Softswitch

by Frank Ohrtman

Overview

A comprehensive look at one of the fastest growing segments of the network industry which is revolutionizing the design and cost of Voice over IP networks.

Product Details

ISBN-13:	9780071409773
Publisher:	McGraw-Hill Professional Publishing
Publication date:	12/10/2002
Series:	McGraw-Hill Networking Professional
Pages:	359
Product dimensions:	7.36(w) x 9.20(h) x 0.99(d)

About the Author

Frank Ohrtman has many years experience in sales of VoIP and softswitch platforms. His career in VoIP began with selling VoIP gateway switches for Netrix Corporation to long distance bypass carriers. He went on to promote softswitch solutions for Lucent Technologies (Qwest Account Manager) and Vsys (Western Region Sales Manager). The genesis of this book lies in answering customer objections to VoIP and, tangentially, softswitch technologies.

Mr. Ohrtman learned to perform in-depth research and write succinct analyses during his years as a Navy Intelligence Officer (1981-1991). He is a veteran of U.S. Navy actions in Lebanon (awarded Navy Expeditionary Medal), Grenada, Libya (awarded Joint Service Commendation Medal) and the Gulf War (awarded National Defense Service Medal). Mr. Ohrtman holds a Master of Science degree in Telecommunications from Colorado University College of Engineering (master's thesis: "Softswitch As Class 4 Replacement--A Disruptive Technology") and a Master of Arts degree in International Relations from Boston University.

