Tutorial: Bluetooth

This tutorial on Bluetooth is Lesson 2: Bluetooth, from Course 2233 “Fixed Wireless”.  Watch the lesson by clicking the picture below.
You can also watch the video on YouTube.
The text is from the Course book / CWA certification study guide.

Enjoy!

Young man illustrating Bluetooth channel as frequency-hopping pattern using a pogo stick. Click the image to watch the full lesson. The text that follows is from the course book.
Young man illustrating Bluetooth channel as frequency-hopping pattern using a pogo stick.
Click the image to watch the full lesson. The text that follows is from the course book.

Bluetooth is a set of standards for short-range digital radio communication published by a consortium of companies called the Special Interest Group. It was originally developed as a wireless link to replace cables connecting computers and communications equipment.

Bluetooth connections are called piconets and Personal Area Networks since (in theory) up to eight devices can communicate on a channel within a range of 1 to 100 meters depending on the power.

In reality, Bluetooth is mostly used point-to-point with ten meters range.

The first data rate for Bluetooth was 0.7 Mb/s, followed by an enhancement to “3” Mb/s (2.1 Mb/s in practice). A High Speed variation employs collocated Wi-Fi for short high-bitrate transmissions at 24 Mb/s. The Smart or Low Energy variation allows coin-sized batteries on devices like heart-rate monitors.

Bluetooth applications
Bluetooth applications

Applications include wireless keyboard, mouse and modem connections… though today, 2 Mb/s Bluetooth is likely slower than the modem.

Bluetooth is used to replace wires connecting a phone to an earpiece, or to an automobile sound system for hands-free phone calls while driving. In this case, both two-way audio and two-way control messages are transmitted.

Bluetooth is also used to stream music from a smartphone to a receiver connected to an amplifier and speakers in an automobile or in a living room.

In the future, wireless collection of readings from devices like heart-rate monitors will be widespread.

Each of these types of applications corresponds to a Bluetooth profile, which is a specified set of capabilities and protocols the devices must support.

Bluetooth implements frequency-hopping, where the devices communicate at one of 79 carriers spaced at 1 MHz in the 2.4 GHz unlicensed band for 625 microseconds (µs), then hop to a different carrier for 625 µs, then to another, in a repeating pattern known to both devices. A particular hop sequence is called a channel, and is identified by an access code.

This is called Frequency-Hopping Spread Spectrum (FHSS), since hopping between 79 carriers spreads energy across spectrum 79 times wider than one carrier. It has the advantage of reduced sensitivity to noise or fading at any particular carrier.

If different pairs of devices are using different hop sequences, they can communicate at the same time in the same place without interfering. There are security advantages if the hop sequence can not be determined by a third party.

The initiator of communications is called the master. It determines the frequency hopping pattern, when the pattern begins, when a packet begins and when a bit begins. The packet and bit timing is based on the master’s clock, which ticks every 312.5 microseconds. Two ticks make a slot. A slot corresponds to a hop. The master transmits and the slave listens in even-numbered slots; vice-versa in odd-numbered slots.

To establish the channel, the master derives a channel access code from its Bluetooth address, and indicates the code to the slave at the beginning of every packet. Both master and slave use this to determine the actual frequency-hopping sequence.

Data is organized into Bluetooth packets for transmission. Packets can be 1, 3 or 5 slots long. A bit rate of 2 Mb/s would mean Bluetooth packets are about 150, 450 or 750 bytes long.

Discovering other devices means sending requests in packets on pre-defined channels called inquiry scan channels. Making a device discoverable means it listens on the inquiry channels, and responds to inquiries with information like its Bluetooth address, name and capabilities. This results in a list of Bluetooth devices displayed on the discovering device, such as a smartphone.

Connecting to a device means paging the device on its paging channel, a channel with access code derived from the target’s Bluetooth address. Devices listen on their paging channel, and respond to pages to establish a session. Once the session setup protocol is completed on the paging channel, the devices begin communicating on the channel defined by the master.

The frequency hopping pattern can be adapted to skip carriers where the signal to noise ratio is permanently low, to improve overall performance.

I hope you’ve enjoyed this tutorial!

This discussion is covered in the following Teracom training courses:
• DVD-Video Course V6: Understanding Wireless
https://www.teracomtraining.com/video_courses.htm

• Online Course 2233 Fixed Wireless
https://www.teracomtraining.com/online-courses-certification/certified-wireless-analyst-cwa.htm#2233

CWA course books released – and the first one is FREE!

The course books for the three Certified Wireless Analyst courses are now available on Google Play Books!

Course 2231: Wireless Fundamentals Course Book  – FREE
Course 2232: Mobile Communications Course Book – US$9.99
Course 2233: Fixed Wireless Course Book – US$5

We’re using Google Play Books because it allows you to read the book on any device: desktop, laptop, tablet, phone, PC, Mac, iPad, android… which is way more flexible than iTunes or other platforms.

The books are formatted the same way as Teracom instructor-led course and DVD course books, with detailed text notes on the left page and the corresponding graphics / bullets page on the right in two-page view.

To get you started, the course book for Course 2231: Wireless Fundamentals is free, downloadable and printable!

To download and print the the course book for Course 2231: Wireless Fundamentals, first add the book to your library (it’s FREE), then on the My Books page, click the three dots and choose “Download PDF” as shown in the screenshot below.

If you print the PDF two-sided then put it in a 3-ring binder, the result will be almost identical to the course books supplied with Teracom instructor-led and DVD courses!

Cheers!
Printable course book

Printable course book

New TCO Certification Package: Certified Wireless Analyst (CWA)

The Certified Wireless Analyst (CWA) Certification Package is released!

CWA includes three training courses covering the full range of wireless technologies, giving you the broad knowledge base required of an analyst in the wireless business — plus certification to prove it.

Learn the fundamentals, jargon and buzzwords, principles of operation and ideas behind today’s wireless.

You get three high-quality courses with our entertaining instructor, graphics and bullets, plus your certification:

Course 2231: Wireless Fundamentals
• Radio fundamentals. Radio spectrum.
• Digital radio: modems and modulation

Course 2232: Mobile Communications
• Cellular principles. Mobility and handoffs.
• Digital voice. Mobile Internet Access.
• The generations: 1G, 2G, 3G, 4G
• The technologies: FDMA, TDMA, CDMA and OFDM
• The systems: GSM, 1X, UMTS, HSPA and LTE

Course 2233: Fixed Wireless
• Wireless LANs, 802.11 standards, WiFi, security
• Bluetooth, WiMAX, point-to-point and satellites

Upgrade your skills – and your résumé – with this training and certification today.

