Voice Over Internet Protocol

1
Voice Over Internet Protocol

• By Eric Rice

2
History

• First telephone was patented in 1870
• Rotary dialing first done in 1891
• 1905-Party Line
• 1910-5.1 million customers
• 1941-Attacks on Pearl Harbor cause a 100-400
  percent spike in long distance nation wide

3
History cont.

• 1949-the average calls placed in a day reach 180
  million.
• 1975-there are 140 million telephone lines in the
  US and ATT controls 85 of them
• 1993-ATT offers Caller ID
• 1995-Vocal Tec release first VOIP software
• 1996-First cable modem service offered by Roger
  Communications
• 2001-Vonage founded
• March 2002-Vonage initiates service

4
The Issues

• Reliability
• 911 service availability
• Voice Quality
• Delay
• Jitter
• Features
• Signaling Protocol

5
Reliability

• The current standard
• Five-nines (5 min of downtime a year)
• Networks go down all the time
• High Internet Traffic

6
911 Availability

• Currently address information is linked to a
  number
• Due to VoIP portability, locations are not
  defined
• In order to receive 911 service it must first be
  set up
• Mobile phones have this same problem
• Alternate solutions include developing new port
  mapping technologies
• Using GPS to locate callers

7
Voice Quality

• Goals
• Make it comparable to wire line
• Minimize bandwidth
• Wire line Voice codec is G.711
• 64kbps
• MOS 4.3 (mean opinion score)
• VoIP Voice codec G.729
• 8kbps
• MOS 4.0

What?
8
Other Codecs

• These codecs use a number of different
  compression algorithms to minimize required
  bandwidth

9
Delay

• Delay is measured using Round Trip Time
• Keep delay less then 300ms
• If greater then 300ms may seem like making an
  international call take this situation

10
Jitter

• Occurs when delay changes
• If the delay increases and decreases sporadically
  it makes conversations sound choppy
• RTP (Real Time Transport Protocol)
• Adds a sequence number and a time stamp to UDP
  packets
• This allows for delay and jitter to be calculated
  accurately

11
Solutions to Jitter and Delay

• Add bandwidth to the entire Internet
• We find ways to use up all the bandwidth we are
  given
• Reserve bandwidth on the routers it uses
• This would not be fair to the rest of the packets
• Temporary solution is to simply route the calls
  through the current switch network.

12
SIP (Session Initiation Protocol)

• Very simple protocol to use
• Allows for advanced features to be applied by the
  user without a subscription

13
Features

• Cheaper Service
• No long distance charges
• Caller ID
• Call Forwarding
• Call Screening
• Users can do other things than just block a call
• If Kitrek were to call, I would be able to
  forward his call to an insult hotline

14
Features

• Voicemail
• Check it online with fast-forward, rewind, and
  pause
• Check it through email
• Check it over the phone
• Require unknown callers to provide an intent for
  calling
• If a telemarketer calls they would have to tell
  what they wanted
• It would then be displayed on the caller ID

15
Conclusion

• VoIP is a technology which will eventually
  replace the current Switch network.
• With new and fully customizable features, along
  with cheaper service and no long distance
  charges. We can expect to see VoIP much more in
  the future.

16
Resources

• 1 Danial Collins. (2001). Carrier Grade Voice
  Over IP. New York. McGraw-Hill.
• 2 John Shepler. (2005). The Holy Grail of
  five-nines reliability.
• Retrieved April 1, 2005 from
  http//searchnetworking.techtarget.com/generic/0,2
  95582,sid7_gci1064318,00.html
• 3 Tim Lorello, Rich Tehrani (2005). E-9-1-1.
  Internet Telephony, 8, (3), 40-41.
• 4 FCC. (2004) VoIP FCC Consumer Facts.
  Retrieved April 1, 2005 from http//www.fcc.gov/cg
  b/consumerfacts/voip.pdf
• 5 Vonage. (2005) Features. Retrieved April 1,
  2005 from
• http//www.vonage.com/features.php