Table of Contents

	Foreword	xiii
	Preface	xv
	Acknowledgments	xvii
Chapter 1	Introduction	1
	Softswitch as an Alternative to Class 4 and Class 5	4
	Reliability	4
	Scalability	5
	Quality of Service (QoS)	5
	Signaling	5
	Features	6
	Regulatory Implications	6
	Economic Advantage of Softswitch	7
	Disruptive or Deconstructive Technology?	7
Chapter 2	The Public Switched Telephone Network (PSTN)	9
	Access	10
	Switching	11
	Class 4 and 5 Switching	12
	Private Branch Exchange (PBX)	14
	Centrex	15
	Multiplexing	16
	Voice Digitization via Pulse Code Modulation	16
	Signaling	21
	The Advanced Intelligent Network (AIN)	27
	Features	29
	Performance Metrics for Class 4 and 5 Switches	30
	Transport	34
	Asynchronous Transfer Mode (ATM)	34
	Optical Transmission Systems	35
	Conclusion	38
Chapter 3	Softswitch Architecture or "It's the Architecture, Stupid!"	39
	Softswitch and Distributed Architecture: A "Stupid" Network	40
	Access	42
	PC to PC and PC to Phone	42
	IP Phones (IP Handsets) Phone-to-Phone VoIP	43
	Media Gateways (a VoIP gateway switch)	46
	Switching	50
	Softswitch (Gatekeeper and Media Gateway Controller)	50
	Signaling Gateway	52
	Application Server	52
	Applications for Softswitch	53
	Class 4 Replacement Softswitch	56
	Class 5 Replacement Softswitch	58
	Transport	60
	Legacy, Converging, and Converged Architecture	60
	IP Networks	61
	ATM	63
	TDM	64
	Conclusion	64
Chapter 4	Voice over Internet Protocol	67
	What Is VoIP?	68
	Origins	68
	How Does VoIP Work?	69
	Protocols Related to VoIP	70
	Signaling Protocols	71
	Routing Protocols	79
	Transport Protocols	84
	IPv6	85
	Conclusion	86
Chapter 5	SIP: Alternative Softswitch Architecture?	87
	What Is SIP?	89
	SIP Architecture	89
	New Standards for SIP	96
	Some SIP Configurations	97
	Comparison of SIP to H.323	98
	Complexity of H.323 Versus SIP	99
	Scalability	102
	Extensibility	105
	Services	108
	H.323 Versus SIP Conclusion	109
	The Big "So What?" about SIP	109
	SIP on Windows XP	109
	How Does That Work?	110
	Conclusion	112
Chapter 6	Softswitch: More Scalable Than CLASS 4 or 5	113
	Scalability	114
	Scaling Up	115
	Scaling Down	119
	Scaling Down for Class 4 Applications	120
	Scaling Down for Class 5 or Central Office Bypass Applications	121
	Scaling Down for Class 5 or Central Office Bypass from the Residence	122
	Access Switching	124
	Scaling Down for Class 5 or Central Office Bypass from the Enterprise	126
	Scaling Down Technical Issues	127
	Conclusion	128
Chapter 7	Softswitch Is Just as Reliable as Class 4/5 Switches	131
	World Trade Center Attack: A Need to Redefine Reliability	132
	One to Five 9s	135
	Standards for Availability	135
	What Is Reliability?	135
	How Availability Is Calculated	137
	How Does a Switch, PSTN or Softswitch, Achieve Five 9s?	138
	Network Equipment Building Standards (NEBS)	144
	Specifications for Softswitch Reliability	145
	Software Reliability Case Study Cisco IOS	147
	Power Availability	149
	Typical Power Outages in a Typical Telephone Network	149
	Human Error	150
	Conclusion	152
Chapter 8	Quality of Service (QoS)	155
	Factors Affecting QoS	156
	Improving QoS in IP Routers and the Gateway	157
	Sources of Delay: IP Routers	157
	Sources of Delay: VoIP Gateways	158
	Other Gateway Improvements	159
	Perceptual Speech Quality Measurement (PSQM)	160
	Improving QoS on the Network	161
	Resource Reservation Setup Protocol (RSVP)	162
	Differentiated Service (DiffServ)	165
	MPLS-Enabled IP Networks	167
	MPLS Architecture	170
	MPLS Traffic Engineering	171
	Measuring Voice Quality	173
	Mean Opinion Score (MOS)	173
	Conclusion	174
Chapter 9	SS7 and Softswitch	175
	Signaling in the PSTN (SS7 or C7)	178
	Message Transfer Part (MTP)	178
	ISDN User Part (ISUP)	179
	Signaling Connection Control Part (SCCP)	179
	Transaction Capabilities Applications Part (TCAP)	179
	Interworking SS7 and VoIP Networks	180
	Signaling in VoIP Networks	181
	Signaling Transport (SIGTRAN)	182
	SIGTRAN Protocols	183
	Stream Control Transmission Protocol (SCTP)	184
	Transporting MTP2 over IP: M2UA	186
	ISDN Q.921-User Adaptation Layer (IUA)	189
	Signaling Network Architecture	190
	SS7 Interworking with SIP and H.323	191
	ISUP Encapsulation in SIP	191
	SIP for Telephones (SIP-T)	192
	PINT and SPIRITS	192
	Interworking H.323 and SS7	193
	Conclusion	194
Chapter 10	Features and Applications: "It's the Infrastructure, Stupid!"	195
	Features in the PSTN	196
	Features and Signaling	198
	The Intelligent Network/Advanced Intelligent Network (IN/AIN)	198
	Service Creation Environment	200
	Application Programming Interfaces (APIs)	202
	APIs and Services	202
	SIP as API: International Softswitch Consortium's Architecture for Enhanced Services in a Softswitch Network	208
	Media Servers	209
	Application Servers	209
	Architecture	209
	Physical Architecture	211
	Interface Between Call Control and Application Servers	212
	Application Server to Media Server Interface	216
	Service APIs	216
	Application Server Interactions	216
	Application and Media Servers Summary	217
	How Softswitch Handles E911 and CALEA Requirements	218
	Enhanced 911 (E911)	218
	Communications Assistance for Law Enforcement Act (CALEA)	219
	Next-Generation Applications Made Possible by Softswitch Features	221
	Web Provisioning	221
	Voice-Activated Web Interface	222
	"The Big So What?" of Enhanced Features	222
	Napster and i Mode: Examples of Killer Apps	222
	Conclusion	223
Chapter 11	Softswitch Economics	225
	A Previous Example of Disruptive Technology in the Long-Distance Industry	226
	Softswitch Is More Cost Effective Than Class 4	229
	Purchase and OAM&P	230
	Bandwidth Saving	231
	Lower Barrier to Entry	232
	Softswitch: A Smaller Footprint	233
	Softswitch Advantages in Power Draw	236
	Advantages of Distributed Architecture	237
	Economic and Regulatory Issues Concerning Softswitch	238
	Net Present Value of Softswitch	239
	Considerations for the Net Present Value Models	241
	Net Present Value: Midsized Long-Distance Service Provider	249
	Leasing Class 4 Versus Softswitch	250
	Buying Class 4 or Softswitch 4,032 DSOs	252
	Buying Class 4 or Softswitch with Class 4 at $50 per DS0	253
	Net Present Value When Softswitch Generates Greater Revenue	255
	Large Long-Distance Service Providers	257
	Summary of Net Present Value Analyses	259
	$0 per port: Subscriber Pays for Access Device Negating "Cost per Port"	261
	Economics of Enterprise Softswitch Applications	262
	Non-Interoffice Free Long Distance	262
	Implications for Developing Economies	265
	Economic Benefits of Converged Networks	266
	Broadband Access and Telephone Services	267
	Conclusion	269
Chapter 12	Is Softswitch Deconstructive, Disruptive, or Both?	271
	Deconstruction	272
	Deconstruction of Service Providers	273
	Vendors	276
	Disruption of the Legacy Telecommunications Value Network	277
	Disruption in Class 4 Market	277
	Disruption in PBX Market	284
	Conclusion	285
Chapter 13	Softswitch and Broadband	287
	Converged Networks Independent of ILEC Infrastructure: "We Have the Technology"	288
	Access Alternatives to the PSTN and Cable TV	289
	Wi-Fi (802.11b Standard)	289
	Fiberless Optics	290
	$500 Billion Economic Benefit of Converged Broadband Networks	291
	Broadband Access and Telephone Services	292
	National Defense Residential Broadband Network (NDRBN)	295
	Better Living Through Telecommunications: The Social Rewards of Softswitch	296
Essay 1	If It Hurts to Commute, Then Don't Commute	296
Essay 2	Affordable Housing Is Where You Find It	299
Essay 3	Family Values	300
	The Role of Softswitch in Better Living Through Telecommunications	300
	Conclusion	302
Chapter 14	Past, Present, and Future of Softswitch	303
	History of Softswitch	304
	The Present of Softswitch: Case Studies	305
	Class 4 Replacing the Class 4 Switch in Long-Distance Applications: Fusion, Sonus Networks, and NexVerse	305
	Replacing the Class 5 Switch: NorVergence and MetaSwitch	306
	The Future of Softswitch: ISC Reference Architecture and the ISC	307
	Functional Planes	309
	Transport Plane	310
	Call Control & Signaling Plane	311
	Service & Application Plane	311
	Management Plane	311
	Functional Entities	311
	Media Gateway Controller Function (MGC-F) a.k.a. Call Agent or Call Controller	312
	Call Routing and Accounting Functions (R-F/A-F)	313
	Signaling Gateway Function (SG-F) and Access Gateway Signaling Function (AGS-F)	314
	Application Server Function (AS-F)	315
	Media Gateway Function (MG-F)	316
	Media Server Function (MS-F)	317
	Media Gateway Controller Building Blocks	318
	MGC Implementation Example	319
	Network Examples	320
	Wireline Network	320
	All-IP Network	322
	VoIP Tandem Switching	323
	POTS Carried over IP	324
	Access Network (V5/ISDN) over IP	324
	Cable Network (e.g. PacketCable) over IP	326
	VoDSL and IAD over IP	327
	Wireless (3GPP R99 Special Case NGN)	327
	Wireless (3GPP R2000 General Case all IP)	328
	WCDMA Mobile Network	328
	Conclusion	329
Chapter 15	Conclusion and Prognostications	331
	Softswitch and the PSTN Metrics of Performance	333
	Softswitch and the PSTN Infrastructure	334
	Alternatives to the Telephone Company	335
	Alternative Private Service Providers	336
	Alternative Public Service Providers	336
	The End of the PSTN as We Know It?	337
	Acronyms List	339
	Index	345

