Comptia+ Convergence

CompTIA Convergence + Certification Study Guide

Module 1

Telephony

Module 1Telephony

Lessons in this module:1. Telecommunication Traffic Engineering

2. Voice System Fundamentals

3. Number and Dialing Plan Components

4. Converged Network Endpoints

Lesson 1Telecommunications Traffic Engineering

Key Point

One traffic engineering goal is to estimate the optimum number of trunks required for a given number of blocked calls.

ObjectivesTo be able to:• Identify various trunk types• Identify common terms for trunk usage• Describe the concepts behind Grade of Service - GoS• Identify call traffic measurement tools• Recognize system capacities and bottlenecks• Describe traffic shaping concepts


TrunksTrunk ConnectivityFrequencyAmplitudeAnalog NoiseDigital Noise

Types of TrunksTypes of TrunksTIE Trunk ConnectionsFX Trunks

Carried LoadTrunk UtilizationExponential Distribution

Probability

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Grade of ServiceTrunk Usage MeasurementsThe Erlang B Traffic Formula

Partial Erlang Table B

Erlang C and Poisson TablesNo Formula is PerfectEstimating Total System Capacity

Independent Locations Linked by Tie TrunkCentral and Satellite Offices Linked by Tie Trunk

Data PrioritizationProtocol Reservation

Protocol Reservation

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Session FairnessSession Fairness

Traffic Shaping

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Activities

1. Describe the difference between a line, loop, and trunk.

2. List some forms local loops can take.

3. How does analog transmission differ from digital transmission?

4. A trunk type that creates an end-to-end, always-on connection between locations most often used for data transmission is a(n) _______________.

a) Tie line

b) Ring down trunk

c) FX trunk

d) Private line


Activities (continued)

5. Which are factors limiting a device’s carried load capacity? (Choose two.) a) The time of dayb) The PBX capacityc) The number of usersd) The available trunks

6. Which two things must we know to estimate the carried load? (Choose two.)a) Call holding timesb) The circuit’s bandwidthc) The incoming call countd) The telephone type



7. Which are the three holding time types particular to telephone system design? (Choose three.)a) Average time per callb) Mean time per callc) Hourly holding timed) Daily holding time

8. Which term describes 100 call seconds, the basic measurement of communications engineering?a) CCSb) Operating timec) Conversation timed) Holding time



9. Which term describes one hour of traffic as a time measurement used in traffic engineering?a) Busy hourb) Operating timec) Erlangd) CCS

10. By adding a call’s operating time and its conversation times, you have calculated which?a) Busy hourb) Holding timec) Blockingd) Erlang



11. Which term describes the condition that occurs when a lack of facilities stops a call’s completion?a) Busy hourb) Holding timec) Blockingd) Erlang


Extended Activities

1. Explore the various trunk types available from your LEC and/or CLEC. How do their rates differ by service, bandwidth, and distance?

2. In your area, what options are available for the local loop? Is fiber access to the CO available? Do any local service providers make wireless data services available? If so, on what type of wireless technology are these based?

3. What is the resulting grade of service given the following information for a company’s busy hour?- 8 calls receive a busy signal- 376 calls go through on the first try


Extended Activities (continued)

4. What is equivalent to the following in CCS?

a) 18-minute call

b) 3-minute call

c) 1.5-minute call

Lesson 2Voice System Fundamentals

Key PointAnalog voice waves are captured by a coder decoder a codec and converted to a digital bit stream.

ObjectivesTo understand:• Telephone Systems• Voice Sampling• Call Creation• Call Signaling both in band and out of band• Signaling System 7


Legacy Hybrid and IP Telephony Systems

Key SystemsKey Telephone System

Cordless Key System

Hybrid Systems

IP Telephony Systems

Voice Transmission Fundamentals

Encoding, Decoding, and Compression

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Digitizing the VoiceAnalog-to-Digital Conversion

Pulse Dial Example 1

DTMF Touchpad and Tones

How a Call is MadeVoice Routing 1

Voice Routing 2

Voice Routing 3

Voice Routing 4

Long Distance Voice Routing

Signaling

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Activities

1. Explain how a key system provides connectivity to each extension.

2. Describe the purpose of a KSU.

3. How would a key system lose its practicality as a business’s communications needs increase?

4. How does a hybrid key system compare to a standard key system?

5. Describe DTMF.



6. Describe the sequence of operations that occur when a call is placed.

7. Describe the difference between switching and routing in telecommunications.


Extended Activities

1. Visit http://www.avaya.com/ and research their line of integrated communications systems.

2. Visit http://www.vodavi.com and http://www.panasonic.com, and compare their key system features. How do the features these hybrid systems provide compare to a standard key system?

3. Contact your LEC or CLEC and inquire which of the discussed switch types they use to complete calls. Do you use tone or pulse dialing in your area?

