Introducing VoIP Networks Chapter 01 Components of a VoIP Network.
© 2006 Cisco Systems, Inc. All rights reserved. 2.1 - Introducing VoIP Networks.
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Transcript of © 2006 Cisco Systems, Inc. All rights reserved. 2.1 - Introducing VoIP Networks.
© 2006 Cisco Systems, Inc. All rights reserved.
Objectives 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.
© 2006 Cisco Systems, Inc. All rights reserved.
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)
© 2006 Cisco Systems, Inc. All rights reserved.
Legacy Analog Interfaces in VoIP Networks
Analog Interface Type Label Description
Foreign Exchange Station FXS Used by the PSTN or PBX side of an FXS–FXO connection
Foreign Exchange Office FXO Used by the end device side of an FXS–FXO connection
Earth and Magneto E&M Trunk, used between switches
© 2006 Cisco Systems, Inc. All rights reserved.
Legacy Analog Interfaces in VoIP Networks
1
1
23
4
5
© 2006 Cisco Systems, Inc. All rights reserved.
Digital Interfaces
Interface Voice Channels (64 kbps Each) SignalingFraming Overhead
Total Bandwidth
BRI 2 1 channel (16 kbps) 48 kbps 192 kbps
T1 CAS 24 (no clean 64 kbps because of robbed-bit signaling)
in-band (robbed-bits in voice channels)
8 kbps 1544 kbps
T1 CCS 23 1 channel (64 kbps) 8 kbps 1544 kbps
E1 CAS 30 64 kbps 64 kbps 2048 kbps
E1 CCS 30 1 channel (64 kbps) 64 kbps 2048 kbps
© 2006 Cisco Systems, Inc. All rights reserved.
Call Setup
Checks call-routing configuration
Determines bandwidth availability
If bandwidth is available, setup message is passed
If bandwidth is not available, busy signal is generated
© 2006 Cisco Systems, Inc. All rights reserved.
Call Maintenance
Tracks quality parameters:
Packet loss
Jitter
Delay
Maintains or drops call based on connection quality
© 2006 Cisco Systems, Inc. All rights reserved.
Call Teardown
Notifies devices to free resources
Resources are made available to subsequent calls
© 2006 Cisco Systems, Inc. All rights reserved.
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?
© 2006 Cisco Systems, Inc. All rights reserved.
Summary The benefits of a VoIP network include more efficient
use of network bandwidth and equipment, lower cost and consolidated expenses.
Legacy analog and VoIP applications and devices can coexist.
The 3 stages of a VoIP call include call setup, call maintenance, and call teardown.
VoIP can be deployed in a centralized or distributed environment.