Telephony networks came first. The price you pay for being a Monopoly
All-analog to all-digital Recycling works in telephony, too
People to people Communication at a Distance
An old problem
Constraints on old methods
"What hath God wrought?"
"Mr. Watson, come here. I want you." Voice Transport Starts with Voice.
Voice characteristics Voiced sounds Unvoiced sounds Silence matters.
Time is of the essence.
Digitizing voice Frequency range Full duplex connections Advantages of digitizing voice How to measure call quality: MOS Digitization and Compression
Compression Waveform coding Source coding Hybrid coding Standards Signaling
In-band vs. out-of-band
Above Level 3
Signaling at the end node
Trunk Signaling Loop-start Signaling Wink-start Signaling Ground-start Signaling
Voice and data signaling parallels Analog Telephony Equivalents to Layer 1 in Data Networks Telephone Networks
That annoying echo
Multiplexing TDM Statistical multiplexing Inverse multiplexing
First time, every time Packetizing Voice -- A Quick Look Conclusion
Voice ≠ Data
Network similarities References