Guaranteed To Pass with the Unlimited Plan!

 

Quality You Can Trust
Benefit from decades of knowledge, insight and experience distilled into clear lessons, logically organized to build one concept on another… in plain English.

Join our thousands of satisfied customers including:
AT&T, Verizon, Bell Canada, Intel, Microsoft, Cisco, Qualcomm, NSA, CIA, FAA, US Army, Navy, Marines and Air Force, Coast Guard, CIA, IRS, CRA, CRTC, RCMP, banks, power companies, police forces, manufacturers, government, local and regional telcos, broadband and fiber carriers and thousands of individuals.

gsa contract holder - assurance of quality
Teracom is a supplier of this training to the US Government under GSA contract GS-02F-0053X. Obtaining this Federal Supply Schedule contract involved a two-year-long process of evaluation including a customer quality rating where we scored 97%!

money-back guarantee
30-day, 100%, no questions asked money back guarantee.
If for any reason you change your mind during the 30 days after purchase, you can get your money back.
You have nothing to lose – and a marketable knowledge skill to gain! Get started now!

 

telecommunications certification organization (TCO)

About TCO Certification
Teracom is a Gold Training Partner of the Telecommunications Certification Organization, authorized to administer exams for TCO certifications on the myTeracom Learning Management System and award TCO certifications.

TCO certification is proof of your knowledge of telecom, datacom and networking fundamentals, jargon, buzzwords, technologies and solutions.

It’s backed up with a Certificate suitable for framing, plus – a Teracom exclusive – a personalized Letter of Reference / Letter of Introduction detailing the knowledge your certification represents and inviting the recipient to contact us for verification.

You may list Teracom Training Institute as a reference on your résumé if desired.

Benefits of Certification for Individuals
TCO Certification differentiates you from the rest of the crowd when applying for a job or angling for a promotion.

The knowledge you gain taking these high-quality courses, confirmed with TCO Certification, is foundational knowledge in radio and wireless: fundamental concepts, mainstream technologies, jargon, buzzwords, the underlying ideas – and how it all fits together.

This type of knowledge and preparation makes you an ideal candidate to hire or promote to a task, as you will be able to build on your knowledge base to quickly get up to speed and work on a particular project – then have the versatility to work on subsequent projects.

TCO Certification will help demonstrate you have this skill… a desirable thought to have in your potential manager’s mind.

Benefits of Certification for Employers
Take advantage of these courses for individual learning, a team, or for an entire organization. The scalable myTeracom Learning Management System can register and manage all of your people through their courses, lessons and exams, and generates reports showing progress and scores.

For larger organizations, the courses and exams can also be licensed and deployed on an organization’s internal LMS.

Teracom certification packages are an extremely cost-effective way of implementing consistent, comprehensive telecommunications and networking technology fundamentals training, ensuring that existing resources and new hires are all up to the same speed, with a common vocabulary, framework and knowledge base.

Get started today with this invaluable addition to your knowledge and skills!

 

Detailed Course Outlines

Course 2231 Wireless Fundamentals is the first course in the CWA Certification Package. We begin with the fundamentals: what radio is, how it’s organized and how and it’s used to communicate information. Since most systems are digital, we spend time understanding how modems represent 1s and 0s on radio, and explain jargon like QAM and QPSK. We finish with penetration and fading.
A. Radio
B. Wireless Spectrum and Radio Bands
C. Analog Radio
D. Digital Radio: How Modems Work
E. Propagation, Penetration and Fading

Course 2232 Mobile Communications is the second course in the CWA Certification Package. With a good foundation in place, we’ll cover mobile communications from A to Z: cellular principles, digital voice, data over cellular, mobile Internet access, the technologies: FDMA, TDMA, CDMA and OFDM, and the generations: 2G GSM, 3G 1X, UMTS and HSPA and 4G LTE. This is where the money is!
A. Mobile Network Components and Operation
B. Cellular
C. 1G: Analog Frequency-Division Multiple Access
D. Second Generation: Digital Cellular
E. Digital Cellular: Voice Communications
F. Internet Access via Cellular: “Data” Communications
G. 2G TDMA (IS-136): Time-Division Multiple Access
H. 2G TDMA (GSM): Time-Division Multiple Access
I. 2G CDMA: Code-Division Multiple Access
J. Spread Spectrum
K. CDMA Operation and Patents
L. 3G: CDMA 1X and UMTS
M. 4G: LTE
N. 4G: OFDM
O. Dynamic Assignment of Subcarriers
P. Spectrum-Sharing Roundup: FDMA, TDMA, CDMA, OFDM

Course 2233 Fixed Wireless is the third and final course in the CWA Certification Package. We’ll round out your knowledge with fixed wireless: WiFi, 802.11, WiFi security, Bluetooth, WiMAX, point-to-point microwave and satellites.
A. Infrared
B. Bluetooth
C. WiFi: Wireless LANs
D. WiFi Security and WPA2
E. 802.16 WiMAX
F. Point-to-Point Microwave
G. Satellite

printable brochure

What You Get With The CWA Certification Package

1. High-quality, up-to-date, comprehensive training
You will get a solid foundation of structured knowledge. Understand the fundamentals, technologies, jargon and buzzwords… and how it all fits together

2. The certification exam
Each course in the certification package has an associated exam, typically ten multiple-choice questions.  You get unlimited repeats of the exam – which means guaranteed to pass.
Plus, on achieving a passing grade:

3. Your certificate, suitable for framing
A full-color TCO Certificate suitable for framing is automatically awarded by the Learning Management System on completion of the required exams.
It can be immediately printed on plain or textured paper on any color printer and framed by student as desired, with no shipping charges. It can also be attached to the electronic version of the student’s CV. An original hard copy of your Certificate, signed and sealed, can be sent to you by mail for $25 plus first-class mail cost.

4. A personalized Letter of Reference / Letter of Introduction
You also receive a personalized Letter of Reference / Letter of Introduction explaining the courses you took and the knowledge you have, and inviting anyone you give it to to contact us as a reference… excellent addition to your CV.

5. Right to display the TCO logo
You’ll have the right to display a high-resolution copy of the TCO logo on your résumé, business card, LinkedIn profile, web page, blog, or email signature.

