ONT Mod 2-Lesson 1_edited

7/30/2019 ONT Mod 2-Lesson 1_edited

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2008 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialONT 1

ONT Module 2 Lesson 1 - Introducing VoIP Networks

Cisco VoIP

Implementations


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2008 Cisco Systems, Inc. All rights reserved.ONT 2

CCNP ONT Bachkhoa Networking Academy

Hc vin mng Bch Khoa - www.bkacad.com

Objectives

Introduction Traditional Telephony

Describe the benefits of a VoIP network. Describe the components of a VoIP network.

Describe the legacy analog interfaces used in VoIP networks.

Describe the digital interfaces used in VoIP networks.

Explain the 3 phases of call control.

Compare and contrast distributed and centralized call control.


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Traditional Telephony - Call Signaling

Call signaling include: Supervisory, address, andinformational signaling


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SupervisorySignaling


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Address Signaling


7/35 2008 Cisco Systems, Inc. All rights reserved.ONT 7



Basic Call Progress

The progress of a telephone call with loopstart signaling

in place can be divided into five phases:

Onhook

Offhook

Dialing

Switching

Ringing

Talking.





On-Hook





Off-Hook

350- and 440-hertz [Hz] tones played continuously





Dialing

CC O





Switching

440 and 480Hz tones

Busy signal consists of 480- and 620-Hz tones

CCNP ONT B hkh N t ki A d





Ringing






Talking






Informational Signaling






Pulse Dialing

Pulse Dialing is an inband signaling technique.

It is used in analog telephones that have a rotary dialing switch

The large numeric dialwheel on a rotarydial telephone spins tosend digits to place a call.

Each pulse consists of a "break" and a "make", which are achievedwhen the local loop circuit is opened and closed.

3






DTMF Dialing

DTMF dialing is an inband signaling technique just like pulse

dialing. This technique is used in analog telephone sets that have a

touchtone pad.

This dialing technique uses only two frequency tones per digit, asshown in Figure






DTMF Dialing - example

CCNP ONT Bachkhoa Net orking Academ


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Digital vs. Analog Connections

Supervisory, address, and informational signaling mustbe carried across both analog and digital connections.



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Benefits of a VoIP Network

More efficient use of bandwidth and equipment

Lower transmission costs Consolidated network expenses

Improved employee productivity through features

provided by IP telephony:

IP phones are complete business communication devices.

Directory lookups and database applications (XML)

Integration of telephony into any

business application

Software-based and wireless

phones offer mobility.

Access to new communications

devices (such as PDAs and

cable set-top boxes)



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Components of a VoIP Network

Gateways interconnect theVoIP network with traditionaltelephony devices

for conferences

Provide XML-based services to IP phones (directory services.)

Gatekeeper: Optional, provide Call AdmissionControl (CAC) Translates telephone numbers or

names to IP for call routing H.323

call control,CAC, bandwidthcontrol, andaddresstranslation

SCCP

MGCP,H323,SIP



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Components of a VoIP Network

Analog Phone vs IP Phone



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Legacy Analog Interfaces in VoIP Networks

Gateways use different types of interfaces to connect to analogdevices, such as telephones, fax machines, or PBX or PSTN

switches. Analog interfaces that are used at the gateways includethese three types:

Foreign Exchange Station (FXS)

Foreign Exchange Office (FXO)

Ear and Mouth (E&M)



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Legacy Analog Interfaces in VoIP Networks

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1. The gateway serves a telephone and a fax machine using two FXS interfaces. For these twodevices, the router acts like a PBX or a PSTN switch.

2. The router connects to the PSTN using an FXO interface. For this connection, the router acts

like a telephone toward the PSTN.3. Another FXO interface connects to a PBX (PBX-1). Again, the router acts like an end system

toward the PBX, and hence uses the same port type as the telephone and fax that connect toPBX-1 use.

4. A second PBX (PBX-2) connects to the router FXS interface. For this connection, the PBXbehaves like a telephone toward the router, and the router acts like a PSTN switch.

5. Finally, the router connects to another PBX (PBX-3), this time using an E&M interface. On this

trunk connection, both the router and PBX-3 act as a PBX.



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Digital Interfaces

Gateways can use digital interfaces to connect to voice

equipment. From a hardware perspective, there areBRIs and T1 and E1 interfaces available. All of theinterfaces use TDM to support multiple logicalchannels.



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Call Setup

Checks call-routing configuration

Determines bandwidth availability

If bandwidth is available, setup message is passedIf bandwidth is not available, busy signal is generated



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Call Maintenance

Tracks quality parameters:

Packet loss

Jitter

Delay

Maintains or drops call based on connection quality



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Call Teardown

Notifies devices to free resources

Resources are made available to subsequent calls



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Stages for Completing a VoIP Telephone Call



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Distributed Call ControlSupervise call: For quality, R1 terminate if Quality too low then inform R2Terminate call: R1 know Phone on-hook, R1 inform R2 terminate



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Centralized Call ControlSupervise call: For quality, R1 terminate if Quality too low then inform CATerminate call: R1 know Phone on-hook, R1 inform CA



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Self Check

1. Which type of call control uses a call agent to route

the call?2. What is a DSP?

3. Name 3 types of analog interfaces used at gateways.

4. What are the 3 components of basic call control?5. What phase of call control involves determining if

bandwidth is available to place the call?



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Summary


Describe the benefits of a VoIP network.

Describe the components of a VoIP network.

Describe the legacy analog interfaces used in VoIP

networks. Describe the digital interfaces used in VoIP networks.

Explain the 3 phases of call control.

Compare and contrast distributed and centralized call

control.



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Q and A



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Resources

Waveform Coding Techniques

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801149b3.shtml

VoIP Overview (NetBit)

http://www.cisco.com/warp/public/779/servpro/solutions/wirele

ss_mobile/kbs/voip_kb.html

IP Telephony Basicshttp://www.intel.com/network/csp/resources/white_papers/4070web.htm

http://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801149b3.shtmlhttp://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801149b3.shtmlhttp://www.cisco.com/warp/public/779/servpro/solutions/wireless_mobile/kbs/voip_kb.htmlhttp://www.cisco.com/warp/public/779/servpro/solutions/wireless_mobile/kbs/voip_kb.htmlhttp://www.intel.com/network/csp/resources/http://www.intel.com/network/csp/resources/white_papers/4070web.htmhttp://www.intel.com/network/csp/resources/white_papers/4070web.htmhttp://www.intel.com/network/csp/resources/white_papers/4070web.htmhttp://www.intel.com/network/csp/resources/white_papers/4070web.htmhttp://www.intel.com/network/csp/resources/http://www.cisco.com/warp/public/779/servpro/solutions/wireless_mobile/kbs/voip_kb.htmlhttp://www.cisco.com/warp/public/779/servpro/solutions/wireless_mobile/kbs/voip_kb.htmlhttp://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801149b3.shtmlhttp://www.cisco.com/en/US/tech/tk1077/technologies_tech_note09186a00801149b3.shtml


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