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VOIP Bandwidth consumption naturally depends
not only on the codec used, but also the
percentage of packet loss. The calculator
below will give you a good idea of the bandwidth
and voice call quality for various codecs
and packet loss percentages. For more detailed
information, visit the
Cisco website.
(Note: the question mark graphics along
each field will give you more information
on that field via small popups. To open,
simply run the cursor over the question
mark. If your browser is blocking popups,
press the "ctrl" key to disable
temporarily.)
Questions?
Contact us today and we can arrange
a VoIP Readiness Asssessment for your enterprise.
"This book is like a good tour guide.It doesn't just describe the major attractions; you share in the history, spirit, language, and culture of the place." --Henning Schulzrinne, Professor, Columbia University
Since its birth in 1996, Session Initiation Protocol (SIP) has grown up. As a richer, much more robust technology, SIP today is fully capable of supporting the communication systems that power our twenty-first century work and life.
This second edition handbook has been revamped to cover the newest standards, services, and products. You'll find the latest on SIP usage beyond VoIP, including Presence, instant messaging (IM), mobility, and emergency services, as well as peer-to-peer SIP applications, quality-of-service, and security issues--everything you need to build and deploy today's SIP services.
This book will help you * Work with SIP in Presence and event-based communications * Handle SIP-based application-level mobility issues * Develop applications to facilitate communications access for users with disabilities * Set up Internet-based emergency services * Explore how peer-to-peer SIP systems may change VoIP * Understand the critical importance of Internet transparency * Identify relevant standards and specifications * Handle potential quality-of-service and security problems
Customer Review: Superficial
I bought this book to better understand the inner workings of SIP but, instead, was greeted with a superficial introduction to a miriad of SIP applications, services and options. At the end of the day RFC3261 is a much better source of information, as dry as it might be. As such, I cannot recommend this book to anyone trying to learn the intricacies of SIP.
More and more businesses today have their receive phone service through Internet instead of local phone company lines. Many businesses are also using their internal local and wide-area network infrastructure to replace legacy enterprise telephone networks. This migration to a single network carrying voice and data is called convergence, and it's revolutionizing the world of telecommunications by slashing costs and empowering users. The technology of families driving this convergence is called VoIP, or Voice over IP.
VoIP has advanced Internet-based telephony to a viable solution, piquing the interest of companies small and large. The primary reason for migrating to VoIP is cost, as it equalizes the costs of long distance calls, local calls, and e-mails to fractions of a penny per use. But the real enterprise turn-on is how VoIP empowers businesses to mold and customize telecom and datacom solutions using a single, cohesive networking platform. These business drivers are so compelling that legacy telephony is going the way of the dinosaur, yielding to Voice over IP as the dominant enterprise communications paradigm.
Developed from real-world experience by a senior developer, O'Reilly's Switching to VoIP provides solutions for the most common VoIP migration challenges. So if you're a network professional who is migrating from a traditional telephony system to a modern, feature-rich network, this book is a must-have. You'll discover the strengths and weaknesses of circuit-switched and packet-switched networks, how VoIP systems impact network infrastructure, as well as solutions for common challenges involved with IP voice migrations. Among the challenges discussed and projects presented:
building a softPBX
configuring IP phones
ensuring quality of service
scalability
standards-compliance
topological considerations
coordinating a complete system ?switchover?
migrating applications like voicemail and directory services
retro-interfacing to traditional telephony
supporting mobile users
security and survivability
dealing with the challenges of NAT
To help you grasp the core principles at work, Switching to VoIP uses a combination of strategy and hands-on "how-to" that introduce VoIP routers and media gateways, various makes of IP telephone equipment, legacy analog phones, IPTables and Linux firewalls, and the Asterisk open source PBX software by Digium. You'll learn how to build an IP-based or legacy-compatible phone system and voicemail system complete with e-mail integration while becoming familiar with VoIP protocols and devices. Switching to VoIP remains vendor-neutral and advocates standards, not brands. Some of the standards explored include:
SIP
H.323, SCCP, and IAX
Voice codecs
802.3af
Type of Service, IP precedence, DiffServ, and RSVP
802.1a/b/g WLAN
If VoIP has your attention, like so many others, then Switching to VoIP will help you build your own system, install it, and begin making calls. It's the only thing left between you and a modern telecom network.