6. TCO Certification Designation
Passing the Certified Wireless Analyst, you will be able to state that you:
– “are a Certified Wireless Analyst”,
– “hold a Certified Wireless Analyst certification from the Telecommunications Certification Organization”,
– are “certified as a Wireless Analyst by the Telecommunications Certification Organization”,
– are a “Telecommunications Certification Organization (TCO) Certified Wireless Analyst”,
– are “TCO-certified”,
and may sign your name
– “Richard Smith, CWA,” or “Jane Smith, Certified Wireless Analyst”

7. A 30-day no-questions-asked 100% money-back guarantee.
If for any reason you change your mind, for 30 days after purchase you can get your money back.

You have nothing to lose! – and a marketable skill to gain!

get started now!

Invest in yourself! Upgrade your résumé with this essential core knowledge.

HTML5 iPad-Friendly Lessons

HTML5 is here!

compatible with windows and mac desktops, laptops and notebooks, iPad, iPhone, android phones, tablets

Courses and exams labelled with this graphic on the Teracom website are HTML5, which is an open standard for displaying multimedia and interaction on webpages.

HTML5 will  run on windows and mac desktops, laptops and notebooks, iPad, iPhone, android notebooks, tablets and smartphones… and pretty much anything else.

Like regular HTML, HTML5 code is interpreted by and displayed in a browser.  We recommend using Chrome browser, as Chrome is fast and gives good results.

The new CWA courses and exams are in HTML5.
test with this free sample

 

compatible with windows and mac desktops, laptops and notebooks. runs on iPad with special browser

Courses and exams with this graphic use flash, which runs great on windows and mac desktops, laptops, notebooks.  They run on iPad, iPhone and android smartphones with a special browser.

CTNS, CIPTS and CTA use flash.
test with this free sample

Chrome browser has a built-in flash player, so CTNS, CIPTS and CTA run great in Chrome on mac or windows desktops, laptops, and notebooks.

But… when Steve Jobs invented the iPad, he wouldn’t allow flash on it. Steve had objections to flash including security, efficiency and power consumption.

The good news is there is an easy solution for iPad.
For iPad, CTNS, CIPTS and CTA run in a special $5 browser.
This one is popular     This one has a free trial
This article in macworld from the UK explains the story in detail

 

use chrome browser for best results

Online course lessons and exams are displayed in a browser. We recommend Google Chrome as it is fast and gives good results.

When using a computer with Windows 8, please download Chrome browser and use that instead of Internet Explorer.

How to implement a WiFi range extender for $20

A volunteer project to set up WiFi in a 150-year-old building with stone walls that I did recently required repeaters, also known as range extenders.

I ended up writing detailed instructions to get a popular WiFi access point / router on Amazon working as a repeater… and thought you might find this useful to extend WiFi coverage in your home or small office.

teracom-tutorial-wifi-repeater

Even if you don’t need to extend your WiFi coverage, understanding the configuration, including the IP addresses, DHCP, subnets and all the other items covered in this tutorial is career-enhancing knowledge.

The IP addressing story including DHCP is covered in
Online Course 2213 “IP Networks, Routers and Addresses”
(part of the CTNS Certification Package), as well as

Instructor-Led Course 101, the Telecom, Datacom and Networking for Non-Engineers textbook, and DVD-Video Course V4 Understanding Networking 1.

The requirement was to provide WiFi coverage in a 150-year old building with thick stone walls. The Internet connection (DSL) was in the basement, and coverage was required to the fourth floor.

We initially looked at pulling a cable to the fourth floor, but the stone walls made wireless a no-brainer.

The WiFi signal produced by the ISP’s Customer Edge device, which contains the DSL modem, a router, switch and WiFi Access Point, did not reach very far.

So WiFi repeaters, sometimes called Range extenders would be required. This had to be implemented with encryption of data over the air for information security.

Special-purpose range extenders can cost $300 each. After a bit of research, I bought these $20 units on Amazon.

They support “300 Mb/s” 802.11n, and most importantly, implement the Wireless Distribution Service (WDS) with WPA2 airlink encryption, which is needed for the repeater function with security.

Here is the product link on Amazon.   I don’t get a commission.

The instructions weren’t very complete, so I looked at the product’s Q&A section on Amazon and found instructions.
But those instructions turned out to be not quite right. And being an Engineer, I couldn’t help but proposing correct instructions…

These instructions assume you are connecting the WiFi access point / router pictured, TP-LINK model TL-WR841N, to any WiFi with a working Internet connection.

teracom-tutorial-wifi-repeater

Abbreviations:
[example] = example values used during my setup.
Yours might be a bit different.
SOURCE-AP = the access point / router generating the wireless signal you want to repeat. This is often supplied by your ISP.
REPEATER-AP = the access point / router repeating the wireless signal, the one that we are setting up.
SOURCE-NET = the SSID (network name) of the wireless signal you want to repeat.
REPEATER-NET = the SSID (network name) of the repeated wireless signal.
GUI = Graphical User Interface.
This is the access point / router’s control panel.

Before starting, gather the following information:
– The LAN/wireless side IP address of the SOURCE-AP GUI. [192.168.3.1]
– The username and password for the SOURCE-AP GUI.
[admin, admin]
– The subnet the SOURCE-AP is using on the LAN/wireless side. [192.168.3.x]
– The SOURCE-NET name [GROUND]
– The encryption type and password [WPA-2 PERSONAL, xxxx]
– The channel the wireless signal to be repeated is on. [3]

If you don’t know the channel, you can find out during the setup below. However, it is preferable to log in to the SOURCE-AP GUI and set the channel to 3 instead of “auto” so it does not change, and uses an unpopular channel likely to have less interference.

To determine the LAN/wireless IP address and subnet of the SOURCE-AP, look at the IP address and default gateway of a device directly connected to the SOURCE-AP. (Open the Network connections folder, click change adapter settings, and view status and then details in Windows). The value in the default gateway field is the IP address of the SOURCE-AP GUI. The part of the address common to the default gateway and the device is the subnet ID.

Do this setup and get it working somewhere comfortable near the SOURCE-AP. Once it’s working, you can place the repeater anywhere near an electrical outlet.

Here we go:

1. Plug the power into the REPEATER-AP. If any settings have already been changed on the device, press and hold the reset button on the back for ten seconds until all lights are illuminated to indicate reset happening. Reset is not necessary if the unit is fresh out of the box.