4. Visit http://www.nortel.com and research the latest of their CO offerings. Likewise, visit http://www.avaya.com to review their CO products.

Lesson 3Number and Dialing Plan Components

Key PointEach country defines its own telephone numbering plan.

ObjectivesThis lesson presents an overview to:• The standards for telephone number selection• Telephone number usage• Assigned telephone prefixes• Local number portability• Emergency service numbers


PrefixesTelephone Numbering System

North American Number Plan

Special Area CodesNumber FormatsNumber BlockingDigit TranslationToll FraudENUM

Electronic Number - ENUM TiersElectronic Number - ENUM Using DNS for Translation


Local Number Portability (LNP)AIN Support for LNP

Emergency ServiceE911 Service Mapping a Caller to a Geographic Location


Activities

1. Within the North American Numbering Plan (NANP) the first three digits after the country code is called what?

a) Prefix

b) Area code

c) Local exchange prefix

d) a and b are both correct

e) All of these are correct

2. In the North American Numbering Plan what does N represent?

a) Any digit from 0 to 9

b) Any digit from 1 to 9

c) Any digit from 2 to 9

d) A local phone number



3. Phone numbers are issued by which of these?

a) Class 1 CO

b) Class 4 CO

c) Class 5 CO

d) Any of these

4. Why might several area codes be used in the same large, urban area?

a) To provide enough unique phone numbers

b) To differentiate between service providers

c) To provide for both land lines and cell phones

d) There are all reasons for several area codes



5. Match the three digit service code with its service.___ 211 ___ 311 ___ 411 ___ 511 ___ 611 ___ 711 ___ 811 ___ 911

a) Community Information and Referral Services (United States)

b) Emergency

c) Impending U.S. nationwide One-Call service for advanced notice of excavation activities. This allows contractors and others to dial a single number and notify utilities of their intent to excavate.

d) Local Directory Assistance (sometimes 1411)

e) Non-emergency Police and other Governmental Services (United States)

f) Repair Service

g) Traffic and Transportation Information (U.S.), Reserved (Canada)

h) TRS



6. When making a call and you do not what the recipient to know your name or phone number, what feature could you use?

a) Number hide

b) Call blocking

c) Digit translation

d) Anonymous Caller

7. Which of these might a hacker use to try to commit toll fraud?

a) Remote access

b) Automated attendants

c) Voice messaging

d) Any of these will be tried by a hacker



8. Which of these, when given a phone number, will return a populated Uniform Resource Identifier (URI)?

a) ENUM

b) NAPTR

c) DNS

d) FTP



9. Which two of these documents describe NEBS requirements? (Choose two.)

a) GR-3053-Signaling interfaces between voice over packet and the SS7 networks

b) GR-3054-Interfacing voice over packet networks to the PSTN

c) GR-1089-Electromagnetic compatibility and electrical safety

d) GR-3060-Transporting legacy telecommunications services across voice over packet networks

e) GR-63-Physical equipment protection



10. Which of these uses the SS7 network to enable carrier switches to share information such as Location Routing Number?

a) Local Number Portability

b) Advanced Intelligent Network

c) Caller ID

d) 911


Extended Activities

1. Research Network Equipment Building Standards (NEBS). Explain what it is used for.

2. What is the ITU-T e.164 recommendation used for? Explain how it aids in international communication.

3. Who is the current telephone number manager selected by the FCC? Describe the function that they serve.

Lesson 4Converged Network Endpoints

Key Point

With today’s technologies, there are a multitude of ways to connect to a TDM or a packet-based telephony network.

ObjectivesTo understand the following phone types:• IP Phones• Analog Phones• PC-based Soft Phones• SIP Phones• WiFi Phones


Voice TerminalsIP PhonesTDM PhonesAnalog Phones

Analog Telephone Adapter Connecting Analog Phones to IP Networks

Dialup Hard PhonePC-Based Soft PhonesMicrophones and Headsets or SpeakersUSB Hand SetsSIP PhonesPDA Soft PhonesWiFi Phones


Activities 1. Match the phone with its description.____ Analog phone ____ Dialup hard phone ____ IP phone____ PC-based soft phone ____ PDA soft phone ____ SIP phone____ TDM phone ____ WiFi phone

a) A computing device with embedded telephone VoIP softwareb) Blocks of voice payload are sent across a bus (a separate Ethernet segment) with a

small header prepended to the payloadc) This device communicates directly with the VoIP server using the configured

protocold) An IP phone with a built-in modem instead of a built-in Ethernet NICe) Requires an audio card, microphone, and headset or speakersf) A soft phone or an adapter allowing the caller to use their “legacy” analog phoneg) Have the same functionality as PC-based soft phones but instead run on a personal

digital assistant on a mobile computing software platformh) Hard phone with an integrated transceiver


Extended Activities

1. Based on advancing and changing technology, are there any other types of phones you can find? What are these phones and how do they work?

