Development #1: All New Phone Systems Are VoIP

A closer look at the first item in our list of eight major recent developments and trends in telecom

Telecommunications technology is constantly changing and improving – seemingly faster and faster every year – and at Teracom, we keep our training courses up to date to reflect these changes. In the last post, we identified eight major developments and trends in telecommunications incorporated in our training.

In this post, we take a closer look at the first one: “All New Phone Systems Are VoIP”:

Basic Principle of Operation
The voice entering the microphone is digitized in the near-end phone. Typically 20 ms of digitized voice is packaged in an IP packet, which is carried in an Ethernet MAC frame on copper and fiber LAN cables to the far-end phone. There, the digitized voice is extracted from the packet and used to re-create the voice coming out of the speaker at the far end.

There are, of course, many details not mentioned, including the digitization method, called a codec, the Real-Time Transport Protocol (RTP) that adds timing information, the User Datagram Protocol (UDP) that adds error control and indicates the port number on the far-end phone, and how the bits are represented on copper and fiber LAN cables, to mention a few.

SIP and Softswitches
In a traditional phone system, voice travels on a dedicated circuit to a telephone switch, which physically transfers it to a different circuit to get it to the far end. Not so with VoIP! The near-end VoIP telephone creates a packet addressed to the far-end telephone, then the packet travels over LAN cables and through routers, interspersed with many other packets, to the far-end telephone. The VoIP packet does not pass through a telephone switch. The two VoIP phones exchange packets directly.

So a question is: how does the near-end telephone know what the far-end telephone’s IP address is? This is accomplished with the Session Initiation Protocol (SIP), which implements servers allowing the calling party to find out the IP address of the called party – if the called party wants to accept the call… a privacy shield to prevent Spam over Internet Telephony (SPIT). The servers implementing SIP are called softswitches. They are call setup assistants, and drop out of the picture once the call is established. The phones communicate packets directly.

SIP Trunking
What happens if the two telephones are in different cities? How does the packet move from the near-end VoIP phone to the far-end VoIP phone? One method is to use a gateway to convert the VoIP to an old-fashioned phone call and carry it over PBX trunks and/or telephone company trunks to the far end, where a gateway converts it back to VoIP… but this loses out on the voice-data-video integration synergy of IP communications. Another method is to carry the VoIP packet over the Internet… but there are no quality guarantees on the Internet. A third choice is to pay a carrier to move the VoIP packet from one building to another, as an IP packet, with guaranteed quality. This is called SIP trunking. It should be called VoIP trunking.

That is a thumbnail sketch of VoIP. If you would like to learn more, this is covered in the following Teracom training:

Course 101 Telecom, Datacom and Networking for Non-Engineers
(about an hour out of three days in-class)

Course 130 Understanding Voice over IP
(two days in-class)

The VoIP DVD-Video courses
(3 DVDs, six hours)

Cheers!

“No longer Greek to me! After taking your course, I sat in on a round table at a conference yesterday where VoIP was discussed by Time Warner Cable and Vonage – and I understood most of their diagrams and explanations – something that would have been Greek to me two weeks ago. Thank you!” — Bob Sabin, Tel Control, Inc.

Recent Developments and Trends in Telecommunications

Eight major developments and trends in telecom that you need to know about

Teracom’s training represents the core knowledge set required for the telecom business.  We’ve been teaching people the fundamentals of telecom and networking since 1992, so there have been many changes to the core knowledge set, and updates to our training over the years!

Check out Teracom’s best-of-breed training – with free tutorials!

For the new school year, we have updated our core training yet again, with some significant shifts. For example, Voice over IP is now part of the fundamentals, and channelized systems like T1 and SONET are now referred to as “legacy technologies” for the first time ever.

Here’s a summary of the recent developments and trends in telecommunications that triggered these updates:

1. All new phone systems are VoIP.  SIP trunking services replace PBX / PRI trunks from LECs.

2. Optical Ethernet has replaced SONET for all new core fiber network projects, and is also routinely used for “last mile” connections, achieving a long-held goal in telecommunications: one technology for all parts of the network.

3. MPLS has replaced ATM for traffic management on carrier networks, achieving another long-held goal: convergence and service integration… one network service, one access circuit, one bill for all telecom services.

4. 4G LTE has achieved the goal of a worldwide standard for mobile wireless.

5. “Data” on cellular plans means Internet access. It can be used for phone calls, video on demand, web surfing, real-time traffic on maps or any other application. Cellular data plans can be replaced with WiFi, which is often free.

6. Broadband carriers, also known as Cable TV companies, have evolved into telecom companies, gaining a majority share of residential Internet access in the USA, and providing services to business using both cable modems and fiber.

7. Telephone companies provide Cable TV service using Fiber to the Neighborhood and VDSL over loops in brownfields, and often Fiber to the Premise in greenfields.

8. In the future, the Internet and the telephone network will be the same thing. Basic telephone service will be “IP dial tone”: the ability to send an IP packet to any other point on the network. There will be no such thing as “long distance”.

To explore and understand these developments in more detail, while getting a firm grounding in the fundamentals and installed base…

Join us at famous instructor-led training Course 101,
totally up-to-date with the new-generation network.