2. Plug a PC into a LAN port on the REPEATER-AP with the supplied LAN patch cable. I used my laptop. Make sure the LAN adapter is set to get an IP address automatically. (Open the Network connections folder, click change adapter settings, and view properties in Windows). Make sure the LAN adapter is the only one enabled. Disable the wireless adapter.

3. Open a browser and go to http://tplinklogin.net . This gets you to the GUI of REPEATER-AP, initially 192.168.0.1. The default username, password is admin, admin. Don’t do the quick setup.

4. Click “Wireless” on the left column menu.
On the Wireless Settings page that appears:
a. Under the dropdown list for “Channel”, select the channel the wireless signal to be repeated is on. [3] If you don’t know, skip this step and the unit will force you to select the correct one after the “Survey” step below.
b. Click the “Enable WDS bridging” checkbox.
c. Click “Survey”. A list of SSIDs appears. Click “connect” on the one that is SOURCE-NET. [GROUND] All of the fields are automatically populated except for the password.
d. Enter the password and click Save. Wait ten seconds for the processing to finish.
e. At the top of the page beside Wireless Network Name, enter a name for REPEATER-NET [R1] and click Save.

5. Click “Wireless Security” on the left column menu. Select Personal WPA2-PSK, AES encryption and enter a password for REPEATER-NET.

6. Click “DHCP” on the left column menu. Click the DHCP disable radio button. Click Save. Ignore the reboot warning.

7. Click “Network” on the left column menu.

8. Click LAN. Change the IP address to one in the SOURCE-AP subnet that is not being used by any other device and click Save [192.168.3.200]. A reboot warning will appear. Click OK and let the unit reboot.

9. The address in the browser will magically change to the IP address you entered in the previous step. This is the new IP address for the GUI on REPEATER-AP. You will be prompted to log in again. The status screen will appear. Under Network, click the WAN MAC menu item on the left.

You should also now have Internet through REPEATER-AP!
Open  news.google.com in a new tab in your browser to verify.
Wireless devices can now connect to REPEATER-NET.
Wired devices can connect to REPEATER- AP.
Both get Internet access through SOURCE-AP.
Ain’t life grand?

10. To avoid problems with dynamic addresses and timeouts, make the IP address of REPEATER-AP static.
Open a new tab in your browser. Enter the address of the SOURCE-AP GUI [192.168.3.1] and log in. Find the screen that lets you assign static IP addresses. The SOURCE-AP could be any brand of device; it is often supplied by your ISP. The function might be called “DHCP reservations” or “IP address reservation”. Make a new entry, with the WAN MAC address displayed in the REPEATER-AP GUI and the REPEATER-AP IP address you entered in Step 8.

I actually set up a chain of four of these units to provide wireless coverage from the basement to the fourth floor of a 150-year-old building with stone walls.  And it worked!

Good luck!

P.S. Don’t forget to go back in to REPEATER-AP and change the password. The menu item is hiding under System Tools on the left.


Notice required by the legal department: This information is provided as general background information only. Design and implementation of a communication system requires professional advice to identify and resolve issues specific to that particular system, including but not limited to performance, availability and security issues. Additionally, while we have strived to be as accurate as possible, we make no representation or warranty that the information provided is 100% accurate. This information is not to be relied upon as professional advice, nor is it to be used as the basis of a design. Users of this information agree to hold the author and Teracom Training Institute Ltd. harmless from any liability or damages. Acceptance and use of this information shall constitute indication of your agreement to these conditions.

Development #3: MPLS has replaced ATM

A closer look at the third 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 a previous post, we identified eight major developments and trends in telecommunications incorporated in our training.

In this post, we take a closer look at the third development:
MPLS has replaced ATM for traffic management, achieving  another long-held goal in the telecommunications business, called convergence or service integration.


A long-held goal in the telecommunications business has been to transport and deliver all types of communications on the same network and access circuit, and in an ideal world, with a single bill to the customer. This idea is sometimes called convergence, though service integration is a more accurate term.

It results in a large cost savings compared to different networks, access circuits and bills for each type of communications.
In days past, this was not the case.

A residence would have at least two entry cables: twisted pair for telephone and coax for television, and separate bills for each.

The situation was even worse and more expensive in the case of a medium or large organization.

At each location, a typical organization would have the requirement to communicate
• Telephone calls to/from the PSTN,
• Telephone calls to/from other locations of the organization,
• Data to/from other locations of the organization, and
• Data, video and possibly voice to/from the Internet.

In days past, the organization might have had four physical access circuits and services – along with four bills:
• ISDN PRI over T1 to a LEC for telephone calls to/from the PSTN,
• Tie lines or a voice VPN with a custom dialing plan from an IXC for telephone calls to/from other locations of the organization,
• Dedicated T1s from an IXC for data to/from other locations of the organization, and
• DSL, Cable or T1 access from an ISP for data, video and possibly voice to/from the Internet.

Not only did this mean four services and four access technologies and four bills for the customer, it also meant the carrier had to implement and support four network technologies… a very expensive situation.

MPLS for Service Integration

The solution to integrate all of this onto one access circuit and one network is twofold:
At the source,
• Format all types of traffic the same way, and
• Paste an identifier on the front of each piece of traffic, indicating what it is and where it goes.

Then all traffic can be carried interspersed on the same access circuit and in the same network, which results in a huge cost savings for both the customer and the carrier.

The identifier on the traffic is used to both route the traffic to the correct destination, and manage the traffic in the network, performing functions like load balancing, prioritization and restoration.

Starting in the 1980s, telephone companies and equipment manufacturers attempted to implement this with a technology called Asynchronous Transfer Mode (ATM). Literally billions of dollars were spent developing and deploying ATM from 1980 to 2000… but it failed and died, becoming too complex and too expensive, and not used for voice at the big telephone companies.

Multiprotocol Label Switching (MPLS) combined with IP has succeeded where ATM failed and is now universally implemented.

Of course, there is a lot of jargon to learn and many components to the “MPLS” story.

Here is a VERY brief explanation:
• All traffic is formatted into IP packets by the equipment that generates it, for example, a telephone or computer.
• Traffic is categorized into classes. A class of traffic goes from the same place to the same place and experiences the same transmission characteristics like delay and lost packets.
• A packet is identified as belonging to a particular class by pasting a number called a label on the front of the IP packet.
• The device that does the classification and labeling of packets is the ingress device, called a Label Edge Router in MPLS. It is normally Provider Equipment (PE), meaning owned and furnished by the service provider, located at the customer premise.
• Network equipment, called Label Switching Routers in MPLS, use the label number to route and in some cases prioritize the packet.
• Labels can be stacked, meaning one label pasted in front of another. This allows the network to manage similar kinds of traffic as a single entity in network control systems.

