 Disruption in connectivity.


11.1.5 Power drain.


11.2 VoIP capacity.


11.2.1 Packet aggregation.


11.2.2 Header compression.


11.2.3 Interference limited capacity.


11.2.4 Call admission control.


11.3 VoIP packet prioritization.


11.3.1 Downlink prioritization.


11.3.2 Uplink prioritization using IEEE 802.11e.


11.3.2.1 Extended distributed channel access (EDCA).


11.3.2.2 Hybrid coordination function controlled channel access (HCCA)s.


11.4 Handoff performance.


11.4.1 Probing process.


11.4.2 Scanning using neighbor graph.


11.4.3 Synchronized scanning.


11.4.4 Multiscanning using dual radio.


11.5 Reliable delivery.


11.6 Client power management.


11.7 Issues in mesh networks.


11.7.1 Capacity in mesh networks.


11.7.2 VoIP call routing.


11.8 Summary.


12 IEEE 802.16 WiMAX.


12.1 WiMAX overview.


12.2 IEEE 802.11 MAC protocol architecture.


12.2.1 QoS management.


12.3 MAC layer framing.


12.3.1 Aggregation.


12.3.2 Fragmentation.


12.3.3 Concatenation.


12.4 Physical layer.


12.4.1 OFDM.


12.4.2 OFDMA.


12.4.3 Slotted allocation.


12.4.4 Subcarrier mapping.


12.4.5 OFDMA frame structure.


12.4.6 OFDMA MIMO.


12.5 Radio resource management.


12.5.1 Duplex modes.


12.5.2 Uplink bandwidth allocation.


12.6 Competing technologies.


12.6.1 Comparison with IEEE 802.11WLAN.


12.6.2 Comparison with 3G cellular technologies.


12.6.3 Comparison with LTE and UMB.


12.7 Summary.


13 Voice over WiMAX.


13.1 Introduction.


13.2 VoIP service delivery overWiMAX network.


13.2.1 Network entry process.


13.2.2 Inter-BS handoff process.


13.2.3 Power-save modes.


13.3 QoS architecture.


13.3.1 Serving downlink queues.


13.3.2 Serving uplink queues.


13.3.3 QoS provisioning.


13.4 Call admission control.


13.5 Uplink QoS control.


13.5.1 Unsolicited Grant Service (UGS).


13.5.2 Real-time Polling Service (rtPS).


13.5.3 Non-real-time Polling Service (nrtPS).


13.5.4 Best effort service.


13.6 Enhanced QoS control for VoIP.


13.6.1 Supporting voice using UGS.


13.6.2 Supporting VoIP using rtPS.


13.6.3 Enhanced rtPS for VoIP.


13.7 MAC enhancement strategies.


13.7.1 Packet loss probability.


13.7.2 Packet delay.


13.7.3 Dynamic adaptation of MPDU size.


13.7.4 Performance of dynamic adaptation.


13.8 Comparison with competing technologies.


13.9 Summary.


PART IV VOIP IN ENTERPRISE NETWORKS.


14 Private Branch Exchange (PBX).


14.1 Private Branch Exchange (PBX).


14.1.1 Basic PBX functions.


14.1.2 PBX features.


14.1.3 IP-PBX.


14.2 Case study: Asterisk open-source IP-PBX.


14.2.1 Software architecture.


14.2.2 Asterisk operation.


14.2.3 Application gateway interface.


14.2.4 System requirements.


14.2.4.1 Summary.


14.2.5 Asterisk as an application server.


14.2.6 Desirable features.


14.3 Summary.


15 Network Address Translation (NAT) and Firewall.


15.1 Introduction.


15.2 NAT fundamentals.


15.3 Applications of NAT.


15.3.1 IP address multiplexing.


15.3.2 Enhanced security.


15.3.3 Load balancing.


15.3.4 Failover protection.


15.3.5 Advantages.


15.3.6 Drawbacks.


15.4 Types of NAT.


15.4.1 Based on type of translation.


15.4.1.1 Basic NAT.


15.4.1.2 Address and port translation.


15.4.2 Based on session binding.


15.4.2.1 Static.


15.4.2.2 Dynamic.


15.4.2.3 Hybrid.


15.4.3 Based on allowed connections.


15.4.3.1 Full cone NAT.


15.4.3.2 Restricted cone NAT.


15.4.3.3 Port restricted cone NAT.


15.4.3.4 Symmetric NAT.


15.4.3.5 Summary.


15.5 Firewall.


15.6 NAT traversal solutions.


15.6.1 Determining the type of NAT.


15.6.2 STUN protocol.


15.6.3 TURN protocol.


15.6.4 Interactive connectivity establishment.


15.6.5 Application Layer Gateway (ALG).


15.6.6 HTTP tunneling.


15.7 NAT traversal in H.323.


15.8 Summary.


PART V VOIP SERVICE DEPLOYMENT.


16 Supporting Services and Applications.


16.1 Domain Name System (DNS).


16.2 ENUM.


16.3 Network monitoring.


16.4 Direct Inward Dialing (DID).


16.5 Emergency calling (911).


16.6 Fax.


16.7 Summary.


17 Security and Privacy.


17.1 Security and privacy issues.


17.2 Generic issues.


17.2.1 Malware.


17.2.2 Spamming.


17.2.3 Denial of Service (DOS).


17.2.4 Access technology weakness.


17.2.5 Improper implementation.


17.3 VoIP-related issues.


17.3.1 Misrepresentation.


17.3.2 Service theft.


17.3.3 Eavesdropping.


17.3.4 Call altering.


17.3.5 Call hijacking.


17.3.6 Privacy.


17.4 Solutions.


17.4.1 Authentication.


17.4.2 Message integrity.


17.4.3 Signaling message encryption.


17.4.4 Data encryption.


17.4.5 Privacy.


17.5 Recommendations.


17.6 Summary.


18 IP Multimedia Subsystem (IMS).


18.1 Introduction.


18.2 Architecture design goals.


18.3 IMS advantages.


18.3.1 End-user experience.


18.3.2 Enterprise-user experience.


18.3.3 Benefits for network operators.


18.3.4 Benefits for service providers.


18.4 IMS architecture organization.


18.5 Network Attachment SubSystem (NASS).


18.6 Resource Admission Control Subsystem (RACS).


18.7 IMS core subsystem.


18.7.1 Call session control.


18.7.1.1 Proxy-CSCF.


18.7.1.2 Serving-CSCF.


18.7.1.3 Interrogating-CSCF.


18.7.2 Other functional control entities.


18.8 IMS QoS management.


18.9 QoS provisioning approach.


18.9.1 Guaranteed QoS.


18.9.2 Relative QoS.


18.9.3 QoS control mechanism in IMS.


18.9.3.1 Session control layer.


18.9.3.2 Transport layer.


18.9.4 Policy based QoS control.


18.10 Summary.


Index.