Can We Talk Presented by Todd McIntire

1
Can We Talk?Presented byTodd McIntire
2
Can We Talk?

• IP Telephony (VoIP)
• Voice/Data Integration
• PC/Telephony Convergence

3
IP Telephony Basics

• Data networks use TCP/IP
• Common protocol for disparate data networks
• Time-share approach to sharing data between
  asynchronous devices
• Packets travel when the network is available
• Networks have variability and latency
• Effective for email, file transfer, web browsing
• Not effective for real time voice, video

4
IP Telephony Basics

• Public Switched Telephone Networks
• Dedicated circuit for each conversation
• Analog voice signals are digitally encoded to
  cross public network then decoded back to analog
  at receiver
• Digital packets must arrive at decoder in
  sequence and in regular increments of time
• Latency and variability must be nearly zero for
  voice message to be intelligible

5
Voice vs. Data Networks

• Voice
• Sound bytes and silence bytes created, accepted,
  multiplexed, switched, transported and delivered
  at the frequent, regular and precise pace of
  every 125ms.
• Data
• packets created whenever there's some data around
  and move through the network whenever it's
  available.

6
ConvergenceVoice over IP

• Voice over IP (VoIP)
• Must keep latency, variability and loss to a
  minimum
• Use compression to reduce vulnerability to
  latency, variability and loss
• Real-time Transport Protocol
• Intelligent continuity algorithms at receiving
  decoder
• Fill voids by stretching and blending voice
  packets

7
Advantages of VoIP

• CostVoIP cost half of PSTN fewer lines
• SimplicityCarry voice and data over same network
• IntegrationSingle workstation for PC and
  telephony
• Unified ServicesSingle mailbox for voice, fax
  and email