In the past five years, technologies have converged to such an extent that one can transmit voice, fax and video over the same internet protocol network that one uses for data. This workshop examines Voice over IP (VoIP) technologies and provides you with the skills to competently implement a VoIP network for your organisation. Numerous case studies and exercises throughout the course ensure that you get a good grasp on the technologies used. Solid practical advice is given on application, implementation and most importantly troubleshooting these systems. MORE INFORMATION: http://www.idc-online.com/content/practical-fundamentals-voice-over-ip-voip-engineers-and-technicians-3

1. Practical Fundamentals of Voice over Internet
Protocol (VOIP) for Engineers and Technicians
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2. Definition
“ Voice Over IP (VOIP) is a converged network application that
allows voice, data, video and fax to be transported over existing IP
data networks instead of conventional Public Switched Telephone
Network (PSTN).”
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3. Voice
Data
Networks
Packet Voice
IP Data
IP+ATM
IP Data
IP Telephony
Circuit Switched Networks (TDM)
IP
Packet Switched (Converged)
Networks
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4. VOIP
• Is a Layer 3 network protocol
• Uses Layer 2 point-to-point or link layer protocols
(such as PPP,Frame relay or ATM for its transport)
• Digital Signal Processors (DSPs) segment the voice
signal into frames and store them in voice packets.
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5. Voice
Source
Voice
VOIP BASIC DIAGRAM
Managed
IP CLOUD
Digital
Signal
ADC DAC Destination
Analogue
Signal
Analogue
Signal
Digital
Signal
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6. VOIP
• Voice packets are transported via IP in compliance
with voice communication protocols or standards
– Such as H.323 ,Media Gateway Control
Protocol(MGCP) or Session Initiation Protocol (SIP)
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7. Relationship of OSI and VOIP
OSI Layer
Number
OSI layer
Name
VOIP Protocols and
Functions
7 Application Net Meeting
6 Presentation CODECS
5 Session H.323/MGCP/SIP
4 Transport RTP/TCP/UDP
3 Network IP
2 Data Link Frame Relay, ATM,
Ethernet, PPP
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8. IP in VOIP
IP is an attractive choice for voice transport
because:
• Lower Equipment Cost –
– IP based switch architecture is an open and distributed
architecture
– Modular in concept
• Integration of Voice and Data application –
– IP offers a converged and unified platform for transport
of data as well as voice
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9. IP in VOIP
• Optimum Bandwidth Utilization –
– Many bandwidth efficient coding algorithms have been
developed which are bandwidth efficient.
• Universal Acceptance and Availability of IP as a
networking protocol
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10. Problems in VOIP
The problems in implementing VOIP are –
• Speech Quality –
– IP basically designed for transporting data traffic
– Data traffic is asynchronous can tolerate delay
– Any appreciable delay in receipt of voice packet badly impairs
quality of speech.
• Delay –
– Voice does not tolerate delay
– ITU-T recommendation G.114 states that the round trip delay
should be less than 300 ms for telephony applications
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11. Problems in VOIP
• Jitter-Jitter is variation in delay – is caused in IP networks in
two ways:
– Packets take different routes from source to destination and
experience different delays
– Different packets experience different queuing time (due to
sharing of available resources by different users)
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12. Problems in VOIP
Packet loss –
• VOIP is based on packet switched network
architecture
– Voice is first digitized, packetized and then transported
in the form of packets
• If packets are lost in transit
– Any retransmission will introduce delay
– Voice quality impaired
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13. Problems in VOIP
• Power Over Ethernet –
– Traditional PSTN Telephones are DC powered on the
same conductors
– For VOIP on LAN environment
• 802.3af compliant powered Ethernet Switches
• Picker
• Two Methods are –
– (Injector) + (POE compatible Device)
– (Injector) + (non-POE compatible Device)+(Picker)
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14. DO YOU WANT TO KNOW MORE?
If you are interested in further training or information,
please visit:
http://idc-online.com/slideshare
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