“I really appreciated the telecommunications training course provided by Teracom Training Institute. I did learn a lot and understand things better, so that I am now able to tie everything together to understand all the facets of Telecommunications. Many of the acronyms, technologies, network designs and services – I would have no idea what they meant if it were not for this class. Thanks, I really enjoyed it.”
— Natasha White, Comcast, West Chester PA

Get career-enhancing telecommunications training
with certification today!

 

Course 101 Content and Schedule Update

Our famous instructor-led training Course 101 “Telecom, Datacom and Networking for Non-Engineering Professionals” covers the key knowledge set required in the telecom business… so must be updated regularly.When the course was first written 20 years ago, the Internet did not exist. In the lastest update, the basics of Voice over IP are in the “Fundamentals of Telephony” chapter!

To quote Loretta Lynn: We’ve come a long way, baby!

Check out the new outline.

The latest edition reflects how “convergence” has finally been achieved by treating voice and video like data, in IP packets.

VoIP is promoted to “fundamentals”, channelized TDM and SONET is demoted to “legacy technology”, replaced with IP/Ethernet backbones. Other updates include fiber to the home, and VDSL and DOCSIS 3.1 for the last mile.

As always, our goal is to bust the buzzwords, demystify jargon, understand technologies and mainstream solutions and – most importantly – the ideas underlying all of this, and how it all works together, in plain English … knowledge you can’t get on the job, talking to vendors or reading articles.

Read more >> 

DVD6: Wireless Released! Free lesson, introduction, launch specials!

We’re very pleased to announce the release of our latest DVD-Video Course DVD6 Wireless: totally new, over 3 hours long with 28 lessons and a 74-page course book and certificate.

You will gain a real understanding of how digital radio communications works, how a cellular network operates, the cellular technologies and generations, plus WiFi, Bluetooth, satellite and much more.

Take advantage of the launch specials to get this career- and productivity-enhancing knowledge upgrade today: https://www.teracomtraining.com/specials.htm#dvd6

DVD6: Wireless introduction and highlights

Free lesson 2.03 Mobile Network Components and Operation

Teracom DVD-Video Course DVD6: Wireless
ISBN 9781894887083 Length 185 minutes. 74-page course book.

Radio Fundamentals • Spectrum • Digital Radio • Mobile Network Components and Operation • Cellular Principles • Digital Voice • Data • Mobile Internet • Cellular Technologies • TDMA • CDMA • OFDM • Generations • 2G GSM • 3G 1X • UMTS • HSPA • 4G LTE • Fixed Wireless • Bluetooth • WiFi • WiFi Security • Encryption • WiMAX • Point-to-Point Microwave • Satellite

detailed course outline

Textbook now available on iTunes, Amazon Kindle and Google Play Books

Almost finished a 3.5-year-long project to get our training courses available online, last major milestone accomplished today with the companion reference textbook now available on iTunes, Amazon Kindle and Google Play Books.

Learning all the material in the book took 25 years.
Writing the book in Word took six months.
Putting it in Adobe inDesign to export it in EPUB format (eBook) took three months.

Amazon took 10 minutes to open an account and upload the book to Amazon kindle.
http://www.amazon.com/dp/B00F3KCDOS
You can read the book on pretty much any device
They take 70% commission and pay 30% to the author.

Google took a week to get the book uploaded and online on Google Play Books.
https://play.google.com/store/books/details/Telecom_Datacom_and_Networking_for_Non_Engineers_C?id=aAQ9Nub9VIMC
You can read the book on pretty much any device.
They take 30% commission and pay 70% to the author.
They put the book on sale at a reduced price, but still pay 70% of the list price to the author.

Apple took two weeks to get uploaded and online on iTunes iBooks.
https://itunes.apple.com/us/book/telecom-datacom-networking/id705339315?mt=11
You can only upload the book from an Apple computer. Not a PC, iPhone, iPad or iPod.
You can only read the book on iPhone, iPad or iPod touch. Not on any computer.
They take 30% commission and pay 70% to the author.
They put the book on sale at a reduced price, but only pay 70% of the sale price to the author.

Why did I put Amazon first on the list?? They keep all the money! Google Play seems the best, since it is both the cheapest and you can read the book on any device. But does anyone actually buy books on Google Play Books? iTunes of course has the most users and so maybe the most people will see it there. Time will tell…

My favorite: the FedEx Analogy to explain the OSI layers, what each layer does and how they work together in protocol stacks.

Here’s the latest free tutorial, with embedded video of yours truly and my favorite analogy: the FedEx Analogy to explain the OSI layers, what each layer does and how they work together in protocol stacks.  Enjoy!

http://www.teracomtraining.com/online-courses-certification/samples/lesson1114-fedex-analogy.htm

Tutorial: MAC Addresses

What is a MAC address?

The term comes from the Institute of Electrical and Electronics Engineers (IEEE) 802 series of standards for LANs and MANs developed following the invention of Ethernet LANs by the Digital Equipment Corporation (now a part of HP), Xerox and Intel in 1979.

And people say Xerox never does anything original!