Returning to our example illustrated above, the four circuits illustrated at the top of the diagram can be replaced with one access circuit with three traffic classes (three labels). The physical access circuit could be 10 Mb/s to 10 Gb/s Optical Ethernet.

The three traffic classes / labels would be:
• A traffic class for telephone calls. This might be called a “SIP trunking service” by the marketing department. This class will carry VoIP phone calls to the carrier for communication to other locations of the organization, or for conversion to traditional telephony for phone calls to the public telephone network.
• A traffic class for data. This might be called a “VPN service” by the marketing department. This class carries file transfers, client-server database communications and the like securely to other locations of the organization.
• A traffic class for Internet traffic. This class carries anything in IP packets to the Internet.

All of this traffic is IP packets interspersed over the single access circuit.

At the other end of the access circuit, the carrier uses the label to route the traffic onward and possibly prioritize it to assure the appropriate service level.

The result is all of the organization’s traffic carried over a single access circuit, using a single technology.

This is one of the Holy Grails of the telecommunications business, called convergence or service integration, having significant advantages in cost and flexibility.


This is a concise description of a story that has many different facets.

In Teracom training, this discussion comes AFTER many other lessons explaining all of the underlying concepts, related technologies like PRI and SIP trunking and their jargon.

If you would like the whole story, it is currently included in the following training:

Course 101: Telecom, Datacom and Networking
for Non-Engineering Professionals

Certified Telecommunications Network Specialist (CTNS)
Online telecommunications certification courses

Telecom, Datacom and Networking for Non-Engineers textbook

and DVD-Video Courses V3 and V4.

Cheers!

Would you attend this course?

Would you attend this two-day course?
Inquiring minds want to know!

Leave a comment ↑


Course 104
Network Fundamentals for Non‑Engineers

A two-day course for finance, strategy, management, software, customer support and other personnel providing a comprehensive overview and update on telecom network technologies.

Our goal is to bust the buzzwords, explain the jargon, technologies and standard practices in the telecom network business, and importantly, the underlying ideas and how it all fits together.

Complete with a detailed book for future reference, this course will fill in the gaps and provide you with the knowledge you need to eliminate frustration and be more accurate and productive.

This training is an investment that will be repaid many times over. Join us for this career-enhancing opportunity!

PDF Brochure Course 104 Network Fundamentals for Non-Engineers

 

Demystify Buzzwords And Jargon

One of the biggest challenges in telecommunications is all of the acronyms, abbreviations, jargon and buzzwords.

The list goes on and on: POTS, PSTN, loops, trunks, VoIP, SIP trunking, Hosted PBX, DSL, DS1, T1, PRI, ILEC, CLEC, POP, MAN, TDMA, CDMA, LAN, WAN, Ethernet, MAC address, MAC frame, IP packet, TCP/IP, OSI, Layer 2, Layer 3, VLAN, TDM, DWDM, FTTN, FTTH, FTTP, DHCP, NAT, MPLS, VPN, SLA, ISP, DNS …

Plus, there is a second-order problem: even if you were to figure out all of the current jargon and buzzwords, it’s certain that new ones will be invented next month!

It can be very frustrating sitting in meetings with these terms flying around and not understanding most of them… particularly when someone asks your opinion.

So the question is: how to get on top of all the jargon and buzzwords, knowing that there is going to be constant change?

Our answer: understand the fundamentals. Take the cover off the box and understand how it works. Once we do this, we discover that there are only a few main ideas in telecom technology, with incremental improvement in each area.

Taking this course and understanding the fundamental ideas puts you back in control, with the confidence to contribute effectively. Even if you don’t know the exact details of a product someone is discussing, you will still know what they are talking about.

Understand The Network Cloud

People like to draw a diagram of a network as a cloud with sticks poking into it, and refer to the network as “The Cloud”. This might be useful for drawing diagrams, but if you are using, planning, ordering, managing, troubleshooting, developing software for or otherwise involved with telecom circuits and services, understanding what’s inside is productivity- and career-enhancing knowledge.

In this course, you will learn how circuits and services are actually provided, giving you the knowledge to make meaningful comparisons and accurate decisions.

We’ll explore every different aspect of The Cloud:

  • The fundamental structure of the network: access, switching and transmission;
  • The companies that physically implement the network: ILECs, CLECs, IXCs, how and where they interconnect, and
  • The components of a service: access circuit technology, network service type and billing plan;
  • The equipment used: switches, routers, multiplexers, fiber and modems;
  • How users share the network: channels, packets and Service Levels.

Gain Vendor-Independent Knowledge You Can Build On

The knowledge you gain taking this training course is vendor-independent foundational knowledge in telecommunications.

You will be able to build on this proven knowledge base to quickly get up to speed for a particular project – then have the versatility to work on subsequent projects.

The cost of this training will be repaid in productivity gain many times over.

Based on Teracom’s proven instructor-led training courses developed and refined over twenty years providing training for organizations including AT&T, Verizon, Bell Canada, Intel, Microsoft, Cisco, Qualcomm, the CIA, NSA, IRS, FAA, US Army, Navy, Marines and Air Force and hundreds of others, Teracom online courses are top-notch, top-quality and right up to date with the topics and knowledge you need.

Teracom was awarded a US Government Federal Supply Schedule (GSA) contract for these training services… which involved an independent evaluation where we scored a 97% quality rating from our customers!

Join us today to make this invaluable addition to your knowledge and skills!

 

Course Outline

  1. Fundamentals of TelephonyIt all begins with the Public Switched Telephone Network and Plain Ordinary Telephone Service. We’ll establish with a model for the PSTN, explaining analog circuits, loops, trunks, remotes, circuit switching and other telephony buzzwords and jargon. We’ll understand how the network is organized into access, switching and transmission. We’ll cover Centrex and traditional PBX, then understand Voice over IP (VoIP) concepts and components, soft switches and SIP trunking.
  • History of Telecommunications
  • The Public Switched Telephone Network (PSTN)
  • Analog Circuits
  • What is Sound?
  • The Voiceband
  • Plain Ordinary Telephone Service (POTS)
  • DTMF Address Signaling
  • Signaling System 7 (SS7)
  • Network Architecture: Access, Switching, Transmission
  • Telephone Switches
  • Traditional PBX and Centrex
  • VoIP
  • SIP, Soft Switches, Hosted PBX and IP Centrex
  • SIP Trunking

 

2. Digital
With the fundamentals in place, we’ll cover digital. You will learn what is really meant by “digital”, how voice is digitized to 64 kb/s, and MP4 digital video. We’ll complete the story understanding how the resulting bits are communicated using binary pulses on copper and fiber.