Customer Review: Good choice for investigating VoIP for your organization...
It seems like Voice over Internet Protocol, aka VoIP, is starting to become much more mainstream. Not only are businesses switching over, but now you can set up your home phone access to use VoIP (aka "broadband") technology. Ted Wallingford has done a nice job in explaining the business side of the possibilities in the book Switching to VoIP - A Solutions Manual for Network Professionals.
Contents: Voice and Data - Two Separate Worlds?; Voice over Data - Many Conversations, One Network; Linux as a PBX; Circuit-Switched Telephony; Enterprise Telephone Applications; Replacing the Voice Circuit with VoIP; Replacing Call Signaling with VoIP; VoIP Readiness; Quality of Service; Security and Monitoring; Troubleshooting Tools; PSTN Trunks; Network Infrastructure for VoIP; Traditional Apps on the Converged Network; What Can Go Wrong?; VoIP Vendors and Services; Asterisk Reference; SIP Methods and Responses; AGI Commands; Asterisk Manager Socket API Syntax; Glossary; Index
I think the biggest thing to keep in mind when approaching this book is the target audience. While there are a few books out there on "internet telephones" that talk to the consumer, this isn't one of them. The tag line of "for Network Professionals" is the key here. While you don't have to be a network guru to read this book, some level of familiarity with network and telephony concepts would help. Someone either working with the communication systems in a company or heading up a communications department would be a perfect match here. You'd probably even do alright if you just have an interest in the subject, as Wellingford does a good job taking what can be complex material and making it understandable. An admirable task in itself...
What makes this book stand out from other books I'd expect to see is that it doesn't just dwell on jargon and theory. There are a number of projects included in the book so you can get your hands dirty actually working with the technology. Add to that the fact that the author uses an open source PBX system called Asterisk for the exercises. So now you have no reason in terms of cost for not diving right in.
Although I'm not necessarily the target audience for this book, I'd have no problem recommending it to someone looking for material that covers this subject. The book is very well written, and after finishing it you should have a very firm grasp of the essentials. You might even know enough to start yourself on your next career path... :)
Sidestep VoIP Catastrophe the Foolproof Hacking Exposed Way
"This book illuminates how remote users can probe, sniff, and modify your phones, phone switches, and networks that offer VoIP services. Most importantly, the authors offer solutions to mitigate the risk of deploying VoIP technologies." --Ron Gula, CTO of Tenable Network Security
Block debilitating VoIP attacks by learning how to look at your network and devices through the eyes of the malicious intruder. Hacking Exposed VoIP shows you, step-by-step, how online criminals perform reconnaissance, gain access, steal data, and penetrate vulnerable systems. All hardware-specific and network-centered security issues are covered alongside detailed countermeasures, in-depth examples, and hands-on implementation techniques. Inside, you'll learn how to defend against the latest DoS, man-in-the-middle, call flooding, eavesdropping, VoIP fuzzing, signaling and audio manipulation, Voice SPAM/SPIT, and voice phishing attacks.
Find out how hackers footprint, scan, enumerate, and pilfer VoIP networks and hardware
Fortify Cisco, Avaya, and Asterisk systems
Prevent DNS poisoning, DHCP exhaustion, and ARP table manipulation
Thwart number harvesting, call pattern tracking, and conversation eavesdropping
Measure and maintain VoIP network quality of service and VoIP conversation quality
Stop DoS and packet flood-based attacks from disrupting SIP proxies and phones
Counter REGISTER hijacking, INVITE flooding, and BYE call teardown attacks
Avoid insertion/mixing of malicious audio
Learn about voice SPAM/SPIT and how to prevent it
Defend against voice phishing and identity theft scams
VoIP Telephony with Asterisk is the best-selling introduction to the leading open source PBX software. You'll learn how to provision telephony, install and compile Linux and Asterisk, and configure an Asterisk dial plan for both analog and SIP telephones. The book's 300 pages cover Cisco and snom telephones, Digium boards, faxing, voicemail, basic IVR and a variety of related topics.