2. Pick at least two of the phone types listed in this lesson and expound upon how they work and what they may be used for.

Module 1Telephony

Module Quiz

1. What type of signal is the human voice?a) Integratedb) Digitalc) Analogd) None of these

2. A connection between switching systems is called what?a) Loopb) Trunkc) Lined) PBX

Module 1Telephony

Module Quiz (continued)

3. What is the difference between analog and digital signals?a) Analog is continuous and digital is a series of changing bitsb) Digital is continuous and analog is a series of changing bitsc) Analog signals are binary and digital signals are octald) Digital signals have amplitude and frequency; analog signals are

binary

4. The height of a wave is called what?a) Noiseb) Bandwidthc) Frequencyd) Amplitude

Module 1Telephony


5. A network between countries is called what?a) Foreign exchangeb) Tie trunkc) Tie lined) None of these

6. A telephone line between two specific phones is known as what?a) Private lineb) Ring downc) PBXd) a and b are both correct

Module 1Telephony


7. Which of these is not part of operating time?a) Ringing timeb) Call set-up timec) Equipment latencyd) All of these are part of operating time

8. The entire time a trunk is used for a call is called what?a) Holding timeb) Conversation timec) Carry timed) Load time

Module 1Telephony


9. Which of these is an example of constant distribution?a) Nightly data backupb) Hotel wakeup callc) Help desk callsd) None of these

10. The probability that any given single call will be blocked is called what?a) Quality of serviceb) CCSc) Class of serviced) Grade of service

Module 1Telephony


11. A CCS represents which of these?a) 10 seconds holding timeb) 100 seconds holding timec) 1 minute holding time.d) 1 hour holding time

12. What does the Erlang B formula calculate?a) Likely grade of serviceb) Likely holding timec) Likely operating timed) Likely class of service

Module 1Telephony


13. The Poisson formula is based on what assumption?a) Trunk capacity it limitedb) A caller who gets a busy signal will immediately call backc) Hold times can be estimatedd) Operating time can be estimated

14. Which two of these measure PBX utilization? (Choose two.)a) Operating usage rateb) Hold usage ratec) Call usage rated) Port usage rate

Module 1Telephony


15. A guaranteed amount of bandwidth on a WAN link for an application is called what?a) Session fairnessb) Traffic shapingc) Protocol reservationd) Traffic balancing

16. A telephone call is sent across the Internet in what form?a) Packetsb) Framesc) Octetsd) Frequency

Module 1Telephony


17. How many lines does a key system provide?a) 10-40b) 4-60c) 4-100d) There is no limit

18. A telephone system that has features of both a key system and a PBX is called what?a) KSUb) Keyless systemc) Hybridd) These are all correct

Module 1Telephony


19. Which of these is an advantage of an IP telephone over a land line?a) It is less expensive to installb) Maintenance costs are lowerc) Monthly operating costs are lessd) All of these

20. To convert a voice to a digital signal for an IP telephone, what sampling rate is used?a) 4 kHzb) 8 kHzc) 64 kHzd) 1 MHz

Module 1Telephony


21. What does DTMF stand for?a) Dial tone multifrequencyb) Dual tone multifrequencyc) Dual telephone multifrequencyd) Dual tone megafrequency

22. How many unique tone does DTMF require?a) 5b) 7c) 8d) 12

Module 1Telephony


23. What is the name of the system that allows for efficient routing of calls all over the world?a) POTSb) PSTNc) SS7d) Each CO handles their own routing

24. In the North American Numbering Plan what does X represent?a) Any digit from 0 to 9b) Any digit from 1 to 9c) Any digit from 2 to 9d) A local phone number

Module 1Telephony


25. What are the N11 numbers called?a) Emergency numbersb) Service codesc) Customer codesd) Special information services

26. In telephone terms, what is a premium number?a) Toll-free phone numbersb) A call that charges the caller for the callc) Special information servicesd) Hearing-impaired services

Module 1Telephony


27. What does DNS use to return a populated URI when given a phone number?a) ENUMb) RIPEc) ARSd) NAPTR

28. What requirements enable telcos to build networks that can survive and continue operating under severe conditions?a) NEBSb) NAPTRc) LNPd) GR-2936

Module 1Telephony


29. What type of phone is a computing device with embedded telephone VoIP software?a) SIP phoneb) WiFi phonec) IP phoned) Dialup hard phone

30. What type of phone is an IP phone with a built-in modem instead of a built-in Ethernet NIC?a) SIP phoneb) WiFi phonec) IP phoned) Dialup hard phone

Module 1Telephony


31. What type of phone communicates directly with the VoIP server using the configured protocol?a) Dialup hard phoneb) Analog phonec) PC-based soft phoned) SIP phone

32. What type of phone is a soft phone or an adapter allowing the caller to use their “legacy” analog phone?a) Dialup hard phoneb) Analog phonec) PC-based soft phoned) SIP phone

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Comptia+ Convergence