  • Analog and Digital: What Do We Really Mean?
  • Continuous Signals, Discrete Signals
  • Voice Digitization (Analog Digital Conversion)
  • Voice Reconstruction (Digital → Analog Conversion)
  • Voice Digitization: 64kb/s G.711 Standard
  • Digital Video: H.264 / MPEG-4 Standard
  • Implementing Digital: Binary Pulses

 

3. The Telecommunications Industry, Competition and Interconnect
In this chapter, you will gain a solid understanding of the telecommunications business and how it is structured, including telephone companies, local and long-distance, and how these companies compete and interconnect. You will understand how each organization fits into the picture, including ILECs, IXCs, resellers, CLECs, collocations, regional rings, POPs and MANs.

  • US Domestic Telcos
  • AT&T and Verizon
  • PSTN Switching Center Hierarchy
  • 1984: LECs, IXCs and POPs – Last Mile: Switched Access from ILEC
  • Competitive Carrier – Last Mile: Dedicated Line from ILEC
  • Competitive Carrier – Last Mile CLEC: Collocation plus ILEC Dark Fiber
  • Competitive Carrier Network Model: Regional Rings, POPs and MANs

 

4. The Cloud
Next, we will demystify the Network Cloud. You will learn why people draw a picture of a cloud to represent a network, then most importantly, what is inside the cloud and understand what’s really going on. You will learn about the three basic kinds of network services available, the equipment used to implement each, and how services are actually provided… highly useful knowledge when planning, ordering, troubleshooting, auditing, or otherwise dealing with carrier services.

  • Anatomy of a Service
  • Inside the Network Cloud
  • Network Equipment: How and Where Each is Used
  • Summary: How Services Are Provided

 

5. “Data” Communications and Network Basics
We’ll begin the second day understanding what “convergence” is and how it was achieved by treating telephone calls and television like data communications. Then, we’ll get you up to speed on the concepts, jargon, buzzwords and technologies that were originally developed for datacom and now used for everything. You’ll learn the basic ITU model for data circuits, then plain English explanations of Ethernet, MAC frames and MAC addresses, IP packets and IP addresses, and how they relate.

  • Convergence: Treat Everything Like Data
  • Data Circuit Model
  • LANs
  • Wide Area Networks
  • Ethernet and 802 standards
  • Frames and MAC Addresses
  • LAN Switches
  • VLANs
  • Packets and IP Addresses
  • Packets vs. Frames

 

6. The OSI Layers and Protocol Stacks
There are so many functions that must be performed to interoperate systems, a structure is required to organize the functions so that separate issues can be treated separately. For this purpose, we’ll use the ISO Open Systems Interconnection 7-Layer Reference Model. You’ll learn what a layer is, the purpose of each layer, examples of protocols like TCP and IP used to implement layers, an overview of many different protocols and functions you’ve heard of, and understand how a protocol stack works for applications like web surfing and VoIP.

  • Protocols and Standards
  • ISO OSI Reference Model
  • OSI 7-Layer Model
  • Physical Layer: 802.3, DSL, DOCSIS
  • Data Link Layer: 802 MAC
  • Network Layer: IP and MPLS
  • Transport Layer: TCP and UDP
  • Session Layer: POP, SIP, HTTP
  • Presentation Layer: ASCII, Encryption, Codecs
  • Application Layer: SMTP, HTML, English …
  • Protocol Stack in Operation: Babushka Dolls
  • Standards Organizations

 

7. IP Networks, Routers and Addresses
This chapter is dedicated to IP. We begin with the simplest framework, a private network, to understand routing and bandwidth on demand. We’ll introduce the term Customer Edge router and examine the functions performed by a router. Then we will cover IPv4 addressing: IPv4 address classes, static vs. dynamic addresses and DHCP, public and private addresses and NAT, and IPv6, how IPv6 addresses are allocated and assigned, and types of IPv6 addresses.

  • Simplest IP Network Example: Routers Connected with Dedicated Lines
  • Routers and Customer Edge (CE)
  • IPv4 Address Classes
  • DHCP, Static and Dynamic Addresses
  • Public and Private IPv4 Addresses
  • Network Address Translation
  • IPv6 Address Allocation and Address Types

 

8. Transmission Systems
We’ll begin with the basics of fiber and wavelengths, then compare older channelized transmission systems like T1 and SONET to newer packet-based transmission systems based on IP and Optical Ethernet.

  • Fiber Optics and Fiber Cables
  • Wave-Division Multiplexing: CWDM and DWDM
  • Channelized Time Division Multiplexing (TDM)
  • DS0s and SONET Framing
  • Channelized Digital Hierarchy: Standard Legacy Transmission Speeds
  • Digital Carrier Systems: Legacy Transmission Technologies
  • Statistical Time Division Multiplexing
  • Overbooking and Bandwidth on Demand
  • IP Packets and Optical Ethernet

 

9. The Last Mile
To complete the transmission story, we’ll briefly explore how the “last mile” is connected: fiber to the premise, active and passive, and fiber to the neighborhood followed by DSL or cable modems on copper.

  • Fiber to the Premise: PONs and Active Ethernet
  • DSL
  • DSLAMs
  • Fiber to the Neighborhood (FTTN), DSL to the Premise
  • Broadband Carriers: FTTN & Broadband Coax to the Premise
  • DOCSIS and Cable Modem Standards

 

10. MPLS and Carrier Networks
IP packets will be used to carry everything, including phone calls and television. But IP in itself does not include any Quality of Service (QoS) mechanism, no way to prioritize or manage traffic. This is implemented with MPLS. In this chapter, you’ll learn the basics of carrier packet networks, identifying Provider Edge (PE), Customer Edge (CE), access and core, and the important concept of a Service Level Agreement. Then without bogging down on details, you’ll get a big-picture understanding of MPLS and how it is used to implement business customer services, differentiated services and Class of Service (CoS), service integration and traffic aggregation.