Customer Review: A must have if you work with VoIP
Even if the book is not perfectly written, in the sense that there are some typos and some glitches in the explanations, it is still a wonderful source to learn Asterisk configuration.
The book alone won't do everything for you, you'll need to read all sample configuration files from Asterisk installation, check as many pages as you can from voip-info.org, and play with configurations as much as possible. So, the book is about one fourth and the friendliest portion of what you need to master Asterisk. Go for it.
VON Publishing’s latest effort is SIP Beyond VoIP, an extraordinary 333-page effort that picks up where previous books have left off about SIP (Session Initiation Protocol), the protocol that has revolutionized the world of VoIP. The book’s three distinguished authors relate in great detail how this versatile and extensible protocol has truly “moved beyond VoIP” and is now starting to have an impact on the whole telecommunication industry, including wireless and enterprise communications. Anyone who thinks that SIP has any real competitors will come away from this book in astonishment. “SIP Events” are the glue that even now integrates communications and applications. And “SIP Presence” may well be the “dial tone” of the 21st century. The book’s advanced discussion of SIP interleaves with such associated topics as DNS (the Domain Name Service), ENUM (electronic numbering), NAT (Network Address Translation) and firewall traversal, security, Peer-to-Peer SIP (P2P SIP) networks, SIP-based conferencing/collaboration and even accessibility to communications for disabled people. This heavily illustrated, footnoted and fully-indexed book also has a foreword by Vinton Cerf, who writes: “It is my honest opinion that we have barely scratched the surface of the various applications to which SIP may be adapted. If we have seen 1% of the applications of SIP so far, then there are still 99% waiting to be invented, developed or deployed. The generality of SIP will make it a major workhorse the Internet of this century.” If you think you “know” SIP, think again. Get this book–its authors will “set you straight” about SIP, once and for all!
Customer Review: SIP Beyond Nothing: A Lightweight Overview of SIP
My first comment is about the title, which promises the book is about SIP beyond VoIP. But the book is virtually all about SIP circa 2003, and almost exclusively about SIP for VoIP transport. Other than a brief excursion into potential uses of SIP in emergency services and mobile communications (still for VoIP, however), the authors never deliver on the promise in the title.
The authors' discussion of SIP is competent, but not remarkable. There are better descriptions available from other authors (e.g. "IP Telephony: Deploying Voice-over-IP Protocols", Hersent et. al, ISBN 0470023597). When the authors talk about current SIP usage, they seem woefully out of touch. For example, they never once mention the open source SIP-based PBX software Asterisk, even though the book has a section on open source software. Asterisk has been a force of nature in the VoIP world since 2004. You'd have to be in a very high ivory tower to miss that.
Much of the book is a rehash of stuff you can read in the SIP RFCs. Sometimes the authors make simple things unclear, as when they say "A SIP transaction consists of a request and a final response." What about the intermediate 1xx responses? Aren't they part of the SIP transaction? The RFC says they are.
Other times the authors express puzzling opinions, such as "[We] believe the IP-PSTN telephony model does not qualify as true VoIP either." What, then, do you call the VoIP services sold by the likes of AT&T, Covad, Sunrocket, and Vonage offering cheap local and long distance phone service to PSTN destinations? I stand perplexed.
When the authors do roll up their sleeves to talk tech, they write a few intriguing paragraphs about a topic and then inexplicably stop, switching gears to the next subject. For example, the discussion on PSTN interactions begins to explain how early media, ringback and other in-band signalling works, then suddenly stops the discussion. Yes, one can scour the Internet for such information, but it would be nice for the authors to simply explain each topic to a consistent level of detail. If they aren't going to talk about things Beyond VoIP, as originally promised, they can at least give readers consistent depth of coverage.