Editorial Reviews

The Barnes & Noble Review
Softswitches are the wave of the telecommunications industry's future! If you want to know more, you should read this excellent book on softswitch technology as the enabling platform for next-generation packet communications -- including voice, broadband, and wireless networks. Franklin D. Ohrtman does an outstanding job of showing how softswitch technology and applications enable global service providers and carriers to optimize their networks and generate new revenue streams with new services and applications. In other words, the author illustrates how softswitch technology disrupts incumbent service providers and their vendors. He helps to identify some of the success and technological challenges of the industry based on the softswitch.

This book focuses on the metrics of performance of the emerging telecommunications infrastructure in terms of scalability, reliability, quality of service (QoS), signaling, and features. Ohrtman analyzes how softswitch technologies might meet or exceed the performance parameters of the Public Switched Telephone Network (PSTN) infrastructure (specifically Class 4 and 5 switches, in addition to Private Branch Exchanges (PBXs). He also explains how it's becoming increasingly clear that Creative Destruction takes place from an engineering perspective. The addition of an acronym list is also a nice touch.

The telecommunications industry is changing, and opportunities abound. Folks who find themselves caught up in this revolution will be delighted with this well-written and coherent account of what's changing and why. Not incidentally, they will also learn how to benefit from these changes. John Vacca

John Vacca, the former computer security official (CSO) for NASA's space station program (Freedom), has written 38 books about advanced storage, computer security, and aerospace technology.

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