  • Carrier Packet Network Basics
  • Service Level Agreement
  • Provider Equipment at the Customer Premise
  • Virtual Circuit Technologies
  • MPLS
  • MPLS VPNs for Business Customers
  • MPLS and Diff-Serv to Support Classes of Service
  • MPLS for Service Integration
  • MPLS for Traffic Aggregation

 

11. The Internet
The Internet is a giant collection of interconnected IP networks called Autonomous Systems across which the public can communicate IP packets. In this chapter, we’ll understand what an ISP is and how they connect to others via transit and peering, and conclude by understanding telephone calls over the Internet and secure VPNs over the Internet.

  • A Network To Survive Nuclear War
  • The Inter-Net Protocol
  • Internet Service Providers
  • Internet Telephony & VSPs
  • Internet VPNs

 

12. Wrapping Up
The final chapter brings all of the concepts together with a top-down review. You’ll learn valuable insight into telecom project management and methodology, and review telecom, datacom and networking technologies, services and solutions. We’ll conclude with a peek at the future of telecommunications, where the telephone network and Internet become the same thing.

  • Technology Deployment Steps
  • Requirements Analysis
  • High-Level Design
  • Review: Circuits and Services
  • Access and Transmission Technology Roundup
  • Private Network
  • Carrier IP Services
  • The Future

 

Our goal is to explain the underlying concepts, providing you with a practical understanding of telecom technologies and services, without bogging down on details. You will gain a solid base of structured knowledge that can be applied to immediate projects and can be built on in the future… an investment in productivity that will be repaid many times over.

Six Reasons to Take This Course

Teracom’s courses have been taught to wide acclaim across North America since 1992 and are designed for professionals needing to fill in the gaps, build a solid base of knowledge and understand how it all fits together.

  1. Cut through the buzzwords, jargon and vendor hype to gain a structured understanding of telecommunications and networking, allowing you to make meaningful comparisons and informed decisions… knowledge skills you can put to use today and in the future.
  2. Get up to speed on the latest developments and trends. This course is totally up to date with SIP trunking, VoIP, Optical Ethernet, MPLS and more.
  3. Get a solid base of vendor-independent knowledge of technologies, service providers, standard practices and mainstream solutions that you can build on.
  4. Understand how it all fits together.
  5. Learn more with instructor-led training – the best kind of training you can get – where you can interact and ask questions with instructors consistently rated “excellent” on student evaluations.
  6. Obtain a course book with detailed notes that will be a valuable reference for years.

Develop a structure for understanding technologies and solutions, allowing you to make informed choices and meaningful comparisons — knowledge you can’t get on the job, reading trade magazines or talking to vendors.

Your Course Materials: An Invaluable Reference

Every course comes complete with a high-quality course book that’s been called the best on-the-job reference tool around. Written in plain English, this easy-to-use reference includes copies of all graphics PLUS extensive detailed text notes. Topics are organized in logical groups to give you easy reference after the seminar to the practical experience, theoretical background, and unbiased information on industry technologies, products and trends you’ll need. With numerous chapters covering all major topics, you’ll obtain an invaluable resource impossible to find anywhere else in one book.

Free Bonuses! Online Courses & CTNS Certification

As a free bonus, you get the full set of Teracom’s Online Courses. Not only are these an excellent way to take a second pass through various topics, the Online Courses include pictures of equipment and additional lessons beyond those in this course.

If you choose to write the optional exams, you can earn Telecommunications Certification Organization (TCO) Certified Telecommunications Network Specialist (CTNS) Certification, complete with Certificate suitable for framing and a personalized Letter of Reference for your résumé.

Certification is concrete proof of your knowledge. The included Unlimited Plan option allows you to repeat exams as needed until you pass… which means guaranteed to pass if you’re willing to learn!

 

Here’s What Seminar Attendees Like You Are Saying

Hundreds of people like you have benefited from Teracom’s core training. Many tell us this was their best course ever; filled gaps in their knowledge and tied everything together… knowledge they’ve been needing for years. Others on course their first week on the job remarked “what a wonderful way to get started in the business.”

Here’s a sampling of comments from Teracom alumni:

“Feedback from my team was TERRIFIC. It gave our entire technical Call Center a common foundation, and you seem to have crafted that perfect balance between technical depth, real-world applications, and lively delivery.  I couldn’t be happier with the results. The things my team learned from this training were applied in real-world situations almost immediately.”
– Rusty Walther, Vice President, Client Services, AboveNet Communications

“Excellent! I learned a lot – everyday terms, definitions, and acronyms. Seminar notebook very helpful. The instructor was the best I ever had – lots of knowledge and experience and stories were GREAT.”
– Serena Laursen, Microsoft

“The selection of material – the order of its presentation – the way it was presented… incredibly effective at presenting concepts and ideas – uses great analogies and stays on topic.”
– Susan Lennon, Nortel

“The seminar delivered exactly what was advertised, at a very high quality.
Truth in advertising!” – Gary Lundberg, Copper Mountain Networks

Whether you work for an organization that produces telecom, datacom or networking products or services; or you buy these products and services – or just have to get up to speed on what all the rest of them are talking about when they say “SIP trunking”, “Ethernet”, “MAC frame”, 4G, MPLS or VPN…

“Best course we have ever had onsite at 3Com”

“Perfect content; well organized, well paced, building block approach,
resulted in a very nice cathedral” – Jim George, Qualcomm

“Course was excellent! One of the best I have taken. Extremely well organized and presented. Seminar workbook is outstanding – a very valuable reference” – Kieran Delaney, Maritime Life

“I liked most the use of analogies to explain complex concepts. It delivered exactly what the brochure promoted. Gave me a thorough understanding so I feel more confident.”
– Judith Myers, Ameritech

“Excellent! Tied the individual pieces of knowledge together into a picture… was interactive and built up the knowledge layers properly.” – Jim Geiss, Qwest

“Filled in a lot of gaps in my knowledge of networking… able to deliver the knowledge effectively and entertainingly. Excellent seminar”- Kirk Kroeker, IEEE Computer Society

“Great information that I will be able to use at work. Very easy to understand all the information especially the IP networking part. I wouldn’t change a thing”
– Orlando Jasso, AboveNet Communications.