The first kind of LAN, Ethernet, employed a bus topology. The term bus comes from the Latin word omnibus, meaning “all”. It is used in electrical power systems, where a bus is a thick metal bar used to distribute electricity to many circuits.

bus bar

see the rest:
https://www.teracomtraining.com/tutorials/teracom-tutorial-mac-address.htm

Cheers

Cisco VoIP phone vulnerability: continuously monitor and record all sound in people's offices, boardrooms and bedrooms

A recent report of a Cisco VoIP phone vulnerability is very disturbing.

http://www.networkworld.com/community/blog/cisco-issues-alert-voip-vulnerability

This is more serious than phone calls.

If the network world article is accurate, its first paragraph “vulnerability in its IP phones that allows hackers to access calls and call data” should read

“vulnerability in its IP phones that allows attackers to eavesdrop in people’s offices, boardrooms and bedrooms”

— or in fact, “continuously monitor and record all sound in people’s offices, boardrooms and bedrooms”.

!

Tutorial: What is a Port?

The term “port” crops up in IP networking, particularly in the context of rules in routers and software firewalls. One hears about “opening a port on a firewall” and “TCP ports” and “UDP ports”.

So just what is a “port”, exactly?

Like about 40% of the words in English after the Norman invasion of southern England following the Battle of Hastings in 1066, the English word “port” is French. Une porte is a door.

Of course, the French got it from Latin: porta (gate, door). The Latin word portus (port, harbor, and earlier, entrance, passage) and the Greek word poros (journey, passage, way) are obviously related.

In the computer hardware business, a port is a doorway into the machine: a jack, where a cable can be connected. In days past, there were serial ports and parallel ports on PCs. Today, we have USB ports and LAN ports. Technicians talk about connecting customers to ports on access equipment, for example, equipment with banks of modems.

In the computer software business, a port can be thought of as a doorway into the software running on the machine, a passageway to a specific computer program running on the computer.

Why is this necessary? Since there can be many computer programs (a.k.a. applications, apps) running on the same computer at the same time, when trying to communicate to a particular program, we require a mechanism to identify it, a way of telling the host computer to which program to relay our communications.

For example, we all know that it’s possible to have multiple applications using the Internet connection on a computer at the same time. Think of an Outlook email program and a Chrome browser program running at the same time on a PC connected to the Internet.

When data arrives at this computer, how does the computer know whether this data is for the email program or for the browser program? And how does it convey the data to the correct program?

The answer: every program is assigned a number called a port number. Your browser is assigned port 80, for example.

Here’s how it works: the sending program creates a message and tags it with the port number identifying the program it wishes to communicate with on the destination computer. This is put in a packet that is tagged with the network address (IP address) of the destination host computer and transmitted. When the packet arrives at the destination computer identified by the IP address, this receiving computer looks at the destination port number and parks the message in a memory space associated with that port number. The program on the destination computer assigned that port number is constantly checking that memory space to see if there is anything new waiting for it.

The result is the ability for a computer program running on one computer to communicate with a specific computer program on another computer.

Visiting our warehouse service a couple of weeks ago, I was struck by the analogy possible between the idea of computer ports and a multi-tenant warehouse, so whipped out my Android smartphone and took a picture with the totally cool panoramic feature.

The warehouse is analogous to the host computer. It has a single street address. It handles goods for multiple users. Users have space allocated inside the warehouse. The warehouse has (on this side) six ports, also called loading docks. Each port has a number. A user can be assigned a port, either temporarily or permanently.

To communicate goods to that user, they’re carried in a shipping container (IP packet) on a truck (Ethernet frame) over a road (LAN cable) to the warehouse at its street address (IP address). To get the contents of the shipping container delivered to the correct user, the truck is backed up to the appropriate loading dock (port) identified by its door number (port number) and the contents of the container are unloaded to the space behind that port.

In computer communications today, the port number is 16 bits long, and the source and destination port number are populated at the beginning of the transport layer header, Layer 4 of the OSI model. The world’s most popular standard protocols for implementing the transport layer are the TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

Hence, one hears of “TCP ports” and “UDP ports”, particularly when configuring rules for packet forwarding on a router or firewall. When one “blocks” a port, that means that communication to a particular computer program is denied. When one “opens” a port, communication to that computer program is being allowed.

Standard practice is to allow communications only to specifically-identified ports and deny all other communications.

The port number of the application and the IP address of the host computer concatenated together is called a socket in UNIX and IP and is called a transport service in the OSI model. The result is the ability to identify the specific source computer program on one computer and the specific desired destination computer program on a different computer.

I hope you’ve enjoyed this tutorial! This discussion is covered in the following Teracom training courses:
Instructor-led Course 101: Telecom, Datacom and Networking for Non-Engineering Professionals, Lesson 12.17
Instructor-led Course 110: IP, VoIP and MPLS for the Non-Engineering Professional, Lesson 8.25-8.27
DVD-Video Course V4: Understanding Networking 1
DVD-Video Course V5: Understanding Networking 2, Lesson 2.11
Online Course L2112 The OSI Layers and Protocol Stacks, Lesson 8
Online Course L2113 IP Networks, Routers and Addresses, Lessons 7 and 9

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