All three authors have impecable credentials, each with a track record in the field and deep involvement in SIP's development. Beyond the misleading title, I expected more quantity and quality from these three experts.
A note on Amazon reviews. Whenever I see a five-star review I always check to see the reviewer's other reviews. It's amazing how often they have none.
With CIM Voice Internetworking: Basic Voice over IP, you can master the telephony and voice internetworking knowledge you need to enhance the versatility and value of your communications infrastructure. Offering self-paced instruction and practice, this robust learning tool gives you a quick and cost-effective way to acquire Cisco knowledge and expertise. From an overview of traditional telephony and voice transmission concepts to the basics of routing voice and fax packets over a data network, you'll learn how to configure typical software features of a VoIP network and perform operational application tasks with interactive voice response (IVR). Using techniques developed by Cisco Technical Assistance Center engineers, you'll practice configuring and troubleshooting both analog and digital voice calls over IP networks. An excellent preparation tool for the Cisco Certified Network Professionals (CCNP) Voice Access Specialization and Cisco Certified Internetwork Expert (CCIE) exam.
Customer Review: Another "pdf on CD-ROM"
I think, for a "Basic" CIM does much more than that, explaining throughly couple of concepts which helps to understand the fundamentals of Cisco VoIP, even though almost everything is copied or rearranged from CCO. For the price paid though, instead of the old-fashioned cheesy text style with a few glossary popups and some really easy labs (where you have to type only a few commands and you're done), one should expect many animated graphics, maybe some movies (check: Intro and Outro on CD-ROM :) ) and labs for people that will support this technology eventually... At least they recommended having a RealPlayer G2 installed on your computer. Not to mention some "tricky" IE double openings and "Cannot find server" messages. I assume CiscoPress knows that nobody out there is interested in having a 2001 looking CIM, with router simulators built-in, where you can practice any combination of commands and troubleshoot, related to "Basic" VoIP. Don't worry people, you can still buy 2,3 routers with VoIP modules, at least 2 PBXes (second hand are cheaper), connect'em to a LEC CO and play all day long! ....
A systematic approach to understanding the basics of Voice over IP
Understand the basics of PSTN services and IP signaling protocols, including SS7
Learn how VoIP can run the same applications as the existing telephony system, but in a more cost-efficient and scalable manner
Delve into such VoIP topics as jitter, latency, packet loss, codecs, quality of service tools, and mean opinion scores
Learn about the functional components involved in using Cisco gateways to deploy VoIP networks
Voice over IP (VoIP), which integrates voice and data transmission, is quickly becoming an important factor in network communications. It promises lower operational costs, greater flexibility, and a variety of enhanced applications. Voice over IP Fundamentals provides a thorough introduction to this new technology to help experts in both the data and telephone industries plan for the new networks.
You will learn how the telephony infrastructure was built and how it works today, the major concepts concerning voice and data networking, transmission of voice over data, and IP signaling protocols used to interwork with current telephony systems. The authors cover various benefits and applications of VoIP and how to ensure good voice quality in your network.
This book is part of the Networking Technology Series from Cisco Press, which offers networking professionals valuable information for constructing efficient networks, understanding new technologies, and building successful careers.
Customer Review: Covers the Underlying Technology
With companies like Vonage beginning to advertise for broad based end user sales on television, VoIP must have become of age. I do notice, however, that Vonage still charges by the minute. I guess they think that this is what customers are used to paying so why not.
This book is aimed not at the Vonage type end user, but at the technically savvy individual. It aimed at three types: people who know circuit switching and want to know more about packet switching, people who know packet switching and want to know more about circuit switching, computer types who know computers but are not expert in communications.
It starts with how the traditional phone system worked and then moves to explain the difference between the old circuit switched system that Ma-Bell developed to the newer packet switched systems of today.
