As PABX vendors implement the latest and greatest VoIP strategies in their PABX systems, an unfortunate design problem often occurs because the phone system is implemented on top of an existing data network system designed for PC and server use, but not for IP phone use.

The Designing & Implementing a Voice-Enabled IP Network course has been designed with three primary goals:


  1. To equip businesses with the necessary network knowledge to plan for and implement current or future VoIP deployment.
  2. To inform the student of the various VoIP networking standards currently used in the industry
  3. To present a selection of implementation strategies suitable for VoIP implementation.

Anyone planning to upgrade or considering expansion of their PABX system in the near future should take advantage of this course.

Students will design and implement a secure network to simulate the introduction of an NEC IP PABX.  To accomplish this, they will configure Cisco routers and switches as well as NEC IP phones, ensuring IP Voice traffic is securely separated from PC IP traffic using VLAN technology and routing.

During the course students will also configure IP phones and observe the various networking standards at work, and use a PC based PABX (Asterisk) as well as the NEC PABX to place VoIP calls.  They will observe the effects of delay and jitter caused by combining voice and data on an IP network, then configure Cisco routers and switches to minimise these problems.  VoIP network design strategies will be discussed including different vendor offerings and implementations.

Students will receive a copy of Theodore Wallingford’s popular book Switching to VoIP around which part of the course is based.

Who Should Attend:

The Designing & Implementing a Voice-Enabled IP Network is ideal for anyone who is planning to replace or upgrade their PABX in the future.


Students who attend this course should have a good understanding of the Internet Protocol (IP) and some familiarity with the Cisco command line interface would be an advantage.


40% lecture, 60% exercises and hands-on labs with two softphones, two NEC DT700 IP phones, an Asterisk IP PABX, one Cisco switch and one Cisco router per group of two students.

Course Content:

Voice and Data: Two Separate Worlds?

• The PSTN

• Key Systems and PBXs

• Limits of Traditional Telephony

• VoIP in the Home

• VoIP in Business

• VoIP’s Changing Reputation

Voice over Data: Many Conversations, One Network

• The Layers of a VoIP Network

• Distributed Versus Centralised

Linux as a PBX

• Free Telephony Software

• Installing Legacy Interface Cards

• Monitoring Asterisk

Circuit-Switched Telephony

• Components of the PSTN

• Customer Premises Equipment

• Time Division Multiplexing

• Point-to-Point Trunking

• Legacy Endpoints

• Dial-Plan and PBX Design

Enterprise Telephony Applications

• Application Terminology

• Basic Call Handling

• Administrative Applications

• Messaging Applications

• Advanced Call-Handling Applications

• CTI Applications

Replacing the Voice Circuit with VoIP

• The “Dumb” Transport

• Voice Channels

• Project:  Set Up Custom Codec Selection and Enable an Independent Call Path

Replacing Call Signalling with VoIP

• VoIP Signalling Protocols

• H.323




• Cisco SCCP

• Heterogeneous Signalling

VoIP Readiness

• Assessing VoIP Readiness

• Business Environment

• Network Environment

• Implementation Plan

Quality of Service

• Latency, Packet Loss, and Jitter

• CoS

• 802.1q VLAN

• Quality of Service

• Residential QoS

• Voice QoS on Windows

• Best Practices for Quality of Service

Troubleshooting Tools

• VoIP Troubleshooting Tools

• The Three Things You’ll Troubleshoot

• SIP Packet Inspection

• Interoperability

• Project:  Trace Both Ends of a Call Setup with Log Comparison

• When, Not if, You Have Problems...

• Simulating Media Loads

PSTN Trunks

• Dial-Tone Trunks

• Routing PSTN Calls at Connect Points

• Timing Trunk Transitions

Network Infrastructure for VoIP

• Legacy Trunks

• VoIP Trunks

• Project:  Build an Interactive Directory on a SIP Display Phone

Traditional Apps on the Converged Network

• Fax and Modems

• Fire and Burglary Systems

• Surveillance Systems and Videoconferencing

• Voice Mail and IVR

• Emergency Dispatch

What Can Go Wrong?

• Common Problem Situations

VoIP Vendors and Services

• Softphones and Instant Messaging Software

• Skype

• Other Desktop Telephony Software

• Developer Tools and SoftPBX Systems

• VoIP Service Providers

• Telephony Hardware Vendors