“Layman’s terms with humor was very relaxing – helped me concentrate… understanding is now CLEAR … the manual will be very helpful” – Linda Côté, Bell Canada

“Best instructor I have had on a course – excellent explainer in layman terms, not techie terms”
– Susan Coleman, Bell Sygma

“Best course materials ever; the full text descriptions are invaluable.
Course filled in so many gaps for me. Bravo!” – Ross Brooks, Vertek

“Outstanding! The best I’ve encountered, and I’ve attended many seminars.”
– Bob Gibbons, WMX Technologies

 

Private Onsite Courses

Since 1992, we have provided high-quality on-site training in telecommunications for non-engineering professionals at AT&T, Verizon, Bell Canada, TELUS, Qualcomm, 3Com, Cisco, Intel, Alcatel, Nortel, Teleglobe, the NSA, Defense Information Systems Agency, US Coast Guard, US Air Force, Office of Naval Intelligence, MindSpring, APEX Telecom, Equifax, Transamerica Insurance, The Hartford, American Broadband, Cap Gemini, ComSec Establishment, MicroCell Telecom, TDS Telecom, Kyocera, Winstar, Western Wireless, US Cellular, Ericsson/Hewlett-Packard, Entergy, Intelsat, RangeTel, Alltel, Vertek, DSCI, Cox Cable, Florida Power and Light, Frontier Communications, Western Iowa Telephone, Genuity, LG Electronics, Panasonic, SouthEast Telephone, State of Nebraska, State of Montana, Tektronix, Bermuda Telecom, UTS and the Universal Service Administrative Company… to name a few. Plus, we have a GSA contract with pre-approved government pricing.

Onsite training has special advantages:

  • Your personnel will be up to a common speed with a solid knowledge base.
  • We’ll fill in the gaps and put in place productivity-enhancing structured understanding of telecom and networking fundamentals, wireless, TCP/IP, MPLS, VoIP… to meet your requirements..
  • The seminar will be a strong team-building exercise.
  • Significant reductions in training costs are often achieved.
  • Each student receives a detailed workbook / textbook that will be a valuable reference for years to come.
  • Pre- and post-training testing is available, including team results on a spreadsheet

We have built a solid reputation for delivering high-quality private team-training programs that are a resounding success. We’d like to do the same for you! Please contact us at 1-877-412-2700 for more information.

 

About the Author

Eric Coll
Eric Coll, M. Eng.

Eric Coll is an international expert in telecommunications, data communications and networking and has been actively involved in the industry since 1983. He holds Bachelor of Engineering and Master of Engineering (Electrical) degrees.

Mr. Coll has taught telecommunications technology training seminars to wide acclaim across North America since 1992, and has broad experience working as an engineer in the telecommunications industry.  He has worked for Nortel’s R&D labs as a design engineer on projects including digital voice and data communications research and digital telecom network equipment design, and on satellite radar systems, consulting on Wide Area Network design, and many other projects in capacities ranging from detailed design and implementation to systems engineering, project leader and consultant.

In addition to being founder and Director of Teracom Training Institute, Mr. Coll provides consulting to the telecommunications industry, specializing in telecommunications technology R&D and as a Subject Matter Expert in tax matters.

Development #2: Optical Ethernet has replaced SONET

A closer look at the second 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 a previous post, we identified eight major developments and trends in telecommunications incorporated in our training.

In this post, we take a closer look at the second one:
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.


Ethernet was a brand name for the first LAN, developed at Xerox’s Palo Alto Research Center in Silicon Valley.  The mouse and the graphical user interface used in Windows and Macs appear to have also been invented there.  And people say Xerox never does anything original…

An almost-identical technology was subsequently codified in the 802 series of standards from the Institute of Electrical and Electronic Engineers (IEEE).  Products conforming to the IEEE 802 standards ended up dominating the market, and Ethernet no longer exists.  When people say “Ethernet” today, they are referring to IEEE 802 standards.

Ethernet moves frames of data between computers that are on the same physical circuit. A frame is a block of data, typically about 1500 bytes, prefaced by the address of the receiver, the address of the sender and control information, followed by an error check.

The addresses are Media Access Control (MAC) addresses, 48-bit numbers identifying the LAN chip in each computer. LAN frames are also called MAC frames.

In the beginning, many computers were connected together by tapping onto a coaxial copper-wire “bus” cable.

teracom-tutorial-lan-switch

Today, one computer is connected with a LAN cable to one port on a LAN switch as illustrated in the diagram.  The LAN switch moves frames internally from one port to another, and hence from one computer to another.

Ethernet was developed for communicating data packets between computers inside a building, in a bursty, as-needed manner.

Ethernet then escaped and took over the world of fiber connections between buildings, replacing the previous technology used for fiber backbones called SONET.

SONET carried 64 kb/s streams of bits called DS0 channels on fiber between buildings.  It was designed to carry phone calls in these channels.  It can also carry data packets on these channels.  But using channels for communications is not efficient, since the bits in the channel are reserved whether there is anything to transmit or not, and the channels only go between fixed places.

The new-generation all-IP telecom network does not use channels.  Everything is put in IP packets, which are created and transmitted only when there is information to be communicated, and routed one-by-one to different destinations.  This is more efficient and much more flexible.

Packets are transmitted from the originating machine in a MAC frame on a physical circuit to a router, then to the next router in another city, to the next router, and finally delivered in a MAC frame on a physical circuit to the destination.

The connections between routers in different cities are LAN cables… but not the familiar blue copper-wire LAN patch cables used in-building.  Inter-city LAN cables are made of glass fiber.  A MAC frame is signaled from one end to the other by pointing a laser into the fiber and turning it on and off.  Light on means “1” and light off means “0”.  This is called Optical Ethernet, and allows much higher bit rates and much longer reach than copper wire LAN cables.

teracom-tutorial-optical-ethernet

Today, Optical Ethernet is not used just for inter-city links, but also for the access circuit, the circuit from the customer to the network, sometimes called the “last mile”.

The use of Ethernet for in-building communications, access circuits and intercity backbones represents the achievement of a long-held goal in the telecommunications business: to save money by using the same technology in all parts of the network.


This is a concise description of a story that has many different facets.  If you would like to learn more, for example, the relationship between Ethernet and IP, how packets and frames work together, the difference between a LAN switch and a router, why Ethernet is “Layer 2” and IP is “Layer 3”, about LAN cables and fiber optics, convergence and service integration, those topics and much more are covered in the following Teracom training:

Course 101: Telecom, Datacom and Networking
for Non-Engineering Professionals

Telecom 101 textbook

Certified Telecommunications Network Specialist (CTNS)
Online telecommunications certification courses

Telecom, Datacom and Networking for Non-Engineers textbook

DVD-Video Courses V2, V3 and V4

and in free tutorials on teracomtraining.com.

Cheers!

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.