Most of the equipment being discussed is Cisco, as is fitting because it seems that they have just about the most complete line, and because this book is put out by Cisco Press. This is a resonably high level book, it is not intended for the absolute beginner who wants to use VOIP, but at the person who wants to understand the underlying technology. You'll learns lots of new With companies like Vonage beginning to advertise for broad based end user sales on television, VoIP must have become of age. I do notice, however, that Vonage still charges by the minute. I guess they think that this is what customers are used to paying so why not.
This book is aimed not at the Vonage type end user, but at the building of a comprehensive understanding of VoIP and would appeal to the sophisticated home user and to the corporate network engineer charged with moving his company to VoIP. It starts with how the traditional phone system worked and then moves to explain the difference between the old circuit switched system that Ma-Bell developed to the newer packet switched systems of today.
Most of the equipment being discussed is Cisco, as is fitting because it seems that they have just about the most complete line, and because this book is put out by Cisco Press. This is a fairly advanced book. It is not intended for the person who wants to set up a system, but for the person who wants to understand the underlying technology. You'll learn lots of new algorithms.
Cisco Voice over IP, Second Edition, is a Cisco®-authorized, self-paced learning tool for Cisco Certified Voice Professional (CCVP) voice over IP (VoIP) foundation learning. This book provides you with the knowledge you need to implement and support data and voice integration solutions at the network-access level. By reading this book, you will gain a thorough understanding of basic IP telephony operation and router configuration, support, troubleshooting, and integration with an existing public switched telephone network (PSTN).
Cisco Voice over IP lays the foundation for gaining hands-on skills and a significant understanding of packet telephony. Coverage includes analog and digital voice connections, voice interface configuration, voice dial peer configuration, VoIP fundamentals, VoIP signaling and call control protocols, and voice quality improvement and maintenance. Chapter review questions, practice items, real-world examples, and hands-on lab exercises all help reinforce learning. Whether you are preparing for CCVP certification or simply want to gain a better understanding of VoIP, you will benefit from the foundation information presented in this book.
Cisco Voice over IP is part of a recommended learning path from Cisco Systems® that includes simulation and hands-on training from authorized Cisco Learning Partners and self-study products from Cisco Press®. To find out more about instructor-led training, e-learning, and hands-on instruction offered by authorized Cisco Learning Partners worldwide, please visit: www.cisco.com/go/authorizedtraining.
Kevin Wallace, CCIE® No. 7945, CCVP, CCNP®, CCDP®, is a full-time instructor for Thomson NETg. With 17 years of Cisco internetworking experience, Kevin has been a network design specialist for The Walt Disney World Resort and a network manager for Eastern Kentucky University.
Understand traditional telephony network concepts and operation as well as the building blocks of packet telephony networks
Examine the interactions of telephony operations at an electrical level
Evaluate strategies for overcoming specific challenges in a VoIP network, such as the transmission of fax and modem tones
Attach a Cisco voice-enabled router to existing telephony devices, such as a PBX or an analog phone
Add call-routing intelligence to a Cisco voice-enabled router through the use of dial peers
Address potential challenges and design considerations associated with sending voice across an IP-based network
Understand the theory and configuration of the call control protocols including H.323, SIP, and MGCP
Mitigate voice quality issues with various Cisco quality of service (QoS) mechanisms
This volume is in the Certification Self-Study Series offered by Cisco Press®. Books in this series provide officially developed self-study solutions to help networking professionals understand technology implementations and prepare for the Cisco Career Certifications examinations.
Category: IP Communications
Covers: VoIP
Customer Review: Great for Self-Study or Reference
Finally, a book I trust when studying for a test. While other vendors may very well contain all of the content necessary for exam preparation, Cisco Press is the only one I feel 100% sure about when taking Cisco exams.
If you come from a data background like myself (not voice), the chapters on voice technologies and analog/digital voice are essential. While you may never have to work with PBXs or care what signaling is used in other countries, its all fair game for test takers. I really never knew how deficient my knowledge of the old voice world was until reading this book. Local Loop Signaling, Trunk Signaling, the Nyquist Theorem (which seems to exist in every book I own), its all in here. As dry as some of these topics are, the understanding of the brick-level voice construct helps in troubleshooting issues with your telco.
If you arent buying this book for test preparation, youll be able to appreciate the chapters on voice interface configuration, configuring dial peers, dial plans, and troubleshooting. It gives details on setting up the above including the syntax of commands. I also own the CallManager Fundamentals book and the Gateway/Gatekeeper study guide. Youll find many of the same commands in this book as the other two. This book is broader in its scope than the Fundamentals or Gateway book.
I always look for troubleshooting tools more than anything else books (any command I can put in my arsenal). I maintain a network as opposed to implement new networks for companies, so Im faced with network complications that consultants largely get to avoid. The Comparing Call Control Models was likely the most useful to me. Whether you use SIP, H.323, or MGCP (we use MGCP), there are plenty of show and debug commands at your disposal and are listed in the text. While I had these commands in other books as well, I personally cant get enough of troubleshooting techniques in books. Keeping the network up and supporting end users is what keeps me employed.
My only gotcha with any book is end of chapter test-type questions. I never completely trust answer keys in the back of books and I thought I found errors in at least one question in this book. It was easy for me to catch because I knew the right answer but be on the lookout.
In all, I'd recommend this book for test takers and non-test takers. It covers some materials (dial peers, signaling and call control protocols, etc..) that are covered in other classes (Gateway/Gatekeeper class for one) and can be used as a quick reference.
Sidestep VoIP Catastrophe the Foolproof Hacking Exposed Way
"This book illuminates how remote users can probe, sniff, and modify your phones, phone switches, and networks that offer VoIP services. Most importantly, the authors offer solutions to mitigate the risk of deploying VoIP technologies." --Ron Gula, CTO of Tenable Network Security
Block debilitating VoIP attacks by learning how to look at your network and devices through the eyes of the malicious intruder. Hacking Exposed VoIP shows you, step-by-step, how online criminals perform reconnaissance, gain access, steal data, and penetrate vulnerable systems. All hardware-specific and network-centered security issues are covered alongside detailed countermeasures, in-depth examples, and hands-on implementation techniques. Inside, you'll learn how to defend against the latest DoS, man-in-the-middle, call flooding, eavesdropping, VoIP fuzzing, signaling and audio manipulation, Voice SPAM/SPIT, and voice phishing attacks.
Find out how hackers footprint, scan, enumerate, and pilfer VoIP networks and hardware
Fortify Cisco, Avaya, and Asterisk systems
Prevent DNS poisoning, DHCP exhaustion, and ARP table manipulation
Thwart number harvesting, call pattern tracking, and conversation eavesdropping
Measure and maintain VoIP network quality of service and VoIP conversation quality
Stop DoS and packet flood-based attacks from disrupting SIP proxies and phones
Counter REGISTER hijacking, INVITE flooding, and BYE call teardown attacks
Avoid insertion/mixing of malicious audio
Learn about voice SPAM/SPIT and how to prevent it
Defend against voice phishing and identity theft scams
Covers the administration of all operating systems, data and network security, new trends in storage options, and server, network, and storage management Thoroughly explores each topic, with attention to various network and system design options, best practices, potential problems, and leading solutions Discusses how to build resiliency into the network, servers, and storage to prevent service outages despite hardware or software failures Includes plenty of real-world examples that illustrate objectives, problems, and solutions, along with a complete best practices section for every topic Shows administrators how to ensure close to 100 percent service uptime with various high-availability options such as redundancy and clustering; how to deal with server and storage proliferation, and how to manage separate networks for voice, IP, and storage
Customer Review: one of the best book for sysadmin , network admin and Datacenter admin
This is one of the best book to read specially for sysadmins , network administrators and Datacenter Administrator.I have read the book and have been benifitted a lot from it.
Thanks
Amitabh Talukdar
Unix System Administrator
Cisco Systems
